gs_can_weact_H7_coreboard

SocketCAN compatibility for the STM32H7 core board from AliExpress, implementing a USB to CAN adapter using the gs_usb protocol.

Dependencies

Required Tools

ARM GCC Toolchain

# Download from ARM official site or install via package manager
# Version tested: gcc-arm-none-eabi-10.3-2021.10
sudo apt update
sudo apt install gcc-arm-none-eabi

ST-Flash Utilities

# For flashing the STM32 via ST-Link
sudo apt install stlink-tools

Make

sudo apt install make
# Version tested: GNU Make 4.3

CAN Utilities

# For CAN interface management and testing
sudo apt install can-utils

Optional Tools

• ST-Link V2 programmer (for flashing firmware)
• WeAct Studio MiniDebugger: A compatible debugger for this board. Link
• Logic analyzer or oscilloscope (for debugging)

Hardware

STM32H7 Core Board

This project uses the WeAct STM32H743VIT6 Core Board available on AliExpress:

• MCU: STM32H743VIT6 (Cortex-M7, 480MHz)
• Flash: 2MB
• RAM: 1MB
• Package: LQFP-100
• Key features: USB-C connector, onboard LED, user buttons

Board Pinout (Relevant Pins)

• LED1: PE3 (Status indicator)
• USER_BTN_K1: Configurable. See troubleshooting for notes on PC13, PE3, and PB12.
• CAN1/CAN2: Pins for external CAN transceiver.
• USB: USB-C connector for communication.

CAN Transceiver Requirements

You'll need external CAN transceivers (e.g., TJA1050, MCP2551) to interface with actual CAN buses, as the STM32 only provides the CAN controller, not the physical layer.

Building and Flashing

Clone and Build

git clone https://github.com/yourusername/gs_can_weact_H7_coreboard.git
cd gs_can_weact_H7_coreboard
make clean
make

Flash Firmware

# Using st-flash utility
make flash

# Or manually:
st-flash --reset write build/DevEBoxH7_fw.bin 0x8000000

SocketCAN Setup

Set Up CAN Interface

# Bring up the CAN interface
sudo ip link set can0 up type can bitrate 500000

# Verify interface is up
ip link show can0

Configure Different Bitrates

# For 125 kbps
sudo ip link set can0 up type can bitrate 125000

# For 250 kbps  
sudo ip link set can0 up type can bitrate 250000

# For 1 Mbps
sudo ip link set can0 up type can bitrate 1000000

Take Down CAN Interface

# Bring down the interface
sudo ip link set can0 down

Usage

Testing with Button

1. Connect the STM32H7 board via USB-C.
2. Set up the CAN interface (see above).
3. Press the K1 button on the board.
4. Observe the CAN message transmission.

The button sends a test frame:

• CAN ID: 0x123
• Data: 11 22 34 44 55 66 77 88
• Length: 8 bytes

Monitor CAN Traffic

# Monitor all CAN traffic
candump can0

# Example output:
# can0  123   [8]  11 22 34 44 55 66 77 88

Send CAN Messages

# Send a test message
cansend can0 456#DEADBEEF

Troubleshooting

Button Not Working

If the K1 button doesn't send messages:

1. Check CAN interface status: Ensure can0 is UP.
2. Verify host channel is active: The firmware only sends when the CAN channel is enabled from the host software.
3. Pin Configuration: The button's GPIO pin is critical.
   • PC13: This pin is connected to button labeled K1 on the board. It must be set as PULLDOWN to work properly
   • PE3: This pin is connected to the onboard LED. See board.c and board.h for details and configuration.

CAN Interface Issues

# Reset CAN interface
sudo ip link set can0 down
sudo ip link set can0 up type can bitrate 500000

# Check kernel logs for errors
dmesg | grep can

Development

Adding Custom CAN Handling

Modify the task_queue_from_host() function in Core/Src/main.c to add custom CAN frame processing.

The onboard LCD display can also be used to do funny things

LED Behavior

• Solid ON: CAN channel active.
• Blinking: CAN traffic activity.

License

MIT License.