Revisions to About ATmega32 event system

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edited Jun 8, 2019 at 17:30

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The 'old' ATmega 8 bit microcontrollers don't have an event system peripheral. The new "megaAVR 0 series" has an event system. Atmega 4809 on Arduino Uno WiFi Rev2 and on Nano 33 EverEvery is "megaAVR 0-series". The event system of the new ATmegas is similar to SAMD event system I know.

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edited Jun 8, 2019 at 16:26

Juraj ♦

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a simple Arduino SAMD lib for a Triac/ZC module (in development):

#ifndef _TRIAC_LIB_
#define _TRIAC_LIB_

namespace Triac {

const unsigned long AC_WAVE_MICROS = 10000; // at 50 Hz
const int TIMER_PRESCALER = 8;
const unsigned long PULSE_PERIOD = ((F_CPU / 1000000) * 200) / TIMER_PRESCALER;

Tcc* TCC;

void syncTCC(Tcc* TCCx) {
  while (TCCxTCC->SYNCBUSY.reg & TCC_SYNCBUSY_MASK);
}

void zeroCrossing() {
}


void triacSetupsetup(byte zcPin, byte triacPin) {

  // setup the external interrupt
  attachInterrupt(ZC_EI_PINzcPin, zeroCrossing, RISING);
  uint8_t ulExtInt = g_APinDescription[ZC_EI_PIN]g_APinDescription[zcPin].ulExtInt;
  EIC->EVCTRL.reg |= (1 << ulExtInt);// enable event
  EIC->INTENCLR.reg = EIC_INTENCLR_EXTINT(1 << ulExtInt); // turn-off interrupt

  const PinDescription& pinDesc = g_APinDescription[TRIAC_PIN];g_APinDescription[triacPin]; // Arduino pin description
  Tcc* TCC = (Tcc*) GetTC(pinDesc.ulPWMChannel);
  uint8_t tcChannel = GetTCChannelNumber(pinDesc.ulPWMChannel);

  // setup the pin as TCC wave out pin
  PORT->Group[pinDesc.ulPort].PINCFG[pinDesc.ulPin].bit.PMUXEN = 1;
  PORT->Group[pinDesc.ulPort].PMUX[pinDesc.ulPin >> 1].reg |= PORT_PMUX_PMUXE_F;

  // setup the timer

  REG_GCLK_CLKCTRL = (uint16_t) (GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID(GCM_TCC0_TCC1)); // assign clock
  while ( GCLK->STATUS.bit.SYNCBUSY == 1 );

  TCC->CTRLA.bit.SWRST = 1; // reset timer
  syncTCC(TCC);
  TCC->WAVE.reg |= TCC_WAVE_WAVEGEN_NPWM; // normal PWM as wave output mode
  syncTCC(TCC);
  TCC->CTRLBSET.reg = TCC_CTRLBSET_ONESHOT | TCC_CTRLBSET_DIR; //one shot and count down
  syncTCC(TCC);

  TCC->PER.reg = ((F_CPU / 1000000) * AC_WAVE_MICROS) / TIMER_PRESCALER; // initial value of period (triac off)
  syncTCC(TCC);
  TCC->CC[tcChannel].reg = PULSE_PERIOD; // pin on at compare match and off at 0 (timer counts down)
  syncTCC(TCC);

  TCC->EVCTRL.reg |= TCC_EVCTRL_TCEI0 | TCC_EVCTRL_EVACT0_RETRIGGER; // retrigger on event
  syncTCC(TCC);
  TCC->CTRLA.reg |= TCC_CTRLA_PRESCALER_DIV8 | TCC_CTRLA_ENABLE; // set prescaler and enable
  syncTCC(TCC);

  // event system
  PM->APBCMASK.reg |= PM_APBCMASK_EVSYS; // power it on
  GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(EVSYS_GCLK_ID_0) | GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN(0); // assign a clock
  while (GCLK->STATUS.bit.SYNCBUSY);

