CRSF C Library

A small and tested C implementation of the CRSF protocol for UART links with no dynamic allocation or external dependencies.

What it includes

• Frame build and parse helpers for supported frame types:
  • Channels
  • GPS
  • Link Statistics
  • Battery Sensor
  • Attitude
  • MSP Request/Response
• Lightweight streaming parser.

Files

• crsf.h Public API and protocol definitions.
• crsf.c Core implementation.
• crsf_parser.h Header-only streaming parser.

Basic Usage

Initialise the parser.

crsf_parser_t parser;
crsf_parser_init(&parser, CRSF_ADDRESS_FC, on_crsf_frame);

Feed incoming UART bytes.

crsf_parser_feed(&parser, rx_buffer, rx_len);

Build and send frames.

crsf_build_payload_channels(payload, &channels);
crsf_build_frame_channels(frame, CRSF_ADDRESS_RX, payload);

Reference

Based on the CRSF protocol specification.