msp-protocol

MSP protocol commands are identified by their command byte and packet structure. Parse MSP packets by reading the header (0x24, 0x4D), direction byte, size, command ID, data payload, and CRC checksum. INAV firmware defines these in msp_protocol.h and msp.c; the configurator provides JavaScript MSP definitions for reference.

MSP v1 uses a fixed 8-byte header with 1-byte size limit (255 bytes max). MSP v2 extends this with a larger frame format supporting bigger payloads. Both versions follow request/response patterns; choose based on your payload size and INAV version compatibility requirements.

Enable MSP debug logging through INAV configurator settings and examine msp_serial.c for low-level frame handling. Use mspapi2 or uNAVlib (Python library) to parse and test MSP packets independently. Benchmark tools help identify communication bottlenecks between device and ground station.

Yes. The MSP protocol is standardized across MultiWii-based systems. The configurator works with any firmware implementing the protocol; uNAVlib and mspapi2 provide portable Python interfaces for automated testing, logging, and packet validation across platforms.

Search the INAV firmware source (msp_protocol.h for definitions, msp.c for handlers) for the command name or ID. Cross-reference the payload structure in the configurator's JavaScript MSP definitions. Use debugging tools to trace command execution and verify payload format during firmware analysis.

Understand the MSP packet structure (header, size, command ID, data, CRC), request/response direction flags, and payload byte order. Review existing command implementations in msp.c for patterns. Validate your handler with uNAVlib or mspapi2 to ensure correct packet encoding and decoding.