RadioLibWrappers: Add blockTaskUntilRXEvent()

This adds a new method blockTaskUntilRXEvent() which uses a FreeRTOS
semaphore to stall the calling task until a packet has been received.

Signed-off-by: Frieder Schrempf <frieder@fris.de>

Author: fschrempf

src/helpers/radiolib/RadioLibWrappers.cpp

@@ -12,6 +12,7 @@
 #define SAMPLING_THRESHOLD  14
 
 static volatile uint8_t state = STATE_IDLE;
+static SemaphoreHandle_t rx_wait_sem;
 
 // this function is called when a complete packet
 // is transmitted by the module
@@ -22,6 +23,8 @@ static
 void setFlag(void) {
   // we sent a packet, set the flag
   state |= STATE_INT_READY;
+
+  if (state & STATE_RX) xSemaphoreGive(rx_wait_sem);
 }
 
 void RadioLibWrapper::begin() {
@@ -38,13 +41,21 @@ void RadioLibWrapper::begin() {
   // start average out some samples
   _num_floor_samples = 0;
   _floor_sample_sum = 0;
+
+  rx_wait_sem = xSemaphoreCreateBinary();
+  xSemaphoreGive(rx_wait_sem);
+  xSemaphoreTake(rx_wait_sem, portMAX_DELAY);
 }
 
 void RadioLibWrapper::idle() {
   _radio->standby();
   state = STATE_IDLE;   // need another startReceive()
 }
 
+int RadioLibWrapper::blockTaskUntilRXEvent(unsigned int timeout = 5000) {
+  return xSemaphoreTake(rx_wait_sem, pdMS_TO_TICKS(timeout));
+}
+
 void RadioLibWrapper::triggerNoiseFloorCalibrate(int threshold) {
   _threshold = threshold;
   if (_num_floor_samples >= NUM_NOISE_FLOOR_SAMPLES) {  // ignore trigger if currently sampling

src/helpers/radiolib/RadioLibWrappers.h

@@ -36,6 +36,8 @@ class RadioLibWrapper : public mesh::Radio {
     return isChannelActive();
   }
 
+  int blockTaskUntilRXEvent(unsigned int timeout);
+
   virtual float getCurrentRSSI() =0;
 
   int getNoiseFloor() const override { return _noise_floor; }