Using TC to count from GPIO

Other Hardware 3rd Party Boards
54

After having a chat with the person I work with, it turned out that this solution is still too bothersome because the actual trigger of the interruption causes a burst, which because of interruptions leads to all other systems' watchdogs to die.
However I learnt enough to continue to search on my own.

I searched in the datasheet and found out that I can set the EVACT0 of TCC0 to increment the counter found in TCC->COUNT.reg on every event.

After setting things up, I still cannot find anything but the value 0 if I take the value of the counter. What am I missing?

Here is my code for the setup of the counter:

void setupGCLK() {
  PM->APBCMASK.reg |= PM_APBCMASK_EVSYS;           // Switch on the event system peripheral

  GCLK->GENDIV.reg = GCLK_GENDIV_DIV(3) |          // Divide the 48MHz system clock by 3 = 16MHz
                     GCLK_GENDIV_ID(4);            // Set division on Generic Clock Generator (GCLK) 4

  GCLK->GENCTRL.reg = GCLK_GENCTRL_IDC |           // Set the duty cycle to 50/50 HIGH/LOW
                      GCLK_GENCTRL_GENEN |         // Enable GCLK 4
                      GCLK_GENCTRL_SRC_DFLL48M |   // Set the clock source to 48MHz
                      GCLK_GENCTRL_ID(4);          // Set clock source on GCLK 4
  while (GCLK->STATUS.bit.SYNCBUSY);               // Wait for synchronization

  GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN |         // Route GCLK4 to TCC0 and TCC1
                      GCLK_CLKCTRL_GEN_GCLK4 |     
                      GCLK_CLKCTRL_ID_TCC0_TCC1;  
  while (GCLK->STATUS.bit.SYNCBUSY);  
}

void setupTCC0() {
  // Enable the port multiplexer on digital pin D7
  //PORT->Group[g_APinDescription[7].ulPort].PINCFG[g_APinDescription[7].ulPin].bit.PMUXEN = 1;
  PORT->Group[PORTA].PINCFG[21].bit.PMUXEN = 1;
  PORT->Group[PORTA].PINCFG[21].bit.PULLEN = 1;
  PORT->Group[PORTA].PINCFG[21].bit.INEN = 1;
  // Set-up the pin as an TCC0 PWM output on D7
  //PORT->Group[g_APinDescription[7].ulPort].PMUX[g_APinDescription[7].ulPin >> 1].reg |= PORT_PMUX_PMUXO_F;
  PORT->Group[PORTA].PMUX[21 >> 1].reg |= PORT_PMUX_PMUXO_A;

  EIC->EVCTRL.reg |= EIC_EVCTRL_EXTINTEO5;                                 // Enable event output on external interrupt 5
  EIC->CONFIG[0].reg |= EIC_CONFIG_SENSE5_HIGH;                            // Set event detecting a HIGH level
  EIC->INTENCLR.reg = EIC_INTENCLR_EXTINT5;                                // Disable interrupts on external interrupt 5
  EIC->CTRL.reg |= EIC_CTRL_ENABLE;                                        // Enable EIC peripheral
  while (EIC->STATUS.bit.SYNCBUSY);                                        // Wait for synchronization
  Serial.println("EIC Set up OK");
  EVSYS->USER.reg = EVSYS_USER_CHANNEL(1) |                                // Attach the event user (receiver) to channel 0 (n + 1)
                    EVSYS_USER_USER(EVSYS_ID_USER_TCC0_EV_0);                // Set the event user (receiver) as TCC0 Event 0

  EVSYS->CHANNEL.reg = EVSYS_CHANNEL_EDGSEL_NO_EVT_OUTPUT |                // No event edge detection
                       EVSYS_CHANNEL_PATH_ASYNCHRONOUS |                   // Set event path as asynchronous
                       EVSYS_CHANNEL_EVGEN(EVSYS_ID_GEN_EIC_EXTINT_5) |    // Set event generator (sender) as external interrupt 5
                       EVSYS_CHANNEL_CHANNEL(0);                           // Attach the generator (sender) to channel 0

  TCC0->EVCTRL.reg = TCC_EVCTRL_TCEI0 |               // Enable the TCC event 0 input
                     //TC_EVCTRL_TCINV |            // Invert the event input
                     TCC_EVCTRL_EVACT0_INC;           // Set up the counting of Events

  Serial.println("TCC0 EV Set up OK");
  
  
  TCC0->CTRLA.reg = TCC_CTRLA_PRESCSYNC_PRESC |     // Reload timer on the next prescaler clock
                    TCC_CTRLA_PRESCALER_DIV1 ;     // Set prescaler to 1
                    
  Serial.println("TCC0 CTRLA Set up OK");
                    
  TCC0->CTRLA.bit.ENABLE = 1;                       // Enable TCC0
  Serial.println("TCC0 CTRLA Enable OK");
  while (TCC0->SYNCBUSY.bit.ENABLE);                // Wait for synchronization
}

And the main arduino file goes like this:

int memo, memo2; // Variables for time counting in loop

void setup()   {                
  SerialUSB.begin(115200);                         // Initialise the native serial port
  while(!SerialUSB);                               // Wait for the console to open
  
  setupGCLK();
  SerialUSB.println("GCLK Set up OK");
  setupTCC0();
}


void loop() {
  // put your main code here, to run repeatedly:
  
  memo=millis();
  if (memo-memo2>1000){
    memo2=memo;
    SerialUSB.print("Counters: ");
    
    SerialUSB.print(TCC0->COUNT.reg);
    SerialUSB.print(" ");
    SerialUSB.println(TCC0->CC[0].reg);
  }
}

I tried the solution @MartinL gave in that old topic, but it does not work either: