STM32 UART Protocol Parser with CRC16/CMS

An interrupt-driven, dual-UART message parser for STM32 (tested on NUCLEO-G431RB) that:

Uses a state machine to validate incoming frames (ID → LEN → DATA → CRC)
Buffers data in a lock-free circular buffer for non-blocking reception
Verifies message integrity using CRC16/CMS (poly 0x8005, init 0xFFFF, xorOut 0x0000)
Sends a fixed 6-byte response on valid CRC

📹 Demo Video

✨ Features

Non-blocking UART RX using HAL HAL_UART_Receive_IT and per-UART circular buffers
Deterministic parsing with strict ID ↔ LEN mapping
Table-driven CRC16/CMS calculation for efficiency
Works with two UART interfaces independently

📦 Repository Structure

. ├─ circular_message.c / .h # Circular buffer implementation
├─ message_state.c / .h # State machine parser & response builder
├─ crc16_cms.c / .h # CRC16/CMS calculation
├─ main.c # UART init, interrupt handling, main loop
├─ STM32-UART-Protocol-Parser-with-CRC16.ioc # STM32CubeMX configuration
├─ PROTOCOL.md # On-wire protocol specification
├─ Message Examples.txt # Example request/response frames
├─ LICENSE
└─ .gitignore

🔌 Protocol Overview

Frame format (big-endian CRC): [ ID(1) | LEN(1) | DATA(LEN-4) | CRC_HI(1) | CRC_LO(1) ]

markdown Kopyala Düzenle

Allowed IDs: 0x55, 0x66, 0x77, 0x88, 0x99
LEN includes all fields; DATA length = LEN − 4
CRC16/CMS is computed over ID..last DATA byte
ID ↔ LEN mapping: 0x55 → 0xFF 0x66 → 0x7F 0x77 → 0x06 0x88 → 0x07 0x99 → 0x05

yaml Kopyala Düzenle

See PROTOCOL.md for full details.

🧪 Example

From Message Examples.txt:

Request: 77 06 88 BD 9F CC

makefile Kopyala Düzenle Response: 33 05 F1 33 E9

yaml Kopyala Düzenle (Last two bytes are CRC16/CMS over [ID..OUT3])

🛠️ Build & Run (STM32CubeIDE)

Open STM32-UART-Protocol-Parser-with-CRC16.ioc in STM32CubeIDE
Generate code and ensure Src/ and Inc/ contain the provided .c and .h files
Connect NUCLEO-G431RB via USB
Flash the program to the board
Open HTerm / Serial Monitor @ 115200-8N1 and send example frames in HEX mode

📜 License

This project is released under the MIT License. See LICENSE.

🙌 Credits

Developed by Erkin Coşkun Ruhi

Coskunruhi/STM32-UART-Protocol-Parser-with-CRC16