Hardware

SPI Protocol

SPI (Serial Peripheral Interface) is a synchronous, full-duplex serial communication protocol in which a controller device exchanges data with peripherals over shared clock (SCLK), data-out (MOSI), and data-in (MISO) lines, selecting targets with per-device chip-select signals. It supports clock rates from megahertz to tens of megahertz with minimal protocol overhead, at the cost of no built-in addressing or acknowledgment. Robots use SPI to read IMUs, magnetic encoders, ADCs, and other sensors at high rates.

Why it matters for physical AI

Kilohertz control loops need sensor reads with microsecond determinism; SPI's simplicity and speed make it the default link between microcontrollers and the encoders and IMUs closing those loops.