Fix XIAO nRF52 BME280 I2C pins

src/helpers/sensors/EnvironmentSensorManager.cpp

@@ -189,9 +189,26 @@ bool EnvironmentSensorManager::begin() {
   #endif
 
   #if ENV_INCLUDE_BME280
-  if (BME280.begin(TELEM_BME280_ADDRESS, TELEM_WIRE)) {
-    MESH_DEBUG_PRINTLN("Found BME280 at address: %02X", TELEM_BME280_ADDRESS);
+  uint8_t bme280_address = TELEM_BME280_ADDRESS;
+  bool bme280_ok = BME280.begin(bme280_address, TELEM_WIRE);
+  if (!bme280_ok) {
+    const uint8_t alt_address = (TELEM_BME280_ADDRESS == 0x76) ? 0x77 : 0x76;
+    bme280_ok = BME280.begin(alt_address, TELEM_WIRE);
+    if (bme280_ok) {
+      bme280_address = alt_address;
+      MESH_DEBUG_PRINTLN("Found BME280 at alternate address: %02X", alt_address);
+    }
+  }
+  if (bme280_ok) {
+    MESH_DEBUG_PRINTLN("Found BME280 at address: %02X", bme280_address);
     MESH_DEBUG_PRINTLN("BME sensor ID: %02X", BME280.sensorID());
+    // Use forced mode to align with takeForcedMeasurement() in querySensors().
+    BME280.setSampling(Adafruit_BME280::MODE_FORCED,
+                       Adafruit_BME280::SAMPLING_X1,   // temperature
+                       Adafruit_BME280::SAMPLING_X1,   // pressure
+                       Adafruit_BME280::SAMPLING_X1,   // humidity
+                       Adafruit_BME280::FILTER_OFF,
+                       Adafruit_BME280::STANDBY_MS_1000);
     BME280_initialized = true;
   } else {
     BME280_initialized = false;

variants/xiao_nrf52/XiaoNrf52Board.cpp

@@ -34,6 +34,9 @@ void XiaoNrf52Board::begin() {
 #endif
 
 #if defined(PIN_WIRE_SDA) && defined(PIN_WIRE_SCL)
+  // Enable weak pullups for external I2C devices if no onboard pullups exist.
+  pinMode(PIN_WIRE_SDA, INPUT_PULLUP);
+  pinMode(PIN_WIRE_SCL, INPUT_PULLUP);
   Wire.setPins(PIN_WIRE_SDA, PIN_WIRE_SCL);
 #endif
 
@@ -93,4 +96,4 @@ bool XiaoNrf52Board::startOTAUpdate(const char *id, char reply[]) {
   return true;
 }
 
-#endif
+#endif

variants/xiao_nrf52/platformio.ini

@@ -24,8 +24,8 @@ build_flags = ${nrf52_base.build_flags}
   -D SX126X_DIO3_TCXO_VOLTAGE=1.8
   -D SX126X_CURRENT_LIMIT=140
   -D SX126X_RX_BOOSTED_GAIN=1
-  -D PIN_WIRE_SCL=D6
-  -D PIN_WIRE_SDA=D7
+  -D PIN_WIRE_SDA=D6
+  -D PIN_WIRE_SCL=D7
   -D PIN_USER_BTN=PIN_BUTTON1
   -D DISPLAY_CLASS=NullDisplayDriver
 build_src_filter = ${nrf52_base.build_src_filter}
@@ -106,4 +106,4 @@ build_flags =
 ;  -D MESH_PACKET_LOGGING=1
 ;  -D MESH_DEBUG=1
 build_src_filter = ${Xiao_nrf52.build_src_filter}
-  +<../examples/simple_room_server/*.cpp>
+  +<../examples/simple_room_server/*.cpp>

variants/xiao_nrf52/variant.h

@@ -111,11 +111,11 @@ static const uint8_t A5  = PIN_A5;
 // Wire Interfaces
 #define WIRE_INTERFACES_COUNT   (1)
 
-// #define PIN_WIRE_SDA            (17) // 4 and 5 are used for the sx1262 !
-// #define PIN_WIRE_SCL            (16) // use WIRE1_SDA
+#define PIN_WIRE_SDA            (6)  // D4/D5 used by SX1262, move I2C to D6/D7
+#define PIN_WIRE_SCL            (7)
 
-// static const uint8_t SDA = PIN_WIRE_SDA;
-// static const uint8_t SCL = PIN_WIRE_SCL;
+static const uint8_t SDA = PIN_WIRE_SDA;
+static const uint8_t SCL = PIN_WIRE_SCL;
 
 //#define PIN_WIRE1_SDA           (17)
 //#define PIN_WIRE1_SCL           (16)