Datasets:

introvoyz041
/

tinybasic

/*
 * Stefan's basic interpreter - Arduino runtime environment runtime.cpp.
 * 
 * This is the Arduino runtime environment for BASIC. It maps the functions 
 * needed for the various subsystems to the MCU specific implementations. 
 *
 * Author: Stefan Lenz, sl001@serverfabrik.de
 *
 * Configure the hardware settings and parameters in hardware.h.
 */

#include "Arduino.h"
#include "hardware.h"
#include "runtime.h"

/* If the BASIC interpreter provides a loop function it will superseed this one */
void __attribute__((weak)) bloop() {};

/*
 * Defining the bssystype variable which informs BASIC about the platform at runtime.
 * bssystype is not used by the interpreter, but can be used by BASIC programs to
 * determine the platform they are running on.
 */

#if defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR)
uint8_t bsystype = SYSTYPE_AVR;
#elif defined(ARDUINO_ARCH_ESP8266)
uint8_t bsystype = SYSTYPE_ESP8266;
#elif defined(ARDUINO_ARCH_ESP32)
uint8_t bsystype = SYSTYPE_ESP32;
#elif defined(ARDUINO_ARCH_RP2040) || defined(ARDUINO_ARCH_MBED_RP2040)
uint8_t bsystype = SYSTYPE_RP2040;
#elif defined(ARDUINO_ARCH_SAM) && defined(ARDUINO_ARCH_SAMD)
uint8_t bsystype = SYSTYPE_SAM;
#elif defined(ARDUINO_ARCH_XMC)
uint8_t bsystype = SYSTYPE_XMC;
#elif defined(ARDUINO_ARCH_SMT32)
uint8_t bsystype = SYSTYPE_SMT32;
#elif defined(ARDUINO_ARCH_RENESAS)
uint8_t bsystype = SYSTYPE_NRENESA;
#elif defined(ARDUINO_ARCH_MBED_GIGA)
uint8_t bsystype = SYSTYPE_GIGA;
#else
uint8_t bsystype = SYSTYPE_UNKNOWN;
#endif

/* 
 *  Global variables of the runtime env.
 * 
 * id: the active input stream
 * od: the active output stream
 * idd: the default input stream in interactive mode
 * odd: the default output stream in interactive mode
 * ioer: the io error variable, always or-ed with ert in BASIC
 */

int8_t id; 
int8_t od;  
int8_t idd = ISERIAL;
int8_t odd = OSERIAL; 
int8_t ioer = 0; 

/*
 * MS Basic and many terminals have a real TAB function advanceing to 
 * the next tab stop. This is emulated by counting the characters on 
 * the output streams 0-4. The feature is activated with the HASMSTAB.
 * The code cannot processes composed characters like Germin Umlauts
 * correctly.
 */

#ifdef HASMSTAB
uint8_t charcount[5]; 
#endif

/* 
 * The pointer to the buffer used for the &0 device.
 * The BASIC input buffer is used. With this feature, a line can be printed
 * to the buffer and then accessed as a string @$ in BASIC. In systems where
 * CHR() is not available, this can be used to convert a number to a string.
 */

char* nullbuffer = ibuffer;
uint16_t nullbufsize = BUFSIZE; 
uint8_t bufferstat(uint8_t ch) { return 1; }

/* 
 * External libraries of the runtime environment for the peripherals.
 * When the runtime environment is brocken down to modules this will 
 * got into the modules. Summerized here for the sake of clarity.
 */

/*
 * OS specific headers.
 */

/*
 * ESPy stuff, pgmspace has changed location in some ESP32 cores.
 */

 #ifdef ARDUINOPROGMEM
 #ifdef ARDUINO_ARCH_ESP32
 #include <pgmspace.h>
 #else
 #include <avr/pgmspace.h>
 #endif
 #endif

/*
 * MBED OS type includes summarized here - tested for GIGA boards. 
*/

#ifdef ARDUINO_ARCH_MBED_GIGA
#include "mbed.h"
#include <mbed_mktime.h>
#endif

/*
 * EEPROM code. Some of the boards bring their own EEPROM classes.
 * 
 * These are: 
 * - AVR boards of all kinds
 * - ESP8266 and ESP32
 * - the LGT8F boards with the newer cores
 * 
 * For XMC my homebrew is now part of the interpreter.
 * See https://github.com/slviajero/XMCEEPROMLib
 * For more information on this or if you want to use it on other platforms.
 * 
 * For SAMD the FlashStorage library is used. It was orginally written by
 * Cristian Maglie. I use the version of Khoi Huang from
 * https://github.com/khoih-prog/FlashStorage_SAMD
 * This is now bundled with the interpreter. The emulation buffers the
 * entire EEPROM in RAM, so 2k should be ok but not more. If the 
 * dual buffer strategy of EepromFS or XMC would be used, larger 
 * EEPROMs could be emulated - this is work to be done. 
 * 
 * RP2040 standard cores and the DUE do not have an EEPROM emulation.
 * This is trapped in hardware.h (EEPROM is disabled).
 */

#ifdef ARDUINOEEPROM
#if defined(ARDUINO_ARCH_XMC)
#include "src/XMCEEPROMLib/XMCEEPROMLib.h"
#elif defined(ARDUINO_ARCH_SAMD)
#define EEPROM_EMULATION_SIZE 2048
#include "src/FlashStorage_SAMD/FlashStorage_SAMD.h"
#else
#include <EEPROM.h>
#endif
#endif

/* Standard SPI coming with the board is used */

#ifdef ARDUINOSPI
#include <SPI.h>
#endif

/* 
 * Standard wire - triggered by the HASWIRE or HASSIMPLEWIR macro.
 * These macros are set in the hardware.h file depending on the subsystems.
 * 
 * If ARDUINODIRECTI2C is set the the Wire library is bypassed. This saves 
 * 200 bytes of RAM and 1kB of program space on an AVR 8bit. It 
 * also removed the blocking of Wire if the slave does not respond.
 * 
 * In this case Wire.h should not be included in the sketch because
 * it allocates the buffers and the Wire object. 
 */

#if defined(HASWIRE)
#include <Wire.h>
#endif 

#if defined(HASSIMPLEWIRE) && !defined(ARDUINODIRECTI2C)
#include <Wire.h>
#endif

/* 
 * IO channel 2 - Keyboards 
 *
 * This is Paul Stoffregen's PS2Keyboard library for PS2 keyboards
 * patched for use with non AVR boards. Please download the patched
 * version from github: https://github.com/slviajero/PS2Keyboard
 */

 #ifdef ARDUINOPS2
 #include <PS2Keyboard.h>
 #endif
 
 /*
  * The USB keyboard code of the Arduino DUE. Keymapping and timing
  * need improvement. Currently not a priority. 
  */
 
 #ifdef ARDUINOUSBKBD
 #include <KeyboardController.h>
 #endif
 
 /*
  * The ZX81 keyboard code - tested on AVR MEGA256. Please download
  * the library from github: https://github.com/slviajero/ZX81Keyboard
  */
 
 #ifdef ARDUINOZX81KBD
 #include <ZX81Keyboard.h>
 #endif
 
 /*
  * This is for the USB keyboard code on a GIGA board
  * https://docs.arduino.cc/tutorials/giga-r1-wifi/giga-usb/#usb-host-keyboard
  * like the DUE keyboard, this code is not recommended.
  */
 
 #ifdef GIGAUSBKBD
 #include "USBHostGiga.h"
 #endif

/* 
 * IO channel 2 - Displays
 *
 * The display library for the parallel LCD, this is a standard 
 * Arduino library.
 */

#ifdef LCDSHIELD 
#include <LiquidCrystal.h>
#endif

/*
 * I2C LCD displays, this library works almost universally despite 
 * a nasty warning message it sometimes gives. 
 */

#ifdef ARDUINOLCDI2C
#include <LiquidCrystal_I2C.h>
#endif

/*
 * This is the monochrome library of Oli Kraus used for Nokia and 
 * SSD1306 displays.
 * https://github.com/olikraus/u8g2/wiki/u8g2reference
 * 
 * It can harware scroll, but this is not yet implemented.
 */

#if defined(ARDUINONOKIA51) || defined(ARDUINOSSD1306)
#include <U8g2lib.h>
#endif

/*
 * This is the (old) ILI9488 library originally created by Jarett Burket
 * for SPI control if the very common ILI9488 displays.
 * I created a fork as the original is no longer maintained (last commits 
 * from 2017). Patches in my version allow use from RP2040.
 * https://github.com/slviajero/ILI9488
 * 
 * It can hardware scroll (not yet used). 
 */

#ifdef ARDUINOILI9488
#include <Adafruit_GFX.h>
#include <ILI9488.h>
#endif

/*
 * This is the MCUFRIED library originally for parallel TFTs
 * https://github.com/prenticedavid/MCUFRIEND_kbv
 * 
 * For R4 boards, use my patched version
 * https://github.com/slviajero/MCUFRIEND_kbv
 * 
 * The original library is board hardware depended as it tries
 * to make use of the port macros. This makes it fast but 
 * it cannot used on non supported boards.
 * 
 * This library can drive the TFT from any board as it has a
 * generic section using the Arduino GPIOs. This is slower but 
 * works. For R4 it uses the port macros.
 */

#ifdef ARDUINOMCUFRIEND
#include <Adafruit_GFX.h>
#include <MCUFRIEND_kbv.h>
#endif

/*
 * For TFT we use the UTFT library
 * http://www.rinkydinkelectronics.com/library.php?id=51
 * Please note the License, it is not GPL but NON COMMERCIAL 
 * Creative Commons. 
 */

#ifdef ARDUINOTFT
#include <memorysaver.h>
#include <UTFT.h>
#endif

/*
 * Lilygo EDP47 displays, 4.7 inch epapers using the respective library 
 * from Lilygo https://github.com/Xinyuan-LilyGO/LilyGo-EPD47
 */

#ifdef ARDUINOEDP47
#include "epd_driver.h"
#include "font/firasans.h"
#endif

/*
 * VGA is only implemented on one platform - TTGO VGA 1.4
 * Needs https://github.com/slviajero/FabGL
 * 
 * There is a side effect to the network code. The Wifi library
 * has to be sourced before FabGL. Reason is unknown.
 */

 #if defined(ARDUINOVGA) && defined(ARDUINO_TTGO_T7_V14_Mini32)
 #include <WiFi.h> 
 #include <fabgl.h> 
 #endif
 
/* 
 * IO channel 9 - Networking.
 *
 * Currently the standard Ethernet shield, ESP Wifi 
 * MKW Wifi, RP2040 Wifi, R4 Wifi and GIGA is supported. 
 * All of them  with the standard library.
 *
 * In addition to this Pubsub is used
 * https://github.com/slviajero/pubsubclient
 * for MQTT. This is the standard library for MQTT on Arduino.
 * 
 * The ARDUINOMQTT macro is set in hardware.h while 
 * the ARDUINOWIFI is just generated by hardware.h if
 * Ethernet is not set but MQTT is set. We assume that 
 * mostly it is Wifi we are dealing with.
 */

 /* the network transport layer, either Ethernet or Wifi */
#ifdef ARDUINOETH
#include <Ethernet.h>
#else
#ifdef ARDUINOWIFI
#if defined(ARDUINO_ARCH_ESP8266)
#include <ESP8266WiFi.h>
#elif defined(ARDUINO_ARCH_ESP32)
#include <WiFi.h>
#elif defined(ARDUINO_ARCH_RP2040) || defined(ARDUINO_ARCH_SAMD)
#include <WiFiNINA.h>
#elif defined(ARDUINO_UNOR4_WIFI)
#include <WiFiS3.h>
#elif defined(ARDUINO_ARCH_MBED_GIGA)
#include <WiFi.h>
#endif
#endif
#endif

/* the protocall */
#if defined(ARDUINOMQTT)
#include <PubSubClient.h>
#endif

/*
 * IO channel 16 - the various filesystems.
 * 
 * SD filesystems with the standard SD driver.
 *
 * For MEGA 256 a soft SPI solution is needed 
 * if standard shields are used, this done in is a 
 * patched SD library https://github.com/slviajero/SoftSD
 */

#ifdef ARDUINOSD
#define FILESYSTEMDRIVER
#if defined(SOFTWARE_SPI_FOR_SD)
#include <SoftSD.h>
#else
#include <SD.h>
#endif
#endif

/*
 * ESPSPIFFS tested on ESP8266 and ESP32 supports formating in BASIC.
 * This is standard on all ESP boards and autoconfigured.
 */ 

#ifdef ESPSPIFFS
#define FILESYSTEMDRIVER
#ifdef ARDUINO_ARCH_ESP8266
#include <FS.h>
#endif
#ifdef ARDUINO_ARCH_ESP32
#include <FS.h>
#include <SPIFFS.h>
#endif
#endif


/*
 * ESP32FAT tested on ESP32 supports formating in BASIC. Only tested 
 * on the T-Deck. Partition at upload must be ffat. This is available
 * on ESP32S3 but not on older boards.
 */ 

#ifdef ESP32FAT
#define FILESYSTEMDRIVER
#ifdef ARDUINO_ARCH_ESP32
#include <FS.h>
#include <FFat.h>
#endif
#endif

/* 
 *  ESPSDMMC code
 */
 
#ifdef ESPSDMMC
#include "FS.h"
#include "SD_MMC.h"
#endif

/* 
 *  ESPSDMMC code, this is an SD card solution with direct access 
 *  only available on ES32 and ESP32-S3
 *  
 *  https://github.com/espressif/arduino-esp32/tree/master/libraries/SD_MMC
 *  
 *  Needed for the ESP32 CAM
 *  
 */

/*
 * The USB filesystem for the GIGA board.
 * USB device has to be connected at boot time. No remount is possible.
 */

#ifdef GIGAUSBFS
#include <DigitalOut.h>
#include <FATFileSystem.h>
#include <Arduino_USBHostMbed5.h>
#endif

/*
 * RP2040 internal filesystem. 
 * This is test code from https://github.com/slviajero/littlefs
 * and the main branch is actively developed.
 */

#ifdef RP2040LITTLEFS
#define FILESYSTEMDRIVER
#define LFS_MBED_RP2040_VERSION_MIN_TARGET      "LittleFS_Mbed_RP2040 v1.1.0"
#define LFS_MBED_RP2040_VERSION_MIN             1001000
#define _LFS_LOGLEVEL_          1
#define RP2040_FS_SIZE_KB       1024
#define FORCE_REFORMAT          false
#include <LittleFS_Mbed_RP2040.h>
#endif

/*
 * STM32 SDIO driver for he SD card slot of the STM32F4 boards (and others).
 */

#ifdef STM32SDIO 
#define FILESYSTEMDRIVER
#include <STM32SD.h> 
#ifndef SD_DETECT_PIN
#define SD_DETECT_PIN SD_DETECT_NONE
#endif
#endif

/*
 * External flash file systems on an SD override internal filesystems
 * (currently BASIC can only have one filesystem).
 */ 

#if defined(ARDUINOSD) ||defined(ESPSDMMC)
#undef ESPSPIFFS
#undef RP2040LITTLEFS
#undef ESP32FAT
#undef GIGAUSBFS
#define FILESYSTEMDRIVER
#endif

/*
 * Support for external EEPROMs as filesystem overriding all 
 * other filessystems. This is a minimalistic filesystem meant 
 * for very small systems with not enough memory for real 
 * filesystems
 * https://github.com/slviajero/EepromFS
 */ 
#ifdef ARDUINOEFS
#undef ESPSPIFFS
#undef ESP32FAT
#undef RP2040LITTLEFS
#undef ARDUINOSD
#undef STM32SDIO
#undef GIGAUSBFS
#define FILESYSTEMDRIVER
#endif

/* The EFS object is used for filesystems and raw EEPROM access. */

#if (defined(ARDUINOI2CEEPROM) && defined(ARDUINOI2CEEPROM_BUFFERED)) || defined(ARDUINOEFS)
#include <EepromFS.h
#endif

/*
 * Software SPI only on Mega2560. This only used for the SD shield typically 
 * but not necessarily with a TFT display. 
 */

 #ifndef ARDUINO_AVR_MEGA2560
 #undef SOFTWARE_SPI_FOR_SD
 #endif

/*
 * TFT_eSPI is a library for the T-Deck from Lilygo.
 * 
 * #include "utilities.h" provided by Lilygo is coded directly into hardware.h
 * For some reason this has to be included after FS and FFat. Not yet fully 
 * understood why.
 */

 #ifdef TFTESPI
 #include <TFT_eSPI.h>
 #endif

/*
 * Global variables of the runtime environment.
 */

/* If there is an unbuffered I2C EEPROM, use an autodetect mechanism. */
#if defined(ARDUINOI2CEEPROM) 
unsigned int i2ceepromsize = 0;
#endif

/* 
 * Arduino default serial baudrate and serial flags for the 
 * two supported serial interfaces. Serial is always active and 
 * connected to channel &1 with 9600 baud. 
 * 
 * Channel 4 (ARDUINOPRT) can be either in character or block 
 * mode. Blockmode is set as default here. This means that all 
 * available characters are always loaded to a string -> inb(). 
 * This is typically needed if you want to receive AT commands from
 * a modem or a GPS device.
 * 
 * Serial baudrate of the second channel is changeable in the BASIC
 * program.
 */

const uint16_t serial_baudrate = 9600;
uint8_t sendcr = 0;

#ifdef ARDUINOPRT
uint32_t serial1_baudrate = 9600; 
uint8_t blockmode = 1;
#else 
const int serial1_baudrate = 0;
uint8_t blockmode = 0;
#endif

/* 
 * Implementation of the global IO function. These are the 
 * functions that are called from the BASIC interpreter. To access 
 * a device. 
 * 
 * ioinit(): called at setup to initialize what ever io is needed.
 * outch(): prints one ascii character to the output channel od.
 * inch(): gets one character (and waits for it) from the input channel id.
 * checkch(): checks for one character (non blocking) on the input channel id.
 * ins(): reads an entire line (uses inch except for pioserial) from the input channel id.
 * availch(): checks for available characters on the input channel id.
 * inb(): reads a block of characters from the input channel id.
 * outs(): prints a string of characters to the output channel od.
 *
 */
void ioinit() {

/* a standalone system runs from keyboard and display, i.e channel 2 */
#ifdef STANDALONE
  idd = IKEYBOARD;
  odd = ODSP;
#endif

/* run standalone on second serial, set the right parameters, this is 
   needed for a few boars where the first serial port is not usable 
   for BASIC */
#ifdef STANDALONESECONDSERIAL
  idd = ISERIAL1;
  odd = OPRT;
  blockmode = 0;
  sendcr = 0;
#endif

/* 
 * Signal handling - by default SIGINT which is ^C is always caught and 
 * leads to program stop. Side effect: the interpreter cannot be stopped 
 * with ^C, it has to be left with CALL 0, works on Linux, Mac and MINGW
 * but not on DOSBOX MSDOS as DOSBOS does not handle CTRL BREAK correctly 
 * DOS can be interrupted with the CONIO mechanism using BREAKCHAR. 
 * Here on Arduino signalon() is currentl unused. 
 */ 

  signalon();

/* This is only for RASPBERRY - wiring has to be started explicitly. */
  wiringbegin();

/* Start all serial protocolls, ttl channels, SPI and Wire. */
  serialbegin();

/* start the second serial port */
#ifdef ARDUINOPRT
  prtbegin();
#endif

/* start SPI (before displays and filesystems)*/
#ifdef ARDUINOSPI
  spibegin();
#endif

/* start wire */
#if defined(HASWIRE) || defined(HASSIMPLEWIRE)
  wirebegin();
#endif

/* Filesystems */
  fsbegin();

/* networks */
#ifdef ARDUINOMQTT
  netbegin();  
  mqttbegin();
#endif

/* the keyboards */
#if defined(HASKEYBOARD) || defined(HASKEYPAD)
  kbdbegin();
#endif

/* the displays */
#if defined(DISPLAYDRIVER) || defined(GRAPHDISPLAYDRIVER)
  dspbegin();
#endif

/* fablib code (and framebuffer on POSIX) do not use the graphics driver startup 
    they use vgabegin(), we also do not use the display driver */
#if defined(ARDUINOVGA)
  vgabegin();  
#endif

/* sensor startup */
#ifdef ARDUINOSENSORS
  sensorbegin();
#endif

/* clocks and time */
#if defined(HASCLOCK)
  rtcbegin();
#endif

/* the eeprom dummy needs a begin method */
  ebegin();

/* activate the iodefaults */
  iodefaults();

}


/* The status of the io streams just on/off on that why (0) for all the stat function */
int iostat(int channel) {
  switch(channel) {
/* channel 0, the buffer */
  case ONULL:
    return bufferstat(0);
    break;
/* channel 1, the serial port */
  case ISERIAL:
    return serialstat(0);
    break;
/* channel 2, the display */
  case ODSP:
    return dspstat(0);
    break;
/* channel 4, the second serial device */
#ifdef ARDUINOPRT
  case ISERIAL1:
    return prtstat(0);
    break;
#endif
/* channel 7 wire */
#if defined(HASWIRE)
  case IWIRE:
    return wirestat(0);
    break;
#endif
/* channel 8 radio adaptors */
#ifdef HASRF24
  case IRADIO:
    return radiostat(0);
    break;
#endif
/* channel 9 mqtt */
#ifdef ARDUINOMQTT
  case IMQTT:
    return mqttstat(0);
    break;
#endif
/* channel 16 file system */
#ifdef FILESYSTEMDRIVER
  case IFILE:
    return fsstat(0);
    break;
#endif
  }
  return 0;
}

/* set the iodefaults at startup and in runtime status change to interactive */
void iodefaults() {
  od=odd;
  id=idd;
}


/* char is sometimes signed and sometimes not */
int cheof(int c) { if ((c == -1) || (c == 255)) return 1; else return 0; }

/* the generic inch code reading one character from a stream, blocking! */
char inch() {
  switch(id) {
  case ONULL:
    return bufferread();
  case ISERIAL:
    return serialread();   
#ifdef ARDUINOPRT
  case ISERIAL1:
    return prtread();
#endif
#if defined(HASKEYBOARD) || defined(HASKEYPAD) || defined(HASVT52)        
  case IKEYBOARD:
#if defined(HASVT52) /* if the display has a message, read it, it acts as a keyboard */
    if (vt52avail()) return vt52read(); 
#endif
#if defined(HASKEYBOARD) || defined(HASKEYPAD)  
    return kbdread();
#endif
#endif
#if defined(HASWIRE)
  case IWIRE:
    return wireread();
#endif
#ifdef HASRF24
  case IRADIO:
    return radioread();
#endif
#ifdef ARDUINOMQTT
   case IMQTT:
    return mqttread();
#endif
#ifdef FILESYSTEMDRIVER
  case IFILE:
    return fileread();
#endif      
  }
  return 0;
}

/* 
 * checking on a character in the stream, this is normally only used 
 * for interrupting a program, for many streams this is just mapped 
 * to avail. This is currently inconsistent.
 */
char checkch(){
  switch (id) {
  case ONULL:
    return buffercheckch();
  case ISERIAL:
    return serialcheckch();
#ifdef FILESYSTEMDRIVER
  case IFILE:
    return fileavailable();
#endif
#ifdef HASRF24
  case IRADIO:
    return radioavailable();
#endif
#ifdef ARDUINOMQTT
  case IMQTT:
    return mqttcheckch();
#endif   
#ifdef HASWIRE 
  case IWIRE:
    return 0;
#endif
#ifdef ARDUINOPRT
  case ISERIAL1:
    return prtcheckch(); 
#endif
  case IKEYBOARD:
#if defined(HASKEYBOARD)  || defined(HASKEYPAD)
    return kbdcheckch(); /* here no display read as this is only for break and scroll control */
#endif
    break;
  }
  return 0;
}

/* character availability */
uint16_t availch(){
  switch (id) {
  case ONULL:
    return bufferavailable();
  case ISERIAL:
    return serialavailable(); 
#ifdef FILESYSTEMDRIVER
  case IFILE:
    return fileavailable();
#endif
#ifdef HASRF24
  case IRADIO:
    return radioavailable();
#endif        
#ifdef ARDUINOMQTT
  case IMQTT:
    return mqttavailable();
#endif        
#if defined(HASWIRE)
  case IWIRE:
    return wireavailable();
#endif
#ifdef ARDUINOPRT
  case ISERIAL1:
    return prtavailable();
#endif
  case IKEYBOARD:
#if defined(HASKEYBOARD) || defined(HASKEYPAD) || defined(HASVT52)
#if defined(HASVT52)  /* if the display has a message, read it */
    if (vt52avail()) return vt52avail();
#endif
#if defined(HASKEYBOARD) || defined(HASKEYPAD) 
    return kbdavailable();
#endif
#endif
    break;
  }
  return 0;
}

/* 
 *  The block mode reader for esp and sensor modules 
 *  on a serial interface, it tries to read as many 
 *  characters as possible into a buffer. 
 * 
 *  blockmode = 1 reads once availch() bytes
 *  blockmode > 1 implements a timeout mechanism and tries 
 *    to read until blockmode milliseconds have expired
 *    this is needed for esps and other sensors without
 *    flow control and volatile timing to receive more 
 *    then 64 bytes.
 * 
 * The function only exists if ARDUINOPRT is defined to 
 * activate the second serial port.
 */
 
uint16_t inb(char *b, uint16_t nb) {
  long m;
  uint16_t z;
  int16_t i = 0; // check this 

  if (blockmode == 1) {
    i=availch();
    if (i>nb-1) i=nb-1;
    b[0]=(unsigned char)i;
    z=i;
    b[i+1]=0;
    b++;
    while (i--) {*b++=inch();}  
  } else if (blockmode > 1) {
    m=millis();
    while (i < nb-1) {
      if (availch()) b[++i]=inch();
      if (millis() > m+blockmode) break;
    }
    b[0]=(unsigned char)i;
    z=i;
    b[i+1]=0;
  } else {
    b[0]=0;
    z=0;
    b[1]=0;
  } 
  return z;
}

