Fixed RX power saving RSSI sampling during listen windows

src/helpers/radiolib/CustomLR1110.h

@@ -65,12 +65,15 @@ class CustomLR1110 : public LR1110 {
 
     bool getRxBoostedGainMode() const { return _rx_boosted; }
 
-    bool isReceiving() {
-      // BUSY high means the chip is asleep (RX duty-cycle sleep window) or mid
-      // command, so it cannot be mid-receive - and the SPI read below would
-      // stall until the chip's next listen window.
+    // BUSY high means the chip is asleep (RX duty-cycle sleep window) or mid
+    // command; any SPI access would stall until the chip's next listen window.
+    bool isChipBusy() {
       uint32_t busy = this->mod->getGpio();
-      if (busy != RADIOLIB_NC && this->mod->hal->digitalRead(busy)) return false;
+      return busy != RADIOLIB_NC && this->mod->hal->digitalRead(busy);
+    }
+
+    bool isReceiving() {
+      if (isChipBusy()) return false;   // asleep, cannot be mid-receive
 
       uint16_t irq = getIrqStatus();
       bool detected = ((irq & RADIOLIB_LR11X0_IRQ_SYNC_WORD_HEADER_VALID) || (irq & RADIOLIB_LR11X0_IRQ_PREAMBLE_DETECTED));

src/helpers/radiolib/CustomLR1110Wrapper.h

@@ -20,6 +20,9 @@ public:
   bool isReceivingPacket() override {
     return ((CustomLR1110 *)_radio)->isReceiving();
   }
+  bool isChipBusy() override {
+    return ((CustomLR1110 *)_radio)->isChipBusy();
+  }
   float getCurrentRSSI() override {
     float rssi = -110;
     ((CustomLR1110 *)_radio)->getRssiInst(&rssi);

src/helpers/radiolib/CustomSX1262.h

@@ -86,12 +86,15 @@ class CustomSX1262 : public SX1262 {
       return true;  // success
     }
 
-    bool isReceiving() {
-      // BUSY high means the chip is asleep (RX duty-cycle sleep window) or mid
-      // command, so it cannot be mid-receive - and the SPI read below would
-      // stall until the chip's next listen window.
+    // BUSY high means the chip is asleep (RX duty-cycle sleep window) or mid
+    // command; any SPI access would stall until the chip's next listen window.
+    bool isChipBusy() {
       uint32_t busy = this->mod->getGpio();
-      if (busy != RADIOLIB_NC && this->mod->hal->digitalRead(busy)) return false;
+      return busy != RADIOLIB_NC && this->mod->hal->digitalRead(busy);
+    }
+
+    bool isReceiving() {
+      if (isChipBusy()) return false;   // asleep, cannot be mid-receive
 
       uint16_t irq = getIrqFlags();
       bool detected = (irq & SX126X_IRQ_HEADER_VALID) || (irq & SX126X_IRQ_PREAMBLE_DETECTED);

src/helpers/radiolib/CustomSX1262Wrapper.h

@@ -20,9 +20,12 @@ public:
     updatePreamble(sf);
   }
 
-  bool isReceivingPacket() override { 
+  bool isReceivingPacket() override {
     return ((CustomSX1262 *)_radio)->isReceiving();
   }
+  bool isChipBusy() override {
+    return ((CustomSX1262 *)_radio)->isChipBusy();
+  }
   float getCurrentRSSI() override {
     return ((CustomSX1262 *)_radio)->getRSSI(false);
   }

src/helpers/radiolib/RadioLibWrappers.cpp

@@ -85,12 +85,11 @@ void RadioLibWrapper::resetAGC() {
 }
 
 void RadioLibWrapper::loop() {
-  // In RX duty-cycle (powersaving) mode the radio auto-sleeps between listen
-  // windows, so getCurrentRSSI() would read a sleeping frontend and corrupt the
-  // noise floor. Skip adaptive sampling; note this also degrades interference
-  // detection (isChannelActive) while powersaving is enabled.
-  if (!_rx_ps_enabled && state == STATE_RX && _num_floor_samples < NUM_NOISE_FLOOR_SAMPLES) {
-    if (!isReceivingPacket()) {
+  if (state == STATE_RX && _num_floor_samples < NUM_NOISE_FLOOR_SAMPLES) {
+    // In RX duty-cycle (powersaving) mode only sample while the chip is in a
+    // listen window: during the sleep window the frontend is off, so the RSSI
+    // is meaningless and the SPI read would stall until the next window.
+    if (!(_rx_ps_armed && isChipBusy()) && !isReceivingPacket()) {
       int rssi = getCurrentRSSI();
       if (rssi < _noise_floor + SAMPLING_THRESHOLD) {  // only consider samples below current floor + sampling THRESHOLD
         _num_floor_samples++;
@@ -231,10 +230,10 @@ int16_t RadioLibWrapper::performChannelScan() {
 
 bool RadioLibWrapper::isChannelActive() {
   // int.thresh: RSSI-based interference detection (relative to noise floor).
-  // Skipped in RX duty-cycle mode: the frontend sleeps part of the time, so an
-  // instantaneous RSSI is meaningless and the SPI read would block until the
-  // chip's next listen window.
-  if (!_rx_ps_enabled && _threshold != 0 && getCurrentRSSI() > _noise_floor + _threshold) return true;
+  // In RX duty-cycle mode only checked while the chip is in a listen window
+  // (during the sleep window the frontend is off and the read would stall).
+  if (_threshold != 0 && !(_rx_ps_armed && isChipBusy())
+      && getCurrentRSSI() > _noise_floor + _threshold) return true;
 
   // cad: hardware channel activity detection
   if (_cad_enabled) {

src/helpers/radiolib/RadioLibWrappers.h

@@ -30,6 +30,9 @@ protected:
   virtual int startReceiveMode();
   virtual void stopReceiveDutyCycle();
   virtual bool isPacketReady();
+  // true while the chip cannot service SPI (RX duty-cycle sleep window, or
+  // briefly while processing a command); radios expose this via the BUSY pin
+  virtual bool isChipBusy() { return false; }
   float packetScoreInt(float snr, int sf, int packet_len);
   virtual bool isReceivingPacket() =0;
   virtual void doResetAGC();