Handle GC1109 LNA gain variance properly

Config.h

@@ -110,7 +110,9 @@
 	#define CSMA_CW_PER_BAND_WINDOWS   15
 	#define CSMA_BAND_1_MAX_AIRTIME    7
 	#define CSMA_BAND_N_MIN_AIRTIME    85
-	#define CSMA_INFR_THRESHOLD_DB     12
+	#define CSMA_INFR_THRESHOLD_DB     6
+	#define CSMA_RFENV_RECAL_MS        2500
+	#define CSMA_RFENV_RECAL_LIMIT_DB -83
 	bool interference_detected      =  false;
 	bool avoid_interference         =  true;
 	int csma_slot_ms                =  CSMA_SLOT_MIN_MS;

Makefile

@@ -211,8 +211,8 @@ upload-heltec32_v4:
 	arduino-cli upload -p /dev/ttyACM0 --fqbn esp32:esp32:esp32s3
 	@sleep 1
 	rnodeconf /dev/ttyACM0 --firmware-hash $$(./partition_hashes ./build/esp32.esp32.esp32s3/RNode_Firmware.ino.bin)
-	@sleep 3
+	#@sleep 3
-	python ./Release/esptool/esptool.py --chip esp32-s3 --port /dev/ttyACM0 --baud 921600 --before default_reset --after hard_reset write_flash -z --flash_mode dio --flash_freq 80m --flash_size 4MB 0x210000 ./Release/console_image.bin
+	#python ./Release/esptool/esptool.py --chip esp32-s3 --port /dev/ttyACM0 --baud 921600 --before default_reset --after hard_reset write_flash -z --flash_mode dio --flash_freq 80m --flash_size 4MB 0x210000 ./Release/console_image.bin
 
 upload-tdeck:
 	arduino-cli upload -p /dev/ttyACM0 --fqbn esp32:esp32:esp32s3

RNode_Firmware.ino

@@ -1383,6 +1383,8 @@ void update_noise_floor() {
 
 #define LED_ID_TRIG 16
 uint8_t led_id_filter = 0;
+uint32_t interference_start = 0;
+bool interference_persists = false;
 void update_modem_status() {
   #if MCU_VARIANT == MCU_ESP32
     portENTER_CRITICAL(&update_lock);
@@ -1404,6 +1406,19 @@ void update_modem_status() {
   if (interference_detected) { if (led_id_filter < LED_ID_TRIG) { led_id_filter += 1; } }
   else                       { if (led_id_filter > 0) {led_id_filter -= 1; } }
 
+  // Handle potential false interference detection due to
+  // LNA recalibration, antenna swap, moving into new RF
+  // environment or similar.
+  if (interference_detected && current_rssi < CSMA_RFENV_RECAL_LIMIT_DB) {
+    if (!interference_persists) {
+      interference_persists = true; interference_start = millis();
+    } else {
+      if (millis()-interference_start >= CSMA_RFENV_RECAL_MS) { noise_floor_sampled = false; interference_persists = false; }
+    }
+  } else {
+    interference_persists = false;
+  }
+
   if (carrier_detected) { dcd = true; } else { dcd = false; }
 
   dcd_led = dcd;

sx126x.cpp

@@ -356,8 +356,13 @@ int sx126x::begin(long frequency) {
       // Keep PA CPS low until actual
       // transmit. Does it save power?
       // Who knows? Will have to measure.
+      // Note from the future: Nope.
+      // Power consumption is the same,
+      // and turning it on and off is
+      // not something that it likes.
+      // Keeping it high for now.
       pinMode(LORA_PA_CPS, OUTPUT);
-      digitalWrite(LORA_PA_CPS, LOW);
+      digitalWrite(LORA_PA_CPS, HIGH);
 
       // On Heltec V4, the PA CTX pin
       // is driven by the SX1262 DIO2
@@ -375,7 +380,10 @@ int sx126x::beginPacket(int implicitHeader) {
   #if HAS_LORA_PA
     #if LORA_PA_GC1109
       // Enable PA CPS for transmit
-      digitalWrite(LORA_PA_CPS, HIGH);
+      // digitalWrite(LORA_PA_CPS, HIGH);
+      // Disabled since we're keeping it
+      // on permanently as long as the
+      // radio is powered up.
     #endif
   #endif
 
@@ -476,7 +484,6 @@ uint8_t sx126x::packetRssiRaw() {
 }
 
 int ISR_VECT sx126x::packetRssi() {
-  // TODO: May need more calculations here
   uint8_t buf[3] = {0};
   executeOpcodeRead(OP_PACKET_STATUS_6X, buf, 3);
   int pkt_rssi = -buf[0] / 2;
@@ -590,7 +597,12 @@ void sx126x::receive(int size) {
   #if HAS_LORA_PA
     #if LORA_PA_GC1109
       // Disable PA CPS for receive
-      digitalWrite(LORA_PA_CPS, LOW);
+      // digitalWrite(LORA_PA_CPS, LOW);
+      // That turned out to be a bad idea.
+      // The LNA goes wonky if it's toggled
+      // on and off too quickly. We'll keep
+      // it on permanently, as long as the
+      // radio is powered up.
     #endif
   #endif