/*
 * Reading one line from the console with inch(). 
 * consins() is used for all channels where individual
 * characters are read. Others which provide entire strings
 * are handled by their respective string methods.
 * (Example: picoserial, radio, wire)
 */
uint16_t consins(char *b, uint16_t nb) {
  char c;
  uint16_t z;
 
  z=1;
  while(z < nb) {
      c=inch();
      if (id == ISERIAL || id == IKEYBOARD) {
        outch(c); /* this is local echo */
      }
      if (c == '\r') c=inch(); /* skip carriage return */
      if (c == '\n' || c == -1 || c == 255) { /* terminal character is either newline or EOF */
        break;
      } else if (c == 127 || c == 8) { /* backspace or delete */
        if (z>1) z--;
      } else {
        b[z++]=c;
      } 
  }
  b[z]=0;
  z--;
  b[0]=z; /* cast to signed char is not good */
  return z;
}

/* 
 * ins() is the generic reader into a string, by default 
 * it works in line mode and ends reading after newline.
 *
 * The first element of the buffer is the lower byte of the length.
 *
 * For streams providing entire strings as an input the 
 * respective string method is called.
 *
 * All other streams are read using consins() for character by character
 * input until a terminal character is reached. For almost all channel
 * this is done in a *ins() method. The advantage is that one can plug in 
 * line oriented input here.
 */
uint16_t ins(char *b, uint16_t nb) {
  switch(id) {
  case ONULL:
    return bufferins(b, nb);
  case ISERIAL:
    return serialins(b, nb);
#if defined(HASKEYBOARD) || defined(HASKEYPAD)
  case IKEYBOARD:
    return kbdins(b, nb);
#endif
#ifdef ARDUINOPRT
  case ISERIAL1:
    return prtins(b, nb);
 #endif   
#if defined(HASWIRE)
  case IWIRE:
    return wireins(b, nb);
#endif
#ifdef HASRF24
  case IRADIO:
    return radioins(b, nb);
#endif
#ifdef ARDUINOMQTT
  case IMQTT:
    return mqttins(b, nb);  
#endif
#ifdef FILESYSTEMDRIVER
  case IFILE:
    return consins(b, nb);
#endif
  default:
    b[0]=0; b[1]=0;
    return 0;
  }  
}

/*
 * outch() outputs one character to a stream.
 * some block oriented i/o like in radio not implemented here.
 * Exception is mqtt where we buffer in the code for the PRINT command.
 * 
 * If BASIC needs a MS style tab command, then count characters on stream 
 * 0-4 this does not work for control characters. 
 */
void outch(char c) {

#ifdef HASMSTAB
  if (od <= OPRT) {
    if (c > 31) charcount[od]+=1;
    if (c == 10) charcount[od]=0;
  }
#endif

  switch(od) {
  case ONULL:
    bufferwrite(c);
    break;
  case OSERIAL:
    serialwrite(c);
    break;
#ifdef ARDUINOPRT
  case OPRT:
    prtwrite(c);
    break;
#endif    
#ifdef FILESYSTEMDRIVER
  case OFILE:
    filewrite(c);
    break;
#endif
#ifdef ARDUINOVGA
  case ODSP: 
    vgawrite(c);
    break;
#elif defined(DISPLAYDRIVER) || defined(GRAPHDISPLAYDRIVER)
  case ODSP: 
    dspwrite(c);
    break;
#endif
#ifdef ARDUINOMQTT
  case OMQTT:
    mqttwrite(c); /* buffering for the PRINT command */
    break;
#endif
  default:
    break;
  }
  byield(); /* yield after every character for ESP8266 */
}

/*
 *  outs() outputs a string of length x at index ir - basic style
 *  default is a character by character operation, block 
 *  oriented write needs special functions
 */
void outs(char *b, uint16_t l){
  uint16_t i;

  switch (od) {
#ifdef HASRF24
    case ORADIO:
      radioouts(b, l);
      break;
#endif
#if (defined(HASWIRE))
    case OWIRE:
      wireouts(b, l);
      break;
#endif
#ifdef ARDUINOMQTT
    case OMQTT:
      mqttouts(b, l);
      break;
#endif
#ifdef GRAPHDISPLAYDRIVER
    case ODSP:
      dspouts(b, l);
      break;
#endif
    default:
      for(i=0; i<l; i++) outch(b[i]);
  }
  byield(); /* triggers yield after each character output for ESP8266 stability */
}

/*  handling time - part of the Arduino core - only needed on POSIX OSes */
void timeinit() {}

/* starting wiring is only needed on raspberry */
void wiringbegin() {}

/* POSIX signals - not needed here */
void signalon() {}

/*
 * helper functions OS, heuristic on how much memory is 
 * available in BASIC
 * Arduino information from
 * data from https://docs.arduino.cc/learn/programming/memory-guide
 */
#if defined(ARDUINO_ARCH_SAMD) || defined(ARDUINO_ARCH_SAM) || defined(ARDUINO_ARCH_XMC) || defined(ARDUINO_ARCH_STM32) || defined(ARDUINO_ARCH_RENESAS)
extern "C" char* sbrk(int incr);
long freeRam() {
  char top;
  return &top - reinterpret_cast<char*>(sbrk(0));
}
#elif defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR) || defined(ARDUINO_ARCH_LGT8F) 
long freeRam() {
  extern int __heap_start,*__brkval;
  int v;
  return (int)&v - (__brkval == 0  
     ? (int)&__heap_start : (int) __brkval); 
}
#elif defined(ARDUINO_ARCH_ESP32) || defined(ARDUINO_ARCH_ESP8266)
long freeRam() {
  return ESP.getFreeHeap();
}
#else
long freeRam() {
  return 0; 
}
#endif

/*
 * Heuristic Wifi systems reserve 4k by default, small 8 bit AVR try to guess sizes conservatively
 * RP2040 cannot measure, we set to 16 bit full address space
 */
long freememorysize() {
#if defined(ARDUINO_ARCH_RENESAS)
  return freeRam() - 2000;
#endif
#if defined(ARDUINO_ARCH_ESP8266) || defined(ARDUINO_ARCH_SAMD) || defined(ARDUINO_ARCH_STM32) 
  return freeRam() - 4000;
#endif
#if defined(ARDUINO_ARCH_ESP32) 
#if defined(ARDUINO_TTGO_T7_V14_Mini32)
  return freeRam() - 4000; 
#else
  return freeRam() - 4000;
#endif
#endif
#if defined(ARDUINO_ARCH_XMC) 
  return freeRam() - 2000;
#endif
#if defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR) || defined(ARDUINO_ARCH_SAM) || defined(ARDUINO_ARCH_LGT8F) 
  int overhead=256;
#ifdef ARDUINO_ARCH_LGT8F
  overhead+=0;
#endif
#ifdef ARDUINO_AVR_MEGA2560
  overhead+=96;
#endif
#if (defined(ARDUINOWIRE) || defined(ARDUINOSIMPLEWIRE)) && !defined(ARDUINODIRECTI2C)
  overhead+=200;
#endif
#ifdef ARDUINORF24
  overhead+=128;
#endif
#if defined(ARDUINOSD)
  overhead+=512;
#endif
#ifdef ARDUINOZX81KBD
  overhead+=64;
#endif
#ifdef ARDUINOETH
  overhead+=256;
#endif
  return freeRam() - overhead;
#endif
#if defined(ARDUINO_NANO_RP2040_CONNECT) || defined(ARDUINO_RASPBERRY_PI_PICO) || defined(ARDUINO_ARCH_MBED_GIGA)
  return 65536;
#endif
  return 0;
}

/* 
 * the sleep and restart functions - only implemented for some controllers
 */
#if defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR)
void(* callzero)() = 0;
#endif

void restartsystem() {
  eflush(); /* if there is a I2C eeprom dummy, flush the buffer */
#if defined(ARDUINO_ARCH_ESP32) || defined(ARDUINO_ARCH_ESP8266)
  ESP.restart();
#endif
#if defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR)
  callzero();
#endif
#if defined(ARDUINO_ARCH_LGT8F)
#endif
}

/*
 * I used these two articles 
 * https://randomnerdtutorials.com/esp8266-deep-sleep-with-arduino-ide/
 * https://randomnerdtutorials.com/esp32-deep-sleep-arduino-ide-wake-up-sources/
 * for this very simple implementation - needs to be improved (pass data from sleep
 * state to sleep state via EEPROM)
 */
#if defined(ARDUINO_ARCH_SAMD) 
#include "RTCZero.h"
#include "ArduinoLowPower.h"
RTCZero rtc;
#endif

/* STM32duino have the same structure */
#if defined(ARDUINO_ARCH_STM32)
#include "STM32RTC.h"
#include "STM32LowPower.h"
STM32RTC& rtc = STM32RTC::getInstance();
#endif

/* the NRENESA board have a buildin RTC as well */
#if defined(ARDUINO_ARCH_RENESAS)
#include "RTC.h"
RTCTime rtc;
#endif

/* for ESP32 we also include the time stuctures and offer a POSIX style clock*/
#if defined(ARDUINO_ARCH_ESP32)
#include "time.h"
#include <sys/time.h>
#endif


/* this is unfinished, don't use */ 
void rtcsqw();

#define LOWPOWERINTPIN 2
void aftersleepinterrupt(void) { }

void activatesleep(long t) {
  eflush(); /* if there is a I2C eeprom dummy, flush the buffer */
#if defined(ARDUINO_ARCH_ESP8266)
  ESP.deepSleep(t*1000);
#endif
#if defined(ARDUINO_ARCH_ESP32)
  esp_sleep_enable_timer_wakeup(t*1000);
  esp_deep_sleep_start();
#endif
#if defined(ARDUINO_ARCH_SAMD)
  LowPower.sleep((int) t);
#endif
#if defined(ARDUINO_AVR_ATmega644)
/* unfinished, don't use, just test code
  rtcsqw();
  pinMode(LOWPOWERINTPIN, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(LOWPOWERINTPIN), aftersleepinterrupt, CHANGE);
  sleepMode(SLEEP_POWER_SAVE);
  sleep();
  detachInterrupt(digitalPinToInterrupt(LOWPOWERINTPIN));
  noSleep();
*/
#endif
}

/* 
 * Start the SPI bus - this is a little mean as some libraries also 
 * try to start the SPI which may lead to on override of the PIN settings
 * if the library code is not clean - currenty no conflict known.
 * 
 * The startup on the T-Deck seems to be tricky and require precautions.
 * The startup sequence used here is from the HelloWorld example of the
 * TFT_eSPI library.
 */
void spibegin() {
#ifdef ARDUINOSPI
#ifdef ARDUINO_TTGO_T7_V14_Mini32
/* this fixes the wrong board definition in the ESP32 core for this board */
  SPI.begin(14, 2, 12, 13);
#else 
#ifdef TFTESPI
  //! The board peripheral power control pin needs to be set to HIGH when using the peripheral
  pinMode(BOARD_POWERON, OUTPUT);
  digitalWrite(BOARD_POWERON, HIGH);

  //! Set CS on all SPI buses to high level during initialization
  pinMode(BOARD_SDCARD_CS, OUTPUT);
  pinMode(RADIO_CS_PIN, OUTPUT);
  pinMode(BOARD_TFT_CS, OUTPUT);

  digitalWrite(BOARD_SDCARD_CS, HIGH);
  digitalWrite(RADIO_CS_PIN, HIGH);
  digitalWrite(BOARD_TFT_CS, HIGH);

  pinMode(BOARD_SPI_MISO, INPUT_PULLUP);
  SPI.begin(BOARD_SPI_SCK, BOARD_SPI_MISO, BOARD_SPI_MOSI);
#else
  SPI.begin();
#endif
#endif
#endif
}

/*
 * DISPLAY driver code section, the hardware models define a set of 
 * of functions and definitions needed for the display driver. 
 * 
 * See runtime.h for the definitions of the display driver functions.
 */

 /* generate a 4 bit vga color from a given rgb color */
uint8_t rgbtovga(uint8_t r, uint8_t g, uint8_t b) {
  short vga;
  if (r>191 || g>191 || b>191) vga=8; else vga=0;
  vga=vga+r/128+g/128*2+b/128*4;
  return vga;
}

/* 
 * global variables for a standard LCD shield. 
 * Includes the standard Arduino LiquidCrystal library
 */
#ifdef LCDSHIELD 
#define DISPLAYDRIVER
#undef DISPLAYHASCOLOR
#undef DISPLAYHASGRAPH
/* LCD shield pins to Arduino
 *  RS, EN, d4, d5, d6, d7; 
 * backlight on pin 10;
 */

 
#ifndef LCDSHIELDPINS 
#ifdef ARDUINO_ESP8266_WEMOS_D1R1
#define LCDSHIELDPINS 0,2,4,14,12,13
#define LCD3VOLTS
#else
#define LCDSHIELDPINS 8,9,4,5,6,7
#endif
#endif
const int dsp_rows=2;
const int dsp_columns=16;
LiquidCrystal lcd(LCDSHIELDPINS);
void dspbegin() { lcd.begin(dsp_columns, dsp_rows); dspsetscrollmode(1, 1);  }
void dspprintchar(char c, uint8_t col, uint8_t row) { lcd.setCursor(col, row); if (c) lcd.write(c);}
void dspclear() { lcd.clear(); }
void dspupdate() {}
void dspsetcursor(uint8_t c) { if (c) lcd.blink(); else lcd.noBlink(); }
void dspsetfgcolor(uint8_t c) {}
void dspsetbgcolor(uint8_t c) {}
void dspsetreverse(uint8_t c) {}
uint8_t dspident() {return 0; }
#define HASKEYPAD
/* elementary keypad reader left=1, right=2, up=3, down=4, select=<lf> */
char keypadread(){
	int a=analogRead(A0);
#ifndef LCD3VOLTS
	if (a >= 850) return 0;
	else if (a>=600 && a<850) return 10;
	else if (a>=400 && a<600) return '1'; 
	else if (a>=200 && a<400) return '3';
	else if (a>=60  && a<200) return '4';
	else return '2';
#else
  if (a >= 1000) return 0;
  else if (a>=900 && a<1000) return 10;
  else if (a>=700 && a<900) return '1'; 
  else if (a>=400 && a<700) return '3';
  else if (a>=100  && a<400) return '4';
  else return '2';
#endif
}
/* repeat mode of the keypad - off means block, on means return immediately */
uint8_t kbdrepeat=0;
#endif

/* 
 * A LCD display connnected via I2C, uses the standard 
 * Arduino I2C display library.
 */ 
#ifdef ARDUINOLCDI2C
#define DISPLAYDRIVER
#undef DISPLAYHASCOLOR
#undef DISPLAYHASGRAPH
const int dsp_rows=4;
const int dsp_columns=20;
LiquidCrystal_I2C lcd(0x27, dsp_columns, dsp_rows);
void dspbegin() { lcd.init(); lcd.backlight(); dspsetscrollmode(1, 1); }
void dspprintchar(char c, uint8_t col, uint8_t row) { lcd.setCursor(col, row); if (c) lcd.write(c); }
void dspclear() { lcd.clear(); }
void dspupdate() {}
void dspsetcursor(uint8_t c) { if (c) lcd.blink(); else lcd.noBlink(); }
void dspsetfgcolor(uint8_t c) {}
void dspsetbgcolor(uint8_t c) {}
void dspsetreverse(uint8_t c) {}
uint8_t dspident() {return 0; }
#endif

/* 
 * A Nokia 5110 with ug8lib2 - can scroll quite well
 * https://github.com/olikraus/u8g2/wiki/u8g2reference
 * This is a buffered display it has a dspupdate() function 
 * it also needs to call dspgraphupdate() after each graphic 
 * operation
 *
 * default PIN settings here are for ESP8266, using the standard 
 * SPI SS for 15 for CS/CE, and 0 for DC, 2 for reset
 *
 */ 
#ifdef ARDUINONOKIA51
#define DISPLAYDRIVER
#define DISPLAYPAGEMODE
#undef DISPLAYHASCOLOR /* display driver not color aware for this display */
#define DISPLAYHASGRAPH
#ifndef NOKIA_CS
#define NOKIA_CS 15
#endif
#ifndef NOKIA_DC
#define NOKIA_DC 0
#endif
#ifndef NOKIA_RST
#define NOKIA_RST 2
#endif
U8G2_PCD8544_84X48_F_4W_HW_SPI u8g2(U8G2_R0, NOKIA_CS, NOKIA_DC, NOKIA_RST); 
const int dsp_rows=6;
const int dsp_columns=10;
typedef uint8_t dspcolor_t;
dspcolor_t dspfgcolor = 1;
dspcolor_t dspbgcolor = 0;
char dspfontsize = 8;
void dspbegin() { u8g2.begin(); u8g2.setFont(u8g2_font_amstrad_cpc_extended_8r); }
void dspprintchar(char c, uint8_t col, uint8_t row) { char b[] = { 0, 0 }; b[0]=c; if (c) u8g2.drawStr(col*dspfontsize+2, (row+1)*dspfontsize, b); }
void dspclear() { u8g2.clearBuffer(); u8g2.sendBuffer(); dspfgcolor=1; }
void dspupdate() { u8g2.sendBuffer(); }
void dspsetcursor(uint8_t c) {}
void dspsetfgcolor(uint8_t c) {}
void dspsetbgcolor(uint8_t c) {}
void dspsetreverse(uint8_t c) {}
uint8_t dspident() {return 0;}
void rgbcolor(uint8_t r, uint8_t g, uint8_t b) {}
void vgacolor(uint8_t c) { dspfgcolor=c%3; u8g2.setDrawColor(dspfgcolor); }
void plot(int x, int y) { u8g2.setDrawColor(dspfgcolor); u8g2.drawPixel(x, y); dspgraphupdate(); }
void line(int x0, int y0, int x1, int y1)   { u8g2.drawLine(x0, y0, x1, y1);  dspgraphupdate(); }
void rect(int x0, int y0, int x1, int y1)   { u8g2.drawFrame(x0, y0, x1-x0, y1-y0);  dspgraphupdate(); }
void frect(int x0, int y0, int x1, int y1)  { u8g2.drawBox(x0, y0, x1-x0, y1-y0);  dspgraphupdate(); }
void circle(int x0, int y0, int r) { u8g2.drawCircle(x0, y0, r); dspgraphupdate(); }
void fcircle(int x0, int y0, int r) { u8g2.drawDisc(x0, y0, r); dspgraphupdate(); }
#endif

/*
 * 4.7 inch epaper displays are derived from the NOKIA51 code, no grayscales 
 * at the moment. Forcing the font into rectangles and hoping this works.
 * 
 * Epapers bypass the display driver here and use a graphics based display 
 * mode instead
 */
#ifdef ARDUINOEDP47
#define GRAPHDISPLAYDRIVER
#define DISPLAYPAGEMODE
#undef DISPLAYHASCOLOR /* display driver not color aware for this display */
#define DISPLAYHASGRAPH
const int dsp_width=960;
const int dsp_height=540;
const int dsp_rows=0;
const int dsp_columns=0;
typedef uint8_t dspcolor_t;
dspcolor_t dspfgcolor = 1;
dspcolor_t dspbgcolor = 0;
char dspfontsize = 24;
int dspgraphcursor_x = 0;
int dspgraphcursor_y = dspfontsize;
void dspbegin() { epd_init(); dspclear(); }
void dspprintstring(char* s) { 
  epd_poweron();
  writeln((GFXfont *)&FiraSans, s, &dspgraphcursor_x, &dspgraphcursor_y, NULL);
  epd_poweroff();
}
void dspclear() { epd_poweron();  epd_clear(); epd_poweroff(); dspfgcolor=1; }
void dspupdate() { }
void dspsetcursor(uint8_t c) {}
void dspsetfgcolor(uint8_t c) {}
void dspsetbgcolor(uint8_t c) {}
void dspsetreverse(uint8_t c) {}
uint8_t dspident() {return 0;}
void rgbcolor(uint8_t r, uint_8 g, uint8_t b) {}
void vgacolor(uint8_t c) { dspfgcolor=c%3; }
void plot(int x, int y) {  }
void line(int x0, int y0, int x1, int y1)   {  }
void rect(int x0, int y0, int x1, int y1)   {   }
void frect(int x0, int y0, int x1, int y1)  { }
void circle(int x0, int y0, int r) {  }
void fcircle(int x0, int y0, int r) {  }
#endif
 

/* 
 * Small SSD1306 OLED displays with I2C interface
 * This is a buffered display it has a dspupdate() function 
 * it also needs to call dspgraphupdate() after each graphic 
 * operation
 */ 
#ifdef ARDUINOSSD1306
#define DISPLAYDRIVER
#define DISPLAYPAGEMODE
#undef DISLAYHASCOLOR /* display driver not color aware for this display */
#define DISPLAYHASGRAPH
#define SSD1306WIDTH 32
#define SSD1306HEIGHT 128
/* constructors may look like this, last argument is the reset pin
 * //U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, U8X8_PIN_NONE);
 * //U8G2_SSD1306_128X64_NONAME_F_SW_I2C u8g2(U8G2_R0,  SCL, SDA, U8X8_PIN_NONE);  
 */
#if SSD1306WIDTH == 32
/* U8G2_SSD1306_128X32_UNIVISION_F_HW_I2C u8g2(U8G2_R0, SCL, SDA, U8X8_PIN_NONE); 
 * use hardware I2C instead of software. Tested (only) on ESP32C3 and ESP8266 so far.
 */
U8G2_SSD1306_128X32_UNIVISION_F_HW_I2C u8g2(U8G2_R0);
#endif
#if SSD1306WIDTH == 64
/* the Heltec board has an internal software I2C on pins 4=SDA and 15=SCL */
#ifdef ARDUINO_heltec_wifi_lora_32_V2
U8G2_SSD1306_128X64_NONAME_F_SW_I2C u8g2(U8G2_R0, 15, 4, 16); 
#else 
/* use hardware I2C instead of software. Tested (only) on ESP32C3 and ESP8266 so far.
 */
U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0); 
#endif
#endif
const char dspfontsize = 8;
const int dsp_rows=SSD1306WIDTH/dspfontsize;
const int dsp_columns=SSD1306HEIGHT/dspfontsize;
typedef uint8_t dspcolor_t;
dspcolor_t dspfgcolor = 1;
dspcolor_t dspbgcolor = 0;
void dspbegin() { u8g2.begin(); u8g2.setFont(u8g2_font_amstrad_cpc_extended_8r); }
void dspprintchar(char c, uint8_t col, uint8_t row) { char b[] = { 0, 0 }; b[0]=c; if (c) u8g2.drawStr(col*dspfontsize+2, (row+1)*dspfontsize, b); }
void dspclear() { u8g2.clearBuffer(); u8g2.sendBuffer(); dspfgcolor=1; }
void dspupdate() { u8g2.sendBuffer(); }
void dspsetcursor(uint8_t c) {}
void dspsetfgcolor(uint8_t c) {}
void dspsetbgcolor(uint8_t c) {}
void dspsetreverse(uint8_t c) {}
uint8_t dspident() {return 0;}
void rgbcolor(uint8_t r, uint8_t g, uint8_t b) {}
void vgacolor(uint8_t c) { dspfgcolor=c%3; u8g2.setDrawColor(dspfgcolor); }
void plot(int x, int y) { u8g2.setDrawColor(dspfgcolor); u8g2.drawPixel(x, y); dspgraphupdate(); }
void line(int x0, int y0, int x1, int y1)   { u8g2.drawLine(x0, y0, x1, y1); dspgraphupdate(); }
void rect(int x0, int y0, int x1, int y1)   { u8g2.drawFrame(x0, y0, x1-x0, y1-y0);  dspgraphupdate(); }
void frect(int x0, int y0, int x1, int y1)  { u8g2.drawBox(x0, y0, x1-x0, y1-y0);  dspgraphupdate(); }
void circle(int x0, int y0, int r) { u8g2.drawCircle(x0, y0, r); dspgraphupdate(); }
void fcircle(int x0, int y0, int r) { u8g2.drawDisc(x0, y0, r); dspgraphupdate(); }
#endif

/* 
 * A ILI9488 with Jarett Burkets version of Adafruit GFX and patches
 * by Stefan Lenz
 * currently only slow software scrolling implemented in BASIC
 * 
 * https://github.com/slviajero/ILI9488
 * 
 * we use 9, 8, 7 as CS, CE, RST by default and A7 for the led brightness control
 */ 
 
