Communication buses

I²C

Inter-Integrated Circuit

2-wire bus (SDA + SCL), multi-drop, slow (100 kHz–1 MHz), needs pull-up resistors.

How it looks

Real geometry: CORE3588 copper, drawn from our board file (top and bottom layers; this net in amber)

An I2C bus on CORE3588: CAM0_SDA and CAM0_SCL (amber), the two wires the computer module uses to set up camera 0.

1Camera socket P1: its two I2C pins.
2The computer module socket: the other end. Two pull-up resistors (R14, R15) sit near the camera.

The two wires are SDA and SCL. Slower but simpler than SPI; works because outputs are open-drain with pull-ups.