For RAK only, fixed reset pin and honour FORCE_GPS_ALIVE

src/helpers/sensors/EnvironmentSensorManager.cpp

@@ -169,7 +169,9 @@ static RAK12035_SoilMoisture RAK12035;
 #endif
 
 #ifdef RAK_WISBLOCK_GPS
-static uint32_t gpsResetPin = 0;
+// -1 = no enable pin; out-of-range values are no-ops in pinMode/digitalWrite,
+// while 0 would be a real GPIO (P0.00 = LFXO crystal on nRF52)
+static uint32_t gpsResetPin = -1;
 static bool i2cGPSFlag = false;
 static bool serialGPSFlag = false;
 #ifndef TELEM_RAK12500_ADDRESS
@@ -812,11 +814,7 @@ void EnvironmentSensorManager::rakGPSInit() {
 
   // search for the correct IO standby pin depending on socket used
   if (gpsIsAwake(WB_IO2)) {
-    _location->setPinEn(WB_IO2);
-  } else if (gpsIsAwake(WB_IO4)) {
-    _location->setPinEn(WB_IO4);
-  } else if (gpsIsAwake(WB_IO5)) {
-    _location->setPinEn(WB_IO5);
+    _location->setPinEn(WB_IO2); // WB_IO2 is the power switch for all sensor and IO slots
   } else {
     MESH_DEBUG_PRINTLN("No GPS found");
     gps_active = false;
@@ -861,11 +859,7 @@ bool EnvironmentSensorManager::gpsIsAwake(uint8_t ioPin) {
     return true;
   } else if (Serial1.available()) { // RAK12501 (L76K) on UART
     MESH_DEBUG_PRINTLN("Serial GPS init correctly and is turned on");
-#ifdef PIN_GPS_EN
-    if (PIN_GPS_EN) {
-      gpsResetPin = PIN_GPS_EN;
-    }
-#endif
+    gpsResetPin = ioPin;
     serialGPSFlag = true;
     gps_active = true;
     gps_detected = true;
@@ -889,8 +883,7 @@ void EnvironmentSensorManager::start_gps() {
 
 #ifdef RAK_WISBLOCK_GPS
     pinMode(gpsResetPin, OUTPUT);
-    digitalWrite(gpsResetPin, HIGH);
-    gpsIsAwake(_location->getPinEn()); // Turn on UART L76K for RAK12500 or I2C for RAK12501
+    digitalWrite(gpsResetPin, HIGH); // WB_IO2
     return;
 #endif
 
@@ -913,9 +906,10 @@ void EnvironmentSensorManager::stop_gps() {
   }
 
   #ifdef RAK_WISBLOCK_GPS
+  #ifndef FORCE_GPS_ALIVE
     pinMode(gpsResetPin, OUTPUT);
-    digitalWrite(gpsResetPin, LOW);
-    digitalWrite(_location->getPinEn(), LOW); // Cut off power
+    digitalWrite(gpsResetPin, LOW); // WB_IO2
+  #endif
     return;
   #endif
 

variants/rak3401/platformio.ini

@@ -7,6 +7,7 @@ build_flags = ${nrf52_base.build_flags}
   ${sensor_base.build_flags}
   -I variants/rak3401
   -D RAK_3401
+  -D RAK_BOARD
 ;  -D NRF52_POWER_MANAGEMENT
   -D RADIO_CLASS=CustomSX1262
   -D WRAPPER_CLASS=CustomSX1262Wrapper
@@ -14,6 +15,9 @@ build_flags = ${nrf52_base.build_flags}
   -D SX126X_CURRENT_LIMIT=140
   -D SX126X_RX_BOOSTED_GAIN=1
   -D SX126X_REGISTER_PATCH=1       ; Patch register 0x8B5 for improved RX with SKY66122 FEM
+  -D FORCE_GPS_ALIVE               ; on RAK3401, gpsResetPin ends up = WB_IO2 (kills 3V3_S rail) or
+                                   ; pin 4 (= SX126X_RESET, holds radio in reset). stop_gps() must not run.
+  -D PIN_GPS_EN=-1                 ; -1 = no dedicated GPS enable pin (power is the shared 3V3_S rail), same as rak4631
 build_src_filter = ${nrf52_base.build_src_filter}
   +<../variants/rak3401>
   +<helpers/sensors>

variants/rak3401/variant.h

@@ -188,8 +188,8 @@ static const uint8_t AREF = PIN_AREF;
 // Power is on the controllable 3V3_S rail
 #define PIN_GPS_PPS (17) // Pulse per second input from the GPS
 
-#define PIN_GPS_RX PIN_SERIAL1_RX
-#define PIN_GPS_TX PIN_SERIAL1_TX
+#define PIN_GPS_RX PIN_SERIAL1_TX
+#define PIN_GPS_TX PIN_SERIAL1_RX
 
 #define PIN_GPS_1PPS PIN_GPS_PPS
 #define GPS_BAUD_RATE 9600

variants/rak4631/platformio.ini

@@ -13,8 +13,6 @@ build_flags = ${nrf52_base.build_flags}
 ;  -D NRF52_POWER_MANAGEMENT
   -D PIN_BOARD_SCL=14
   -D PIN_BOARD_SDA=13
-  -D PIN_GPS_TX=PIN_SERIAL1_RX
-  -D PIN_GPS_RX=PIN_SERIAL1_TX
   -D PIN_GPS_EN=-1
   -D PIN_OLED_RESET=-1
   -D USE_SX1262

variants/rak4631/variant.h

@@ -182,6 +182,9 @@ extern "C"
 #define EXTERNAL_FLASH_DEVICES IS25LP080D
 #define EXTERNAL_FLASH_USE_QSPI
 
+#define PIN_GPS_RX PIN_SERIAL1_TX
+#define PIN_GPS_TX PIN_SERIAL1_RX
+
 #define PIN_GPS_1PPS      17  //GPS PPS pin
 #define GPS_BAUD_RATE   9600
 #define GPS_ADDRESS   0x42  //i2c address for GPS