#ifdef ARDUINOILI9488
#define DISPLAYDRIVER
#define DISPLAYHASCOLOR
#define DISPLAYHASGRAPH
#ifndef ILI_CS
#define ILI_CS  9
#endif
#ifndef ILI_DC
#define ILI_DC  8
#endif
#ifndef ILI_RST
#define ILI_RST 7
#endif
#ifndef ILI_LED
#define ILI_LED A3
#endif
ILI9488 tft = ILI9488(ILI_CS, ILI_DC, ILI_RST);
/* ILI in landscape */
const int dsp_rows=20;
const int dsp_columns=30;
char dspfontsize = 16;
typedef uint16_t dspcolor_t;
const uint16_t dspdefaultfgcolor = 0xFFFF;
const uint8_t dspdefaultfgvgacolor = 0x0F;
dspcolor_t dspfgcolor = dspdefaultfgcolor;
dspcolor_t dspbgcolor = 0;
dspcolor_t dsptmpcolor = 0;
uint8_t dspfgvgacolor = dspdefaultfgvgacolor;
uint8_t dsptmpvgacolor = 0;
void dspbegin() { 
  tft.begin(); 
  tft.setRotation(3); /* ILI in landscape, SD slot up */
  tft.setTextColor(dspfgcolor);
  tft.setTextSize(2);
  tft.fillScreen(dspbgcolor); 
  pinMode(ILI_LED, OUTPUT);
  analogWrite(ILI_LED, 255);
  dspsetscrollmode(1, 4);
}
void dspprintchar(char c, uint8_t col, uint8_t row) {  if (c) tft.drawChar(col*dspfontsize, row*dspfontsize, c, dspfgcolor, dspbgcolor, 2); }
void dspclear() { 
  tft.fillScreen(dspbgcolor); 
  dspfgcolor = dspdefaultfgcolor; 
  dspfgvgacolor = dspdefaultfgvgacolor; 
}
void dspupdate() {}
void dspsetcursor(uint8_t c) {}
void dspsavepen() { dsptmpcolor=dspfgcolor; dsptmpvgacolor=dspfgvgacolor; }
void dsprestorepen() { dspfgcolor=dsptmpcolor; dspfgvgacolor=dsptmpvgacolor; }
void dspsetfgcolor(uint8_t c) { vgacolor(c); }
void dspsetbgcolor(uint8_t c) { }
void dspsetreverse(uint8_t c) {}
uint8_t dspident() {return 0; }
void rgbcolor(uint8_t r, uint8_t g, uint8_t b) { dspfgvgacolor=rgbtovga(r, g, b); dspfgcolor=tft.color565(r, g, b);}
void vgacolor(uint8_t c) {  
  short base=128;
  dspfgvgacolor=c;
  if (c==8) { dspfgcolor=tft.color565(64, 64, 64); return; }
  if (c>8) base=255;
  dspfgcolor=tft.color565(base*(c&1), base*((c&2)/2), base*((c&4)/4)); 
}
void plot(int x, int y) { tft.drawPixel(x, y, dspfgcolor); }
void line(int x0, int y0, int x1, int y1)   { tft.drawLine(x0, y0, x1, y1, dspfgcolor); }
void rect(int x0, int y0, int x1, int y1)   { tft.drawRect(x0, y0, x1, y1, dspfgcolor);}
void frect(int x0, int y0, int x1, int y1)  { tft.fillRect(x0, y0, x1, y1, dspfgcolor); }
void circle(int x0, int y0, int r) { tft.drawCircle(x0, y0, r, dspfgcolor); }
void fcircle(int x0, int y0, int r) { tft.fillCircle(x0, y0, r, dspfgcolor); }
#endif

/* 
 * A MCUFRIEND parallel port display for the various tft shields 
 * This implementation is mainly for Arduino MEGA
 * 
 * currently only slow software scrolling implemented in BASIC
 * 
 */ 

#ifdef ARDUINOMCUFRIEND
#define DISPLAYDRIVER
#define DISPLAYHASCOLOR
#define DISPLAYHASGRAPH
#ifndef LCD_CS
#define LCD_CS  A3
#endif
#ifndef LCD_CD
#define LCD_CD  A2
#endif
#ifndef LCD_WR
#define LCD_WR  A1
#endif
#ifndef LCD_RD
#define LCD_RD  A0
#endif
#ifndef LCD_RESET
#define LCD_RESET A4
#endif
MCUFRIEND_kbv tft;
/* ILI in landscape */
const int dsp_rows=20;
const int dsp_columns=30;
char dspfontsize = 16;
typedef uint16_t dspcolor_t;
const uint16_t dspdefaultfgcolor = 0xFFFF;
const uint8_t dspdefaultfgvgacolor = 0x0F;
dspcolor_t dspfgcolor = dspdefaultfgcolor;
dspcolor_t dspbgcolor = 0;
dspcolor_t dsptmpcolor = 0;
uint8_t dspfgvgacolor = dspdefaultfgvgacolor;
uint8_t dsptmpvgacolor = 0;
void dspbegin() { 
  uint16_t ID = tft.readID();
  if (ID == 0xD3D3) ID = 0x9481; /* write-only shield - taken from the MCDFRIEND demo */
  tft.begin(ID); 
  tft.setRotation(1); /* ILI in landscape, 3: SD slot on right the side */
  tft.setTextColor(dspfgcolor);
  tft.setTextSize(2);
  tft.fillScreen(dspbgcolor); 
  dspsetscrollmode(1, 4); /* scrolling is on, scroll 4 lines at once */
 }
void dspprintchar(char c, uint8_t col, uint8_t row) {  if (c) tft.drawChar(col*dspfontsize, row*dspfontsize, c, dspfgcolor, dspbgcolor, 2); }
void dspclear() { 
  tft.fillScreen(dspbgcolor); 
  dspfgcolor = dspdefaultfgcolor; 
  dspfgvgacolor = dspdefaultfgvgacolor; 
}
void dspupdate() {}
void dspsetcursor(uint8_t c) {}
void dspsavepen() { dsptmpcolor=dspfgcolor; dsptmpvgacolor=dspfgvgacolor; }
void dsprestorepen() { dspfgcolor=dsptmpcolor; dspfgvgacolor=dsptmpvgacolor; }
void dspsetfgcolor(uint8_t c) { vgacolor(c); }
void dspsetbgcolor(uint8_t c) { }
void dspsetreverse(uint8_t c) {}
uint8_t dspident() {return 0; }
void rgbcolor(uint8_t r, uint8_t g, uint8_t b) { dspfgvgacolor=rgbtovga(r, g, b); dspfgcolor=tft.color565(r, g, b);}
void vgacolor(uint8_t c) {  
  short base=128;
  dspfgvgacolor=c;
  if (c==8) { dspfgcolor=tft.color565(64, 64, 64); return; }
  if (c>8) base=255;
  dspfgcolor=tft.color565(base*(c&1), base*((c&2)/2), base*((c&4)/4)); 
}
void plot(int x, int y) { tft.drawPixel(x, y, dspfgcolor); }
void line(int x0, int y0, int x1, int y1)   { tft.drawLine(x0, y0, x1, y1, dspfgcolor); }
void rect(int x0, int y0, int x1, int y1)   { tft.drawRect(x0, y0, x1, y1, dspfgcolor);}
void frect(int x0, int y0, int x1, int y1)  { tft.fillRect(x0, y0, x1, y1, dspfgcolor); }
void circle(int x0, int y0, int r) { tft.drawCircle(x0, y0, r, dspfgcolor); }
void fcircle(int x0, int y0, int r) { tft.fillCircle(x0, y0, r, dspfgcolor); }
#endif

#ifdef TFTESPI
#define DISPLAYDRIVER
#define DISPLAYHASCOLOR
#define DISPLAYHASGRAPH
/* 
 * first draft od the code taken from the hello world demo 
 * of Lilygo. This code only works on the 2.0.14 version of the ESP32 core.
 * Physical display dimensions is 320x240. We use the 12pf font for a first 
 * test. With this font we can display 26 columns and 20 rows. This is set 
 * statically in the code at the moment. 
 */
/* constants for 16 bit fonts */
const int dsp_rows=15;
const int dsp_columns=20;
char dspfontsize = 16;
const char dspfontsizeindex = 2;
/* constants for 8 bit fonts */
/*
const int dsp_rows=30;
const int dsp_columns=40;
char dspfontsize = 8;
const char dspfontsizeindex = 1;
*/
/* unchanged from the ILI code */
typedef uint16_t dspcolor_t;
const uint16_t dspdefaultfgcolor = 0xFFFF;
const uint8_t dspdefaultfgvgacolor = 0x0F;
dspcolor_t dspfgcolor = dspdefaultfgcolor;
dspcolor_t dspbgcolor = 0;
dspcolor_t dsptmpcolor = 0;
uint8_t dspfgvgacolor = dspdefaultfgvgacolor;
uint8_t dsptmpvgacolor = 0;
/* this is new for TFT_eSPI*/
TFT_eSPI tft;
/* change the brightness, taken from HelloWorld as well */
void tftespisetBrightness(uint8_t value)
{
    static uint8_t level = 0;
    static uint8_t steps = 16;
    if (value == 0) {
        digitalWrite(BOARD_BL_PIN, 0);
        delay(3);
        level = 0;
        return;
    }
    if (level == 0) {
        digitalWrite(BOARD_BL_PIN, 1);
        level = steps;
        delayMicroseconds(30);
    }
    int from = steps - level;
    int to = steps - value;
    int num = (steps + to - from) % steps;
    for (int i = 0; i < num; i++) {
        digitalWrite(BOARD_BL_PIN, 0);
        digitalWrite(BOARD_BL_PIN, 1);
    }
    level = value;
}
void dspbegin() { 
  tft.begin(); 
  tft.setRotation(1);
  tft.setTextDatum(6); /* upper left*/
  tft.setTextColor(dspfgcolor);
  tft.fillScreen(dspbgcolor); 
  dspsetscrollmode(1, 4); /* scrolling is on, scroll 4 lines at once */
  pinMode(BOARD_BL_PIN, OUTPUT);
  tftespisetBrightness(16); /* maximum brightness */
}
void dspprintchar(char c, uint8_t col, uint8_t row) {  
  if (c) tft.drawChar(col*dspfontsize, row*dspfontsize, c, dspfgcolor, dspbgcolor, dspfontsizeindex);  
}
void dspclear() { 
  tft.fillScreen(dspbgcolor); 
  dspfgcolor = dspdefaultfgcolor; 
  dspfgvgacolor = dspdefaultfgvgacolor; 
}
void dspupdate() {}
void dspsetcursor(uint8_t c) {}
void dspsavepen() { dsptmpcolor=dspfgcolor; dsptmpvgacolor=dspfgvgacolor; }
void dsprestorepen() { dspfgcolor=dsptmpcolor; dspfgvgacolor=dsptmpvgacolor; }
void dspsetfgcolor(uint8_t c) { vgacolor(c); }
void dspsetbgcolor(uint8_t c) { }
void dspsetreverse(uint8_t c) {}
uint8_t dspident() {return 0; }
void rgbcolor(uint8_t r, uint8_t g, uint8_t b) { dspfgvgacolor=rgbtovga(r, g, b); dspfgcolor=tft.color565(r, g, b);}
void vgacolor(uint8_t c) {  
  short base=128;
  dspfgvgacolor=c;
  if (c==8) { dspfgcolor=tft.color565(64, 64, 64); return; }
  if (c>8) base=255;
  dspfgcolor=tft.color565(base*(c&1), base*((c&2)/2), base*((c&4)/4)); 
}
void plot(int x, int y) { tft.drawPixel(x, y, dspfgcolor); }
void line(int x0, int y0, int x1, int y1)   { tft.drawLine(x0, y0, x1, y1, dspfgcolor); }
void rect(int x0, int y0, int x1, int y1)   { tft.drawRect(x0, y0, x1, y1, dspfgcolor);}
void frect(int x0, int y0, int x1, int y1)  { tft.fillRect(x0, y0, x1, y1, dspfgcolor); }
void circle(int x0, int y0, int r) { tft.drawCircle(x0, y0, r, dspfgcolor); }
void fcircle(int x0, int y0, int r) { tft.fillCircle(x0, y0, r, dspfgcolor); }
#endif

/* 
 * A no operations graphics dummy  
 * Tests the BASIC side of the graphics code without triggering 
 * any output
 */ 
#ifdef ARDUINOGRAPHDUMMY
#define DISPLAYDRIVER
#undef DISPLAYHASCOLOR
#define DISPLAYHASGRAPH
const int dsp_rows=20;
const int dsp_columns=30;
const uint16_t dspdefaultfgcolor = 1;
char dspfontsize = 16;
typedef uint16_t dspcolor_t;
dspcolor_t dspfgcolor = 0xFFFF;
dspcolor_t dspbgcolor = 0x0000;
void dspbegin() { dspsetscrollmode(1, 4); }
void dspprintchar(char c, uint8_t col, uint8_t row) {}
void dspclear() {}
void dspupdate() {}
void dspsetcursor(uint8_t c) {}
void dspsetfgcolor(uint8_t c) {}
void dspsetbgcolor(uint8_t c) {}
void dspsetreverse(uint8_t c) {}
uint8_t dspident() {return 0; }
void rgbcolor(uint8_t r, uint8_t g, uint8_t b) { dspfgcolor=0; }
void vgacolor(uint8_t c) {  
  short base=128;
  if (c==8) { rgbcolor(64, 64, 64); return; }
  if (c>8) base=255;
  rgbcolor(base*(c&1), base*((c&2)/2), base*((c&4)/4)); 
}
void plot(int x, int y) {}
void line(int x0, int y0, int x1, int y1) {}
void rect(int x0, int y0, int x1, int y1) {}
void frect(int x0, int y0, int x1, int y1) {}
void circle(int x0, int y0, int r) {}
void fcircle(int x0, int y0, int r) {}
#endif

/*
 * SD1963 TFT display code with UTFT.
 * Tested witth SD1963 800*480 board. 
 *	it is mainly intended for a MEGA or DUE as a all in one system
 *	this is for a MEGA shield and the CTE DUE shield, for the due 
 *	you need to read the comment in Arduino/libraries/UTFT/hardware/arm
 *	HW_ARM_defines.h -> uncomment the DUE shield
 * See also 
  * https://github.com/slviajero/tinybasic/wiki/Projects:-4.-A-standalone-computer-with-a-TFT-screen-based-on-a-DUE
 */
#ifdef ARDUINOTFT
#define DISPLAYDRIVER
#define DISPLAYHASCOLOR 
#define DISPLAYHASGRAPH
extern uint8_t SmallFont[];
extern uint8_t BigFont[];
#ifdef ARDUINO_SAM_DUE
UTFT tft(CTE70,25,26,27,28);
#else 
UTFT tft(CTE70,38,39,40,41);
#endif
const int dsp_rows=30;
const int dsp_columns=50;
char dspfontsize = 16;
const uint32_t dspdefaultfgcolor = 0x00FFFFFF;
const uint8_t dspdefaultfgvgacolor = 0x0F;
typedef uint32_t dspcolor_t;
dspcolor_t dspfgcolor = dspdefaultfgcolor;
dspcolor_t dspbgcolor = 0;
dspcolor_t dsptmpcolor = 0;
uint8_t dspfgvgacolor = dspdefaultfgvgacolor;
uint8_t dsptmpvgacolor = 0;
void dspbegin() { tft.InitLCD(); tft.setFont(BigFont); tft.clrScr(); dspsetscrollmode(1, 4); }
void dspprintchar(char c, uint8_t col, uint8_t row) { if (c) tft.printChar(c, col*dspfontsize, row*dspfontsize); }
void dspclear() { 
  tft.clrScr();  
  dspfgcolor = dspdefaultfgcolor; 
  dspfgvgacolor = dspdefaultfgvgacolor; 
  vgacolor(dspfgvgacolor);
}
void rgbcolor(uint8_t r, uint8_t g, uint8_t b) { 
  tft.setColor(r,g,b); 
  dspfgcolor=(r << 16) + (g << 8) + b;
  dspfgvgacolor=rgbtovga(r, g, b);
}
void vgacolor(uint8_t c) {
  short base=128;
  dspfgvgacolor=c;
  if (c==8) { tft.setColor(64, 64, 64); return; }
  if (c>8) base=255;
  tft.setColor(base*(c&1), base*((c&2)/2), base*((c&4)/4));  
}
void dspupdate() {}
void dspsetcursor(uint8_t c) {}
void dspsavepen() { dsptmpcolor=dspfgcolor; dsptmpvgacolor=dspfgvgacolor; }
void dsprestorepen() { dspfgcolor=dsptmpcolor; dspfgvgacolor=dsptmpvgacolor; }
void dspsetfgcolor(uint8_t c) { vgacolor(c); }
void dspsetbgcolor(uint8_t c) { }
void dspsetreverse(uint8_t c) {}
uint8_t dspident() {return 0;}
void plot(int x, int y) { tft.drawPixel(x, y); }
void line(int x0, int y0, int x1, int y1)   { tft.drawLine(x0, y0, x1, y1); }
void rect(int x0, int y0, int x1, int y1)   { tft.drawRect(x0, y0, x1, y1); }
void frect(int x0, int y0, int x1, int y1)  { tft.fillRect(x0, y0, x1, y1); }
void circle(int x0, int y0, int r) { tft.drawCircle(x0, y0, r); }
void fcircle(int x0, int y0, int r) { tft.fillCircle(x0, y0, r); }
#endif

/* 
 * This is the VGA code for fablib.
 *
 * Not all modes and possibilities explored. It leaves enough memory for the 
 * interpreter. Networking is not possible an a TTGO T7 V1.4. 
 * 
 * This code overrides the display driver logic as fabgl brings an own 
 * terminal emulation.
 * 
 * Default settings is a 640*480 VGA screen with 16 colors
 * and default fonts for the Terminal
 */
#if defined(ARDUINOVGA) && defined(ARDUINO_TTGO_T7_V14_Mini32) 
#ifndef TTGOVGACONTROLLER
#define TTGOVGACONTROLLER VGA16Controller
#endif
#ifndef TTGOVGACOLUMNS
#define TTGOVGACOLUMNS -1
#endif
#ifndef TTGOVGAROWS
#define TTGOVGAROWS -1
#endif
#ifndef TTGOVGARESOLUTION
#define TTGOVGARESOLUTION VGA_640x480_60Hz
#endif
fabgl::TTGOVGACONTROLLER VGAController; /* 16 color object with less memory */
static fabgl::Terminal Terminal;
static Canvas cv(&VGAController);
TerminalController tc(&Terminal);
Color vga_graph_pen = Color::BrightWhite;
Color vga_graph_brush = Color::Black;
Color vga_txt_pen = Color::BrightGreen;
Color vga_txt_background = Color::Black;
fabgl::SoundGenerator soundGenerator;

/* this starts the vga controller and the terminal right now */
void vgabegin() {
	VGAController.begin(GPIO_NUM_22, GPIO_NUM_21, GPIO_NUM_19, GPIO_NUM_18, GPIO_NUM_5, GPIO_NUM_4, GPIO_NUM_23, GPIO_NUM_15);
  VGAController.setResolution(TTGOVGARESOLUTION);
	Terminal.begin(&VGAController, TTGOVGACOLUMNS, TTGOVGAROWS);
	Terminal.setBackgroundColor(vga_txt_background);
	Terminal.setForegroundColor(vga_txt_pen);
 #ifdef TTGOVGAFONT
  Terminal.loadFont(&fabgl::TTGOVGAFONT);
 #endif
  Terminal.connectLocally();
  Terminal.clear();
  Terminal.enableCursor(1); 
  Terminal.setTerminalType(TermType::VT52);
}

/* for Arduino just a dummy, needed in the POSIX branch of the code */
void vgaend() {}

/* this is a dummy function, we do not have a status line */
int vgastat(uint8_t c) {return 0; }

/* scale the screen size to make a circle round, unneeded if the right resulution is set */
void vgascale(int* x, int* y) {
	/* *y=*y*10/16; */
}

void rgbcolor(uint8_t r, uint8_t g, uint8_t b) {
	short vga;
	if (r>191 || g>191 || b>191) vga=8; else vga=0;
	vga=vga+r/128+g/128*2+b/128*4;
	vga_graph_pen=fabgl::Color(vga);
}

void vgacolor(uint8_t c) { vga_graph_pen = fabgl::Color(c%16); }
void plot(int x, int y) { 
	vgascale(&x, &y);
	cv.setPenColor(vga_graph_pen);
	cv.setPixel(x,y);
	cv.setPenColor(vga_txt_pen);
}

void line(int x0, int y0, int x1, int y1) {
	vgascale(&x0, &y0);
	vgascale(&x1, &y1);
	cv.setPenColor(vga_graph_pen);
	cv.setPenWidth(1);
 	cv.drawLine(x0, y0, x1, y1);
 	cv.setPenColor(vga_txt_pen);
}

void rect(int x0, int y0, int x1, int y1) { 
	vgascale(&x0, &y0);
	vgascale(&x1, &y1);
	cv.setPenColor(vga_graph_pen);
	cv.setPenWidth(1);
	cv.drawRectangle(x0, y0, x1, y1);
	cv.setPenColor(vga_txt_pen);
}

void frect(int x0, int y0, int x1, int y1) {  
	vgascale(&x0, &y0);
	vgascale(&x1, &y1);
	cv.setBrushColor(vga_graph_pen);
	cv.fillRectangle(x0, y0, x1, y1);
	cv.setBrushColor(vga_txt_background);
}

void circle(int x0, int y0, int r) {  
	int rx = r;
	int ry = r;
	vgascale(&x0, &y0);
	vgascale(&rx, &ry);
	cv.setPenColor(vga_graph_pen);
	cv.setPenWidth(1);
	cv.drawEllipse(x0, y0, rx, ry);
	cv.setPenColor(vga_txt_pen);
}

void fcircle(int x0, int y0, int r) {  
	int rx = r;
	int ry = r;
	vgascale(&x0, &y0);
	vgascale(&rx, &ry);
	cv.setBrushColor(vga_graph_pen);
	cv.fillEllipse(x0, y0, rx, ry);
	cv.setBrushColor(vga_txt_background);	
}

void vgawrite(char c){
	switch(c) {
    case 12: /* form feed is clear screen */
  		Terminal.write(27); Terminal.write('H');
    	Terminal.write(27); Terminal.write('J');
      return;
    case 10: /* this is LF Unix style doing also a CR */
      Terminal.write(10); Terminal.write(13);
    	return;
  	}
  	Terminal.write(c);
}
#else 
void vgabegin(){}
int vgastat(uint8_t c) {return 0; }
void vgawrite(char c){}
void vgaend() {}
#endif

/* 
 * Keyboard code for either the Fablib Terminal class or 
 * PS2Keyboard - please note that you need the ESP patched 
 * version here as mentioned above
 * 
 * sets HASKEYBOARD to inform basic about this capability
 * 
 * keyboards can implement 
 * 	kbdbegin()
 * they need to provide
 * 	kbdavailable(), kbdread(), kbdcheckch()
 * the later is for interrupting running BASIC code
 */
#if defined(ARDUINO_TTGO_T7_V14_Mini32) && defined(ARDUINOVGA)
fabgl::PS2Controller PS2Controller;
char fabgllastchar = 0;
#else
#if defined(ARDUINO) && defined(ARDUINOPS2)
PS2Keyboard keyboard;
#else 
#if defined(ARDUINO) && defined(ARDUINOUSBKBD)
USBHost usb;
KeyboardController keyboard(usb);
char usbkey=0;
#else 
#if defined(ARDUINOZX81KBD)
ZX81Keyboard keyboard;
#else
#if defined(ARDUINOI2CKBD)
/* with an I2C keyboard we remeber the last key, this is similar to the USB keyboard */
char i2ckey=0;
#else
#if defined(GIGAUSBKBD)
Keyboard keyb;
#endif
#endif
#endif
#endif
#endif
#endif

/*
 * Experimental, unfinished, rudimentary
 */
#if defined(ARDUINOUSBKBD)
/* not really needed, only here for reference */
char usbkeymapUS[] = 
{' ', '"', '!', '#', '$', '%', '&', '\'', '(', ')', '*', '+', 
 ',', '-', '.', '/', '0', '1', '2', '3', '4', '5', '6', '7', 
 '8', '9', ':', ';', '<', '=', '>', '?', '@', 'A', 'B', 'C', 
 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 
 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '[', 
 '\\', ']', '^', '_', '`', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 
 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's',
 't', 'u', 'v', 'w', 'x', 'y', 'z', '{', '|', '}', 0, 0};
/* map the ASCII codes of the essential keys for BASIC of a
 *  German keyboard, most notable is < and > which is ö/a
 */
char usbkeymapGerman[] = 
{' ', '!',  '!', '#', '$', '%', '/', '>', ')', '=', '(', '+', 
 ',', '-', '.', '-', '0', '1', '2', '3', '4', '5', '6', '7', 
 '8', '9', ':', '<', ';', '=', ':', '_', '"', 'A', 'B', 'C', 
 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 
 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Z', 'Y', '[', 
 '#', '+', '&', '?', '@', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 
 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's',
 't', 'u', 'v', 'w', 'x', 'z', 'y', '{', '\'', '*', 0, 0};

/*
 * he weak functions from the keyboard controller class implemented
 */
void keyPressed() {}
void keyReleased() {
  switch (keyboard.getOemKey()) {
    case 40:
      usbkey=10;
      break;
    case 42:
    case 76:
      usbkey=127;
      break;
    case 41:
      usbkey=27;
      break;
    default:
      usbkey=keyboard.getKey(); 
#if ARDUINOKBDLANG_GERMAN
      if (usbkey>31 && usbkey<128) usbkey=usbkeymapGerman[usbkey-32]; 
#else 
      if (usbkey>31 && usbkey<128) usbkey=usbkeymapUS[usbkey-32]; 
#endif
  }
}
#endif

/* 
 * keyboard controller code 
 */

#ifdef ZX81KEYBOARD
const byte zx81pins[] = {ZX81PINS}; 
#endif

/* 
 *  A helper function for the I2C keyboard code. We get one character 
 *  from the board. A -1 is an I2C error condition for a non reply of 
 *  the keyboard. 
 */
#ifdef ARDUINOI2CKBD
char i2ckbdgetkey() {
  char c=0;
  Wire.requestFrom(I2CKBDADDR, 1);
    if (Wire.available()) {
      c=Wire.read();
      if (c == -1) { ioer=1; c=0; }
    }
    return c;
}
#endif

