HardwareTimer Unusually slow on F103, does not accept pin names from PeripheralPins.c

[LightningStalker]

Original post by @fpistm in #1922 (reply in thread)

I have attempted as above with the F103 black pill board and it does not work. Pins must be referenced as "B0" or "A8". Using something like "PB_0_ALTn" there is no output and no execution of callback functions. The timer is also running very slow like it's prescaled when it shouldn't be. Highest frequency is about 1kHz. I can set timings below this but it is not practical for buck converter.

The code is nearly identical.

#define pin  PB_0_ALT2
#define pin2 LED_BUILTIN

#if !defined(STM32_CORE_VERSION) || (STM32_CORE_VERSION  < 0x01090000)
#error "Due to API change, this sketch is compatible with STM32_CORE_VERSION  >= 0x01090000"
#endif

// Automatically retrieve TIM instance and channel associated to pin
// This is used to be compatible with all STM32 series automatically.
TIM_TypeDef *Instance = (TIM_TypeDef *)pinmap_peripheral(digitalPinToPinName(pin), PinMap_PWM);
uint32_t channel = STM_PIN_CHANNEL(pinmap_function(digitalPinToPinName(pin), PinMap_PWM));

// Instantiate HardwareTimer object. Thanks to 'new' instantiation, HardwareTimer is not destructed when setup function is finished.
HardwareTimer *MyTim = new HardwareTimer(Instance);

void Update_IT_callback(void)
{ // Update event correspond to Rising edge of PWM when configured in PWM1 mode
  digitalWrite(pin2, LOW); // pin2 will be complementary to pin
}

void Compare_IT_callback(void)
{ // Compare match event correspond to falling edge of PWM when configured in PWM1 mode
  digitalWrite(pin2, HIGH);
}

void setup()
{
  // No need to configure pin, it will be done by HardwareTimer configuration
  // pinMode(pin, OUTPUT);

  // Need to configure pin2, as it is not managed by HardwareTimer
  pinMode(pin2, OUTPUT);

  MyTim->setMode(channel, TIMER_OUTPUT_COMPARE_PWM1, pin);
  MyTim->setPrescaleFactor(1); // Due to setOverflow with MICROSEC_FORMAT, prescaler will be computed automatically based on timer input clock
  MyTim->setOverflow(128, TICK_FORMAT); // 100000 microseconds = 100 milliseconds
  MyTim->setCaptureCompare(channel, 50, PERCENT_COMPARE_FORMAT); // 50%
  MyTim->attachInterrupt(Update_IT_callback);
  MyTim->attachInterrupt(channel, Compare_IT_callback);
  MyTim->resume();
}


void loop()
{
  /* Nothing is done */
}

[fpistm]

Hi @LightningStalker
use the pin number PB0_ALT2

[LightningStalker]

LED pin shows PWM but PB0 is still dead. I tried with PA8 but also dead. It only comes on when increasing overflow ticks but the frequency is low.

I have it working on a F411 so it does work. The F411 is a bit of an overkill though. I much prefer working the F103.

[fpistm]

Will check deeply tomorrow. It's a day off in France.

[LightningStalker]

When interrupts callbacks are not attached, it begins to work! I comment out lines 38&39 attachInterrupt. I don't need them. Then it works as expected. Must be something to do with too much interrupt triggering. Thanks for your help.

[LightningStalker]

I should add that I also did a full chip erase. Not sure if it helped