RP2040 PWM stop timer before begin

Author: pschatzmann

src/AudioPWM/AudioPWM.h

@@ -26,7 +26,10 @@ class PWMAudioOutput : public AudioOutput {
     }
   }
 
-  virtual PWMConfig defaultConfig() { return pwm.defaultConfig(); }
+  virtual PWMConfig defaultConfig(RxTxMode mode=TX_MODE) { 
+    if (mode!=TX_MODE) LOGE("mode not supported: using TX_MODE");
+    return pwm.defaultConfig(); 
+  }
 
   PWMConfig config() { return audio_config; }
 

src/AudioPWM/PWMAudioBase.h

@@ -188,7 +188,7 @@ class DriverPWMBase {
       LOGW("Could not write all data: %u -> %d", (unsigned int)size, result);
     }
     // activate the timer now - if not already done
-    startTimer();
+    if (!is_timer_started) startTimer();
     return result * decimation();
   }
 

src/AudioPWM/PWMAudioRP2040.h

@@ -66,13 +66,10 @@ class PWMDriverRP2040 : public DriverPWMBase {
   TimerAlarmRepeating ticker;
 
   virtual void startTimer() override {
-    if (!is_timer_started) {
-      TRACED();
-      long wait_time = 1000000l / audio_config.sample_rate;
-      ticker.setCallbackParameter(this);
-      ticker.begin(defaultPWMAudioOutputCallbackPico, wait_time, US);
-      is_timer_started = true;
-    }
+    TRACED();
+    ticker.setCallbackParameter(this);
+    ticker.begin(defaultPWMAudioOutputCallbackPico, audio_config.sample_rate, HZ);
+    
     is_timer_started = true;
   }
 

src/AudioTimer/AudioTimer.h

@@ -38,6 +38,9 @@ class TimerAlarmRepeating {
 
   bool begin(repeating_timer_callback_t callback_f, uint32_t time,
              TimeUnit unit = MS) {
+    // stop timer if it is already active          
+    if (is_active) end();
+    // start timer
     is_active = p_timer->begin(callback_f, time, unit);
     return is_active;
   }

src/AudioTimer/AudioTimerBase.h

@@ -38,6 +38,10 @@ class TimerAlarmRepeatingDriverBase {
 
  protected:
   void* object = nullptr;
+
+  const char* toString(TimeUnit unit){
+    return TimeUnitStr[(int)unit];
+  }
 };
 
 }  // namespace audio_tools

src/AudioTimer/AudioTimerRP2040.h

@@ -34,7 +34,7 @@ class TimerAlarmRepeatingDriverRP2040 : public TimerAlarmRepeatingDriverBase {
   bool begin(const my_repeating_timer_callback_t callback_f, uint32_t time,
              TimeUnit unit = MS) override {
     bool result = false;
-    LOGI("timer time: %u %s", (unsigned int)time, unit == MS ? "ms" : "us");
+    LOGI("timer time: %u %s", (unsigned int)time, toString(unit));
     this->instanceCallback = callback_f;
 
     // we determine the time in microseconds
@@ -45,7 +45,7 @@ class TimerAlarmRepeatingDriverRP2040 : public TimerAlarmRepeatingDriverBase {
         break;
       case US:
         result = alarm_pool_add_repeating_timer_us(ap, time, &staticCallback,
-                                                   this, &timer);
+                                                  this, &timer);
         break;
       case HZ:
         // convert hz to time in us