/* start the keyboard */
void kbdbegin() {
#ifdef PS2KEYBOARD
#ifdef ARDUINOKBDLANG_GERMAN
	keyboard.begin(PS2DATAPIN, PS2IRQPIN, PS2Keymap_German);
#else
  keyboard.begin(PS2DATAPIN, PS2IRQPIN, PS2Keymap_US);
#endif
#else
#ifdef PS2FABLIB
	PS2Controller.begin(PS2Preset::KeyboardPort0);
#ifdef ARDUINOKBDLANG_GERMAN
  PS2Controller.keyboard()->setLayout(&fabgl::GermanLayout);
#else
  PS2Controller.keyboard()->setLayout(&fabgl::USLayout);
#endif
#else 
#ifdef USBKEYBOARD
/* nothing to be done here */
#else
#ifdef ZX81KEYBOARD
  keyboard.begin(zx81pins);
#else
#ifdef ARDUINOI2CKBD
/* this is from the T-Deck examples, time needed for the keyboard to start */
  delay(500);
#else 
#ifdef GIGAUSBKBD
  pinMode(PA_15, OUTPUT); /* no digitalWrite in original example file */
  keyb.begin();
#endif
#endif
#endif
#endif
#endif
#endif
}

uint8_t kbdstat(uint8_t c) {return 0; }

uint16_t kbdins(char* b, uint16_t nb) { return consins(b, nb); }

uint8_t kbdavailable(){
#ifdef PS2KEYBOARD
	return keyboard.available(); 
#else
#ifdef PS2FABLIB
  if (fabgllastchar) return Terminal.available()+1; else return Terminal.available();
#else 
#ifdef USBKEYBOARD
/* if we already have a key, tell the caller we have one */
  if (usbkey) return 1; 
/* if not, look it up */
  if (usbkey) return 1; else return 0;
#else
#ifdef ZX81KEYBOARD
  return keyboard.available();
#else
#ifdef ARDUINOI2CKBD
/* do we have a key stored, then return it */
  if (i2ckey) {
    return 1; 
  } else {
    i2ckey=i2ckbdgetkey(); 
    if (i2ckey != 0) return 1;
  }
#else
#if defined(GIGAUSBKBD)
  return keyb.available();
#endif
#endif
#endif
#endif
#endif
#endif
#ifdef HASKEYPAD
/* a poor man's debouncer, unstable state returns 0 */
  char c=keypadread();
  if (c != 0) {
    bdelay(2); 
    if (c == keypadread()) return 1;
  }
#endif	
	return 0;
}

char kbdread() {
  char c = 0;
/* wait for the keystrike in a tight loop, yielding a lot */
  while(!kbdavailable()) byield();
#ifdef PS2KEYBOARD  
	c=keyboard.read();
#endif
#ifdef PS2FABLIB
  if (fabgllastchar) { c=fabgllastchar; fabgllastchar=0; }
  else c=Terminal.read();
#else 
#ifdef USBKEYBOARD
/* if we have read a key before, return it else look it up */
  c=usbkey; 
  usbkey=0; 
#else
#ifdef ZX81KEYBOARD
  c=keyboard.read();
#else
#ifdef ARDUINOI2CKBD
/* a key is stored from a previous kbdavailable() */
 if (i2ckey) {
    c=i2ckey;
    i2ckey=0;
  } else {
/* if not look for a key, no need to store it */
    c=i2ckbdgetkey();
  }
#else
#if defined(GIGAUSBKBD)
/* sometimes 0s are returned even with avail > 0 */
      auto _key = keyb.read();
      c=keyb.getAscii(_key);
#endif
#endif
#endif
#endif
#endif
#ifdef HASKEYPAD
  if (c == 0) { /* we have no character from a real keyboard, ask the keypad */
	  c=keypadread();
/* if the keypad is in non repeat mode, block */
	  if (!kbdrepeat) while(kbdavailable()) byield();
  }
#endif	
	if (c == 13) c=10;
	return c;
}

char kbdcheckch() {
#ifdef PS2KEYBOARD
/*
 * only works with the patched library https://github.com/slviajero/PS2Keyboard
 */
#ifdef PS2KEYBOARD_HASPEEK
 return keyboard.peek();
#else 
/*
 * for the original library  https://github.com/PaulStoffregen/PS2Keyboard 
 * GET does not work properly with it as there is no peek functionality which is needed
 * for non blocking IO and the ability to stop programs
 */
  if (kbdavailable()) return kbdread(); else return 0;
#endif
#else
#ifdef PS2FABLIB
  if (fabgllastchar) return fabgllastchar;
	if (kbdavailable()) { fabgllastchar=Terminal.read(); return fabgllastchar; }
#else 
#ifdef USBKEYBOARD
  return usbkey;
#else 
#ifdef ZX81KEYBOARD
  return keyboard.lastKey; /* dont peek here as checkch called in a fast loop in statement(), peek done in byield*/
#else 
#ifdef ARDUINOI2CKBD
  if (!i2ckey) {
    i2ckey=i2ckbdgetkey();
  }
  return i2ckey;
#else
#if defined(GIGAUSBKBD)
    auto _key = keyb.peek();
    return keyb.getAscii(_key);
#endif
#endif
#endif
#endif
#endif
#endif
#ifdef HASKEYPAD
	return keypadread();
#endif	
	return 0;
}

/*
 * Display driver code - documentation is in the header file
 */

#ifdef DISPLAYDRIVER

/* the cursor position */
uint8_t dspmycol = 0;
uint8_t dspmyrow = 0;

/* the escape state of the vt52 terminal */
uint8_t dspesc = 0;

/* which update mode do we have */
uint8_t dspupdatemode = 0;

/* how do we handle wrap 0 is wrap, 1 is no wrap */
uint8_t dspwrap = 0; 

/* the print mode */
uint8_t dspprintmode = 0;

/* the scroll control variables */
uint8_t dspscrollmode = 0;
uint8_t dsp_scroll_rows = 1;

uint8_t dspstat(uint8_t c) { return 1; }

void dspsetcursorx(uint8_t c) {
  if (c>=0 && c<dsp_columns) dspmycol=c;
  dspprintchar(0, dspmycol, dspmyrow); /* needed to really position the cursor if there is a hardware cursor */
}

void dspsetcursory(uint8_t r) {
  if (r>=0 && r<dsp_rows) dspmyrow=r;
    dspprintchar(0, dspmycol, dspmyrow); /* needed to really position the cursor if there is a hardware cursor */
}

uint8_t dspgetcursorx() { return dspmycol; }

uint8_t dspgetcursory() { return dspmyrow; }

uint8_t dspactive() {
	return od == ODSP;
}

/* to whom the bell tolls - implement this to you own liking */
void dspbell() {}

/*
 * Control the update modes for page update displays
 * like Epaper, Nokia 5110 and SSD1306
 * dspgraphupdate is the helper for the graphics functions.
 */

void dspsetupdatemode(uint8_t c) {
  dspupdatemode=c;
}

uint8_t dspgetupdatemode() {
  return dspupdatemode;
}

void dspgraphupdate() {
  if (dspupdatemode == 0) dspupdate();
}

/* scrollable displays need a character buffer */
#ifdef DISPLAYCANSCROLL

#ifndef DISPLAYHASCOLOR
const uint16_t dspfgvgacolor = 0;
#endif

dspbuffer_t dspbuffer[dsp_rows][dsp_columns];

/* buffer access functions */

/* needed for @D() */
dspbuffer_t dspget(uint16_t i) {
  if (i>=0 && i<=dsp_columns*dsp_rows-1) return dspbuffer[i/dsp_columns][i%dsp_columns]; else return 0;
}

/* print line and screen helpers */
dspbuffer_t dspgetrc(uint8_t r, uint8_t c) { return dspbuffer[r][c]; }
dspbuffer_t dspgetc(uint8_t c) { return dspbuffer[dspmyrow][c]; }

/* this functions prints a character and updates the display buffer */
void dspsetxy(dspbuffer_t ch, uint8_t c, uint8_t r) {
  if (r>=0 && c>=0 && r<dsp_rows && c<dsp_columns) {
    dspbuffer[r][c]=(dspbuffer_t)ch | (dspfgvgacolor << 8);
    if (ch != 0) dspprintchar(ch, c, r); else dspprintchar(' ', c, r);
  }
}

/* needed for @D() access */
void dspset(uint16_t i, dspbuffer_t ch) {
  uint8_t c=i%dsp_columns;
  uint8_t r=i/dsp_columns;
  dspsetxy(ch, c, r);
}

/* 0 normal scroll, 1 enable waitonscroll function */
void dspsetscrollmode(uint8_t c, uint8_t l) {
	dspscrollmode = c;
	dsp_scroll_rows = l;
}

/* clear the buffer */
void dspbufferclear() {
	uint8_t r,c;
	for (r=0; r<dsp_rows; r++)
		for (c=0; c<dsp_columns; c++)
      dspbuffer[r][c]=0;
  dspmyrow=0;
  dspmycol=0;
}

#ifdef DISPLAYHASCOLOR
/* separates characters and color/font */
const uint16_t charmask = 0x80FF;
#endif

/* do the scroll */
void dspscroll(uint8_t scroll_rows, uint8_t scroll_top=0){
	uint8_t r,c;
  dspbuffer_t a,b;
  
/* scroll data up and redraw the display */
  for (r=scroll_top; r<dsp_rows-scroll_rows; r++) { 
    for (c=0; c<dsp_columns; c++) {
			a=dspbuffer[r][c];
			b=dspbuffer[r+scroll_rows][c];
			if ( a != b ) {
  			if (b != 0) { 
#ifdef DISPLAYHASCOLOR
            dspsavepen();
            dspsetfgcolor((b >> 8) & 15);
            dspprintchar(b & charmask, c, r); 
            dsprestorepen();
#else
  			    dspprintchar(b, c, r); 
#endif     
  			} else {
  			  dspprintchar(' ', c, r);
  			}
      }      
			dspbuffer[r][c]=b;
		} 
	}

/* delete the characters in the remaining lines */
	for (r=dsp_rows-scroll_rows; r<dsp_rows; r++) {
		for (c=0; c<dsp_columns; c++) {
			if (dspbuffer[r][c] != 0 && ( dspbuffer[r][c]) != 32) dspprintchar(' ', c, r); 
			dspbuffer[r][c]=0;     
    }
	}
  
/* set the cursor to the first free line	*/ 
  dspmycol=0;
	dspmyrow=dsp_rows-scroll_rows;
}

/* do the reverse scroll only one line implemented */
void dspreversescroll(uint8_t line){
  uint8_t r,c;
  dspbuffer_t a,b;
  
/* scroll data up and redraw the display */
  for (r=dsp_rows; r>line; r--) { 
    for (c=0; c<dsp_columns; c++) {
      a=dspbuffer[r][c];
      b=dspbuffer[r-1][c];
      if ( a != b ) {
        if (b != 0) { 
#ifdef DISPLAYHASCOLOR
            dspsavepen();
            dspsetfgcolor((b >> 8) & 15);
            dspprintchar(b & charmask, c, r); 
            dsprestorepen();
#else
            dspprintchar(b, c, r); 
#endif 
        } else {
          dspprintchar(' ', c, r);
        }
      }      
      dspbuffer[r][c]=b;
    } 
  }

/* delete the characters in the remaining line */
  for (c=0; c<dsp_columns; c++) {
    if (dspbuffer[line][c] != 0 && dspbuffer[line][c] != 32) dspprintchar(' ', c, r); 
    dspbuffer[line][c]=0;     
  }
 
/* set the cursor to the free line  */ 
  dspmyrow=line;
}

/* again a break in API, using inch here */
char dspwaitonscroll() {
  char c;

	if ( dspscrollmode == 1 ) {
		if (dspmyrow == dsp_rows-1) {
      c=inch();
      if (c == ' ') dspwrite(12);
		  return c;
		}
	}
	return 0;
}
#else 

/* code for low memory simple display access */

/* buffer access functions - stubs for displays without buffer */
dspbuffer_t dspget(uint16_t i) { return 0; }
dspbuffer_t dspgetrc(uint8_t r, uint8_t c) { return 0; }
dspbuffer_t dspgetc(uint8_t c) { return 0; }

void dspsetxy(dspbuffer_t ch, uint8_t c, uint8_t r) {
  if (ch != 0) dspprintchar(ch, c, r); else dspprintchar(' ', c, r);
}

void dspset(uint16_t i, dspbuffer_t ch) {
  uint8_t c=i%dsp_columns;
  uint8_t r=i/dsp_columns;
  dspsetxy(ch, c, r);
}

/* unbuffered display, the only thing we can do is go home */
void dspbufferclear() {
  dspmyrow=0;
  dspmycol=0;
}

/* no scroll no wait */
char dspwaitonscroll() { return 0; }

/* a stub for dspwrite */
void dspscroll(uint8_t scroll_rows, uint8_t scroll_top=0){
  dspmyrow=dsp_rows-1;
}

/* no scroll without buffer */
void dspsetscrollmode(uint8_t c, uint8_t l) {}
void dspreversescroll(uint8_t a){}
#endif

/* the generic write function for displays with and without buffers */
void dspwrite(char c){
int8_t dspmycolt;

/* on escape call the vt52 state engine, it modifies the character */
#ifdef HASVT52
  if (dspesc) { 
    dspvt52(&c); 
  }
#endif

/* do we print? */
#ifdef ARDUINOPRT
  if (dspprintmode) {
    prtwrite(c);
    if (sendcr && c == 10) prtwrite(13); /* some printers want cr */
    if (dspprintmode == 2) return; /* do not print in mode 2 */
  }
#endif 
  
/* the buildin control characters for all displays */
  switch(c) {
    case 0:
      return;
    case 7: // the function dspbell() is not implemented.
      dspbell();
      return;
    case 9: // tab moves on 8 positions
      dspmycolt = dspmycol/8;
      if ((dspmycolt+1)*8<dsp_columns-1) dspmycol=(dspmycolt+1)*8;
      return;
    case 10: // this is LF Unix style doing also a CR
      dspmyrow++;
      if (dspmyrow >= dsp_rows) dspscroll(dsp_scroll_rows);  
      dspmycol=0;
      if (dspupdatemode == 1) dspupdate();
      return;
    case 11: // vertical tab - converted to line feed without carriage return
      if (dspmyrow < dsp_rows-1) dspmyrow++;
      return; 
    case 12: // form feed is clear screen plus home
      dspbufferclear();
      dspclear();
      return;
    case 13: // classical carriage return, no form feed 
      dspmycol=0;
      return;
    case 27: // escape - initiate vtxxx mode
      dspesc=1;
      return;
    case 28: // cursor back - this is what terminal applications send for cursor back
      if (dspmycol > 0) dspmycol--;
      return;
    case 29: // cursor forward - this is what terminal applications send for cursor back
      if (dspmycol < dsp_columns-1) dspmycol++;
      return;
    case 8:   // back space is delete the moment
    case 127: // delete
      if (dspmycol > 0) {
        dspmycol--;
        dspsetxy(0, dspmycol, dspmyrow);
      }
      return;
    case 2: // we abuse start of text as a home sequence, may also be needed for Epaper later
      dspmycol=dspmyrow=0;
      return;
    case 3: //  ETX = Update display for buffered display like Epaper 
      dspupdate();
      return;
    default: // eliminate all non printables - problematic for LCD special character
      if (c<32) return;
      break;
  }
  
  dspsetxy(c, dspmycol, dspmyrow);
  dspmycol++;
  if (dspmycol == dsp_columns) {
    if (!dspwrap) { /* we simply ignore the cursor */
      dspmycol=0;
      dspmyrow=(dspmyrow + 1);
    }
    if (dspmyrow >= dsp_rows) dspscroll(dsp_scroll_rows); 
  }
  if (dspupdatemode == 0) dspupdate();
}

/* 
 * This is the minimalistic VT52 state engine. It is an interface to 
 * process single byte control sequences of the form <ESC> char 
 */
 
#ifdef HASVT52
/* the state variable */
char vt52s = 0;

/* the graphics mode mode - unused so far */
uint8_t vt52graph = 0;

/* the secondary cursor */
uint8_t vt52mycol = 0;
uint8_t vt52myrow = 0;

/* temp variables for column and row , do them here and not in the case: guess why */
uint8_t vt52tmpr;
uint8_t vt52tmpc;

/* an output buffer for the vt52 terminal */
const uint8_t vt52buffersize = 4; 
char vt52outbuffer[vt52buffersize] = { 0, 0, 0, 0 };
uint8_t vt52bi = 0;
uint8_t vt52bj = 0;

/* the reader from the buffer */
char vt52read() {
  if (vt52bi<=vt52bj) { vt52bi = 0; vt52bj = 0; } /* empty, reset */
  if (vt52bi>vt52bj) return vt52outbuffer[vt52bj++];
  return 0;
}

/* the avail from the buffer */
uint8_t vt52avail() { if (vt52bi > vt52bj) return vt52bi-vt52bj; else return 0; }

/* putting something into the buffer */
void vt52push(char c) {
  if (vt52bi < vt52buffersize) vt52outbuffer[vt52bi++]=c; 
}

/* clear the buffer */
void vt52clear() {
  vt52bi=0;
}

/* something little */
uint8_t vt52number(char c) {
  uint8_t b=c;
  if (b>31) return b-32; else return 0;
}

/*
 * The VT52 data registers for the graphics and wiring extension.
 * x,y are 14 bit and z is 7bit. Data is transferred in VT52 style
 * -> numerical value plus 32 to map the data to printable characters
 * Access is done through the the ESC x, ESC y and ESC z sequences:
 * ESC x #1 #2 
 * sets the xregister to (#1-32)+(#2-32)*128
 */

#if defined(DISPLAYHASGRAPH) || defined(VT52WIRING)
#define VT52HASREGISTERS
/* the three register variables */
uint16_t vt52regx = 0;
uint16_t vt52regy = 0;
uint8_t  vt52regz = 0;

/* one argument cache for two byte arguments */
uint8_t vt52arg = 0;
#endif

/* 
 * graphics code in VT52, if you want to control graphics from the character stream 
 * The ESC g <ch> sequence sends a graphics command as the second byte after the g
 * 
 * Valid values for g are
 *  s: set the graphics cursor
 *  p: plot a point
 *  l: draw a line
 *  L: draw a line and move the cursor to the endpoint
 *  r: draw a rectangle
 *  R: draw a filled rectangle
 *  c: draw a circle
 *  C: draw a filled circle
 * 
 */
#ifdef DISPLAYHASGRAPH
/* the grahics cursor of VT52 */
uint16_t vt52graphx = 0;
uint16_t vt52graphy = 0;

/* execute one graphics command */
void vt52graphcommand(uint8_t c) {
  switch(c) {
    case 's': /* set the cursor */
      vt52graphx=vt52regx;
      vt52graphy=vt52regy;
      break;
    case 'p': /* plot a point at the cursor */
      plot(vt52graphx, vt52graphy);
      break;
    case 'l': /* plot a line */
      line(vt52graphx, vt52graphy, vt52regx, vt52regy);
      break;
    case 'L': /* plot a line and update the cursor, needed for drawing shapes */
      line(vt52graphx, vt52graphy, vt52regx, vt52regy);
      vt52graphx=vt52regx;
      vt52graphy=vt52regy;
      break;
    case 'r': /* plot a rectangle */
      rect(vt52graphx, vt52graphy, vt52regx, vt52regy);
      break;
    case 'c': /* plot a circle */
      circle(vt52graphx, vt52graphy, vt52regx);
      break;
    case 'R': /* plot a filled rectangle */
      frect(vt52graphx, vt52graphy, vt52regx, vt52regy);
      break;
    case 'C': /* plot a filled circle */
      fcircle(vt52graphx, vt52graphy, vt52regx);
      break;
  }  
}
#endif

/* 
 * This is an odd part of the vt52 code with this, the terminal 
 * can control the digital and analog pins.
 */

#ifdef VT52WIRING
#define VT52HASREGISTERS
  void vt52wiringcommand(uint8_t c) {
    switch(c) { 
      case 'p': /* pinMode z */
        pinMode(vt52regz, vt52regx);
        break;
      case 'l': /* digital write low pin z*/
        digitalWrite(vt52regz, LOW);
        break;
      case 'h': /* digital write high pin z*/
        digitalWrite(vt52regz, HIGH);
        break;
      case 'r': /* digital read from pin z */
        vt52push(digitalRead(vt52regz)+32);
        break;      
      case 'a': /* analog write pin z to value x */
        analogWrite(vt52regz, vt52regx);
        break;
      case 'A': /* analog read from pin z */
        break;
      case 't': /* tone at pin z, frequency x, duration y */
        tone(vt52regz, vt52regx, vt52regy);
        break;
    }  
  }
#endif


/* the actual vt52 state engine */
void dspvt52(char* c){
  
/* reading and processing multi byte commands */
  switch (vt52s) {
    case 'Y':
      if (dspesc == 2) { 
        dspsetcursory(vt52number(*c));
        dspesc=1; 
        *c=0;
        return;
      }
      if (dspesc == 1) { 
        dspsetcursorx(vt52number(*c)); 
        *c=0; 
      }
      vt52s=0; 
      break;
    case 'b':
      dspsetfgcolor(vt52number(*c));
      *c=0;
      vt52s=0;
      break;
    case 'c':
      dspsetbgcolor(vt52number(*c));
      *c=0;
      vt52s=0;
      break;
#ifdef VT52HASREGISTERS
    case 'x':
      if (dspesc == 2) { 
        vt52arg=vt52number(*c);
        dspesc=1; 
        *c=0;
        return;
      }
      if (dspesc == 1) { 
        vt52regx=vt52arg+vt52number(*c)*128;
        *c=0; 
      }
      vt52s=0; 
      break;
    case 'y':
      if (dspesc == 2) { 
        vt52arg=vt52number(*c);
        dspesc=1; 
        *c=0;
        return;
      }
      if (dspesc == 1) { 
        vt52regy=vt52arg+vt52number(*c)*127;
        *c=0; 
      }
      vt52s=0; 
      break;
    case 'z':
      vt52regz=vt52number(*c);
      *c=0;
      vt52s=0;
      break;
#endif
#ifdef DISPLAYHASGRAPH
    case 'g':
      vt52graphcommand(*c);
      *c=0;
      vt52s=0;
      break;      
#endif
#ifdef VT52WIRING
    case 'a':
      vt52wiringcommand(*c);
      *c=0;
      vt52s=0;
      break; 
#endif
  }
 
/* commands of the terminal in text mode */
  
  switch (*c) {
    case 'v': /* GEMDOS / TOS extension enable wrap */
      dspwrap=0;
      break;
    case 'w': /* GEMDOS / TOS extension disable wrap */
      dspwrap=1;
      break;
    case '^': /* Printer extensions - print on */
      dspprintmode=1;
      break;
    case '_': /* Printer extensions - print off */
      dspprintmode=0;
      break;
    case 'W': /* Printer extensions - print without display on */
      dspprintmode=2;
      break;
    case 'X': /* Printer extensions - print without display off */
      dspprintmode=0;
      break;
    case 'V': /* Printer extensions - print cursor line */
#if defined(ARDUINOPRT) && defined(DISPLAYCANSCROLL)
      for (uint8_t i=0; i<dsp_columns; i++) prtwrite(dspgetc(i));
#endif
      break;
    case ']': /* Printer extension - print screen */
#if defined(ARDUINOPRT) && defined(DISPLAYCANSCROLL)
      for (uint8_t j=0; j<dsp_rows; j++)
        for (uint8_t i=0; i<dsp_columns; i++) prtwrite(dspgetrc(j, i));
#endif
      break;
    case 'F': /* enter graphics mode */
      vt52graph=1;
      break;
    case 'G': /* exit graphics mode */
      vt52graph=0;
      break;
    case 'Z': // Ident 
      vt52clear();
      vt52push(27);
      vt52push('/');
#ifndef ARDUINOPRT
      vt52push('K');
#else
      vt52push('L');
#endif
      break;
    case '=': // alternate keypad on 
    case '>': // alternate keypad off 
      break;
    case 'b': // GEMDOS / TOS extension text color 
    case 'c': // GEMDOS / TOS extension background color 
      vt52s=*c;
      dspesc=1;
      *c=0;
      return;
    case 'e': // GEMDOS / TOS extension enable cursor
      dspsetcursor(1);
      break;
    case 'f': // GEMDOS / TOS extension disable cursor 
      dspsetcursor(0);
      break;
    case 'p': // GEMDOS / TOS extension reverse video 
      dspsetreverse(1);
      break;
    case 'q': // GEMDOS / TOS extension normal video 
      dspsetreverse(0);
      break;
    case 'A': // cursor up
      if (dspmyrow>0) dspmyrow--;
      break;
    case 'B': // cursor down 
      if (dspmyrow < dsp_rows-1) dspmyrow++;
      break;
    case 'C': // cursor right 
      if (dspmycol < dsp_columns-1) dspmycol++;
      break; 
    case 'D': // cursor left 
      if (dspmycol>0) dspmycol--;
      break;
    case 'E': // GEMDOS / TOS extension clear screen 
      dspbufferclear();
      dspclear();
      break;
    case 'H': // cursor home 
      dspmyrow=dspmycol=0;
      break;  
    case 'Y': // Set cursor position 
      vt52s='Y';
      dspesc=2;
      *c=0;
      return;
    case 'J': // clear to end of screen 
      for (int i=dspmycol+dsp_columns*dspmyrow; i<dsp_columns*dsp_rows; i++) dspset(i, 0);
      break;
    case 'd': // GEMDOS / TOS extension clear to start of screen 
      for (int i=0; i<dspmycol+dsp_columns*dspmyrow; i++) dspset(i, 0);
      break;
    case 'K': // clear to the end of line
      for (uint8_t i=dspmycol; i<dsp_columns; i++) dspsetxy(0, i, dspmyrow);
      break;
    case 'l': // GEMDOS / TOS extension clear line 
      for (uint8_t i=0; i<dsp_columns; i++) dspsetxy(0, i, dspmyrow);
      break;
    case 'o': // GEMDOS / TOS extension clear to start of line
      for (uint8_t i=0; i<=dspmycol; i++) dspsetxy(0, i, dspmyrow);
      break;
    case 'k': // GEMDOS / TOS extension restore cursor
      dspmycol=vt52mycol;
      dspmyrow=vt52myrow;
      break;
    case 'j': // GEMDOS / TOS extension save cursor
      vt52mycol=dspmycol;
      vt52myrow=dspmyrow;
      break;
    case 'I': // reverse line feed
      if (dspmyrow>0) dspmyrow--; else dspreversescroll(0);
      break;
    case 'L': // Insert line
      dspreversescroll(dspmyrow);
      break;
    case 'M': 
      vt52tmpr = dspmyrow;
      vt52tmpc = dspmycol;
      dspscroll(1, dspmyrow);
      dspmyrow=vt52tmpr;
      dspmycol=vt52tmpc;
      break;
#ifdef VT52HASREGISTERS
    case 'x': // set the x register 
    case 'y': // set the y register 
      vt52s=*c;
      dspesc=2;
      *c=0;
      return;
    case 'z': // set the z register
      vt52s=*c;
      dspesc=1;
      *c=0;
      return;
      break;
#endif   
#ifdef DISPLAYHASGRAPH 
    case 'g': // execute a graphics command 
      vt52s=*c;
      dspesc=1;
      *c=0;
      return;
      break;
#endif
#ifdef VT52WIRING
    case 'a': // execute a wiring command
      vt52s=*c;
      dspesc=1;
      *c=0;
      return;
      break;
#endif
  }
  dspesc=0;
  *c=0;
}
#endif

