change implmementation from HAL to SMT32Duino official examples for timer usage

examples/STM32UartMasterMidiClock/STM32UartMasterMidiClock.ino

@@ -36,21 +36,21 @@ void handle_bpm_led(uint32_t tick)
 // Internal clock handlers
 void ClockOut96PPQN(uint32_t tick) {
   // Send MIDI_CLOCK to external gears
-  Serial.write(MIDI_CLOCK);
+  //Serial.write(MIDI_CLOCK);
   handle_bpm_led(tick);
 }
 
 void onClockStart() {
-  Serial.write(MIDI_START);
+  //Serial.write(MIDI_START);
 }
 
 void onClockStop() {
-  Serial.write(MIDI_STOP);
+  //Serial.write(MIDI_STOP);
 }
 
 void setup() {
   // Initialize serial communication at 31250 bits per second, the default MIDI serial speed communication:
-  Serial.begin(31250);
+  //Serial.begin(31250);
 
   // A led to count bpms
   pinMode(LED_BUILTIN, OUTPUT);

src/platforms/stm32.h

@@ -1,59 +1,33 @@
 #include <Arduino.h>
 
-static TIM_HandleTypeDef _uclockTimer = {0};
+#if !defined(STM32_CORE_VERSION) || (STM32_CORE_VERSION  < 0x01090000)
+  #error "Due to API change, this library is compatible with STM32_CORE_VERSION >= 0x01090000. Please update your stm32duino core."
+#endif
+
+#if defined(TIM1)
+  TIM_TypeDef * TimerInstance = TIM1;
+#else
+  TIM_TypeDef * TimerInstance = TIM2;
+#endif
+
+// Instantiate HardwareTimer object. Thanks to 'new' instanciation, HardwareTimer is not destructed when setup() function is finished.
+HardwareTimer * _uclockTimer = new HardwareTimer(TimerInstance);
 
 #define ATOMIC(X) noInterrupts(); X; interrupts();
 
 // forward declaration of ISR
 void uclockISR();
 
-void timer_attachInterrupt(TIM_TypeDef *tim, uint32_t us_interval)
-{
-  // Enable timer clock
-  if (tim == TIM2) __HAL_RCC_TIM2_CLK_ENABLE();
-  else if (tim == TIM3) __HAL_RCC_TIM3_CLK_ENABLE();
-  else if (tim == TIM4) __HAL_RCC_TIM4_CLK_ENABLE();
-
-  // Calculate the prescaler value
-  uint32_t prescaler = (SystemCoreClock / 1000000UL) - 1;
-
-  // Calculate the period value
-  uint32_t period = (us_interval * 2UL) - 1UL;
-
-  // Set up the timer instance
-  _uclockTimer.Instance = tim;
-  _uclockTimer.Init.Prescaler = prescaler;
-  _uclockTimer.Init.CounterMode = TIM_COUNTERMODE_UP;
-  _uclockTimer.Init.Period = period;
-  _uclockTimer.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
-
-  // Configure the timer instance
-  HAL_TIM_Base_Init(&_uclockTimer);
-  HAL_TIM_Base_Start_IT(&_uclockTimer);
-}
-
-void TIM2_IRQHandler()
-{
-  // Call the uClock ISR handler
-  uclockISR();
-
-  // Clear the interrupt flag
-  __HAL_TIM_CLEAR_FLAG(&_uclockTimer, TIM_FLAG_UPDATE);
-}
-
 void initTimer(uint32_t us_interval)
 {
-  // Set up the timer to call the callback function every us_interval microseconds
-  timer_attachInterrupt(TIM2, us_interval);
+  _uclockTimer->setOverflow(us_interval, MICROSEC_FORMAT);
+  _uclockTimer->attachInterrupt(uclockISR);
+  _uclockTimer->resume();
 }
 
 void setTimer(uint32_t us_interval)
 {
-  // Calculate the period value
-  uint32_t period = (us_interval * 2UL) - 1UL;
-
-  // Update the timer instance with the new period value
-  _uclockTimer.Init.Period = period;
-  HAL_TIM_Base_Init(&_uclockTimer);
+  _uclockTimer->setOverflow(us_interval, MICROSEC_FORMAT);
+  _uclockTimer->refresh();
 }