  EVSYS->CTRL.bit.SWRST = 1; // reset
  while(EVSYS->CTRL.bit.SWRST);

  EVSYS->USER.reg = EVSYS_ID_USER_TCC0_EV_0 | EVSYS_USER_CHANNEL(1); // set user TCC0 event 0 on channel 0
  EVSYS->CHANNEL.reg = EVSYS_CHANNEL_CHANNEL(0) | EVSYS_CHANNEL_PATH_ASYNCHRONOUS | // channel 0 is async
      EVSYS_CHANNEL_EDGSEL_FALLING_EDGE | EVSYS_CHANNEL_EVGEN(EVSYS_ID_GEN_EIC_EXTINT_0 + ulExtInt); // source is ext.interrupt
  while (!EVSYS->CHSTATUS.bit.USRRDY0);
}

/*
 * r is from interval <0.0, 1.0>
 */
void triacSetPeriodsetPeriod(float r) {
  unsigned long period = ((F_CPU / 1000000) * ((1.0 - r) * AC_WAVE_MICROS)) / TIMER_PRESCALER;
  Tcc* TCC = (Tcc*) GetTC(g_APinDescription[TRIAC_PIN].ulPWMChannel);
  TCC->PER.reg = period + PULSE_PERIOD;
  syncTCC(TCC);
}

}
#endif

const unsigned long AC_WAVE_MICROS = 10000; // at 50 Hz
const int TIMER_PRESCALER = 8;
const unsigned long PULSE_PERIOD = ((F_CPU / 1000000) * 200) / TIMER_PRESCALER;

void syncTCC(Tcc* TCCx) {
  while (TCCx->SYNCBUSY.reg & TCC_SYNCBUSY_MASK);
}

void zeroCrossing() {
}


void triacSetup() {

  // setup the external interrupt
  attachInterrupt(ZC_EI_PIN, zeroCrossing, RISING);
  uint8_t ulExtInt = g_APinDescription[ZC_EI_PIN].ulExtInt;
  EIC->EVCTRL.reg |= (1 << ulExtInt);// enable event
  EIC->INTENCLR.reg = EIC_INTENCLR_EXTINT(1 << ulExtInt); // turn-off interrupt

  const PinDescription& pinDesc = g_APinDescription[TRIAC_PIN]; // Arduino pin description
  Tcc* TCC = (Tcc*) GetTC(pinDesc.ulPWMChannel);
  uint8_t tcChannel = GetTCChannelNumber(pinDesc.ulPWMChannel);

  // setup the pin as TCC wave out pin
  PORT->Group[pinDesc.ulPort].PINCFG[pinDesc.ulPin].bit.PMUXEN = 1;
  PORT->Group[pinDesc.ulPort].PMUX[pinDesc.ulPin >> 1].reg |= PORT_PMUX_PMUXE_F;

  // setup the timer

  REG_GCLK_CLKCTRL = (uint16_t) (GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID(GCM_TCC0_TCC1)); // assign clock
  while ( GCLK->STATUS.bit.SYNCBUSY == 1 );

  TCC->CTRLA.bit.SWRST = 1; // reset timer
  syncTCC(TCC);
  TCC->WAVE.reg |= TCC_WAVE_WAVEGEN_NPWM; // normal PWM as wave output mode
  syncTCC(TCC);
  TCC->CTRLBSET.reg = TCC_CTRLBSET_ONESHOT | TCC_CTRLBSET_DIR; //one shot and count down
  syncTCC(TCC);

  TCC->PER.reg = ((F_CPU / 1000000) * AC_WAVE_MICROS) / TIMER_PRESCALER; // initial value of period (triac off)
  syncTCC(TCC);
  TCC->CC[tcChannel].reg = PULSE_PERIOD; // pin on at compare match and off at 0 (timer counts down)
  syncTCC(TCC);