#else
#ifdef GRAPHDISPLAYDRIVER
/* a super simple display driver for graphics only systems, only handles drawing 
  and graphics cursor stuff, experimental for epapers */
#undef HASVT52
#define GBUFFERSIZE 80
static char gbuffer[GBUFFERSIZE];
void dspouts(char* s, uint16_t l) {
  int i;
  for (i=0; i<l-1 && i<GBUFFERSIZE-1; i++) gbuffer[i]=s[i];
  gbuffer[i]=0;
  dspprintstring(gbuffer);
}
/* single character handling is triggered by PUT, it controls cursor movement */
void dspwrite(char c) {
  switch(c) {
    case 0:
      return;
    case 10: // this is LF Unix style doing also a CR
      dspgraphcursor_x=0;
    case 11: // vertical tab - converted to line feed without carriage return
      dspgraphcursor_y+=dspfontsize;
      return; 
    case 12: // form feed is clear screen plus home
      dspclear();
    case 2: // we abuse start of text as a home sequence, may also be needed for Epaper later
      dspgraphcursor_x=0;
      dspgraphcursor_y=dspfontsize;
      return;
    case 13: // classical carriage return, no form feed, we stay in the same line
      dspgraphcursor_x=0;
      return;
    default: // eliminate all non printables
      if (c<32) return;
      break;
  }
  dspouts(&c, 1);
}
int dspstat(char c) { return 1; }
int dspgetcursorx() { return dspgraphcursor_x; }
int dspgetcursory() { return dspgraphcursor_y; }
void dspsetcursorx(int v) { dspgraphcursor_x = v; }
void dspsetcursory(int v) { dspgraphcursor_y = v; } 
char dspwaitonscroll() { return 0; };
uint8_t dspactive() {return 1; }
void dspsetupdatemode(uint8_t c) {}
#else
/* stubs for systems without a display driver, BASIC uses these functions */
const int dsp_rows=0;
const int dsp_columns=0;
void dspsetupdatemode(uint8_t c) {}
void dspwrite(char c){};
void dspbegin() {};
uint8_t dspstat(uint8_t c) {return 0; }
char dspwaitonscroll() { return 0; };
uint8_t dspactive() {return 0; }
void dspsetscrollmode(uint8_t c, uint8_t l) {}
void dspscroll(uint8_t a, uint8_t b){}
char vt52read() { return 0; }
uint8_t vt52avail() { return 0; }
#endif
#endif

/* 
 * Real time clock access for the system. See runtime.h for the
 * configuration of the clock access. 
 */

#if defined(ARDUINORTC)
/*
 * I2C clocks DS1307, DS3231, and DS3232 using Wire directly
 * no buffering of values, access directly to the clock registers
 */

/* No begin method needed */
void rtcbegin() {}

/* get the time from the registers */
uint16_t rtcget(uint8_t i) {
  
    /* set the address of the read */
    wirestart(RTCI2CADDR, 0);
    wirewritebyte(i);
    wirestop();

    /* now read */
    wirestart(RTCI2CADDR, 1);
    uint8_t v=wirereadbyte();
    
    switch (i) {
    case 0: 
    case 1:
      return (v & 0b00001111)+((v >> 4) & 0b00000111) * 10;      
    case 2:
      return (v & 0b00001111)+((v >> 4) & 0b00000011) * 10 ; /* only 24 hour support */
    case 3:
      return (v & 0b00001111);
    case 4:
      return (v & 0b00001111) + ((v >> 4) & 0b00000011) * 10;
    case 5:
      return (v & 0b00001111) + ((v >> 4) & 0b00000001) * 10;
    case 6:
      return (v & 0b00001111) + (v >> 4) * 10;
    default:
      return v;
   }
}

/* set the registers */
void rtcset(uint8_t i, uint16_t v) { 
  uint8_t b;

  /* to bcd if we deal with a clock byte (0-6) */
  if (i<7) b=(v%10 + ((v/10) << 4)); else b=v;
   
  switch (i) {
    case 0: 
    case 1:  
      b = b & 0b01111111; 
      break; 
    case 2:
    case 4:
      b = b & 0b00111111; /* only 24 hour support */
      break;
    case 3:
      b = b & 0b00000111;
      break;
    case 5:
      b = b & 0b00011111;
   }

/* send the address and then the byte */
    wirestart(RTCI2CADDR, 0);
    wirewritebyte(i);
    wirewritebyte(b);
    wirestop();

}
#elif defined(HASBUILTINRTC) 
/*
 * Built-in clocks of STM32 and MKR are based on the RTCZero interface
 * an rtc object is created after loading the libraries
 * for NRENESAs the interface is slightly different
 */
#ifndef ARDUINO_ARCH_RENESAS
/* begin method */
void rtcbegin() {
  rtc.begin(); /* 24 hours mode */ 
}

/* get the time */
uint16_t rtcget(uint8_t i) { 
    switch (i) {
    case 0: 
      return rtc.getSeconds();
    case 1:
      return rtc.getMinutes();      
    case 2:
      return rtc.getHours();
    case 3:
      // return rtc.getWeekDay();
      return 0;
    case 4:
      return rtc.getDay();
    case 5:
      return rtc.getMonth();
    case 6:
      return rtc.getYear();
    default:
      return 0;
   }
}

/* set the time */
void rtcset(uint8_t i, uint16_t v) { 
  switch (i) {
    case 0: 
      rtc.setSeconds(v);
      break;
    case 1: 
      rtc.setMinutes(v);
      break;    
    case 2:
      rtc.setHours(v);
      break;
    case 3:
      // rtc.setWeekDay(v);
      break;
    case 4:
      rtc.setDay(v);
      break;
    case 5:
      rtc.setMonth(v);
      break;
    case 6:
      rtc.setYear(v);
      break;
    default:
      return; 
   }
}
#else 
/* NRENESA code, interface different to my great ennui! */
/* begin method */
void rtcbegin() {
  RTC.begin(); /* 24 hours mode */ 
}

/* get the time */
uint16_t rtcget(uint8_t i) { 
    RTC.getTime(rtc);
    switch (i) {
    case 0: 
      return rtc.getSeconds();
    case 1:
      return rtc.getMinutes();      
    case 2:
      return rtc.getHour();
    case 3:
      return static_cast<int>(rtc.getDayOfWeek());
    case 4:
      return rtc.getDayOfMonth();
    case 5:
      return Month2int(rtc.getMonth());
    case 6:
      return rtc.getYear();
    default:
      return 0;
   }
}

/* set the time */
void rtcset(uint8_t i, uint16_t v) { 
  RTC.getTime(rtc);
  switch (i) {
    case 0: 
      rtc.setSecond(v);
      break;
    case 1: 
      rtc.setMinute(v);
      break;    
    case 2:
      rtc.setHour(v);
      break;
    case 3:
      rtc.setDayOfWeek(static_cast<DayOfWeek>(v));
      break;
    case 4:
      rtc.setDayOfMonth(v);
      break;
    case 5:
      rtc.setMonthOfYear(static_cast<Month>(v-1));
      break;
    case 6:
      rtc.setYear(v);
      break;
    default:
      return; 
   }
   RTC.setTime(rtc);
}
#endif
#elif defined(ARDUINORTCEMULATION)
/* 
 * A millis() based real time clock emulation. It creates a 32bit Unix time 
 * variable and adds millis()/1000 
 */

/* the begin method - standard interface to BASIC*/
void rtcbegin() {}

/* the current unix time - initialized to the begin of the epoch */
long rtcutime = 0; 

/* the offset of millis()/1000 when we last set the clock */
long rtcutimeoffset = 0;

/* the current unix date - initialized to the begin of the epoch */
struct { uint8_t second; uint8_t minute; uint8_t hour; uint8_t weekday; uint8_t day; uint8_t month; uint16_t year; } 
  rtctime = { 0, 0, 0, 4, 1, 1, 1970 };

/* the number of days per month */
const int rtcmonthdays[12] = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};


/* convert the time to a unix time number from https://de.wikipedia.org/wiki/Unixzeit  */
void rtctimetoutime() {
  int leapyear = ((rtctime.year-1)-1968)/4 - ((rtctime.year-1)-1900)/100 + ((rtctime.year-1)-1600)/400;
  long epochdays = (rtctime.year-1970)*365 + leapyear + rtcmonthdays[rtctime.month-1] + rtctime.day - 1;
  if ((rtctime.month > 2) && (rtctime.year%4 == 0 && (rtctime.year%100 != 0 || rtctime.year%400 == 0))) epochdays+=1;
  rtcutime = rtctime.second + 60*(rtctime.minute + 60*(rtctime.hour + 24*epochdays));
}

/* convert the unix time to time and date from https://de.wikipedia.org/wiki/Unixzeit */
void rtcutimetotime() {
  const unsigned long int secondsperday   =  86400ul; /*  24* 60 * 60 */
  const unsigned long int daysperyear     =    365ul; /* no leap year */
  const unsigned long int daysinfoury     =   1461ul; /*   4*365 +   1 */
  const unsigned long int daysinhundredy  =  36524ul; /* 100*365 +  25 - 1 */
  const unsigned long int daysinfourhundredy = 146097ul; /* 400*365 + 100 - 4 + 1 */
  const unsigned long int daynumberzero      = 719468ul; /* day number of March, 1 1970 */
  
  unsigned long int daynumber = daynumberzero + rtcutime/secondsperday;
  unsigned long int secondssincemidnight = rtcutime%secondsperday;
  unsigned long int temp;

  /* the weekday is based in the daynumber since March, 1, 1970 a SUNDAY */
  rtctime.weekday = daynumber % 7;

  /* leap years of the Gregorian calendar */
  temp = 4 * (daynumber + daysinhundredy + 1) / daysinfourhundredy - 1;
  rtctime.year = 100 * temp;
  daynumber -= daysinhundredy * temp + temp / 4;

  /* leap years of the Julian calendar */
  temp = 4 * (daynumber + daysperyear + 1) / daysinfoury - 1;
  rtctime.year += temp;
  daynumber -= daysperyear * temp + temp / 4;

  /* calculate day and month, reference March 1 */
  rtctime.month = (5 * daynumber + 2) / 153;
  rtctime.day = daynumber - (rtctime.month * 153 + 2) / 5 + 1;

  /* recalulate to a normal year */
  rtctime.month += 3;
  if (rtctime.month > 12) {
    rtctime.month -= 12;
    rtctime.year++;
  }

  /* calculate hours, months, seconds */
    rtctime.hour  = secondssincemidnight / 3600;
    rtctime.minute = secondssincemidnight % 3600 / 60;
    rtctime.second = secondssincemidnight % 60;
}

/* get the time elements -> standard interface to BASIC */
uint16_t rtcget(uint8_t i) { 
/* add to the last time we set the clock and subtract the offset*/
  rtcutime = millis()/1000 + rtcutimeoffset;
/* calulate the time data */
  rtcutimetotime();

  switch (i) {
    case 0: 
      return rtctime.second;
    case 1:
      return rtctime.minute;      
    case 2:
      return rtctime.hour;
    case 3:
      return rtctime.weekday;
    case 4:
      return rtctime.day;
    case 5:
      return rtctime.month;
    case 6:
      return rtctime.year;
    default:
      return 0;
   }
}

/* set the time elements -> standard interface to BASIC */
void rtcset(uint8_t i, uint16_t v) {
/* how much time has elapsed since we last set the clock */
  rtcutime = millis()/1000 + rtcutimeoffset;

/* generate the time structure */
  rtcutimetotime();

/* set the clock */
  switch (i) {
    case 0: 
      if (v>=0 && v<60) rtctime.second=v;
      break;
    case 1:
      if (v>=0 && v<60) rtctime.minute=v;
      break;     
    case 2:
      if (v>=0 && v<24) rtctime.hour=v;
      break;
    case 3:
      if (v>=0 && v<7) rtctime.weekday=v;
      break;
    case 4:
      if (v>0 && v<32) rtctime.day=v;
      break;
    case 5:
      if (v>0 && v<13) rtctime.month=v;
      break;
    case 6:
      if (v>=1970 && v<2100) rtctime.year=v;
      break;
    default:
      return;
   }

 /* recalulate the right offset by first finding the second value of the new date*/
  rtctimetoutime();
  
/* remember when we set the clock */
  rtcutimeoffset = rtcutime - millis()/1000;  
}
#elif defined(ARDUINO_ARCH_ESP32) || defined(ARDUINO_ARCH_MBED_GIGA)
/* 
 * On ESP32 we use the builtin clock, this is a generic Unix time mechanism equivalent
 * to the code in hardware-posix.h. The code works also for the GIGA which is surprising!
 */

/* no begin needed */
void rtcbegin() {}

/* get the time */
uint16_t rtcget(uint8_t i) { 
  struct tm rtctime;
  time_t now;
  time(&now);
  localtime_r(&now, &rtctime);

  switch (i) {
    case 0: 
      return rtctime.tm_sec;
    case 1:
      return rtctime.tm_min;      
    case 2:
      return rtctime.tm_hour;
    case 3:
      return rtctime.tm_wday;
    case 4:
      return rtctime.tm_mday;
    case 5:
      return rtctime.tm_mon+1;
    case 6:
      if (rtctime.tm_year > 100) return rtctime.tm_year-100; else return rtctime.tm_year;
    default:
      return 0;
  }

  return 0; 
}

/* set the time */
void rtcset(uint8_t i, uint16_t v) { 
  struct tm rtctime;
  struct timeval tv;

  /* get the time stucture from the system */
  time_t now;
  time(&now);
  localtime_r(&now, &rtctime);

  /* change what needs to be changed */
  switch (i) {
    case 0: 
      rtctime.tm_sec = v%60;
      break;
    case 1:
      rtctime.tm_min = v%60; 
      break;     
    case 2:
      rtctime.tm_hour = v%24;
      break;
    case 3:
      rtctime.tm_wday = v%7;
      break;
    case 4:
      rtctime.tm_mday = v;
      break;
    case 5:
      rtctime.tm_mon = v-1;
      break;
    case 6:
      if (v > 1900) v=v-1900; /* get years to the right value */
      if (v < 50) v=v+100; 
      rtctime.tm_year = v;
      break;
  }

  /* calculate the seconds and put it back*/
  time_t epocht = mktime(&rtctime);
  if (epocht > 2082758399){
    tv.tv_sec = epocht - 2082758399;  
  } else {
    tv.tv_sec = epocht;  
  }
  tv.tv_usec = 0;
  settimeofday(&tv, NULL);
}
#else
/* no clock at all, no operations */
void rtcbegin() {}
uint16_t rtcget(uint8_t i) { return 0; }
void rtcset(uint8_t i, uint16_t v) { }
#endif

/* 
 * External EEPROM as a filesystem is handled through an EFS filesystem 
 * object, see https://github.com/slviajero/EepromFS  for details. 
 * Here the most common parameters are set as a default.
 * The EFS library is now part of the interpreter runtime.
 */

#ifdef ARDUINOEFS
#undef ARDUINOI2CEEPROM
#ifndef EFSEEPROMADDR
#define EFSEEPROMADDR 0x50
#endif
#ifdef EFSEEPROMSIZE
EepromFS EFS(EFSEEPROMADDR, EFSEEPROMSIZE);
#else
EepromFS EFS(EFSEEPROMADDR);
#endif
#endif

/* 
 * External EEPROM is also handled through an EFS filesystem object 
 * in raw mode. This handles buffering with a minium of ram. 
*/

#if defined(ARDUINOI2CEEPROM) && defined(ARDUINOI2CEEPROM_BUFFERED)
#ifndef I2CEEPROMADDR
#define I2CEEPROMADDR 0x50
#endif
#ifdef I2CEEPROMSIZE
EepromFS EFSRAW(I2CEEPROMADDR, I2CEEPROMSIZE);
#else
EepromFS EFSRAW(I2CEEPROMADDR);
#endif
#endif

/*
 * definitions for ESP Wifi and MQTT, super experimental.
 * As networking is only used for MQTT at the moment, 
 * mqtt, Wifi and Ethernet comes all in one. 
 *
 * No encryption/authetication is implemented in MQTT. 
 * Only public, open servers can be used.
 *
 * MQTT topics can only be 32 bytes long.
 * Buffered incoming and outgoing messages can be 128 bytes
 * per default.
 *
 * wifisettings.h is the generic network definition file
 * all network settings are compiled into the code 
 * BASIC cannot change them at runtime.
 */
#ifdef ARDUINOMQTT
#include "wifisettings.h"
#ifdef ARDUINOETH
EthernetClient bethclient;
PubSubClient bmqtt(bethclient);
#else
WiFiClient bwifi;
PubSubClient bmqtt(bwifi);
#endif

/* the buffers of the outgoing and incoming MQTT topic, they are char!! */ 
char mqtt_otopic[MQTTLENGTH];
char mqtt_itopic[MQTTLENGTH];

/* 
 * the buffers for MQTT messages, input and output goes 
 * through these static buffers. 
 */

volatile char mqtt_buffer[MQTTBLENGTH];
volatile uint16_t mqtt_messagelength;
volatile char mqtt_obuffer[MQTTBLENGTH];
volatile uint16_t mqtt_charsforsend;

/* the name of the client, generated pseudo randomly to avoind 
		naming conflicts */
char mqttname[MQTTNAMELENGTH] = "iotbasicxxx";
void mqttsetname() {
	uint32_t m = millis();
	mqttname[8]=(char)(65+m%26);
	m=m/26;
	mqttname[9]=(char)(65+m%26);
	m=m/26;
	mqttname[10]=(char)(65+m%26);
}

/* 
 *	network begin method 
 *	needs the settings from wifisettings.h
 * 
 * Default is right now that Wifi is started at boot
 * This may change in the future.
 * 
 * Ethernet begin has to be reviewed to avoid DHCP 
 * start timeout if network is not connected
 */
void netbegin() {
#ifdef ARDUINOETH
#ifdef ETHPIN
  Ethernet.init(ETHPIN);
#endif
  Ethernet.begin(mac);
#else  
#if defined(ARDUINO_ARCH_ESP32) || defined(ARDUINO_ARCH_ESP8266)
	WiFi.mode(WIFI_STA);
	WiFi.begin(ssid, password);
	WiFi.setAutoReconnect(1);
#endif
#if defined(ARDUINO_ARCH_RP2040) || defined(ARDUINO_ARCH_SAMD) || defined(ARDUINO_UNOR4_WIFI)
	WiFi.begin(ssid, password);
#endif
#if defined(ARDUINO_ARCH_MBED_GIGA)
  int counter=0;
  int status=WL_IDLE_STATUS;
  while (status != WL_CONNECTED && counter++ < 10) {
    status=WiFi.begin(ssid, password);
    bdelay(500);  
  }
#endif
#endif
}

/*
 * network stop methode, needed sometime to reinit networking
 * completely or to save power
 * 
 */
void netstop() {
#ifdef ARDUINOETH
/* to be done */
#else  
#if defined(ARDUINO_ARCH_ESP32) || defined(ARDUINO_ARCH_ESP8266)
  WiFi.mode(WIFI_OFF);
#endif
#if defined(ARDUINO_ARCH_RP2040) || defined(ARDUINO_ARCH_SAMD) || defined(ARDUINO_UNOR4_WIFI) || defined(ARDUINO_ARCH_MBED_GIGA)
  WiFi.end();
#endif
#endif
}

/*
 * network reconnect methode
 * 
 */
void netreconnect() {
#ifdef ARDUINOETH
/* */
#else 
#if defined(ARDUINO_ARCH_ESP32) || defined(ARDUINO_ARCH_ESP8266)
  WiFi.reconnect(); 
  bdelay(1000); 
#elif defined(ARDUINO_ARCH_SAMD) || defined(ARDUINO_UNOR4_WIFI) || defined(ARDUINO_ARCH_MBED_GIGA)
/* on these platforms there is no reconnect method, we simply stop and start again */
  netstop();
  netbegin();
#endif  
#endif
}

/*
 * network connected method
 * on ESP Wifi try to reconnect, the delay is odd 
 * This is a partial reconnect, BASIC needs to handle 
 * repeated reconnects
 */
uint8_t netconnected() {
#ifdef ARDUINOETH
  return bethclient.connected();
#else
	return WiFi.status() == WL_CONNECTED;
#endif
}

/*
 * mqtt callback function, using the byte type here
 * because payload can be binary - interface to BASIC 
 * strings need to be done
 *
 * mqtt event handling in BASIC can be triggered here
 * we leave the types Arduino style
 */
void mqttcallback(char* t, byte* p, unsigned int l) {
	short i;
	mqtt_messagelength=l;
	for(i=0; i<l; i++) mqtt_buffer[i]=(char)p[i];
}

/*
 * starting mqtt 
 * set the server, register the callback and purge all topics
 */
void mqttbegin() {
	bmqtt.setServer(mqtt_server, mqtt_port);
	bmqtt.setCallback(mqttcallback);
	*mqtt_itopic=0;
	*mqtt_otopic=0;
	mqtt_charsforsend=0;
}

/* the interface to the usr function */
uint8_t mqttstat(uint8_t c) {
#if defined(ARDUINOMQTT)
  if (c == 0) return 1;
  if (c == 1) return mqttstate();
#endif
  return 0; 
}

/*
 * reconnecting mqtt - exponential backoff here 
 * exponental backoff reconnect in 10 ms * 2^n intervals
 * no randomization 
 */
uint8_t mqttreconnect() {
	uint16_t timer=10;
	uint8_t reconnect=0;

/* all good and nothing to be done, we are connected */
	if (bmqtt.connected()) return 1;

/* try to reconnect the network */
  if (!netconnected()) { netreconnect(); bdelay(5000); }
  if (!netconnected()) return 0;
	
/* create a new random name right now */
	mqttsetname();

/* try to reconnect assuming that the network is connected */
	while (!bmqtt.connected() && timer < 400) {
    if (*mqtt_user == 0) {
      bmqtt.connect(mqttname);
    } else {
      bmqtt.connect(mqttname, mqtt_user, mqtt_passwd);
    }
		bmqtt.connect(mqttname);
		bdelay(timer);
		timer=timer*2;
    reconnect=1;
	}

/* after reconnect resubscribe if there is a valid topic */
	if (*mqtt_itopic && bmqtt.connected() && reconnect) bmqtt.subscribe(mqtt_itopic);
 
	return bmqtt.connected();
}

/* mqtt state information */
uint8_t mqttstate() {
	return bmqtt.state();
}

/* subscribing to a topic  */
void mqttsubscribe(const char* t) {
	uint16_t i;

	for (i=0; i<MQTTLENGTH; i++) {
		if ((mqtt_itopic[i]=t[i]) == 0 ) break;
	}
	if (!mqttreconnect()) {ioer=1; return;};
	if (!bmqtt.subscribe(mqtt_itopic)) ioer=1;
}

void mqttunsubscribe() {
	if (!mqttreconnect()) {ioer=1; return;};
	if (!bmqtt.unsubscribe(mqtt_itopic)) ioer=1;
	*mqtt_itopic=0;
}

