enhance esp32 usage by hidding concurrency handle implementation using freertos task

examples/ESP32UartMasterMidiClock/ESP32UartMasterMidiClock.ino

@@ -18,8 +18,6 @@
 // the blue led
 #define LED_BUILTIN    2
 
-volatile bool _midi_clk_income = false;
-
 uint8_t bpm_blink_timer = 1;
 void handle_bpm_led(uint32_t tick)
 {
@@ -38,8 +36,7 @@ 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);
-  _midi_clk_income = true;
   handle_bpm_led(tick);
 }
 
@@ -74,11 +71,5 @@ void setup() {
 
 // Do it whatever to interface with Clock.stop(), Clock.start(), Clock.setTempo() and integrate your environment...
 void loop() {
-  // watch for income signal from uClock to fire the clock over midi
+  
-  if (_midi_clk_income) {
-    Serial.write(MIDI_CLOCK);
-    noInterrupts();
-    _midi_clk_income = false;
-    interrupts();
-  }
 }

library.json

@@ -1,6 +1,6 @@
 {
   "name": "uClock",
-  "version": "1.4.1",
+  "version": "1.4.2",
   "description": "A Library to implement BPM clock tick calls using hardware interruption. Supported and tested on AVR boards(ATmega168/328, ATmega16u4/32u4 and ATmega2560) and ARM boards(Teensy, Seedstudio XIAO M0. ESP32 and STM32)",
   "keywords": "bpm, clock, timing, tick, music, generator",
   "repository":

library.properties

@@ -1,5 +1,5 @@
 name=uClock
-version=1.4.1
+version=1.4.2
 author=Romulo Silva <contact@midilab.co>
 maintainer=Romulo Silva <contact@midilab.co>
 sentence=BPM clock generator for Arduino platform.

src/platforms/esp32.h

@@ -1,26 +1,71 @@
 #include <Arduino.h>
+#include <freertos/task.h>
+#include <freertos/semphr.h>
 
 #define TIMER_ID	0
-
 hw_timer_t * _uclockTimer = NULL;
-portMUX_TYPE _uclockTimerMux = portMUX_INITIALIZER_UNLOCKED;
+// mutex control for ISR
-#define ATOMIC(X) portENTER_CRITICAL_ISR(&_uclockTimerMux); X; portEXIT_CRITICAL_ISR(&_uclockTimerMux);
+//portMUX_TYPE _uclockTimerMux = portMUX_INITIALIZER_UNLOCKED;
+//#define ATOMIC(X) portENTER_CRITICAL_ISR(&_uclockTimerMux); X; portEXIT_CRITICAL_ISR(&_uclockTimerMux);
+
+// FreeRTOS main clock task size in bytes
+#define CLOCK_STACK_SIZE    2048
+// semaphore to signal the task from the ISR
+SemaphoreHandle_t _semaphore;
+// mutex to protect the shared resource
+SemaphoreHandle_t _mutex;
+// mutex control for task
+#define ATOMIC(X)     \
+    do {              \
+        xSemaphoreTake(_mutex, portMAX_DELAY); \
+        X;            \
+        xSemaphoreGive(_mutex); \
+    } while (0);
+
+// forward declaration of uClockHandler
+void uClockHandler();
+
+// ISR handler
+void ARDUINO_ISR_ATTR handlerISR(void)
+{
+    // notify the clockTask using the semaphore
+    BaseType_t xHigherPriorityTaskWoken = pdFALSE;
+    xSemaphoreGiveFromISR(_semaphore, &xHigherPriorityTaskWoken);
+
+    // context switch is required? request it
+    if (xHigherPriorityTaskWoken == pdTRUE)
+        portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
+}
 
-// forward declaration of ISR
+// task for user clock process
-void ARDUINO_ISR_ATTR uclockISR();
+void clockTask(void *pvParameters)
+{
+    while (1)
+        if (xSemaphoreTake(_semaphore, portMAX_DELAY) == pdTRUE)
+            uClockHandler();
+}
 
 void initTimer(uint32_t init_clock)
 {
     _uclockTimer = timerBegin(TIMER_ID, 80, true);
 
