Replace RAK GPS attempted reset pin control with 3V3_EN control

The previous code only worked by accident.

1. Regardless of which slot the GPS module was present in, it would always be detected as Slot A
2. Slot A reset pin (WB_IO2) overlaps with PIN_3V3_EN.
3. Per u-blox ZOE-M8Q documentation: "In reset state, the SiP consumes a significant amount of current. It is therefore recommended to use RESET_N only as a reset signal and not as an enable/disable."
So using reset PIN to control GPS status is not desirable anyway.

This commit replaces the faulty reset pin detection and control logic by instead just controlling the 3V3 bus.

Note: 3V3 control is disabled on the RAK3401 as this board is most commonly used in the "1W LoRa Booster Kit", and turning 3V3 off would also disable 5V power supply to the SKY66122 PA.

Changes tested with RAK3401 with a RAK12500 in both Slot A and Slot C, as well as a RAK12501 in Slot A.

src/helpers/sensors/EnvironmentSensorManager.cpp

@@ -165,16 +165,15 @@ static RAK12035_SoilMoisture RAK12035;
 #endif
 
 #ifdef RAK_WISBLOCK_GPS
-static uint32_t gpsResetPin = 0;
 static bool i2cGPSFlag = false;
 static bool serialGPSFlag = false;
 #ifndef TELEM_RAK12500_ADDRESS
-#define TELEM_RAK12500_ADDRESS   0x42     //RAK12500 Ublox GPS via i2c
+#define TELEM_RAK12500_ADDRESS   0x42     // RAK12500 u-blox ZOE-M8Q GPS via i2c
 #endif
 #include <SparkFun_u-blox_GNSS_Arduino_Library.h>
-static SFE_UBLOX_GNSS ublox_GNSS;
+static SFE_UBLOX_GNSS ublox_GNSS; // RAK12500 u-blox ZOE-M8Q GPS via UART
 
-class RAK12500LocationProvider : public LocationProvider {
+class RAKI2CLocationProvider : public LocationProvider {
   long _lat = 0;
   long _lng = 0;
   long _alt = 0;
@@ -207,7 +206,7 @@ public:
   bool isEnabled() override { return true; }
 };
 
-static RAK12500LocationProvider RAK12500_provider;
+static RAKI2CLocationProvider RAK12500_provider;
 #endif
 
 // ============================================================
@@ -783,14 +782,14 @@ void EnvironmentSensorManager::rakGPSInit(){
   Serial1.begin(9600);
   #endif
 
-  //search for the correct IO standby pin depending on socket used
+  #ifdef PIN_3V3_EN
-  if(gpsIsAwake(WB_IO2)){
+  digitalWrite(PIN_3V3_EN,LOW);
-  }
+  delay(1000);
-  else if(gpsIsAwake(WB_IO4)){
+  digitalWrite(PIN_3V3_EN,HIGH);
-  }
+  delay(2000);
-  else if(gpsIsAwake(WB_IO5)){
+  #endif
-  }
+
-  else{
+  if(!gpsIsAwake()){
     MESH_DEBUG_PRINTLN("No GPS found");
     gps_active = false;
     gps_detected = false;
@@ -804,18 +803,10 @@ void EnvironmentSensorManager::rakGPSInit(){
   #endif
 }
 
