Timer Interrupts on Due

Hardware Arduino Due
91

mnpumar:

[quote author=Sebastian Vik link=topic=130423.msg984328#msg984328 date=1352148520]
Using this code, you can set a timer for any of the ISRs TC0_Handler through TC8_Handler, see table of parameters below. It is possible to use the timers without a physically mapped pin, such as TC1 channel 0 (TC3_Handler) shown here:

volatile boolean l;

//TC1 ch 0
void TC3_Handler()
{
       TC_GetStatus(TC1, 0);
       digitalWrite(13, l = !l);
}

void startTimer(Tc *tc, uint32_t channel, IRQn_Type irq, uint32_t frequency) {
       pmc_set_writeprotect(false);
       pmc_enable_periph_clk((uint32_t)irq);
       TC_Configure(tc, channel, TC_CMR_WAVE | TC_CMR_WAVSEL_UP_RC | TC_CMR_TCCLKS_TIMER_CLOCK4);
       uint32_t rc = VARIANT_MCK/128/frequency; //128 because we selected TIMER_CLOCK4 above
       TC_SetRA(tc, channel, rc/2); //50% high, 50% low
       TC_SetRC(tc, channel, rc);
       TC_Start(tc, channel);
       tc->TC_CHANNEL[channel].TC_IER=TC_IER_CPCS;
       tc->TC_CHANNEL[channel].TC_IDR=~TC_IER_CPCS;
       NVIC_EnableIRQ(irq);
}

void setup(){
       pinMode(13,OUTPUT);
       startTimer(TC1, 0, TC3_IRQn, 4); //TC1 channel 0, the IRQ for that channel and the desired frequency
}

void loop(){
}




Here is the table of parameters:


| ISR/IRQ | TC | Channel | Due pins |
| - | - | - | - |
| TC0 | TC0 | 0 | 2, 13 |
| TC1 | TC0 | 1 | 60, 61 |
| TC2 | TC0 | 2 | 58 |
| TC3 | TC1 | 0 | none <- this line in the example above |
| TC4 | TC1 | 1 | none |
| TC5 | TC1 | 2 | none |
| TC6 | TC2 | 0 | 4, 5 |
| TC7 | TC2 | 1 | 3, 10 |
| TC8 | TC2 | 2 | 11, 12 |

Noob question here, could someone please explain the inputs to the startTimer function? What is channel, and how do we use the frequency input? Also, what are the pins in the table for?
[/quote]

Can anyone kindly answer to the following question please?
How can we disable the Timer by turning off the PWM? (Outside of Timer Function)