     // attach to generic uclock ISR
-    timerAttachInterrupt(_uclockTimer, &uclockISR, false);
+    timerAttachInterrupt(_uclockTimer, &handlerISR, false);
 
     // init clock tick time
     timerAlarmWrite(_uclockTimer, init_clock, true); 
 
     // activate it!
     timerAlarmEnable(_uclockTimer);
+
+    // initialize the semaphore
+    _semaphore = xSemaphoreCreateBinary();
+
+    // initialize the mutex for shared resource access
+    _mutex = xSemaphoreCreateMutex();
+
+    // create the clockTask
+    xTaskCreate(clockTask, "clockTask", CLOCK_STACK_SIZE, NULL, 1, NULL);
 }
 
 void setTimer(uint32_t us_interval)

src/platforms/samd.h

@@ -11,14 +11,14 @@
 IntervalTimer _uclockTimer;
 
 // forward declaration of ISR
-void uclockISR();
+void uClockHandler();
 
 void initTimer(uint32_t init_clock)
 {
     TimerTcc0.initialize(init_clock);
 
     // attach to generic uclock ISR
-    TimerTcc0.attachInterrupt(uclockISR);
+    TimerTcc0.attachInterrupt(uClockHandler);
 }
 
 void setTimer(uint32_t us_interval)

src/platforms/stm32.h

@@ -16,12 +16,12 @@ HardwareTimer * _uclockTimer = new HardwareTimer(TimerInstance);
 #define ATOMIC(X) noInterrupts(); X; interrupts();
 
 // forward declaration of ISR
-void uclockISR();
+void uClockHandler();
 
 void initTimer(uint32_t us_interval)
 {
   _uclockTimer->setOverflow(us_interval, MICROSEC_FORMAT);
-  _uclockTimer->attachInterrupt(uclockISR);
+  _uclockTimer->attachInterrupt(uClockHandler);
   _uclockTimer->resume();
 }
 

src/platforms/teensy.h

@@ -5,11 +5,11 @@
 IntervalTimer _uclockTimer;
 
 // forward declaration of ISR
-void uclockISR();
+void uClockHandler();
 
 void initTimer(uint32_t init_clock)
 {
-    _uclockTimer.begin(uclockISR, init_clock); 
+    _uclockTimer.begin(uClockHandler, init_clock); 
 
     // Set the interrupt priority level, controlling which other interrupts
     // this timer is allowed to interrupt. Lower numbers are higher priority, 

src/uClock.cpp

@@ -2,7 +2,7 @@
  *  @file       uClock.cpp
  *  Project     BPM clock generator for Arduino
  *  @brief      A Library to implement BPM clock tick calls using hardware interruption. Supported and tested on AVR boards(ATmega168/328, ATmega16u4/32u4 and ATmega2560) and ARM boards(Teensy, Seedstudio XIAO M0 and ESP32)
- *  @version    1.4.1
+ *  @version    1.4.2
  *  @author     Romulo Silva
  *  @date       10/06/2017
  *  @license    MIT - (c) 2022 - Romulo Silva - contact@midilab.co
@@ -414,10 +414,8 @@ volatile uint32_t _timer = 0;
 //
 #if defined(ARDUINO_ARCH_AVR)
 ISR(TIMER1_COMPA_vect)
-#elif defined(ARDUINO_ARCH_ESP32) || defined(ESP32)
-void ARDUINO_ISR_ATTR uclockISR()
 #else
-void uclockISR() 
+void uClockHandler() 
 #endif
 {
     // global timer counter

src/uClock.h

@@ -2,7 +2,7 @@
  *  @file       uClock.h
  *  Project     BPM clock generator for Arduino
  *  @brief      A Library to implement BPM clock tick calls using hardware interruption. Supported and tested on AVR boards(ATmega168/328, ATmega16u4/32u4 and ATmega2560) and ARM boards(Teensy, Seedstudio XIAO M0 and ESP32)
- *  @version    1.4.1
+ *  @version    1.4.2
  *  @author     Romulo Silva
  *  @date       10/06/2017
  *  @license    MIT - (c) 2022 - Romulo Silva - contact@midilab.co