/*
 * set the topic we pushlish, coming from OPEN
 * BASIC can do only one topic.
 * 
 */
void mqttsettopic(const char *t) {
	uint16_t i;

	for (i=0; i<MQTTLENGTH; i++) {
		if ((mqtt_otopic[i]=t[i]) == 0 ) break;
	}
}

/* 
 *	print a mqtt message 
 *  we buffer until we reach either cr or until the buffer is full
 *	this is needed to do things like PRINT A,B,C as one message
 */
void mqttouts(const char *m, uint16_t l) {
	uint16_t i=0;

	while(mqtt_charsforsend < MQTTBLENGTH && i<l) mqtt_obuffer[mqtt_charsforsend++]=m[i++];
	if (mqtt_obuffer[mqtt_charsforsend-1] == '\n' || mqtt_charsforsend > MQTTBLENGTH) {
		if (!mqttreconnect()) {ioer=1; return;};
		if (!bmqtt.publish(mqtt_otopic, (uint8_t*) mqtt_obuffer, (unsigned int) mqtt_charsforsend-1, false)) ioer=1;
		mqtt_charsforsend=0;
	}
} 

/* the write command is simple */
void mqttwrite(const char c) { mqttouts(&c, 1); }

/* return the messagelength as avail */
uint16_t mqttavailable() {
    return mqtt_messagelength;
}

/* checkch is just a dummy */
char mqttcheckch() {
    if (mqtt_messagelength>0) return mqtt_buffer[0]; else return 0;
}

/* 
 * ins copies the buffer into a basic string 
 *  - behold the jabberwock - length gynmastics 
 */
uint16_t mqttins(char *b, uint16_t nb) {
  uint16_t z;
  
	for (z=0; z<nb && z<mqtt_messagelength; z++) b[z+1]=mqtt_buffer[z];
 	b[0]=z;
 	mqtt_messagelength=0;
 	*mqtt_buffer=0;
  return z;
}

/* just one character to emulate basic get */
char mqttread() {
	char ch=0;
	uint16_t i;

	if (mqtt_messagelength>0) {
		ch=mqtt_buffer[0];
		for (i=0; i<mqtt_messagelength-1; i++) mqtt_buffer[i]=mqtt_buffer[i+1];
    mqtt_messagelength--;
	}
	
	return ch;
}

#else 
void netbegin() {}
uint8_t netconnected() { return 0; }
void mqttbegin() {}
uint8_t mqttstate() {return 0;}
void mqttsubscribe(char *t) {}
void mqttsettopic(char *t) {}
void mqttouts(char *m, uint16_t l) {}
uint16_t mqttins(char *b, uint16_t nb) { return 0; };
char mqttread() {return 0;};
#endif

/* 
 *	EEPROM handling, these function enable the @E array and 
 *	loading and saving to EEPROM with the "!" mechanism
 */ 
void ebegin(){
/* this is the EEPROM dummy */
#if (defined(ARDUINO_ARCH_ESP8266) || defined(ARDUINO_ARCH_ESP32) ) && defined(ARDUINOEEPROM)
  EEPROM.begin(EEPROMSIZE);
#endif
#if (defined(ARDUINO_ARCH_STM32)) && defined(ARDUINOEEPROM)
  eeprom_buffer_fill();
#endif
#if (defined(ARDUINO_ARCH_XMC)) && defined(ARDUINOEEPROM)
  EEPROM.begin();
#endif
#if (defined(ARDUINO_ARCH_SAMD)) && defined(ARDUINOEEPROM)
/* no begin method needed */
#endif
#if (defined(ARDUINO_ARCH_MBED_NANO)) && defined(ARDUINOEEPROM)
  EEPROM.begin();
#endif
/* an unbuffered EEPROM, typically used to store a program */
#if defined(ARDUINOI2CEEPROM) && !defined(ARDUINOI2CEEPROM_BUFFERED)
/* 
 * we test the size with a heuristic, but beware, EEPROM addressing
 * is circular. We only consider the two most common sizes, 4096 and 32768.
 * This is tricky.
 */

#ifndef I2CEEPROMSIZE
  int c4=eread(4094);
  int c32=eread(32766);
  eupdate(4094, 42);
  eupdate(32766, 84);
  if (ioer !=0 ) return;
  if (eread(32766) == 84 && eread(4094) == 42) i2ceepromsize = 32767; else i2ceepromsize = 4096;
  eupdate(4094, c4);
  eupdate(32766, c32);  
#else
  i2ceepromsize = I2CEEPROMSIZE;
#endif
#endif
/* there also can be a raw EFS object */
#if defined(ARDUINOI2CEEPROM) && defined(ARDUINOI2CEEPROM_BUFFERED)
  EFSRAW.begin();
#ifndef I2CEEPROMSIZE
  i2ceepromsize = EFSRAW.esize();
#else
  i2ceepromsize = I2CEEPROMSIZE;
#endif
#endif
} 

void eflush(){
/* code for the EEPROM dummy */
#if (defined(ARDUINO_ARCH_ESP8266) || defined(ARDUINO_ARCH_ESP32) || \
    defined(ARDUINO_ARCH_XMC) || defined(ARDUINO_ARCH_SAMD)) \
    && defined(ARDUINOEEPROM) 
  EEPROM.commit();
#endif 
#if (defined(ARDUINO_ARCH_STM32)) && defined(ARDUINOEEPROM) 
  eeprom_buffer_flush();
#endif
/* flushing the I2C EEPROM */
#if defined(ARDUINOI2CEEPROM) && defined(ARDUINOI2CEEPROM_BUFFERED)
  EFSRAW.rawflush();
#endif
}

#if defined(ARDUINOEEPROM) && !defined(ARDUINOI2CEEPROM)
uint16_t elength() { 
#if defined(ARDUINO_ARCH_ESP8266) || defined(ARDUINO_ARCH_ESP32)
  return EEPROMSIZE;
#endif
#if defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR) || defined(ARDUINO_ARCH_XMC) || \
    defined(ARDUINO_ARCH_STM32) || defined(ARDUINO_ARCH_RENESAS) || defined(ARDUINO_ARCH_SAMD)
  return EEPROM.length(); 
#endif
#ifdef ARDUINO_ARCH_LGT8F 
  return EEPROM.length();
#endif
  return 0;
}

void eupdate(uint16_t a, int8_t c) { 
#if defined(ARDUINO_ARCH_ESP8266) || defined(ARDUINO_ARCH_ESP32)|| defined(AARDUINO_ARCH_LGT8F) || \
    defined(ARDUINO_ARCH_XMC) || defined(ARDUINO_ARCH_SAMD)
  EEPROM.write(a, c);
#else
#if defined(ARDUINO_ARCH_STM32)
  eeprom_buffered_write_byte(a, c);
#else
  EEPROM.update(a, c); 
#endif
#endif
}

int8_t eread(uint16_t a) { 
#ifdef ARDUINO_ARCH_STM32
  return (int8_t) eeprom_buffered_read_byte(a); 
#else
  return (int8_t) EEPROM.read(a); 
#endif
}
#else 
#if defined(ARDUINOI2CEEPROM)
uint16_t elength() { 
  return i2ceepromsize;
}

void eupdate(uint16_t a, int8_t c) { 
#if defined(ARDUINOI2CEEPROM_BUFFERED)
  EFSRAW.rawwrite(a, c);
#else
/* go directly into the EEPROM */
  if (eread(a) != c) {
  /* set the address and send the byte*/

/*
    Wire.beginTransmission(I2CEEPROMADDR);
    Wire.write((int)a/256);
    Wire.write((int)a%256);
    Wire.write((int)c);
    ioer=Wire.endTransmission();
*/
    wirestart(I2CEEPROMADDR, 0);
    wirewritebyte((int)a/256);
    wirewritebyte((int)a%256);
    wirewritebyte((int)c);
    ioer=wirestop();

  /* wait the max time */
    bdelay(5);
  }
#endif
}

int8_t eread(uint16_t a) { 
#ifdef ARDUINOI2CEEPROM_BUFFERED
  return (int8_t) EFSRAW.rawread(a); 
#else
/* read directly from the EEPROM */

/* set the address */
  wirestart(I2CEEPROMADDR, 0);
  wirewritebyte((int)a/256);
  wirewritebyte((int)a%256);
  ioer=wirestop();
  
/* read a byte */
  if (ioer == 0) {
    wirestart(I2CEEPROMADDR, 1);
    return wirereadbyte();
  } else return 0;
 
#endif
}
#else
/* no EEPROM present */
uint16_t elength() { return 0; }
void eupdate(uint16_t a, int8_t c) { return; }
int8_t eread(uint16_t a) { return 0; }
#endif
#endif

/*
 * A set of function to directly accessing IO ports. This is 
 * hardware dependend and needs to be implemented for each
 * platform.
 *  
 * Unfinished code right now, test code for the UNO.
 */
#if defined(ARDUINO_AVR_UNO) || defined(ARDUINO_AVR_DUEMILANOVE) || defined(ARDUINO_AVR_NANO)
void portwrite(uint8_t p, int v) { 
  switch (p) {
    case 0: PORTB = v; break;
    case 1: PORTC = v; break;
    case 2: PORTD = v; break; 
    default: break;
  }
}
int portread(uint8_t p) { 
  switch (p) {
    case 0: return PORTB; break;
    case 1: return PORTC; break;
    case 2: return PORTD; break; 
    default: return 0;
  }
}
void ddrwrite(uint8_t p, int v) { 
  switch (p) {
    case 0: DDRB = v; break;
    case 1: DDRC = v; break;
    case 2: DDRD = v; break; 
    default: break;
  }
}
int ddrread(uint8_t p) { 
  switch (p) {
    case 0: return DDRB; break;
    case 1: return DDRC; break;
    case 2: return DDRD; break; 
    default: return 0;
  }
}
int pinread(uint8_t p) { 
  switch (p) {
    case 0: return PINB; break;
    case 1: return PINC; break;
    case 2: return PIND; break; 
    default: return 0;
  }
}
#else
void portwrite(uint8_t p, int v) {}
int portread(uint8_t p) { return 0; }
void ddrwrite(uint8_t p, int v) {}
int ddrread(uint8_t p) { return 0; }
int pinread(uint8_t p) { return 0; }
#endif

/* 
 *	the wrappers of the arduino io functions
 *  awrite requires ESP32 2.0.2 core, else disable awrite() 
 */ 

uint16_t aread(uint8_t p) { return analogRead(p); }
uint8_t dread(uint8_t p) { return digitalRead(p); }
void awrite(uint8_t p, uint16_t v){ analogWrite(p, v); }
void dwrite(uint8_t p, uint8_t v){ if (v) digitalWrite(p, HIGH); else digitalWrite(p, LOW); }

/* we normalize the pinMode as ESP32, ESP8266, and other boards behave rather
 *  differently. Following Arduino conventions we map 0 always to INPUT  
 *  and 1 always to OUTPUT, all the other numbers are passed through to the HAL 
 *  layer of the platform.
 *  Example: OUTPUT on ESP32 is 3 and 1 is assigned to INPUT.
 *  XMC also needs special treatment here.
 *  uint8_t is here for a reason.
 */
void pinm(uint8_t p, uint8_t m){
  if (m == 0) m=INPUT; 
  else if (m == 1) m=OUTPUT;
  pinMode(p,m);
}

/* wrapper around pulsein */
uint32_t pulsein(uint8_t pin, uint8_t val, uint32_t t) { 
  return pulseIn(pin, val, t);
}

/* write a pulse in microsecond range */
void pulseout(uint16_t unit, uint8_t pin, uint16_t duration, uint16_t val, uint16_t repetition, uint16_t interval) { 
  
  pinMode(pin, OUTPUT);
  while (repetition--) {
    digitalWrite(pin, val);
    delayMicroseconds(duration*unit);
    digitalWrite(pin, !val);
    delayMicroseconds(interval*unit);
  }
}

/* the BREAKPIN mechanism */
#if defined(BREAKPIN) && defined(INPUT_PULLUP)
void breakpinbegin() { pinm(BREAKPIN, INPUT_PULLUP); }
uint8_t getbreakpin() { return dread(BREAKPIN); } 
#else 
/* there is no pins hence no breakpin */
void breakpinbegin() {}
uint8_t getbreakpin() { return 1; } /* we return 1 because the breakpin is defined INPUT_PULLUP */
#endif


/*
 * A tone emulation based on the byield loop. The maximum frequency depends 
 * on the byield call speed. 10-20 kHz is possible. Will be unreliable if 
 * the loop functions need a lot of CPU cycles.
 */
#if defined(ARDUINOTONEEMULATION)
uint8_t tone_enabled;
uint8_t tone_pinstate = 0;
uint32_t tone_intervall;
uint32_t tone_micros;
uint16_t tone_duration;
uint32_t tone_start;
uint8_t tone_pin;

void playtone(uint8_t pin, uint16_t frequency, uint16_t duration, uint8_t volume) {

/* the pin we are using is reset every time this is called*/
  tone_pin=pin;
  pinMode(tone_pin, OUTPUT);
  digitalWrite(tone_pin, LOW);
  tone_pinstate=0;

/* duration 0 is a long tone */
  if (duration == 0) duration=32767;

/* frequency 0 stops playing */ 
  if (frequency == 0) {
    tone_enabled=0;
    return;
  }

/* calculate the toggle intervall in micros and remember where we are */
  tone_intervall=1000000/frequency/2;
  tone_micros=micros();

/* set the duration and remember where we are*/
  tone_duration=duration;
  tone_start=millis();

/* start the play */
  tone_enabled=1;
}

void tonetoggle() {

/* is this active? */
  if (!tone_enabled) return;

/* check if we are done playing */
  if (millis() > tone_duration+tone_start) {
    tone_enabled=0;
    digitalWrite(tone_pin, LOW);
    tone_pinstate=0;
    return;
  }

/* if not, check if the intervall is over */
  if (micros() > tone_intervall+tone_micros) {
    tone_micros=micros();
    tone_pinstate=!tone_pinstate;
    digitalWrite(tone_pin, tone_pinstate);
  }
}
#elif defined(ARDUINO_TTGO_T7_V14_Mini32) && defined(PS2FABLIB)
/* fabGL soundgenerator code of suggestes by testerrossa
 * pin numbers below 128 are real arduino pins while 
 * pin numvers from 128 onwards are sound generator capabilities
 * this is different from the original code
 * 
 * Sound generator capabilities are numbered as follows
 * 128: Sine wave 
 * 129: Symmetric square wave 
 * 130: Sawtooth
 * 131: Triangle
 * 132: VIC noise
 * 133: noise
 *
 * 256-511: square wave with variable duty cycle
 * 
 */
void playtone(uint8_t pin, uint16_t frequency, uint16_t duration, uint8_t volume) {

/* frequency 0 is off */
  if (frequency == 0) {
    soundGenerator.play(false);
    soundGenerator.clear();
    return;
  } 

/* duration 0 is a long tone */
  if (duration == 0) duration=60000;
  
  if (pin == 128) soundGenerator.playSound(SineWaveformGenerator(), frequency, duration, volume); 
  if (pin == 129) soundGenerator.playSound(SquareWaveformGenerator(), frequency, duration, volume);
  if (pin == 130) soundGenerator.playSound(SawtoothWaveformGenerator(), frequency, duration, volume);
  if (pin == 131) soundGenerator.playSound(TriangleWaveformGenerator(), frequency, duration, volume); 
  if (pin == 132) soundGenerator.playSound(VICNoiseGenerator(), frequency, duration, volume);
  if (pin == 133) soundGenerator.playSound(NoiseWaveformGenerator(), frequency, duration, volume);
  if (pin >= 255 && pin < 512 ) {
      pin=pin-255;
      SquareWaveformGenerator sqw;
      sqw.setDutyCycle(pin);
      soundGenerator.playSound(sqw, frequency, duration, volume); 
  }
}
#else 
/* playtone is just a wrapper around tone and noTone */
void playtone(uint8_t pin, uint16_t frequency, uint16_t duration, uint8_t volume) {
  if (frequency == 0) {
    noTone(pin);
  } else if (duration == 0) {
    tone(pin, frequency);
  } else {
    tone(pin, frequency, duration);
  }
}
#endif

/* 
 *	The byield function is called after every statement
 *	it allows two levels of background tasks. 
 *
 *	BASICBGTASK controls if time for background tasks is 
 * 	needed, usually set by hardware features
 *
 * 	YIELDINTERVAL by default is 32, generating a 32 ms call
 *		to the network loop function. 
 *
 * 	LONGYIELDINTERVAL by default is 1000, generating a one second
 *		call to maintenance functions. 
 */

uint32_t lastyield=0;
uint32_t lastlongyield=0;
int countfasttick = 0;

void byield() { 

/* the fast ticker for all fast timing functions */
  fastticker();

/* the loop function for non BASIC stuff */
  bloop();

#if defined(BASICBGTASK)
/* what time is it, call millis only once */
  long m=millis();

/* yield all 32 milliseconds */

  if (m-lastyield > YIELDINTERVAL-1) {
    yieldfunction();
    lastyield=m;
  }

/* yield every second */
  if (m-lastlongyield > LONGYIELDINTERVAL-1) {
    longyieldfunction();
    lastlongyield=m;
  }
 #endif
 
 /* call the background task scheduler on some platforms implemented in hardware-* */

}

/* delay must be implemented to use byield() while waiting */
void bdelay(uint32_t t) { 
  unsigned long i;
  if (t>0) {
    i=millis();
    while (millis() < i+t) byield();
  } 
}

/* 
 * This code measures the fast ticker frequency in microseconds 
 * It leaves the data in variable F. Activate this only for test 
 * purposes.
 */

#ifdef FASTTICKERPROFILE
int avgfastticker() {
  return countfasttick;
}

void clearfasttickerprofile() {
  countfasttick=0;
}
#endif


/* fastticker is the hook for all fast timing functions */
void fastticker() {
/* fastticker profiling test code */
#if defined(FASTTICKERPROFILE)
  countfasttick++;
#endif
/* toggle the tone pin */
#ifdef ARDUINOTONEEMULATION
  tonetoggle();
#endif
}

/* everything that needs to be done often - 32 ms */
void yieldfunction() {
#ifdef ARDUINOMQTT
  bmqtt.loop();
#endif
#ifdef ARDUINOUSBKBD
  usb.Task();
#endif
#ifdef ARDUINOZX81KBD
  (void) keyboard.peek(); /* scan once and set lastkey properly every 32 ms */
#endif
/* delay(0) is only needed on ESP8266! it calls the scheduler - no bdelay here!! */
#if defined(ARDUINO_ARCH_ESP8266)
 delay(0);
#endif
}

/* everything that needs to be done not so often - 1 second */
void longyieldfunction() {
#ifdef ARDUINOETH
  Ethernet.maintain();
#endif 
#ifdef BREAKINBACKGROUND
  if (checkch() == BREAKCHAR) breakcondition=1;
#endif
}

/* 
 *	The file system driver - all methods needed to support BASIC fs access
 * 	Different filesystems need different prefixes and fs objects, these 
 * 	filesystems use the stream API
 */

/* typical file name length */
#define FBUFSIZE 32
 
#if defined(ARDUINOSD) || defined(ESPSPIFFS) || defined(ESP32FAT) || defined(STM32SDIO) ||defined(ESPSDMMC)
File ifile;
File ofile;
char tempname[FBUFSIZE]; /* this is needed for the catalog code as these platforms do not give static C strings back */
#if defined(ARDUINOSD) || defined(STM32SDIO) ||defined(ESPSDMMC)
File root;
File file;
#ifdef ARDUINO_ARCH_ESP32
const char rootfsprefix[2] = "/";
#else
const char rootfsprefix[1] = "";
#endif
#endif
#if defined(ESPSPIFFS) || defined(ESP32FAT)
const char rootfsprefix[2] = "/";
#ifdef ARDUINO_ARCH_ESP8266
Dir root;
File file;
#endif
#ifdef ARDUINO_ARCH_ESP32
File root;
File file;
#endif
#endif
#ifdef ARDUINO_ARCH_ESP8266
/* #define FILE_OWRITE (O_READ | O_WRITE | O_CREAT | O_TRUNC) */
/* this is the ESP8266 definition for kernel 3.0, 3.1 has fixed this */
#define FILE_OWRITE (sdfat::O_READ | sdfat::O_WRITE | sdfat::O_CREAT | sdfat::O_TRUNC)
#else 
#if defined(ARDUINO_ARCH_ESP32) || defined(ARDUINO_ARCH_STM32)
#define FILE_OWRITE FILE_WRITE
#else 
#define FILE_OWRITE (O_READ | O_WRITE | O_CREAT | O_TRUNC)
#endif
#endif
#endif

/* using the POSIX API in LittleFS */
#ifdef RP2040LITTLEFS
#define FILESYSTEMDRIVER
FILE* ifile;
FILE* ofile;
DIR* root;
struct dirent* file;
LittleFS_MBED *myFS;
const char rootfsprefix[10] = MBED_LITTLEFS_FILE_PREFIX;
#endif

/* 
 * the API of the USB filesystem on GIGA and Portenta. 
 * Looks like LITTLEFS. Pointers to the objects msd and usb are used and 
 * allocation is postponed to fsbegin(). This was done to try to get the code 
 * restartable, but it doesn't really work. Still, using the pointers
 * is cleaner and more C++ish.
 */
#ifdef GIGAUSBFS
#define FILESYSTEMDRIVER
USBHostMSD* msdp;
mbed::FATFileSystem* usbp;
FILE* ifile;
FILE* ofile;
DIR* root;
struct dirent *file;
const char rootfsprefix[10] = "/usb/";
#endif

/* use EEPROM as filesystem */
#ifdef ARDUINOEFS
byte ifile;
byte ofile;
byte file;
#endif

/* the buildin file system for ro access */
#ifdef HASBUILDIN
char* buildin_ifile = 0;
uint16_t buildin_ifilepointer = 0;
char* buildin_file = 0;
char* buildin_pgm = 0;
uint8_t buildin_rootactive = 0;
uint16_t buildin_rootpointer = 0;
char buildin_tempname[FBUFSIZE]; /* this is needed for the catalog code as strings need to be copied from progmem */
#endif


/* these filesystems may have a path prefixes, we treat STM32SDIO like an SD here */
#if defined(RP2040LITTLEFS) || defined(ESPSPIFFS) || defined(ESP32FAT) || defined(ARDUINOSD) || defined(GIGAUSBFS) || defined(ESPSDMMC)
char tmpfilename[10+FBUFSIZE];

/* add the prefix to the filename */
char* mkfilename(const char* filename) {
	uint8_t i,j;
	for(i=0; i<10 && rootfsprefix[i]!=0; i++) tmpfilename[i]=rootfsprefix[i];
	tmpfilename[i++]='/';
	for(j=0; j<FBUFSIZE && filename[j]!=0; j++) tmpfilename[i++]=filename[j];
	tmpfilename[i]=0;
	return tmpfilename;
}

/* remove the prefix from the filename */
const char* rmrootfsprefix(const char* filename) {
	uint8_t i=0;
	while (filename[i] == rootfsprefix[i] && rootfsprefix[i] !=0 && filename[i] !=0 ) i++;
	if (filename[i]=='/') i++;
	return &filename[i];
}
#endif

/* 
 *	filesystem starter for SPIFFS and SD on ESP, ESP32 and Arduino plus LittleFS
 *  and then also GIGAUSBFS
 *	the verbose option needs to be checked .
 *  
 *  Also here the driver for the buildin file system.
 * 
 * if SDPIN is empty it is the standard SS pin of the platfrom
 * 
 */

uint8_t fsstart;
 
void fsbegin() {
#ifdef ARDUINOSD 
#ifndef SDPIN
#define SDPIN
#endif
  if (SD.begin(SDPIN)) fsstart=1; else fsstart=0;	
#endif
#ifdef STM32SDIO
  static int fsbegins = 0;
  while (fsbegins<100) { 
    if (SD.begin(SD_DETECT_PIN)) { fsstart=1; break; } else fsstart=0;
    bdelay(20); 
    fsbegins++;
  } 
#endif
#if defined(ESPSPIFFS) && defined(ARDUINO_ARCH_ESP8266) 
 	if (SPIFFS.begin()) fsstart=1; else fsstart=0;
#endif
#if defined(ESPSPIFFS) && defined(ARDUINO_ARCH_ESP32) 
 	if (SPIFFS.begin()) fsstart=1; else fsstart=0;
#endif
#if defined(ESP32FAT) && defined(ARDUINO_ARCH_ESP32)
  if (FFat.begin()) fsstart=1; else fsstart=0;
#endif
#if defined(ESPSDMMC) && defined(ARDUINO_ARCH_ESP32)
  if (SD_MMC.begin()) fsstart=1; else fsstart=0;
#endif
#ifdef RP2040LITTLEFS
	myFS = new LittleFS_MBED();
	if (myFS->init()) fsstart=1; else fsstart=0;
#endif
#ifdef GIGAUSBFS
  static int fsbegins = 0;
  int usbfsstat;
  if (RTDEBUG) consolelog("Starting USB file system.\n");
/* power up the USB A port */
  pinMode(PA_15, OUTPUT);
  if (RTDEBUG) consolelog("Power down USB port.\n");
  digitalWrite(PA_15, LOW); 
  bdelay(100);
  if (RTDEBUG) consolelog("Power up USB port.\n");
  digitalWrite(PA_15, HIGH);
  bdelay(100);

/* delete old objects */
  if (msdp) delete msdp;
  if (usbp) delete usbp;

 /* create the msdp and the filesystem object */ 
  msdp=new USBHostMSD();
  usbp=new mbed::FATFileSystem("usb"); 

