Timer interrupts on Arduino Due

Using Arduino Project Guidance
1

This link shows how we do the timer interrupts on Arduino Uno or any board with ATMEL 328/168. Following this instruction, now I can change the interrupt frequency at whatever I want.

However, now I want to do this on Arduino Due, and I searched for some time but got nothing. Could anyone can teach me how I can do the same things on Due or show me where I can learn this with some examples...

Thanks very much!

2

Search in the DUE sub forum for Timer Counter or PWM programming. TC_lib or PWM_lib from antodom are a good starting point plus there are numerous example sketches with direct register programing either for Timer Counters or PWM.

3

Hi, many thanks for ard_newbie. I have also found your code for another question.

/******************************************************************/
/*       Timer Counter 2 Channel 2, namely TC8, 1 MHz frequency   */
/******************************************************************/
void setup() {

  pinMode(LED_BUILTIN, OUTPUT);
  tc_setup();

}

void loop() {

}

void tc_setup() {

  PMC->PMC_PCER1 |= PMC_PCER1_PID35;                        // TC8 power ON : Timer Counter 2 channel 2 IS TC8 - see page 38

  //PIOD->PIO_PDR |= PIO_PDR_P7;                            // Set the pin to the peripheral
  //PIOD->PIO_ABSR |= PIO_PD7B_TIOA8;                       // Peripheral type B

  TC2->TC_CHANNEL[2].TC_CMR = TC_CMR_TCCLKS_TIMER_CLOCK1  // MCK/2 = 42 M Hz, clk on rising edge
                              | TC_CMR_WAVE               // Waveform mode
                              | TC_CMR_WAVSEL_UP_RC;       // UP mode with automatic trigger on RC Compare
  //  | TC_CMR_ACPA_CLEAR         // Clear TIOA2 on RA compare match
  //  | TC_CMR_ACPC_SET;          // Set TIOA2 on RC compare match


  TC2->TC_CHANNEL[2].TC_RC = 42;  //<*********************  Frequency = (Mck/2)/TC_RC  Hz
  //TC2->TC_CHANNEL[2].TC_RA = 21;  //<********************   Any Duty cycle in between 1 and TC_RC


  TC2->TC_CHANNEL[2].TC_IER = TC_IER_CPCS;//TC_IER_CPAS;
  NVIC_EnableIRQ(TC8_IRQn);
  TC2->TC_CHANNEL[2].TC_CCR = TC_CCR_SWTRG | TC_CCR_CLKEN; // Software trigger TC2 counter and enable
}

void TC8_Handler() {

  static uint32_t Count;

  TC2->TC_CHANNEL[2].TC_SR;                               // Read and clear status register
  if (Count++ == 1000000) {
    Count = 0;
    PIOB->PIO_ODSR ^= PIO_ODSR_P27;                       // Toggle LED every 1 Hz
  }
}

Now, I came up with some new questions.... If you can answer it or anyone else, I will very appreciate it.

MC->PMC_PCER1 |= PMC_PCER1_PID35;                        // TC8 power ON : Timer Counter 2 channel 2 IS TC8 - see page 38
  1. Whether I change number 35 to 27, the TC0 will be switched on? The instance ID of TC0 is 27 based on the datasheet.
TC2->TC_CHANNEL[2].TC_CMR = TC_CMR_TCCLKS_TIMER_CLOCK1  // MCK/2 = 42 M Hz, clk on rising edge
  1. Whether the reason why MCK is divided by 2 is [2]? If I would like to change it, should I change that?
    Moreover, I don't quite understand the TC2 and CLCOK1 here... Can they be changed?

TC2->TC_CHANNEL[2].TC_RC = 42;  //<*********************  Frequency = (Mck/2)/TC_RC  Hz
3. I assume this is a kind of Compare Match. Can we change it? What is the maximum value? Is the maximum value the same as other TC0, TC1, TC2, etc.?

  1. Finally question. I assume that TC is counting for a specific value to have a timer interrupt. Suppose I would like to interrupt this timer interrupt and let it restart counting from 0. How do I do that?

Many many many thanks!

4

Topics on the same subject merged

Why did you start a new topic with a follow-on question ?