Serial protocols

A UART sends and receives bytes. A protocol gives those bytes meaning. Without one, the receiver sees a stream with no message boundary, payload length, checksum, or recovery rule.

UART configuration

Both sides must agree on baud rate, word length, stop bits, parity, and whether FIFOs and interrupts are enabled. A mismatch can produce data that looks random or is only occasionally wrong. Configuration is part of the protocol: both programs must agree on byte representation and readiness before messages flow.

From bytes to messages

A robust protocol usually needs a start marker or length, payload bytes, a checksum or sequence number, acknowledgement or retry behavior, and timeout rules. Lab 7 starts with raw UART helpers. Final projects can build higher-level protocols on top.

run-pair

run-pair creates two independent runtime machines and bridges their serial ports. Unlike loopback inside one machine, this is two programs connected by a cable, each with its own state, timeouts, and failure modes.