  TCC->EVCTRL.reg |= TCC_EVCTRL_TCEI0 | TCC_EVCTRL_EVACT0_RETRIGGER; // retrigger on event
  syncTCC(TCC);
  TCC->CTRLA.reg |= TCC_CTRLA_PRESCALER_DIV8 | TCC_CTRLA_ENABLE; // set prescaler and enable
  syncTCC(TCC);

  // event system
  PM->APBCMASK.reg |= PM_APBCMASK_EVSYS; // power it on
  GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(EVSYS_GCLK_ID_0) | GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN(0); // assign a clock
  while (GCLK->STATUS.bit.SYNCBUSY);

  EVSYS->CTRL.bit.SWRST = 1; // reset
  while(EVSYS->CTRL.bit.SWRST);

  EVSYS->USER.reg = EVSYS_ID_USER_TCC0_EV_0 | EVSYS_USER_CHANNEL(1); // set user TCC0 event 0 on channel 0
  EVSYS->CHANNEL.reg = EVSYS_CHANNEL_CHANNEL(0) | EVSYS_CHANNEL_PATH_ASYNCHRONOUS | // channel 0 is async
      EVSYS_CHANNEL_EDGSEL_FALLING_EDGE | EVSYS_CHANNEL_EVGEN(EVSYS_ID_GEN_EIC_EXTINT_0 + ulExtInt); // source is ext.interrupt
  while (!EVSYS->CHSTATUS.bit.USRRDY0);
}

/*
 * r is interval <0.0, 1.0>
 */
void triacSetPeriod(float r) {
  unsigned long period = ((F_CPU / 1000000) * ((1.0 - r) * AC_WAVE_MICROS)) / TIMER_PRESCALER;
  Tcc* TCC = (Tcc*) GetTC(g_APinDescription[TRIAC_PIN].ulPWMChannel);
  TCC->PER.reg = period + PULSE_PERIOD;
  syncTCC(TCC);
}

a simple Arduino SAMD lib for a Triac/ZC module (in development):

#ifndef _TRIAC_LIB_
#define _TRIAC_LIB_

namespace Triac {

const unsigned long AC_WAVE_MICROS = 10000; // at 50 Hz
const int TIMER_PRESCALER = 8;
const unsigned long PULSE_PERIOD = ((F_CPU / 1000000) * 200) / TIMER_PRESCALER;

Tcc* TCC;

void syncTCC() {
  while (TCC->SYNCBUSY.reg & TCC_SYNCBUSY_MASK);
}

void zeroCrossing() {
}


void setup(byte zcPin, byte triacPin) {

  // setup the external interrupt
  attachInterrupt(zcPin, zeroCrossing, RISING);
  uint8_t ulExtInt = g_APinDescription[zcPin].ulExtInt;
  EIC->EVCTRL.reg |= (1 << ulExtInt);// enable event
  EIC->INTENCLR.reg = EIC_INTENCLR_EXTINT(1 << ulExtInt); // turn-off interrupt

  const PinDescription& pinDesc = g_APinDescription[triacPin]; // Arduino pin description
  TCC = (Tcc*) GetTC(pinDesc.ulPWMChannel);
  uint8_t tcChannel = GetTCChannelNumber(pinDesc.ulPWMChannel);

  // setup the pin as TCC wave out pin
  PORT->Group[pinDesc.ulPort].PINCFG[pinDesc.ulPin].bit.PMUXEN = 1;
  PORT->Group[pinDesc.ulPort].PMUX[pinDesc.ulPin >> 1].reg |= PORT_PMUX_PMUXE_F;

  // setup the timer

  REG_GCLK_CLKCTRL = (uint16_t) (GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID(GCM_TCC0_TCC1)); // assign clock
  while ( GCLK->STATUS.bit.SYNCBUSY == 1 );

  TCC->CTRLA.bit.SWRST = 1; // reset timer
  syncTCC();
  TCC->WAVE.reg |= TCC_WAVE_WAVEGEN_NPWM; // normal PWM as wave output mode
  syncTCC();
  TCC->CTRLBSET.reg = TCC_CTRLBSET_ONESHOT | TCC_CTRLBSET_DIR; //one shot and count down
  syncTCC();

