flow-and-error-control

🔬 Microprocessors & Microcontrollers — Lab 5

STM32F103C6 — UART Communication, ADC Reading & Command Protocol FSM

Student	Dang Thai Khang — 2352464
Course	C03010 — CC02
Institution	Ho Chi Minh University of Technology (HCMUT)
Lecturer	Phan Van Sy
Semester	2025

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📌 Overview

This lab implements a UART-based command-response protocol on the STM32F103C6. The MCU reads an ADC sensor value and communicates it over UART using a structured message format. The system uses two FSMs: one for parsing incoming commands and one for managing the communication flow (with retry/timeout logic).

Tech Stack

• MCU: STM32F103C6 (ARM Cortex-M3)
• IDE: STM32CubeIDE (HAL Library)
• Simulation: Proteus 8
• Language: C
• Peripherals: USART2 (9600 baud), ADC1 (Channel 0), GPIO

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📂 Repository Structure

VXL_VDK_Lab_5_2352464/
└── FULL_EXERCISE/
    ├── Lab_5.c                        # Main program (UART ISR, ADC init, main loop)
    ├── Lab_5.hex                      # Compiled firmware for Proteus
    ├── Lab_5.pdsprj                   # Proteus schematic & simulation
    └── Core/
        ├── Inc/
        │   ├── command_parser_fsm.h   # Command parser header
        │   └── uart_communication_fsm.h # UART comm FSM header
        └── Src/
            ├── command_parser_fsm.c   # Parses "!RST#" and "!OK#" commands
            └── uart_communication_fsm.c # UART state machine with retry logic

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🧪 System Architecture

Communication Protocol

The system uses a simple request-response protocol over UART:

PC → STM32:  "!RST#"          (Request ADC reading)
STM32 → PC:  "!ADC=<value>#"  (Respond with ADC value)
PC → STM32:  "!OK#"           (Acknowledge receipt)

Message Format

• All messages start with ! and end with #
• Commands: !RST# (request), !OK# (acknowledge)
• Response: !ADC=XXXX# where XXXX is the raw 12-bit ADC value (0–4095)

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🔄 FSM Diagrams

Command Parser FSM (command_parser_fsm.c)

Incoming buffer
    ├── contains "!RST#"  →  command_flag = 1 (request)
    └── contains "!OK#"   →  command_flag = 2 (acknowledge)

UART Communication FSM (uart_communication_fsm.c)

State 0: IDLE
    │  command_flag == 1 (RST received)
    │  → Read ADC, send "!ADC=value#", start timeout
    ▼
State 1: WAIT_ACK
    ├── command_flag == 2 (OK received) → back to State 0
    └── timeout (3 seconds) → retransmit same ADC value, reset timeout

UART Receive (Interrupt-driven)

HAL_UART_RxCpltCallback()
    → Append byte to buffer
    → If byte == '#' → set buffer_flag = 1
    → Re-enable interrupt for next byte

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📝 Module Descriptions

Lab_5.c — Main Program

• Initializes UART2 (9600/8N1), ADC1 (Channel 0, continuous), GPIO
• UART RX interrupt fills a 30-byte circular buffer
• Main loop: LED heartbeat (500ms), command parsing, UART FSM

command_parser_fsm.c — Command Parser

• Uses strstr() to detect !RST# and !OK# in the receive buffer
• Sets command_flag for the communication FSM to act on

uart_communication_fsm.c — Communication Controller

• State 0 (IDLE): Waits for RST command, then reads ADC and sends response
• State 1 (WAIT_ACK): Waits for OK acknowledgment, retransmits after 3s timeout

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⚙️ How to Run

Proteus Simulation

1. Open FULL_EXERCISE/Lab_5.pdsprj in Proteus 8+
2. Load Lab_5.hex into the STM32 component
3. Click Run — use the Virtual Terminal to send !RST# and !OK#

Flash to Hardware

1. Create STM32F103C6 project in STM32CubeIDE
2. Enable USART2 (9600 baud, TX/RX), ADC1 (Channel 0), GPIO PA5 output
3. Copy source files and build
4. Connect via USB-UART adapter, open serial terminal at 9600 baud

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📝 UART Configuration

Parameter	Value
Baud Rate	9600
Word Length	8 bits
Stop Bits	1
Parity	None
Flow Control	None
Mode	TX + RX (interrupt-driven RX)

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📄 Report

The full lab report (PDF) with schematics, protocol diagrams, and source code explanations is available in the course submission.

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📜 License

This project is developed for educational purposes as part of the Microprocessors & Microcontrollers course at HCMUT.