Feather RP2040 Adalogger \*\*Issue: Feather RP2040 Adalogger not detecting I2C devices (mux)\*\* I’m trying to get I2C working on an Adafruit Feather RP2040 Adalogger with a TCA9548A multiplexer. \* Using Arduino I2C scanner (\`Wire.begin()\`, scanning 1–127) \* Code compiles and uploads successfully (via bootloader / UF2 if needed) \* Serial monitor shows scanner running, but \*\*no devices are detected\*\* \* Expected to see mux at \`0x70\` \*\*Hardware setup:\*\* \* Feather 3.3V → mux VIN \* Feather GND → mux GND \* Feather SDA → mux SDA \* Feather SCL → mux SCL \* No devices connected to mux channels yet \*\*Observations:\*\* \* With just Feather + mux, SDA/SCL measure \~0–0.27V instead of \~3.3 V idle \* Using STEMMA QT cable vs header pins makes no real difference \* New USB cable (data + power) didn’t change behavior \* Pins have not been reassigned (default I2C) \*\*Question:\*\* \* Does this setup require external pull-ups (e.g., 4.7kΩ to 3.3V)?…