Unitialized variable `BusOwner`

[zfields]

/home/zak/.arduino15/packages/arduino/hardware/samd/1.8.14/libraries/Wire/Wire.cpp: In member function 'virtual size_t arduino::TwoWire::requestFrom(uint8_t, size_t, bool)':
/home/zak/.arduino15/packages/arduino/hardware/samd/1.8.14/libraries/Wire/Wire.cpp:99:5: warning: 'busOwner' may be used uninitialized in this function [-Wmaybe-uninitialized]
     if (!busOwner)
     ^~

[APerelet]

I encountered this issue while using a Bosch BMP390 sensor on an Arduino MKR WAN 1310 (SAMD) under PlatformIO.

The symptoms were initially very confusing. The BMP390 would fail to initialize through both the Bosch BMP3 SensorAPI and the Adafruit BMP3XX library, typically reporting I2C communication failures during chip ID reads. However, manual I2C register accesses would sometimes succeed, making the hardware and wiring appear correct. The hardware and wiring were confirmed to be okay as this was a project being migrated from Arduino IDE to PlatformIO and there were no I2C issues in Arduino IDE. Other I2C devices had no issues in PlatformIO.

The root cause turned out to be the uninitialized busOwner variable discussed in this issue. After initializing busOwner = true, the sensor initialized and operated normally.

The bug can appear as:

• I2C communication failure
• Sensor initialization failure
• BMP390 initialization failure
• Bosch BMP3 SensorAPI BMP3_E_COMM_FAIL
• Adafruit BMP3XX begin_I2C() failure
• PlatformIO-specific migration issues
• SAMD Wire library problems

Keywords

• "BMP390"

• "BMP3"

• "I2C"

• "Wire"

• "Wire.cpp"

• "BMP3_E_COMM_FAIL"

• "sensor initialization failure"

• "I2C communication failure"