  TCC->PER.reg = ((F_CPU / 1000000) * AC_WAVE_MICROS) / TIMER_PRESCALER; // initial value of period (triac off)
  syncTCC();
  TCC->CC[tcChannel].reg = PULSE_PERIOD; // pin on at compare match and off at 0 (timer counts down)
  syncTCC();

  TCC->EVCTRL.reg |= TCC_EVCTRL_TCEI0 | TCC_EVCTRL_EVACT0_RETRIGGER; // retrigger on event
  syncTCC();
  TCC->CTRLA.reg |= TCC_CTRLA_PRESCALER_DIV8 | TCC_CTRLA_ENABLE; // set prescaler and enable
  syncTCC();

  // event system
  PM->APBCMASK.reg |= PM_APBCMASK_EVSYS; // power it on
  GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(EVSYS_GCLK_ID_0) | GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN(0); // assign a clock
  while (GCLK->STATUS.bit.SYNCBUSY);

  EVSYS->CTRL.bit.SWRST = 1; // reset
  while(EVSYS->CTRL.bit.SWRST);

  EVSYS->USER.reg = EVSYS_ID_USER_TCC0_EV_0 | EVSYS_USER_CHANNEL(1); // set user TCC0 event 0 on channel 0
  EVSYS->CHANNEL.reg = EVSYS_CHANNEL_CHANNEL(0) | EVSYS_CHANNEL_PATH_ASYNCHRONOUS | // channel 0 is async
      EVSYS_CHANNEL_EDGSEL_FALLING_EDGE | EVSYS_CHANNEL_EVGEN(EVSYS_ID_GEN_EIC_EXTINT_0 + ulExtInt); // source is ext.interrupt
  while (!EVSYS->CHSTATUS.bit.USRRDY0);
}

/*
 * r is from interval <0.0, 1.0>
 */
void setPeriod(float r) {
  unsigned long period = ((F_CPU / 1000000) * ((1.0 - r) * AC_WAVE_MICROS)) / TIMER_PRESCALER;
  TCC->PER.reg = period + PULSE_PERIOD;
  syncTCC();
}

}
#endif

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edited Jun 8, 2019 at 14:14

Juraj ♦

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const unsigned long AC_WAVE_MICROS = 10000; // at 50 Hz
const int TIMER_PRESCALER = 8;
const unsigned long PULSE_PERIOD = ((F_CPU / 1000000) * 200) / TIMER_PRESCALER;

void syncTCC(Tcc* TCCx) {
  while (TCCx->SYNCBUSY.reg & TCC_SYNCBUSY_MASK);
}

void zeroCrossing() {
}


void triacSetup() { 

  // setup the external interrupt
  attachInterrupt(ZC_EI_PIN, zeroCrossing, RISING);
  uint8_t ulExtInt = g_APinDescription[ZC_EI_PIN].ulExtInt;
  EIC->EVCTRL.reg |= (1 << ulExtInt);// enable event
  EIC->INTENCLR.reg = EIC_INTENCLR_EXTINT(1 << ulExtInt); // turn-off interrupt

  const PinDescription& pinDesc = g_APinDescription[TRIAC_PIN]; // Arduino pin description
  Tcc* TCC = (Tcc*) GetTC(pinDesc.ulPWMChannel);
  uint8_t tcChannel = GetTCChannelNumber(pinDesc.ulPWMChannel);

  // setup the pin as TCC wave out pin
  PORT->Group[pinDesc.ulPort].PINCFG[pinDesc.ulPin].bit.PMUXEN = 1;
  PORT->Group[pinDesc.ulPort].PMUX[pinDesc.ulPin >> 1].reg |= PORT_PMUX_PMUXE_F;

