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Arduino-Development / libraries /LiquidCrystal /src /LiquidCrystal.cpp
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Archive original Arduino development files (part 8)
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#include "LiquidCrystal.h"
#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include "Arduino.h"
// When the display powers up, it is configured as follows:
//
// 1. Display clear
// 2. Function set:
// DL = 1; 8-bit interface data
// N = 0; 1-line display
// F = 0; 5x8 dot character font
// 3. Display on/off control:
// D = 0; Display off
// C = 0; Cursor off
// B = 0; Blinking off
// 4. Entry mode set:
// I/D = 1; Increment by 1
// S = 0; No shift
//
// Note, however, that resetting the Arduino doesn't reset the LCD, so we
// can't assume that its in that state when a sketch starts (and the
// LiquidCrystal constructor is called).
LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
{
init(0, rs, rw, enable, d0, d1, d2, d3, d4, d5, d6, d7);
}
LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
{
init(0, rs, 255, enable, d0, d1, d2, d3, d4, d5, d6, d7);
}
LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
{
init(1, rs, rw, enable, d0, d1, d2, d3, 0, 0, 0, 0);
}
LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
{
init(1, rs, 255, enable, d0, d1, d2, d3, 0, 0, 0, 0);
}
void LiquidCrystal::init(uint8_t fourbitmode, uint8_t rs, uint8_t rw, uint8_t enable,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
{
_rs_pin = rs;
_rw_pin = rw;
_enable_pin = enable;
_data_pins[0] = d0;
_data_pins[1] = d1;
_data_pins[2] = d2;
_data_pins[3] = d3;
_data_pins[4] = d4;
_data_pins[5] = d5;
_data_pins[6] = d6;
_data_pins[7] = d7;
if (fourbitmode)
_displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
else
_displayfunction = LCD_8BITMODE | LCD_1LINE | LCD_5x8DOTS;
begin(16, 1);
}
void LiquidCrystal::begin(uint8_t cols, uint8_t lines, uint8_t dotsize) {
if (lines > 1) {
_displayfunction |= LCD_2LINE;
}
_numlines = lines;
setRowOffsets(0x00, 0x40, 0x00 + cols, 0x40 + cols);
// for some 1 line displays you can select a 10 pixel high font
if ((dotsize != LCD_5x8DOTS) && (lines == 1)) {
_displayfunction |= LCD_5x10DOTS;
}
pinMode(_rs_pin, OUTPUT);
// we can save 1 pin by not using RW. Indicate by passing 255 instead of pin#
if (_rw_pin != 255) {
pinMode(_rw_pin, OUTPUT);
}
pinMode(_enable_pin, OUTPUT);
// Do these once, instead of every time a character is drawn for speed reasons.
for (int i=0; i<((_displayfunction & LCD_8BITMODE) ? 8 : 4); ++i)
{
pinMode(_data_pins[i], OUTPUT);
}
// SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
// according to datasheet, we need at least 40ms after power rises above 2.7V
// before sending commands. Arduino can turn on way before 4.5V so we'll wait 50
delayMicroseconds(50000);
// Now we pull both RS and R/W low to begin commands
digitalWrite(_rs_pin, LOW);
digitalWrite(_enable_pin, LOW);
if (_rw_pin != 255) {
digitalWrite(_rw_pin, LOW);
}
//put the LCD into 4 bit or 8 bit mode
if (! (_displayfunction & LCD_8BITMODE)) {
// this is according to the hitachi HD44780 datasheet
// figure 24, pg 46
// we start in 8bit mode, try to set 4 bit mode
write4bits(0x03);
delayMicroseconds(4500); // wait min 4.1ms
// second try
write4bits(0x03);
delayMicroseconds(4500); // wait min 4.1ms
// third go!
write4bits(0x03);
delayMicroseconds(150);
// finally, set to 4-bit interface
write4bits(0x02);
} else {
// this is according to the hitachi HD44780 datasheet
// page 45 figure 23
// Send function set command sequence
command(LCD_FUNCTIONSET | _displayfunction);
delayMicroseconds(4500); // wait more than 4.1ms
// second try
command(LCD_FUNCTIONSET | _displayfunction);
delayMicroseconds(150);
// third go
command(LCD_FUNCTIONSET | _displayfunction);
}
// finally, set # lines, font size, etc.
command(LCD_FUNCTIONSET | _displayfunction);
// turn the display on with no cursor or blinking default
_displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;
display();
// clear it off
clear();
// Initialize to default text direction (for romance languages)
_displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
// set the entry mode
command(LCD_ENTRYMODESET | _displaymode);
}
void LiquidCrystal::setRowOffsets(int row0, int row1, int row2, int row3)
{
_row_offsets[0] = row0;
_row_offsets[1] = row1;
_row_offsets[2] = row2;
_row_offsets[3] = row3;
}
/********** high level commands, for the user! */
void LiquidCrystal::clear()
{
command(LCD_CLEARDISPLAY); // clear display, set cursor position to zero
delayMicroseconds(2000); // this command takes a long time!