-bool EnvironmentSensorManager::gpsIsAwake(uint8_t ioPin){
+bool EnvironmentSensorManager::gpsIsAwake(){
-
-  //set initial waking state
-  pinMode(ioPin,OUTPUT);
-  digitalWrite(ioPin,LOW);
-  delay(500);
-  digitalWrite(ioPin,HIGH);
-  delay(500);
-
   //Try to init RAK12500 on I2C
   if (ublox_GNSS.begin(Wire) == true){
-    MESH_DEBUG_PRINTLN("RAK12500 GPS init correctly with pin %i",ioPin);
+    MESH_DEBUG_PRINTLN("RAK12500 I2C GPS init");
     ublox_GNSS.setI2COutput(COM_TYPE_UBX);
     ublox_GNSS.enableGNSS(true, SFE_UBLOX_GNSS_ID_GPS);
     ublox_GNSS.enableGNSS(true, SFE_UBLOX_GNSS_ID_GALILEO);
@@ -826,7 +817,6 @@ bool EnvironmentSensorManager::gpsIsAwake(uint8_t ioPin){
     ublox_GNSS.enableGNSS(true, SFE_UBLOX_GNSS_ID_QZSS);
     ublox_GNSS.setMeasurementRate(1000);
     ublox_GNSS.saveConfigSelective(VAL_CFG_SUBSEC_IOPORT);
-    gpsResetPin = ioPin;
     i2cGPSFlag = true;
     gps_active = true;
     gps_detected = true;
@@ -834,20 +824,13 @@ bool EnvironmentSensorManager::gpsIsAwake(uint8_t ioPin){
     _location = &RAK12500_provider;
     return true;
   } else if (Serial1.available()) {
-    MESH_DEBUG_PRINTLN("Serial GPS init correctly and is turned on");
+    MESH_DEBUG_PRINTLN("Serial GPS init correctly");
-#ifdef PIN_GPS_EN
-    if(PIN_GPS_EN){
-      gpsResetPin = PIN_GPS_EN;
-    }
-#endif
     serialGPSFlag = true;
     gps_active = true;
     gps_detected = true;
     return true;
   }
 
-  pinMode(ioPin, INPUT);
-  MESH_DEBUG_PRINTLN("GPS did not init with this IO pin... try the next");
   return false;
 }
 #endif
@@ -855,8 +838,8 @@ bool EnvironmentSensorManager::gpsIsAwake(uint8_t ioPin){
 void EnvironmentSensorManager::start_gps() {
   gps_active = true;
   #ifdef RAK_WISBLOCK_GPS
-    pinMode(gpsResetPin, OUTPUT);
+    pinMode(PIN_3V3_EN, OUTPUT);
-    digitalWrite(gpsResetPin, HIGH);
+    digitalWrite(PIN_3V3_EN, HIGH);
     return;
   #endif
 
@@ -871,8 +854,12 @@ void EnvironmentSensorManager::start_gps() {
 void EnvironmentSensorManager::stop_gps() {
   gps_active = false;
   #ifdef RAK_WISBLOCK_GPS
-    pinMode(gpsResetPin, OUTPUT);
+    #ifdef SKY66122
-    digitalWrite(gpsResetPin, LOW);
+      MESH_DEBUG_PRINTLN("GPS cannot be disabled as this would also disable SKY66122.");
+      return;
+    #endif
+    pinMode(PIN_3V3_EN, OUTPUT);
+    digitalWrite(PIN_3V3_EN, LOW);
     return;
   #endif
 

src/helpers/sensors/EnvironmentSensorManager.h

@@ -30,7 +30,7 @@ protected:
   void initBasicGPS();
   #ifdef RAK_BOARD
   void rakGPSInit();
-  bool gpsIsAwake(uint8_t ioPin);
+  bool gpsIsAwake();
   #endif
   #endif
 

variants/rak3401/variant.h

@@ -181,6 +181,7 @@ static const uint8_t AREF = PIN_AREF;
 //   in hardware via SetDIO2AsRfSwitchCtrl (microsecond-accurate, no GPIO needed).
 //   The 5V boost for the PA is enabled by WB_IO2 (P0.34 = PIN_3V3_EN).
 #define SX126X_POWER_EN (21)        // P0.21 = IO3 -> SKY66122 CSD+CPS (FEM enable)
+#define SKY66122
 
 // CTX is driven by SX1262 DIO2, not a GPIO
 #define SX126X_DIO2_AS_RF_SWITCH
@@ -194,8 +195,8 @@ static const uint8_t AREF = PIN_AREF;
 #define P_LORA_BUSY SX126X_BUSY
 #define P_LORA_RESET SX126X_RESET
 
-// enables 3.3V periphery like GPS or IO Module
+// enables 3.3V periphery like GPS, the IO Module, and the SKY66122 5V boost
-// Do not toggle this for GPS power savings
+// Do NOT use this for GPS power savings as this will interfere with LoRa functionality
 #define PIN_3V3_EN (34)
 
 #define PIN_GPS_RX PIN_SERIAL1_RX