Raspberry Pi I2C Connectors and Pinout
I2C - Inter Integrated Circuit I2C pins in BCM mode are: 2, 3 I2C pins in WiringPi are: 8, 9 The UART pins are 14 and 15, TXD, RXD. /dev/serial0 The Raspberry Pi's I2C pins are an extremely useful way to talk to many different types of external peripheral; from the MCP23017 digital IO expander, to a connected ATmega. The I2C pins include a fixed 1.8 kohms pull-up resistor to 3.3v. This means they are not suitable for use as general purpose IO where a pull-up is not required. You can verify the address of connected I2C peripherals with a simple one-liner: sudo apt - get install i2c - tools sudo i2cdetect - y 1 You can then access I2C from Python using the smbus library: import smbus DEVICE_BUS = 1 DEVICE_ADDR = 0x15 bus = smbus . SMBus ( DEVICE_BUS ) bus . write_byte_data ( DEVICE_ADDR , 0x00 , 0x01 ) Example with a pimoroni scrollphathd pi@raspberrypi:/usr/lib/python3/dist-packages/scrollphathd $ sudo i2cdetect -y 1 0 1 2 3 4 5 ...