Use TCC1 timer to generate PWM on personnal board built with SAMD21E18A

Question

I'm trying to generate a PWM signal from TCC1. I have a personnal board built with SAMD21E18A. I want to use pin 27 PA30, in my variant.cpp I have this line:

{ PORTA, 30, PIO_PWM, PIN_ATTR_DIGITAL|PIO_SERCOM, No_ADC_Channel, NOT_ON_PWM, TCC1_CH0, EXTERNAL_INT_10 }, // SWCLK

I understand I can use TCC1_CH0 on this pin with PIO_TIMER. Here is what I've tried at the end of my setup:

 pinPeripheral(27, PIO_TIMER);
 pinMode(27, OUTPUT);
 ....
 Tcc* TC = (Tcc*)GetTC(TCC1_CH0);
 TC->CTRLA.reg &= ~TCC_CTRLA_ENABLE; 
 TC->CTRLA.reg |= TCC_CTRLA_PRESCALER_DIV1; 
 TC->WAVE.reg |= TCC_WAVE_WAVEGEN_NPWM; 
 TC->PER.reg = 255; 
 TC->CC[0].reg = 128; 
 TC->CTRLA.reg |= TCC_CTRLA_ENABLE; 

But it's not working: I have nothing on my pin.

Edit: I've also tried this in my setup:

 GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(TCC1_GCLK_ID) |
 GCLK_CLKCTRL_GEN_GCLK0 |
 GCLK_CLKCTRL_CLKEN;
 while (GCLK->STATUS.bit.SYNCBUSY);
 Tcc* TC = (Tcc*) TCC1;
 TC->CTRLA.reg &= ~TCC_CTRLA_ENABLE; 
 TC->WAVE.reg = TCC_WAVE_WAVEGEN_NPWM;
 TC->CTRLA.reg |= TCC_CTRLA_PRESCALER_DIV1 | 
 TCC_CTRLA_RUNSTDBY; 
 PORT->Group[PORTA].PINCFG[30].bit.PMUXEN = 1; 
 PORT->Group[PORTA].PMUX[15].reg = PORT_PMUX_PMUXE_E; 
 TC->CC[0].reg = 1000; 
 TC->CC[1].reg = 4000; 
 // Activer le timer
 TC->CTRLA.reg |= TCC_CTRLA_ENABLE;
 while (TC->SYNCBUSY.bit.ENABLE);

I have something on my oscilloscope, but the signal seems not to be good, HIGH signal is very very quick and low signal very long.

Answer 1

For example, settings for ATSAMR21G18A (it is similar to you MCU), PA08 PWM:

Pin init:

// GPIO PA08 PWM (DO)
PORT->Group[0].PINCFG[8].reg = PORT_PINCFG_PMUXEN;
PORT->Group[0].PMUX[8/2].bit.PMUXE = PORT_PMUX_PMUXE_E_Val; // TCC0/WO[0]

Timer init:

void timer0_init()
{ 
 GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID_TCC0_TCC1 // Gen Clk Sel ID TCC0_TCC1
 | GCLK_CLKCTRL_GEN_GCLK0 // Generic clock generator 0
 | GCLK_CLKCTRL_CLKEN; // Clock Enable
 
 PM->APBCSEL.reg = PM_APBCSEL_APBCDIV_DIV1; // Divide by 1
 PM->APBCMASK.reg |= PM_APBCMASK_TCC0; // TCC0 APB Clock Enable
 
 TCC0->WAVE.reg = TCC_WAVEB_WAVEGENB_NPWM;
 TCC0->PER.reg = 80; //TCC0/WO[0] PWM 100kHz DT=50%
 TCC0->CC->reg = 40;
 
 TCC0->CTRLA.reg = TCC_CTRLA_CPTEN0 | TCC_CTRLA_ENABLE; // Enable 
}

• simon: I have tried something similar @Dimitri but it's doesn't work my doubt come from this line in my variant.cpp{ PORTA, 30, PIO_PWM, PIN_ATTR_DIGITAL|PIO_SERCOM, No_ADC_Channel, NOT_ON_PWM, TCC1_CH0, EXTERNAL_INT_10 }, // SWCLKI'm not sure about NOT_ON_PWM` can I use TCC1_CH0for PWM??