  // setup the timer

  REG_GCLK_CLKCTRL = (uint16_t) (GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID(GCM_TCC0_TCC1)) ; // assign clock
  while ( GCLK->STATUS.bit.SYNCBUSY == 1 );

  TCC->CTRLA.bit.SWRST = 1; // reset timer
  syncTCC(TCC);
  TCC->WAVE.reg |= TCC_WAVE_WAVEGEN_NPWM; // normal PWM as wave output mode
  syncTCC(TCC);
  TCC->CTRLBSET.reg = TCC_CTRLBSET_ONESHOT | TCC_CTRLBSET_DIR; //one shot and count down
  syncTCC(TCC);

  TCC->PER.reg = ((F_CPU / 1000000) * AC_WAVE_MICROS) / TIMER_PRESCALER; // initial value of period (triac off)
  syncTCC(TCC);
  TCC->CC[tcChannel].reg = PULSE_PERIOD; // pin on at compare match and off at 0 (timer counts down)
  syncTCC(TCC);

  TCC->EVCTRL.reg |= TCC_EVCTRL_TCEI0 | TCC_EVCTRL_EVACT0_RETRIGGER; // retrigger on event
  syncTCC(TCC);
  TCC->CTRLA.reg |= TCC_CTRLA_PRESCALER_DIV8 | TCC_CTRLA_ENABLE; // set prescaler and enable
  syncTCC(TCC);

  // event system
  PM->APBCMASK.reg |= PM_APBCMASK_EVSYS; // power it on
  GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(EVSYS_GCLK_ID_0) | GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN(0); // assign a clock
  while (GCLK->STATUS.bit.SYNCBUSY);

  EVSYS->CTRL.bit.SWRST = 1; // reset
  while(EVSYS->CTRL.bit.SWRST);

  EVSYS->USER.reg = EVSYS_ID_USER_TCC0_EV_0 | EVSYS_USER_CHANNEL(1); // set user TCC0 event 0 on channel 0
  EVSYS->CHANNEL.reg = EVSYS_CHANNEL_CHANNEL(0) | EVSYS_CHANNEL_PATH_ASYNCHRONOUS | // channel 0 is async
      EVSYS_CHANNEL_EDGSEL_FALLING_EDGE | EVSYS_CHANNEL_EVGEN(EVSYS_ID_GEN_EIC_EXTINT_0 + ulExtInt); // source is ext.interrupt
  while (!EVSYS->CHSTATUS.bit.USRRDY0);
}

/*
 * r is interval <0.0, 1.0>
 */
void triacSetPeriod(float r) {
  unsigned long period = ((F_CPU / 1000000) * ((1.0 - r) * AC_WAVE_MICROS)) / TIMER_PRESCALER;
  Tcc* TCC = (Tcc*) GetTC(g_APinDescription[TRIAC_PIN].ulPWMChannel);
  TCC->PER.reg = period + PULSE_PERIOD;
  syncTCC(TCC);
}

const unsigned long AC_WAVE_MICROS = 10000; // at 50 Hz
const int TIMER_PRESCALER = 8;
const unsigned long PULSE_PERIOD = ((F_CPU / 1000000) * 200) / TIMER_PRESCALER;

void syncTCC(Tcc* TCCx) {
  while (TCCx->SYNCBUSY.reg & TCC_SYNCBUSY_MASK);
}

void zeroCrossing() {
}


void triacSetup() {
  attachInterrupt(ZC_EI_PIN, zeroCrossing, RISING);
  uint8_t ulExtInt = g_APinDescription[ZC_EI_PIN].ulExtInt;
  EIC->EVCTRL.reg |= (1 << ulExtInt);// enable event
  EIC->INTENCLR.reg = EIC_INTENCLR_EXTINT(1 << ulExtInt); // turn-off interrupt

  const PinDescription& pinDesc = g_APinDescription[TRIAC_PIN];
  Tcc* TCC = (Tcc*) GetTC(pinDesc.ulPWMChannel);
  uint8_t tcChannel = GetTCChannelNumber(pinDesc.ulPWMChannel);