}
void LiquidCrystal::home()
{
command(LCD_RETURNHOME); // set cursor position to zero
delayMicroseconds(2000); // this command takes a long time!
}
void LiquidCrystal::setCursor(uint8_t col, uint8_t row)
{
const size_t max_lines = sizeof(_row_offsets) / sizeof(*_row_offsets);
if ( row >= max_lines ) {
row = max_lines - 1; // we count rows starting w/0
}
if ( row >= _numlines ) {
row = _numlines - 1; // we count rows starting w/0
}
command(LCD_SETDDRAMADDR | (col + _row_offsets[row]));
}
// Turn the display on/off (quickly)
void LiquidCrystal::noDisplay() {
_displaycontrol &= ~LCD_DISPLAYON;
command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LiquidCrystal::display() {
_displaycontrol |= LCD_DISPLAYON;
command(LCD_DISPLAYCONTROL | _displaycontrol);
}
// Turns the underline cursor on/off
void LiquidCrystal::noCursor() {
_displaycontrol &= ~LCD_CURSORON;
command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LiquidCrystal::cursor() {
_displaycontrol |= LCD_CURSORON;
command(LCD_DISPLAYCONTROL | _displaycontrol);
}
// Turn on and off the blinking cursor
void LiquidCrystal::noBlink() {
_displaycontrol &= ~LCD_BLINKON;
command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LiquidCrystal::blink() {
_displaycontrol |= LCD_BLINKON;
command(LCD_DISPLAYCONTROL | _displaycontrol);
}
// These commands scroll the display without changing the RAM
void LiquidCrystal::scrollDisplayLeft(void) {
command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
}
void LiquidCrystal::scrollDisplayRight(void) {
command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
}
// This is for text that flows Left to Right
void LiquidCrystal::leftToRight(void) {
_displaymode |= LCD_ENTRYLEFT;
command(LCD_ENTRYMODESET | _displaymode);
}
// This is for text that flows Right to Left
void LiquidCrystal::rightToLeft(void) {
_displaymode &= ~LCD_ENTRYLEFT;
command(LCD_ENTRYMODESET | _displaymode);
}
// This will 'right justify' text from the cursor
void LiquidCrystal::autoscroll(void) {
_displaymode |= LCD_ENTRYSHIFTINCREMENT;
command(LCD_ENTRYMODESET | _displaymode);
}
// This will 'left justify' text from the cursor
void LiquidCrystal::noAutoscroll(void) {
_displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
command(LCD_ENTRYMODESET | _displaymode);
}
// Allows us to fill the first 8 CGRAM locations
// with custom characters
void LiquidCrystal::createChar(uint8_t location, uint8_t charmap[]) {
location &= 0x7; // we only have 8 locations 0-7
command(LCD_SETCGRAMADDR | (location << 3));
for (int i=0; i<8; i++) {
write(charmap[i]);
}
}
/*********** mid level commands, for sending data/cmds */
inline void LiquidCrystal::command(uint8_t value) {
send(value, LOW);
}
inline size_t LiquidCrystal::write(uint8_t value) {
send(value, HIGH);
return 1; // assume sucess
}
/************ low level data pushing commands **********/
// write either command or data, with automatic 4/8-bit selection
void LiquidCrystal::send(uint8_t value, uint8_t mode) {
digitalWrite(_rs_pin, mode);
// if there is a RW pin indicated, set it low to Write
if (_rw_pin != 255) {
digitalWrite(_rw_pin, LOW);
}
if (_displayfunction & LCD_8BITMODE) {
write8bits(value);
} else {
write4bits(value>>4);
write4bits(value);
}
}
void LiquidCrystal::pulseEnable(void) {
digitalWrite(_enable_pin, LOW);
delayMicroseconds(1);
digitalWrite(_enable_pin, HIGH);
delayMicroseconds(1); // enable pulse must be >450ns
digitalWrite(_enable_pin, LOW);
delayMicroseconds(100); // commands need > 37us to settle
}
void LiquidCrystal::write4bits(uint8_t value) {
for (int i = 0; i < 4; i++) {
digitalWrite(_data_pins[i], (value >> i) & 0x01);
}
pulseEnable();
}
void LiquidCrystal::write8bits(uint8_t value) {
for (int i = 0; i < 8; i++) {
digitalWrite(_data_pins[i], (value >> i) & 0x01);
}
pulseEnable();
}