| /* IRLibSAMD21.h | |
| * Part of IRLib Library for Arduino receiving, decoding, and sending | |
| * infrared signals. See COPYRIGHT.txt and LICENSE.txt for more information. | |
| * | |
| * This type of content is normally stored in IRLibHardware.h but we have | |
| * moved at her because the SAMD21 support is significantly different than the | |
| * AVR 8-bit hardware support. Separating it out into a separate file | |
| * will make it easier to include comments and to maintain the code. | |
| */ | |
| /* See IRLibSAMD21.h for details about this implementation. | |
| */ | |
| //Save some typing | |
| void initializeSAMD21PWM(uint16_t khz) { | |
| // Enable the port multiplexer for the PWM channel on pin | |
| PORT->Group[IR_APD.ulPort].PINCFG[IR_APD.ulPin].bit.PMUXEN = 1; | |
| // Connect the TCC timer to the port outputs - port pins are paired odd PMUXO and even PMUXE | |
| // F & E peripherals specify the timers: TCC0, TCC1 and TCC2 | |
| PORT->Group[IR_APD.ulPort].PMUX[IR_APD.ulPin >> 1].reg |= IR_MUX_EF; | |
| // Feed GCLK0 to TCC0 and TCC1 | |
| REG_GCLK_CLKCTRL = GCLK_CLKCTRL_CLKEN | // Enable GCLK0 to TCC0 and TCC1 | |
| GCLK_CLKCTRL_GEN_GCLK0 | // Select GCLK0 | |
| GCLK_CLKCTRL_ID_TCC0_TCC1; // Feed GCLK0 to TCC0 and TCC1 | |
| syncGCLK; // Wait for synchronization | |
| // Normal (single slope) PWM operation: timers countinuously count up to PER | |
| // register value and then is reset to 0 | |
| IR_TCCx->WAVE.reg |= TCC_WAVE_WAVEGEN_NPWM; // Setup single slope PWM on TCCx | |
| while (IR_TCCx->SYNCBUSY.bit.WAVE); // Wait for synchronization | |
| // Each timer counts up to a maximum or TOP value set by the PER register, | |
| // this determines the frequency of the PWM operation. | |
| uint32_t cc = F_CPU/(khz*1000) - 1; | |
| IR_TCCx->PER.reg = cc; // Set the frequency of the PWM on IR_TCCx | |
| while(IR_TCCx->SYNCBUSY.bit.PER); | |
| // The CCx register value corresponds to the pulsewidth in microseconds (us) | |
| IR_TCCx->CC[(IR_CCn & 0x03)].reg = cc/3; // Set the duty cycle of the PWM on TCC0 to 33% | |
| while(IR_TCCx->SYNCBUSY.bit.IR_CCx); | |
| // Enable IR_TCCx timer but do not turn on PWM yet. Will turn it on later. | |
| IR_TCCx->CTRLA.reg |= TCC_CTRLA_PRESCALER_DIV1; // Divide GCLK0 by 1 | |
| while (IR_TCCx->SYNCBUSY.bit.ENABLE); | |
| IR_TCCx->CTRLA.reg &= ~TCC_CTRLA_ENABLE; //initially off will turn on later | |
| while (IR_TCCx->SYNCBUSY.bit.ENABLE); | |
| } | |
| /* | |
| * Setup the 50 microsecond timer hardware interrupt for the IRrecv class. | |
| */ | |
| void initializeSAMD21timerInterrupt(void) { | |
| GCLK->CLKCTRL.reg = (uint16_t)(GCLK_CLKCTRL_CLKEN | | |
| GCLK_CLKCTRL_GEN_GCLK0 | | |
| GCLK_CLKCTRL_ID(IR_GCM)); | |
| syncGCLK; | |
| IR_TCx->COUNT16.CTRLA.reg &= ~TC_CTRLA_ENABLE; | |
| syncTC; | |
| IR_TCx->COUNT16.CTRLA.reg = TC_CTRLA_SWRST; | |
| while (IR_TCx->COUNT16.CTRLA.bit.SWRST); | |
| IR_TCx->COUNT16.CTRLA.reg |= TC_CTRLA_MODE_COUNT16; | |
| IR_TCx->COUNT16.CTRLA.reg |= TC_CTRLA_WAVEGEN_MFRQ; | |
| IR_TCx->COUNT16.CC[0].reg = F_CPU/(1000000/USEC_PER_TICK) - 1; | |
| syncTC; | |
| } | |