  PORT->Group[pinDesc.ulPort].PINCFG[pinDesc.ulPin].bit.PMUXEN = 1;
  PORT->Group[pinDesc.ulPort].PMUX[pinDesc.ulPin >> 1].reg |= PORT_PMUX_PMUXE_F;

  REG_GCLK_CLKCTRL = (uint16_t) (GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID(GCM_TCC0_TCC1)) ;
  while ( GCLK->STATUS.bit.SYNCBUSY == 1 );

  TCC->CTRLA.bit.SWRST = 1; // reset timer
  syncTCC(TCC);
  TCC->WAVE.reg |= TCC_WAVE_WAVEGEN_NPWM; // normal PWM as wave output mode
  syncTCC(TCC);
  TCC->CTRLBSET.reg = TCC_CTRLBSET_ONESHOT | TCC_CTRLBSET_DIR; //one shot and count down
  syncTCC(TCC);

  TCC->PER.reg = ((F_CPU / 1000000) * AC_WAVE_MICROS) / TIMER_PRESCALER; // initial value of period (triac off)
  syncTCC(TCC);
  TCC->CC[tcChannel].reg = PULSE_PERIOD; // pin on at compare match and off at 0 (timer counts down)
  syncTCC(TCC);

  TCC->EVCTRL.reg |= TCC_EVCTRL_TCEI0 | TCC_EVCTRL_EVACT0_RETRIGGER; // retrigger on event
  syncTCC(TCC);
  TCC->CTRLA.reg |= TCC_CTRLA_PRESCALER_DIV8 | TCC_CTRLA_ENABLE; // set prescaler and enable
  syncTCC(TCC);

  // event system
  PM->APBCMASK.reg |= PM_APBCMASK_EVSYS; // power it on
  GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(EVSYS_GCLK_ID_0) | GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN(0); // assign a clock
  while (GCLK->STATUS.bit.SYNCBUSY);

  EVSYS->CTRL.bit.SWRST = 1; // reset
  while(EVSYS->CTRL.bit.SWRST);

  EVSYS->USER.reg = EVSYS_ID_USER_TCC0_EV_0 | EVSYS_USER_CHANNEL(1); // set user TCC0 event 0 on channel 0
  EVSYS->CHANNEL.reg = EVSYS_CHANNEL_CHANNEL(0) | EVSYS_CHANNEL_PATH_ASYNCHRONOUS | // channel 0 is async
      EVSYS_CHANNEL_EDGSEL_FALLING_EDGE | EVSYS_CHANNEL_EVGEN(EVSYS_ID_GEN_EIC_EXTINT_0 + ulExtInt); // source is ext.interrupt
  while (!EVSYS->CHSTATUS.bit.USRRDY0);
}

void triacSetPeriod(float r) {
  unsigned long period = ((F_CPU / 1000000) * (r * AC_WAVE_MICROS)) / TIMER_PRESCALER;
  Tcc* TCC = (Tcc*) GetTC(g_APinDescription[TRIAC_PIN].ulPWMChannel);
  TCC->PER.reg = period + PULSE_PERIOD;
  syncTCC(TCC);
}

const unsigned long AC_WAVE_MICROS = 10000; // at 50 Hz
const int TIMER_PRESCALER = 8;
const unsigned long PULSE_PERIOD = ((F_CPU / 1000000) * 200) / TIMER_PRESCALER;

void syncTCC(Tcc* TCCx) {
  while (TCCx->SYNCBUSY.reg & TCC_SYNCBUSY_MASK);
}

void zeroCrossing() {
}


void triacSetup() { 

  // setup the external interrupt
  attachInterrupt(ZC_EI_PIN, zeroCrossing, RISING);
  uint8_t ulExtInt = g_APinDescription[ZC_EI_PIN].ulExtInt;
  EIC->EVCTRL.reg |= (1 << ulExtInt);// enable event
  EIC->INTENCLR.reg = EIC_INTENCLR_EXTINT(1 << ulExtInt); // turn-off interrupt

  const PinDescription& pinDesc = g_APinDescription[TRIAC_PIN]; // Arduino pin description
  Tcc* TCC = (Tcc*) GetTC(pinDesc.ulPWMChannel);
  uint8_t tcChannel = GetTCChannelNumber(pinDesc.ulPWMChannel);