/* connect and mount */
  while(!msdp->connect() && fsbegins++ < 10) { bdelay(500); }
  if (msdp->connected()) {
    if (RTDEBUG) { consolelog("msd connected\n"); } 
    usbfsstat=usbp->mount(msdp);
    if (RTDEBUG) {
      consolelog("USB mount status is "); 
      consolelognum(usbfsstat);
      consolelog("\n");
    }
    fsstart=!usbfsstat;
  } else {
    if (RTDEBUG) { consolelog("msd not connected\n"); } 
    fsstart=0;
  }
  
  if (RTDEBUG) { consolelog("fsstart is: "); consolelognum(fsstart); 
      consolelog("\n"); }
#endif
#ifdef ARDUINOEFS
	uint8_t s=EFS.begin();
	if (s>0) {
		fsstart=s;
	} else {
		if (EFS.format(32)) fsstart=32; else fsstart=0;;
	}
#endif
#ifdef HASBUILDIN
/* hopefully nothing to be done */
#endif
}

/* 
 *  Maps information of the start of the filesystem to 
 *  the USR(16,x) call. USR(16,0) checks if a filesystem is 
 *  present and USR(16,1) checks if the filesystem has been mounted.
 */
uint8_t fsstat(uint8_t c) { 
#if defined(FILESYSTEMDRIVER)
  if (c == 0) return 1;
  if (c == 1) return fsstart;
#endif
  return 0;
}

/*
 *	File I/O function on an Arduino
 * 
 * filewrite(), fileread(), fileavailable() as byte access
 * open and close is handled separately by (i/o)file(open/close)
 * only one file can be open for write and read at the same time
 */
void filewrite(char c) {
#if defined(ARDUINOSD) || defined(ESPSPIFFS)||defined(ESP32FAT)||defined(STM32SDIO)|| defined(ESPSDMMC)
	if (ofile) { ofile.write(c); return; }
#endif
#if defined(RP2040LITTLEFS) || defined(GIGAUSBFS)
	if (ofile) { fputc(c, ofile); return; }
#endif
#if defined(ARDUINOEFS)
	if (ofile) { 
    if (!EFS.fputc(c, ofile)) ioer=-1; 
    return;
  }
#endif
/* if there is no open ofile, set the ioerror flag to notify BASIC about it */
  ioer=1;
}

char fileread() {
	char c;

/* the buildin file is active, we handle this first, else we allow for another FS */
#if defined(HASBUILDIN)
  if (buildin_ifile != 0) { 
    c=pgm_read_byte(buildin_ifile+buildin_ifilepointer);
    if (c != '\f') buildin_ifilepointer++; else { ioer=-1; c=255; }
    return c;
  }
#endif
#if defined(ARDUINOSD) || defined(ESPSPIFFS)||defined(ESP32FAT)||defined(STM32SDIO) || defined(ESPSDMMC)
	if (ifile) c=ifile.read(); else { ioer=1; return 0; }
	if (c == -1 || c == 255) ioer=-1;
	return c;
#endif
#if defined(RP2040LITTLEFS)||defined(GIGAUSBFS)
	if (ifile) c=fgetc(ifile); else { ioer=1; return 0; }
	if (c == -1 || c == 255) ioer=-1;
	return c;
#endif
#ifdef ARDUINOEFS
	if (ifile) c=EFS.fgetc(ifile); else { ioer=1; return 0; }
	if (c == -1|| c == 255) ioer=-1;
	return c;
#endif
	return 0;
}

int fileavailable(){
/* for the buildin file \f is the end of file, return true is it has not been reached */
#if defined(HASBUILDIN)
  char c;
  if (buildin_ifile != 0) { 
    c=pgm_read_byte(buildin_ifile+buildin_ifilepointer);
    if (c != '\f') return 1; else return 0;
  }
#endif
#if defined(ARDUINOSD) || defined(ESPSPIFFS) || defined(ESP32FAT) || defined(STM32SDIO) || defined(ESPSDMMC)
	return ifile.available();
#endif
#if defined(RP2040LITTLEFS) || defined(GIGAUSBFS)
	return !feof(ifile);
#endif
#ifdef ARDUINOEFS
	return EFS.available(ifile);
#endif
	return 0;
}

uint8_t ifileopen(const char* filename){
/* we first try to open a file on the builin file system, then of the other ones */
#if defined(HASBUILDIN)
  byte i, file;
  char* name;

/* opening a new file */
  buildin_ifilepointer=0;
  buildin_ifile=0;

  file=0;
  while(1) {

/* find a name in progmem, 0 if no more name */
    name=(char*)pgm_read_ptr(&buildin_program_names[file]);    
    if (name == 0) break;

/* compare the name with the filename */  
    for(i=0;i<32;i++) {
    char c=pgm_read_byte(&name[i]);

/* we are at the end of the name, if filename is also ending, we got it */
      if (c == 0 && filename[i] == 0) {
        buildin_ifile=(char*)pgm_read_ptr(&buildin_programs[file]);
        return (buildin_ifile != 0);
      }

/* a character mismatch means we need to go to the next name */
      if (c != filename[i]) {
          file++;
          break;  
      }
    }
  }
#endif
/*
 * All filesystems that are not buildin are checked for correct open
 * This is needed for GIGA as the USB host tends to block.
 */
  if (!fsstart) return 0;

#if defined(ARDUINOSD)
	ifile=SD.open(mkfilename(filename), FILE_READ);
	return ifile != 0;
#endif
#ifdef ESPSDMMC
  ifile=SD_MMC.open(mkfilename(filename), FILE_READ);
  return ifile != 0;
#endif
#if defined(STM32SDIO)
  ifile=SD.open(filename);
  return ifile != 0;
#endif
#ifdef ESPSPIFFS
	ifile=SPIFFS.open(mkfilename(filename), "r");
	return ifile != 0;
#endif
#ifdef ESP32FAT
  ifile=FFat.open(mkfilename(filename), "r"); 
  return ifile != 0;
#endif
#if defined(RP2040LITTLEFS) || defined(GIGAUSBFS)
	ifile=fopen(mkfilename(filename), "r");
	return ifile != 0;
#endif
#ifdef ARDUINOEFS
	ifile=EFS.fopen(filename, "r");
	return ifile != 0;
#endif
	return 0;
}
void ifileclose(){
#if defined(HASBUILDIN)
  if (buildin_ifile) {
    buildin_ifile=0;
    buildin_ifilepointer=0;   
  }
#endif
#if defined(ARDUINOSD) || defined(ESPSPIFFS) || defined(ESP32FAT) || defined(STM32SDIO) || defined(ESPSDMMC)
	if (ifile) ifile.close();
#endif	
#if defined(RP2040LITTLEFS) || defined(GIGAUSBFS)
	if (ifile) fclose(ifile);
#endif
#ifdef ARDUINOEFS
	if (ifile) EFS.fclose(ifile);	
#endif

}

uint8_t ofileopen(const char* filename, const char* m){

/*
 * All filesystems that are not buildin are checked for correct open
 * This is needed for GIGA as the USB host tends to block.
 */
  if (!fsstart) return 0;
    
#if defined(ARDUINOSD) 
	if (*m == 'w') ofile=SD.open(mkfilename(filename), FILE_OWRITE);
/* ESP32 has FILE_APPEND defined */
#ifdef FILE_APPEND
  if (*m == 'a') ofile=SD.open(mkfilename(filename), FILE_APPEND);
#else
	if (*m == 'a') ofile=SD.open(mkfilename(filename), FILE_WRITE);
#endif
	return ofile != 0;
#endif
#if defined(ESPSDMMC) 
  if (*m == 'w') ofile=SD_MMC.open(mkfilename(filename), FILE_OWRITE);
/* ESP32 has FILE_APPEND defined */
#ifdef FILE_APPEND
  if (*m == 'a') ofile=SD_MMC.open(mkfilename(filename), FILE_APPEND);
#else
  if (*m == 'a') ofile=SD_MMC.open(mkfilename(filename), FILE_WRITE);
#endif
  return ofile != 0;
#endif
#if  defined(STM32SDIO)
  if (*m == 'w') ofile=SD.open(filename, FILE_OWRITE);
/* ESP32 has FILE_APPEND defined */
#ifdef FILE_APPEND
  if (*m == 'a') ofile=SD.open(filename, FILE_APPEND);
#else
  if (*m == 'a') ofile=SD.open(filename, FILE_WRITE);
#endif
  return ofile != 0;
#endif
#ifdef ESPSPIFFS
	ofile=SPIFFS.open(mkfilename(filename), m);
	return ofile != 0;
#endif
#ifdef ESP32FAT
  ofile=FFat.open(mkfilename(filename), m);
  return ofile != 0;
#endif
#if defined(RP2040LITTLEFS) || defined(GIGAUSBFS)
	ofile=fopen(mkfilename(filename), m);
	return ofile != 0; 
#endif
#ifdef ARDUINOEFS
	ofile=EFS.fopen(filename, m);
	return ofile != 0; 
#endif
/* if no other filesystem has satisfied the write open BUILDIN reports the error */
#if defined(HASBUILDIN)
  ioer=-1;
  return 0;
#endif
	return 0;
}

void ofileclose(){
#if defined(ARDUINOSD) || defined(ESPSPIFFS)||defined(ESP32FAT)|| defined(STM32SDIO) || defined(ESPSDMMC)
  if (ofile) ofile.close();
#endif
#if defined(RP2040LITTLEFS) || defined(GIGAUSBFS)
	if (ofile) fclose(ofile); 
#endif
#ifdef ARDUINOEFS
	if (ofile) EFS.fclose(ofile); 
#endif	
}

/*
 * directory handling for the catalog function
 * these methods are needed for a walkthtrough of 
 * one directory
 *
 * rootopen()
 * while rootnextfile()
 * 	if rootisfile() print rootfilename() rootfilesize()
 *	rootfileclose()
 * rootclose()
 */
void rootopen() {
/* we first open the buildin and remember we are processing it, if there is another root, we also open it */
#ifdef HASBUILDIN
  buildin_rootpointer=0;
  buildin_rootactive=1;
#endif
/*
 * All filesystems that are not buildin are checked for correct open
 * This is needed for GIGA as the USB host tends to block.
 */
  if (!fsstart) return;
  
#if defined(ARDUINOSD) || defined(STM32SDIO)
	root=SD.open("/");
#endif
#if defined(ESPSDMMC)
  root=SD_MMC.open("/");
#endif
#ifdef ESPSPIFFS
#ifdef ARDUINO_ARCH_ESP8266
	root=SPIFFS.openDir("/");
#endif
#ifdef ARDUINO_ARCH_ESP32
	root=SPIFFS.open("/");
#endif
#endif
#ifdef ESP32FAT
  root=FFat.open("/");
#endif
#if defined(RP2040LITTLEFS) || defined(GIGAUSBFS)
	root=opendir(rootfsprefix);
#endif
#ifdef ARDUINOEFS
	EFS.dirp=0;
#endif
}

uint8_t rootnextfile() {
/* we first iterate through the buildins, then fall through to the other filesystems */
#ifdef HASBUILDIN
  if (buildin_rootactive) {
    buildin_file=(char*)pgm_read_ptr(&buildin_program_names[buildin_rootpointer]);
    if (buildin_file != 0) {
      buildin_pgm=(char*)pgm_read_ptr(&buildin_programs[buildin_rootpointer]);
      buildin_rootpointer++;
      return 1;
    } else {
      buildin_rootactive=0;
    }
  }
#endif
/*
 * All filesystems that are not buildin are checked for correct open
 * This is needed for GIGA as the USB host tends to block.
 */
  if (!fsstart) return 0;
  
#if defined(ARDUINOSD) || defined(STM32SDIO)||defined(ESPSDMMC)
	file=root.openNextFile();
	return (file != 0);
#endif
#ifdef ESPSPIFFS
#ifdef ARDUINO_ARCH_ESP8266
  	if (root.next()) {
    	file=root.openFile("r");
    	return 1;
  	} else {
    	return 0;
	}
#endif
#ifdef ARDUINO_ARCH_ESP32
	file=root.openNextFile();
	return (file != 0);
#endif
#endif
#ifdef ESP32FAT
#ifdef ARDUINO_ARCH_ESP32
  file=root.openNextFile();
  return (file != 0);
#endif
#endif
#if defined(RP2040LITTLEFS) || defined(GIGAUSBFS)
	file = readdir(root);
	return (file != 0);
#endif
#ifdef ARDUINOEFS
	file = EFS.readdir();
	return (file != 0);
#endif
  return 0;
}

uint8_t rootisfile() {
#ifdef HASBUILDIN
  if (buildin_rootactive) return 1;
#endif
#if defined(ARDUINOSD) || defined(STM32SDIO) || defined(ESPSDMMC)
	return (!file.isDirectory());
#endif

#ifdef ESPSPIFFS
#ifdef ARDUINO_ARCH_ESP8266
	return 1;
#endif
#ifdef ARDUINO_ARCH_ESP32
	return (!file.isDirectory());
#endif
#endif
#ifdef ESP32FAT
#ifdef ARDUINO_ARCH_ESP32
  return (!file.isDirectory());
#endif
#endif
#if defined(RP2040LITTLEFS)||defined(GIGAUSBFS)
	return (file->d_type == DT_REG);
#endif
#ifdef ARDUINOEFS
	return 1;
#endif	
	return 0;
}

const char* rootfilename() {
#ifdef HASBUILDIN
  if (buildin_rootactive) {
    for(int i=0; i<FBUFSIZE; i++) {
      buildin_tempname[i]=(char)pgm_read_byte(&buildin_file[i]);
      if (buildin_tempname[i] == 0) return buildin_tempname;
    }
  }
#endif
#if defined(ARDUINOSD) || defined(ESPSDMMC)
  return rmrootfsprefix(file.name());
#endif
#if defined(STM32SDIO)
  return (char*) file.name();
#endif
#ifdef ESPSPIFFS
#ifdef ARDUINO_ARCH_ESP8266
  int i=0;
	String s=root.fileName();
 	for (i=0; i<s.length(); i++) tempname[i]=s[i];
 	tempname[i]=0;
	return rmrootfsprefix(tempname);
#endif
#ifdef ARDUINO_ARCH_ESP32
	return rmrootfsprefix(file.name());
#endif
#endif
#ifdef ESP32FAT
#ifdef ARDUINO_ARCH_ESP32
  return rmrootfsprefix(file.name());
#endif
#endif
#if defined(RP2040LITTLEFS)||defined(GIGAUSBFS)
	return (file->d_name);
#endif
#ifdef ARDUINOEFS
	return EFS.filename(file);
#endif
	return 0; 
}

uint32_t rootfilesize() {
#ifdef HASBUILDIN
  int i=0;
  if (buildin_rootactive && buildin_pgm) {
    for (;;i++) {
      char ch=pgm_read_byte(&buildin_pgm[i]);
      if (ch == 0) return i;
    }
  }
#endif
#if defined(ARDUINOSD) || defined(ESPSPIFFS) || defined(ESP32FAT) || defined(STM32SDIO) || defined(ESPSDMMC)
  return file.size();
#endif  
#if defined(RP2040LITTLEFS)||defined(GIGAUSBFS)
/* to be done */
#endif
#ifdef ARDUINOEFS
	return EFS.filesize(file);
#endif
  return 0;
}

void rootfileclose() {
#if defined(ARDUINOSD) || defined(ESPSPIFFS) || defined(ESP32FAT) || defined(STM32SDIO) || defined(ESPSDMMC)
  file.close();
#endif 
#if defined(RP2040LITTLEFS) || defined(GIGAUSBFS)
/* nothing to be done here as we work on dirents */
#endif
#ifdef ARDUINOEFS
#endif
}

void rootclose(){
#ifdef HASBUILDIN
  buildin_rootactive=0;
#endif
#if defined(ARDUINOSD) || defined(STM32SDIO) || defined(ESPSDMMC)
  root.close();
#endif
#ifdef ESPSPIFFS
#ifdef ARDUINO_ARCH_ESP8266
  return;
#endif
#ifdef ARDUINO_ARCH_ESP32
  root.close();
#endif
#endif
#ifdef ESP32FAT
#ifdef ARDUINO_ARCH_ESP32
  root.close();
#endif
#endif
#ifdef RP2040LITTLEFS
#endif
#ifdef GIGAUSBFS
  if (root) (void) closedir(root);
#endif
#ifdef ARDUINOEFS
#endif
}

/*
 * remove method for files
 */
void removefile(const char *filename) {
#if defined(ARDUINOSD)	
	SD.remove(mkfilename(filename));
	return;
#endif
#if defined(ESPSDMMC)
  SD_MMC.remove(mkfilename(filename));
  return;
#endif
#if defined(STM32SDIO)  
  SD.remove(filename);
  return;
#endif
#ifdef ESPSPIFFS
	SPIFFS.remove(mkfilename(filename));
	return;
#endif
#ifdef ESP32FAT
  FFat.remove(mkfilename(filename));
  return;
#endif
#if defined(RP2040LITTLEFS) || defined(GIGAUSBFS)
	remove(mkfilename(filename));
	return;
#endif
#ifdef ARDUINOEFS
	EFS.remove(filename);
	return;
#endif
}

/*
 * formatting for fdisk of the internal filesystems
 */
void formatdisk(uint8_t i) {
#if defined(ARDUINOSD) || defined(STM32SDIO)||defined(GIGAUSBFS) || defined(ESPSDMMC)
  return;
	return;
#endif
#ifdef ESPSPIFFS
	if (SPIFFS.format()) { SPIFFS.begin(); fsstart=1; } else { fsstart=0; }
#endif
#ifdef ESP32FAT
  FFat.end();
  if (FFat.format()) { FFat.begin(); fsstart=1; } else { fsstart=0; }
#endif
#ifdef RP2040LITTLEFS
  fs.reformat(&bd); /* bd: this comes from the header */
	return;
#endif
#ifdef ARDUINOEFS
	if (i>0) {
		if (EFS.format(i)) { EFS.begin(); fsstart=1; } else { fsstart=0; }
	} else ioer=1;
	return;
#endif
}

/* 
 *  The buffer code, a simple buffer to store output and 
 *  input data. It can be used as a device in BASIC using the 
 *  modifier &0. 
 */

/* use the input buffer variable from BASIC here, it is extern to runtime */
void bufferbegin() {}

/* write to the buffer, works only until 127 
  uses vt52 style commands to handle the buffer content*/
void bufferwrite(char c) {
  if (!nullbuffer) return;
  switch (c) {
  case 12: /* clear screen */
    //nullbuffer[nullbuffer[0]+1]=0;
    nullbuffer[0]=0;
    nullbuffer[1]=0;
    break;
  case 10: 
  case 13: /* cr and lf ignored */
    break;
  case 8: /* backspace */
    if (nullbuffer[0]>0) nullbuffer[0]--;
    break;
  default:
    if (nullbuffer[0] < nullbufsize-1 && nullbuffer[0] < 127) {
      nullbuffer[++nullbuffer[0]]=c;
      nullbuffer[nullbuffer[0]+1]=0; /* null terminate */
    }    
    break;
  }
}

/* read not needed right now */
char bufferread() { return 0; }
uint16_t bufferavailable() { return 0; }
char buffercheckch() { return 0; }
void bufferflush() { }
uint16_t bufferins(char *b, uint16_t nb) { return 0; }

/*
 *	Primary serial code uses the Serial object or Picoserial
 *
 *	The picoseria an own interrupt function. This is used to fill 
 *  the input buffer directly on read. Write is standard like in 
 *  the serial code.
 *  
 * As echoing is done in the interrupt routine, the code cannot be 
 * used to receive keystrokes from serial and then display the echo
 * directly to a display. To do this the write command in picogetchar
 * would have to be replaced with a outch() that then redirects to the 
 * display driver. This would be very tricky from the timing point of 
 * view if the display driver code is slow. 
 * 
 * The code for the UART control is mostly taken from PicoSerial
 * https://github.com/gitcnd/PicoSerial, originally written by Chris Drake
 * and published under GPL3.0 just like this code
 * 
 */
#ifdef ARDUINOPICOSERIAL
volatile char picochar;
volatile uint8_t picoa = 0;
volatile char* picob = NULL;
int16_t picobsize = 0;
volatile int16_t picoi = 1;
volatile uint16_t picoz; /* ugly */

/* this is mostly taken from PicoSerial */
const uint16_t MIN_2X_BAUD = F_CPU/(4*(2*0XFFF + 1)) + 1;

/* the begin code */
void picobegin(uint32_t baud) {
    uint16_t baud_setting;
    cli();               
    if ((F_CPU != 16000000UL || baud != 57600) && baud > MIN_2X_BAUD) {
      UCSR0A = 1 << U2X0;
      baud_setting = (F_CPU / 4 / baud - 1) / 2;
    } else {
      UCSR0A = 0;
      baud_setting = (F_CPU / 8 / baud - 1) / 2;
    }
/* assign the baud_setting */
    UBRR0H = baud_setting >> 8;
    UBRR0L = baud_setting;
/* enable transmit and receive */
    UCSR0B |= (1 << TXEN0) | (1 << RXEN0) | (1 << RXCIE0);
    sei();                   
}

/* the write code, sending bytes directly to the UART */
void picowrite(char b) {
    while (((1 << UDRIE0) & UCSR0B) || !(UCSR0A & (1 << UDRE0))) {}
    UDR0 = b;
}

/* 
 *  picogetchar: this is the interrupt service routine.  It 
 *  recieves a character and feeds it into a buffer and echos it
 *  back. The logic here is that the ins() code sets the buffer 
 *  to the input buffer. Only then the routine starts writing to the 
 *  buffer. Once a newline is received, the length information is set 
 *  and picoa is also set to 1 indicating an available string, this stops
 *  recevieing bytes until the input is processed by the calling code.
 */
void picogetchar(char c){
	if (picob && (!picoa)) {
    picochar=c;
		if (picochar != '\n' && picochar != '\r' && picoi<picobsize-1) {
      if (c == 127 || c == 8) {
        if (picoi>1) picoi--; else return;
      } else 
			  picob[picoi++]=picochar;
      picowrite(picochar);
		} else {
			picoa = 1;
			picob[picoi]=0;
			picob[0]=picoi;
			picoz=picoi;
			picoi=1;
		}
		picochar=0; /* every buffered byte is deleted */
	} else {
    	if (c != 10) picochar=c;
	}
}

/* the ins code of picoserial, called like this in consins */
uint16_t picoins(char *b, uint16_t nb) {
  picob=b;
  picobsize=nb;
  picoa=0;
/* once picoa is set, the interrupt routine records characters 
 *  until a cr and then resets picoa to 0 */
  while (!picoa) byield();
  outch(10);
  return picoz;
 }

/* on an UART interrupt, the getchar function is called */
#ifdef USART_RX_vect
ISR(USART_RX_vect) {
  char c=UDR0;
  picogetchar(c);
}
#else
/* for MEGAs and other with many UARTs */
  ISR(USART0_RX_vect) {
  char c=UDR0;
  picogetchar(c);
}
#endif
#endif

/* 
 * blocking serial single char read for Serial
 * unblocking for Picoserial because it is not 
 * character oriented -> blocking is handled in 
 * consins instead.
 */
char serialread() {
#ifdef ARDUINOPICOSERIAL
	char c;
	c=picochar;
	picochar=0;
	return c;	
#else
	while (!SERIALPORT.available()) byield();
  return SERIALPORT.read();
#endif
}

/*
 *  serial begin code with a one second delay after start
 *	this is not needed any more 
 */
void serialbegin() {
#ifdef ARDUINOPICOSERIAL
	picobegin(serial_baudrate); 
#else
	SERIALPORT.begin(serial_baudrate);
#endif
	bdelay(1000);
}

/* state information on the serial port */
uint8_t serialstat(uint8_t c) {
  if (c == 0) return 1;
  if (c == 1) return serial_baudrate/100;
  return 0;
}

/* write to a serial stream */
void serialwrite(char c) {
#ifdef ARDUINOPICOSERIAL
	picowrite(c);
#else
/* write never blocks. discard any bytes we can't get rid of */
  SERIALPORT.write(c);  
/* if (Serial.availableForWrite()>0) Serial.write(c);	*/
#endif
}

/* check on a character, needed for breaking */
char serialcheckch() {
#ifdef ARDUINOPICOSERIAL
	return picochar;
#else
	if (SERIALPORT.available()) return SERIALPORT.peek(); else return 0; // should really be -1
#endif	
}

/* avail method, needed for AVAIL() */ 
uint16_t serialavailable() {
#ifdef ARDUINOPICOSERIAL
	return picoi;
#else
	return SERIALPORT.available();
#endif	
}

/* flush serial */
void serialflush() {
#ifdef ARDUINOPICOSERIAL
  return;
#else
  while (SERIALPORT.available()) SERIALPORT.read();
#endif 
}

/* the serial ins */
uint16_t serialins(char *b, uint16_t nb) {
#ifdef ARDUINOPICOSERIAL
  return picoins(b, nb);
#else
  return consins(b, nb);
#endif  
}

/* 
 * Start a secondary serial port for printing and/or networking 
 * This is either Serial1 on a MEGA or DUE or Nano Every or a SoftwareSerial 
 * instance
 */
#ifdef ARDUINOPRT
#if !defined(ARDUINO_AVR_MEGA2560) && !defined(ARDUINO_SAM_DUE) && !defined(ARDUINO_AVR_NANO_EVERY) \
    && !defined(ARDUINO_NANO_RP2040_CONNECT) && !defined(ARDUINO_RASPBERRY_PI_PICO) \
    && !defined(ARDUINO_SEEED_XIAO_M0) && !defined(ARDUINO_ARCH_RENESAS) &&! defined(ARDUINO_ARCH_MBED)
#include <SoftwareSerial.h>
SoftwareSerial PRTSERIAL(SOFTSERIALRX, SOFTSERIALTX);
#endif

