Wire (I2C Master and Slave)
The RP2040 has two I2C devices,
i2c0 (Wire) and
The default pins for Wire and Wire1 vary depending on which board you’re using. (Here are the pinout diagrams for Pico and Adafruit Feather.)
You may change these pins before calling Wire.begin() or Wire1.begin() using:
bool setSDA(pin_size_t sda); bool setSCL(pin_size_t scl);
Be sure to use pins labeled
I2C0 for Wire and
I2C1 for Wire1 on the pinout
diagram for your board, or it won’t work.
Other than that, the API is compatible with the Arduino standard. Both master and slave operation are supported.
Master transmissions are buffered (up to 128 bytes) and only performed
endTransmission, as is standard with modern Arduino Wire implementations.
For more detailed information, check the Arduino Wire documentation .