  // setup the pin as TCC wave out pin
  PORT->Group[pinDesc.ulPort].PINCFG[pinDesc.ulPin].bit.PMUXEN = 1;
  PORT->Group[pinDesc.ulPort].PMUX[pinDesc.ulPin >> 1].reg |= PORT_PMUX_PMUXE_F;

  // setup the timer

  REG_GCLK_CLKCTRL = (uint16_t) (GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID(GCM_TCC0_TCC1)); // assign clock
  while ( GCLK->STATUS.bit.SYNCBUSY == 1 );

  TCC->CTRLA.bit.SWRST = 1; // reset timer
  syncTCC(TCC);
  TCC->WAVE.reg |= TCC_WAVE_WAVEGEN_NPWM; // normal PWM as wave output mode
  syncTCC(TCC);
  TCC->CTRLBSET.reg = TCC_CTRLBSET_ONESHOT | TCC_CTRLBSET_DIR; //one shot and count down
  syncTCC(TCC);

  TCC->PER.reg = ((F_CPU / 1000000) * AC_WAVE_MICROS) / TIMER_PRESCALER; // initial value of period (triac off)
  syncTCC(TCC);
  TCC->CC[tcChannel].reg = PULSE_PERIOD; // pin on at compare match and off at 0 (timer counts down)
  syncTCC(TCC);

  TCC->EVCTRL.reg |= TCC_EVCTRL_TCEI0 | TCC_EVCTRL_EVACT0_RETRIGGER; // retrigger on event
  syncTCC(TCC);
  TCC->CTRLA.reg |= TCC_CTRLA_PRESCALER_DIV8 | TCC_CTRLA_ENABLE; // set prescaler and enable
  syncTCC(TCC);

  // event system
  PM->APBCMASK.reg |= PM_APBCMASK_EVSYS; // power it on
  GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(EVSYS_GCLK_ID_0) | GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN(0); // assign a clock
  while (GCLK->STATUS.bit.SYNCBUSY);

  EVSYS->CTRL.bit.SWRST = 1; // reset
  while(EVSYS->CTRL.bit.SWRST);

  EVSYS->USER.reg = EVSYS_ID_USER_TCC0_EV_0 | EVSYS_USER_CHANNEL(1); // set user TCC0 event 0 on channel 0
  EVSYS->CHANNEL.reg = EVSYS_CHANNEL_CHANNEL(0) | EVSYS_CHANNEL_PATH_ASYNCHRONOUS | // channel 0 is async
      EVSYS_CHANNEL_EDGSEL_FALLING_EDGE | EVSYS_CHANNEL_EVGEN(EVSYS_ID_GEN_EIC_EXTINT_0 + ulExtInt); // source is ext.interrupt
  while (!EVSYS->CHSTATUS.bit.USRRDY0);
}

/*
 * r is interval <0.0, 1.0>
 */
void triacSetPeriod(float r) {
  unsigned long period = ((F_CPU / 1000000) * ((1.0 - r) * AC_WAVE_MICROS)) / TIMER_PRESCALER;
  Tcc* TCC = (Tcc*) GetTC(g_APinDescription[TRIAC_PIN].ulPWMChannel);
  TCC->PER.reg = period + PULSE_PERIOD;
  syncTCC(TCC);
}

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edited Jun 8, 2019 at 13:03

Juraj ♦

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edited Jun 8, 2019 at 10:57

Juraj ♦

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answered Jun 8, 2019 at 10:53

Juraj ♦

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