/* second serial port */
void prtbegin() {
	PRTSERIAL.begin(serial1_baudrate);
}

/* the open functions are not needed here */
char prtopen(char* filename, uint16_t mode) {}
void prtclose() {}

uint8_t prtstat(uint8_t c) {
  if (c == 0) return 1;
  if (c == 1) return serial1_baudrate;
  return 0;
}

void prtwrite(char c) {
	PRTSERIAL.write(c);
}

char prtread() {
	while (!PRTSERIAL.available()) byield();
	return PRTSERIAL.read();
}

char prtcheckch() {
	if (PRTSERIAL.available()) return PRTSERIAL.peek(); else return 0;
}

uint16_t prtavailable() {
	return PRTSERIAL.available();
}

void prtset(uint32_t s) {
  serial1_baudrate=s;
  prtbegin();
}

uint16_t prtins(char* b, uint16_t nb) {
    if (blockmode > 0) return inb(b, nb); else return consins(b, nb);
}
#endif


/* 
 * The wire code, direct access to wire communication
 * in master mode wire_slaveid is the I2C address bound 
 * to channel &7 and wire_myid is 0
 * in slave mode wire_myid is the devices slave address
 * and wire_slaveid is 0
 * ARDUINOWIREBUFFER is the maximum length of meesages the 
 * underlying library can process. This is 32 for the Wire
 * library
 */ 

/* this is always here, if Wire is needed by a subsysem, full wire always loads the Arduino wire library */
#if defined(HASWIRE)
/* default begin is as a master 
 * This doesn't work properly on the ESP32C3 platform
 * See  https://github.com/espressif/arduino-esp32/issues/6376 
 * for more details
 */
void wirebegin() {
#ifndef SDA_PIN   
  Wire.begin();
#else
  Wire.begin(SDA_PIN, SCL_PIN);
#endif
}
#endif

/* this is code needed for the OPEN/CLOSE and wireslave mechanisms */
#if defined(HASWIRE)
uint8_t wire_slaveid = 0;
uint8_t wire_myid = 0;
#define ARDUINOWIREBUFFER 32
#ifdef ARDUINOWIRESLAVE
char wirereceivebuffer[ARDUINOWIREBUFFER];
short wirereceivechars = 0;
char wirerequestbuffer[ARDUINOWIREBUFFER];
short wirerequestchars = 0;
#endif

void wireslavebegin(uint8_t s) {
#ifndef SDA_PIN
  Wire.begin(s);
#else
  Wire.begin(SDA_PIN, SCL_PIN, s);
#endif
}

/* wire status - just checks if wire is compiled */
uint8_t wirestat(uint8_t c) {
  switch (c) {
    case 0: 
      return 1;
#ifdef ARDUINOWIRESLAVE
    case 1:
      return wirerequestchars;
#endif    
    default:
      return 0;
  }
}

/* available characters - test code ecapsulation prep for slave*/
uint16_t wireavailable() {
/* as a master we return 1, as a slave the received chars*/
  if (wire_myid == 0) return 1;
#ifdef ARDUINOWIRESLAVE
  else return wirereceivechars; 
#else
  else return 0;
#endif
}

#ifdef ARDUINOWIRESLAVE
/* event handler for receive */
void wireonreceive(int h) {
  wirereceivechars=h;
  if (h>ARDUINOWIREBUFFER) h=ARDUINOWIREBUFFER;
  for (int i=0; i<h; i++) wirereceivebuffer[i]=Wire.read();
}

/* event handler for request, deliver the message and forget the buffer */ 
void wireonrequest() {
  Wire.write(wirerequestbuffer, wirerequestchars);
  wirerequestchars=0;
}
#endif

/*
 *	as a master open sets the slave id for the communication
 *	no extra begin while we stay master
 */
void wireopen(uint8_t s, uint8_t m) {
	if (m == 0) {
		wire_slaveid=s;
/* we have been a slave and become master, restart wire*/
    if (wire_myid != 0) {
      wirebegin();
      wire_myid=0;    
    }
	} else if ( m == 1 ) { 
		wire_myid=s;
		wire_slaveid=0;
#ifdef ARDUINOWIRESLAVE
		wireslavebegin(wire_myid);
    Wire.onReceive(&wireonreceive);
    Wire.onRequest(&wireonrequest);
#endif
	} 
}

/* input an entire string */
uint16_t wireins(char *b, uint8_t l) {
  uint16_t z;
  if (wire_myid == 0) {
    z=0;
    if (l>ARDUINOWIREBUFFER) l=ARDUINOWIREBUFFER;
    if (!Wire.requestFrom(wire_slaveid, l)) ioer=1;
    while (Wire.available() && z<l) b[++z]=Wire.read();
  } else {
#ifdef ARDUINOWIRESLAVE
    for (z=0; z<wirereceivechars && z<l; z++) b[z+1]=wirereceivebuffer[z];
    wirereceivechars=0; /* clear the entire buffer on read, bytewise read not really supported */
#endif
  }
  b[0]=z;
  return z;
}

/* just a helper to make GET work, wire is string oriented */
char wireread() {
    char wbuffer[2];
    if (wireins(wbuffer, 1)) return wbuffer[1]; else return 0;
}

/* send an entire string - truncate radically */
void wireouts(char *b, uint8_t l) {
  int16_t z;
  if (l>ARDUINOWIREBUFFER) l=ARDUINOWIREBUFFER; 
  if (wire_myid == 0) {
    Wire.beginTransmission(wire_slaveid); 
#ifdef ARDUINO_ARCH_ESP32
    for(z=0; z<l; z++) Wire.write(b[z]);  
#else
    Wire.write(b, l);
#endif
    ioer=Wire.endTransmission(); 
  } else {
#ifdef ARDUINOWIRESLAVE
    for (int i=0; i<l; i++) wirerequestbuffer[i]=b[i];
    wirerequestchars=l;
#endif
  }
}
#endif

/* plain wire without FILE I/O functions */
#if defined(HASSIMPLEWIRE) || defined(HASWIRE)

/* AVR boards can be handled with a smaller Wire implementation, this 
   should go into a separate library soon */
#if defined(ARDUINODIRECTI2C)

/* a few constants */ 
uint32_t const F_TWI = 100000L;                               
uint8_t const TWSR_MTX_DATA_ACK = 0x28;
uint8_t const TWSR_MTX_ADR_ACK = 0x18;
uint8_t const TWSR_MRX_ADR_ACK = 0x40;
uint8_t const TWSR_START = 0x08;
uint8_t const TWSR_REP_START = 0x10;
uint8_t const I2C_READ = 1;
uint8_t const I2C_WRITE = 0;

/* counts the bytes to be read, in this implementation not used, kept for later */
uint8_t wirecount;

/* start the bus and set the frequency in TWBR */
void wirebegin() {
  digitalWrite(SDA, HIGH);                                      
  digitalWrite(SCL, HIGH);
  TWSR = 0;
  TWBR = (F_CPU/F_TWI - 16)/2;
}

/* a generic start function for read and write*/
void wirestart (uint8_t port, uint8_t n) {
  
  /* form the right address*/
  port=port<<1;

  /* remember the requested bytes and go to read mode if read */
  if (n) { 
    wirecount=n;  
    port |= I2C_READ;
  }
  
  /* start the bus and wait */
  TWCR = 1<<TWINT | 1<<TWSTA | 1<<TWEN;
  while (!(TWCR & 1<<TWINT));
  
  /* check the status */
  if ((TWSR & 0xF8) != TWSR_START && (TWSR & 0xF8) != TWSR_REP_START) { ioer=1; return; }
  
  /* send the address and direction */
  TWDR = port;
  TWCR = 1<<TWINT | 1<<TWEN;
  while (!(TWCR & 1<<TWINT));
  
  /* check the status */
  if (port & I2C_READ) {
    if ((TWSR & 0xF8) == TWSR_MRX_ADR_ACK) ioer=0; else ioer=1;
  } else { 
    if ((TWSR & 0xF8) == TWSR_MTX_ADR_ACK) ioer=0; else ioer=1;
  }
}

/* stop, return value just a formality, error handling is done differently*/
uint8_t wirestop () {
  TWCR = 1<<TWINT | 1<<TWEN | 1<<TWSTO;
  while (TWCR & 1<<TWSTO);
  return ioer;
}

/* one byte write */
void wirewritebyte(uint8_t b) {
  TWDR = b;
  TWCR = 1<<TWINT | 1<<TWEN;
  while (!(TWCR & 1<<TWINT));
  if (!((TWSR & 0xF8) == TWSR_MTX_DATA_ACK)) ioer=1;
}

/* one byte read without stopping the bus */
int16_t wirereadbyte () {
  if (wirecount != 0) wirecount--;
  TWCR = 1<<TWINT | 1<<TWEN | ((wirecount == 0) ? 0 : (1<<TWEA));
  while (!(TWCR & 1<<TWINT));
  return TWDR;
}
#else /* not ARDUINODIRECTI2C this uses the standard Wire objects but provide the same API */

/* start the Wire object*/
void wirebegin() {
#ifndef SDA_PIN   
  Wire.begin();
#else
  Wire.begin(SDA_PIN, SCL_PIN);
#endif
}

/* initiate communication for read or write */
void wirestart(uint8_t port, uint8_t n) { 
  if (n) {
    if (!Wire.requestFrom(port, n)) ioer=1;
  } else {
    Wire.beginTransmission(port); 
  }
}

/* stop is only explicitly used on write */
uint8_t wirestop() { return Wire.endTransmission(); }
void wirewritebyte(uint8_t data) { Wire.write(data); }
int16_t wirereadbyte() { return Wire.read(); }
#endif
#endif

/* 
 *	Read from the radio interface, radio is always block 
 *	oriented. This function is called from ins for an entire 
 *	line.
 *
 *	In blockmode the entire message is returned in the 
 *	receiving string while in line mode the length of the 
 *	string is adapted. Blockmode can be used to transfer
 *	binary data.
 */

#ifdef ARDUINORF24
/*
 * definitions for the nearfield module, still very experimental
 * We use the standard RF24 nearfield library 
 */
const char rf24_ce = RF24CEPIN; 
const char rf24_csn = RF24CSNPIN; 
#include <nRF24L01.h>
#include <RF24.h>
rf24_pa_dbm_e rf24_pa = RF24_PA_MAX;
RF24 radio(rf24_ce, rf24_csn);

/* radio status */
uint8_t radiostat(uint8_t c) {
  if (c == 0) return 1;
  if (c == 1) return radio.isChipConnected();
  return 0; 
}

/* generate a uint64_t pipe address from the filename string for RF24 */
uint64_t pipeaddr(const char *f){
	uint64_t t = 0;
	t=(uint8_t)f[0];
	for(short i=1; i<=4; i++) t=t*256+(uint8_t)f[i];
	return t;
} 


/* read an entire string */
uint16_t radioins(char *b, uint8_t nb) {
    uint16_t z;
    
    if (radio.available()) {
    	radio.read(b+1, nb);
    	if (!blockmode) {
        for (z=0; z<nb; z++) if (b[z+1]==0) break;		
    	} else {
    		z=radio.getPayloadSize();
      	if (z > nb) z=nb;
    	}
      b[0]=z;
	} else {
    b[0]=0; 
    b[1]=0;
    z=0;
	}
  return z;
}


 /* radio is not character oriented, this is only added to make GET work
    or single byte payloads, radio, like file is treated nonblocking here */   
char radioread() {
    char rbuffer[2];
    if (radioins(rbuffer, 1)) return rbuffer[1]; else return 0;
}

/* write to radio, no character mode here */
void radioouts(char *b, uint8_t l) {
	radio.stopListening();
	if (!radio.write(b, l)) ioer=1;
	radio.startListening();
}

/* radio available */
uint16_t radioavailable() {
  return radio.available();
}

/* 
 *	we always read from pipe 1 and use pipe 0 for writing, 
 *	the filename is the pipe address, by default the radio 
 *	goes to reading mode after open and is only stopped for 
 *	write
 */
void iradioopen(const char *filename) {
	if (!radio.begin()) ioer=1;
	radio.openReadingPipe(1, pipeaddr(filename));
	radio.startListening();
}

void oradioopen(const char *filename) {
	if (!radio.begin()) ioer=1;
	radio.openWritingPipe(pipeaddr(filename));
}

void radioset(uint8_t s) {
  if ((s<0) && (s>3)) {ioer=1; return; } 
  rf24_pa=(rf24_pa_dbm_e) s;
  radio.setPALevel(rf24_pa);
}

#else 
uint8_t radiostat(uint8_t c) { return 0; }
uint64_t pipeaddr(const char *f){ return 0; } 
uint16_t radioins(char *b, uint8_t nb) { b[0]=0; b[1]=0; return 0; }
void radioouts(char *b, uint8_t l) {}
uint16_t radioavailable() { return 0; }
void iradioopen(const char *filename) {}
void oradioopen(const char *filename) {}
void radioset(uint8_t s) {}
#endif


/* 
 *	Arduino Sensor library code 
 *		The sensorread() is a generic function called by 
 *		SENSOR basic function and command. The first argument
 *		is the sensor and the second argument the value.
 *		sensorread(n, 0) checks if the sensorstatus.
 */
#ifdef ARDUINOSENSORS
#ifdef ARDUINODHT
#include "DHT.h"
DHT dht(DHTPIN, DHTTYPE);
#endif
#ifdef ARDUINOSHT
#include <SHT3x.h>
SHT3x SHT;
#endif
#ifdef ARDUINOMQ2
#include <MQ2.h>
MQ2 mq2(MQ2PIN);
#endif
#ifdef ARDUINOLMS6
#include <Arduino_LSM6DSOX.h>
/* https://www.arduino.cc/en/Reference/Arduino_LSM6DSOX */
#endif
#ifdef ARDUINOAHT
#include <Adafruit_AHTX0.h>
Adafruit_AHTX0 aht;
#endif
#ifdef ARDUINOBMP280
#include <Adafruit_BMP280.h>
Adafruit_BMP280 bmp;
#endif
#ifdef ARDUINOBME280
#include <Adafruit_BME280.h>
Adafruit_BME280 bme;
/* add your own code here */
#endif


void sensorbegin(){
#ifdef ARDUINODHT
dht.begin();
#endif
#ifdef ARDUINOSHT
  SHT.Begin();
#endif
#ifdef ARDUINOMQ2
  mq2.begin();
#endif
#ifdef ARDUINOAHT
  aht.begin();
#endif
#ifdef ARDUINOBMP280
  bmp.begin(); 
  bmp.setSampling(Adafruit_BMP280::MODE_NORMAL,   /* Operating Mode. */
                  Adafruit_BMP280::SAMPLING_X2,     /* Temp. oversampling */
                  Adafruit_BMP280::SAMPLING_X16,    /* Pressure oversampling */
                  Adafruit_BMP280::FILTER_X16,      /* Filtering. */
                  Adafruit_BMP280::STANDBY_MS_500); /* Standby time. */
#endif
#ifdef ARDUINOBME280
  bme.begin(); 
#endif
}

float sensorread(uint8_t s, uint8_t v) {
  switch (s) {
    case 0:
      return analogRead(A0+v);
    case 1:
#ifdef ARDUINODHT
			switch (v) {
				case 0:
					return 1;
				case 1:
					return dht.readHumidity();
				case 2:
					return dht.readTemperature();
			}     	
#endif
      return 0;
    case 2:
#ifdef ARDUINOSHT
      switch (v) {
        case 0:
          return 1;
        case 1:
          SHT.UpdateData();
          return SHT.GetRelHumidity();
        case 2:
          SHT.UpdateData();
          return SHT.GetTemperature();
      }       
#endif
      return 0;
    case 3:
#ifdef ARDUINOMQ2
      switch (v) {
        case 0:
          return 1;
        case 1:
          (void) mq2.read(false);
          return mq2.readLPG();;
        case 2:
          (void) mq2.read(false);
          return mq2.readCO();
        case 3:
          (void) mq2.read(false);
          return mq2.readSmoke();
      }       
#endif
      return 0;
    case 4:
#ifdef ARDUINOAHT
      sensors_event_t humidity, temp;
      switch (v) {
        case 0:
          return 1;
        case 1:
          aht.getEvent(&humidity, &temp);
          return temp.temperature;
        case 2:
          aht.getEvent(&humidity, &temp);
          return humidity.relative_humidity;
      }       
#endif
      return 0;
    case 5:
#ifdef ARDUINOBMP280  
      switch (v) {
        case 0:
          return 1;
        case 1:
          return bmp.readTemperature();
        case 2:
          return bmp.readPressure() / 100.0;
        case 3:
          return bmp.readAltitude(1013.25);
      }       
#endif
      return 0;
    case 6:
#ifdef ARDUINOBME280
      switch (v) {
        case 0:
          return 1;
        case 1:
          return bme.readTemperature();
        case 2:
          return bme.readPressure() / 100.0;
        case 3:
          return bme.readAltitude(1013.25);
        case 4:
          return bme.readHumidity();
      }       
#endif
/* add your own sensor code here */
      return 0;  
    default:
      return 0;
  }
}

#else
void sensorbegin() {}
float sensorread(uint8_t s, uint8_t v) {return 0;};
#endif

/* 
 *  event handling wrappers, to keep Arduino specifics out of BASIC
 */

#ifdef ARDUINOINTERRUPTS
uint8_t pintointerrupt(uint8_t pin) { return digitalPinToInterrupt(pin); }
void attachinterrupt(uint8_t interrupt, void (*f)(), uint8_t mode) { attachInterrupt(interrupt, f, (PinStatus) mode); };
void detachinterrupt(uint8_t pin) { detachInterrupt(digitalPinToInterrupt(pin)); };
#else 
uint8_t pintointerrupt(uint8_t pin) { return 0; }
void attachinterrupt(uint8_t interrupt, void (*f)(), uint8_t mode) {  };
void detachinterrupt(uint8_t pin) {  };
#endif

/*
 * Experimental code to drive SPI SRAM 
 *
 * Currently only the 23LCV512 is implemented, assuming a 
 * 64kB SRAM
 * The code below is taken in part from the SRAMsimple library
 * 
 * two buffers are implemented: 
 * - a ro buffer used by memread, this buffer is mainly reading the token 
 *  stream at runtime. 
 * - a rw buffer used by memread2 and memwrite2, this buffer is mainly accessing
 *  the heap at runtime. In interactive mode this is also the interface to read 
 *  and write program code to memory 
 * 
 */

#ifdef ARDUINOSPIRAM

/* 
 *  we use the standard slave select pin as default 
 *  RAMPIN
 */
#ifndef RAMPIN
#define RAMPIN SS
#endif

#define SPIRAMWRMR  1 
#define SPIRAMRDMR  5
#define SPIRAMREAD  3     
#define SPIRAMWRITE 2     
#define SPIRAMRSTIO 0xFF
#define SPIRAMSEQ   0x40
#define SPIRAMBYTE  0x00

/* the RAM begin method sets the RAM to sequential mode */
uint16_t spirambegin() {
  pinMode(RAMPIN, OUTPUT);
  digitalWrite(RAMPIN, LOW);
  SPI.transfer(SPIRAMRSTIO);
  SPI.transfer(SPIRAMWRMR);
  //SPI.transfer(SPIRAMBYTE);
  SPI.transfer(SPIRAMSEQ);
  digitalWrite(RAMPIN, HIGH);
  return 65535;
}

/* the simple unbuffered byte read, with a cast to signed 8 bit integer */
int8_t spiramrawread(uint16_t a) {
  uint8_t c;
  digitalWrite(RAMPIN, LOW);
  SPI.transfer(SPIRAMREAD);
  SPI.transfer((uint8_t)(a >> 8));
  SPI.transfer((uint8_t)a);
  c = SPI.transfer(0x00);
  digitalWrite(RAMPIN, HIGH);
  return c;
}

/* one read only buffer for access from the token stream 
    memread calls this */
uint16_t spiram_robufferaddr = 0;
uint8_t spiram_robuffervalid=0;
const uint8_t spiram_robuffersize = 32;
int8_t spiram_robuffer[spiram_robuffersize];

/* one rw buffer for access to the heap and all the program editing 
    memread2 and memwrite2 call this*/
uint16_t spiram_rwbufferaddr = 0;
uint8_t spiram_rwbuffervalid=0;
const uint8_t spiram_rwbuffersize = 32; /* also change the addressmask if you want to play here */
int8_t spiram_rwbuffer[spiram_rwbuffersize];
uint8_t spiram_rwbufferclean = 1; 

const uint16_t spiram_addrmask=0xffe0;
/* const address_t spiram_addrmask=0xffd0; // 64 byte frame */

/* the elementary buffer access functions used almost everywhere */

void spiram_bufferread(uint16_t a, int8_t* b, uint16_t l) {
  digitalWrite(RAMPIN, LOW);
  SPI.transfer(SPIRAMREAD);
  SPI.transfer((uint8_t)(a >> 8));
  SPI.transfer((uint8_t)a);
  SPI.transfer(b, l);
  digitalWrite(RAMPIN, HIGH);
} 

void spiram_bufferwrite(uint16_t a, int8_t* b, uint16_t l) {
  digitalWrite(RAMPIN, LOW); 
  SPI.transfer(SPIRAMWRITE);
  SPI.transfer((uint8_t)(a >> 8));
  SPI.transfer((uint8_t)a);
  SPI.transfer(b, l);
  digitalWrite(RAMPIN, HIGH);
}

int8_t spiram_robufferread(uint16_t a) {
/* we address a byte known to the rw buffer, then get it from there */
  if (spiram_rwbuffervalid && ((a & spiram_addrmask) == spiram_rwbufferaddr)) {
    return spiram_rwbuffer[a-spiram_rwbufferaddr];
  }
  
/* page fault, we dont have the byte in the ro buffer, so read from the chip*/
  if (!spiram_robuffervalid || a >= spiram_robufferaddr + spiram_robuffersize || a < spiram_robufferaddr ) {
      spiram_bufferread(a, spiram_robuffer, spiram_robuffersize);
      spiram_robufferaddr=a;
      spiram_robuffervalid=1;
  }
  return spiram_robuffer[a-spiram_robufferaddr];
}

/* flush the buffer */
void spiram_rwbufferflush() {
  if (!spiram_rwbufferclean) {
    spiram_bufferwrite(spiram_rwbufferaddr, spiram_rwbuffer, spiram_rwbuffersize);
    spiram_rwbufferclean=1;
   }
}

int8_t spiram_rwbufferread(uint16_t a) {
/* page fault, do read, ignore the ro buffer buffer */
  uint16_t p=a & spiram_addrmask;
  if (!spiram_rwbuffervalid || (p != spiram_rwbufferaddr)) {
/* flush the buffer if needed */
    spiram_rwbufferflush();
/* and reload it */
    spiram_bufferread(p, spiram_rwbuffer, spiram_rwbuffersize);
    spiram_rwbufferaddr=p; /* we only handle full pages here */
    spiram_rwbuffervalid=1;
  }
  return spiram_rwbuffer[a-spiram_rwbufferaddr];
}

/* the buffered file write */
void spiram_rwbufferwrite(uint16_t a, int8_t c) {
  uint16_t p=a&spiram_addrmask;
/* correct the two buffers if needed */
  if (spiram_robuffervalid && a >= spiram_robufferaddr && a < spiram_robufferaddr + spiram_robuffersize) {
    spiram_robuffer[a-spiram_robufferaddr]=c;
  }
/* if we have the frame, write it, mark the buffer dirty and return */
  if (spiram_rwbuffervalid && p == spiram_rwbufferaddr) {
    spiram_rwbuffer[a-spiram_rwbufferaddr]=c;
    spiram_rwbufferclean=0;
    return;
  }
/* if we end up here the write was impossible because we dont have the frame, so flush and then get it */
  spiram_rwbufferflush();
  (void) spiram_rwbufferread(a);
  spiram_rwbuffer[a-spiram_rwbufferaddr]=c;
  spiram_rwbufferclean=0;
}

/* the simple unbuffered byte write, with a cast to signed char */
void spiramrawwrite(uint16_t a, int8_t c) {
  digitalWrite(RAMPIN, LOW);
  SPI.transfer(SPIRAMWRITE);
  SPI.transfer((uint8_t)(a >> 8));
  SPI.transfer((uint8_t)a);
  SPI.transfer((uint8_t) c);
  digitalWrite(RAMPIN, HIGH);
/* also refresh the ro buffer if in the frame */
  if (a >= spiram_robufferaddr && a < spiram_robufferaddr + spiram_robuffersize && spiram_robufferaddr > 0) 
    spiram_robuffer[a-spiram_robufferaddr]=c;
/* and the rw buffer if needed) */
  if (a >= spiram_rwbufferaddr && a < spiram_rwbufferaddr + spiram_rwbuffersize && spiram_rwbufferaddr > 0) 
    spiram_rwbuffer[a-spiram_rwbufferaddr]=c;
}
#endif

#if defined(USEMEMINTERFACE)
/* 
 * to handle strings in situations with a memory interface two more buffers are 
 * needed they store intermediate results of string operations. The buffersize 
 * limits the maximum string length indepents of how big strings are set
 * 
 * default is 128, on an MEGA 512 is possible
 */
#ifdef ARDUINO_AVR_MEGA2560
#define SPIRAMSBSIZE 512
#else
#define SPIRAMSBSIZE 128
#endif

/* the string buffers of the memory interface */
char spistrbuf1[SPIRAMSBSIZE];
char spistrbuf2[SPIRAMSBSIZE];
#endif