FaSTTUBe CAN HAL Abstraction Layer

This repository contains an abstraction layer to provide a simplified & unified interface to the STM32 bxCAN and FDCAN peripherals.

Installation

Simply add the repository to your Core/Lib directory. You can also add it as a git submodule:

mkdir -p Core/Lib
cd Core/Lib
git submodule add ssh://git@git.fasttube.de:313/FaSTTUBe/can-halal.git

The library needs to be told what STM family you're using, so make sure one of the following symbols is defined when can-halal.c is compiled or can-halal.h is included:

• STM32F3
• STM32H7
• STM32F0

When using the FDCAN peripheral (H7 series), you also need to define FTCAN_NUM_FILTERS (and set it to the value of "Std Filters Nbr" you configured in your .ioc).

If you want to use the dedicated buffers of the FDCAN, you must additionally define FTCAN_NUM_TX_BUFFERS (set to value of "Tx Buffers Nbr" in CubeMX).

If you use VSCode with the stm-32-for-vscode extension, you can add these definitions in the STM32-for-VSCode-config.yaml file, e.g.:

# Compiler definitions. The -D prefix for the compiler will be automatically added.
cDefinitions:
  - STM32H7
  - FTCAN_NUM_FILTERS=32
  - FTCAN_NUM_TX_BUFFERS=10 # optional, only if using dedicated tx buffers

Usage

1. Include can-halal.h
2. Call ftcan_init() with the appropriate handle
3. Call ftcan_add_filter() with all your filters
4. To transmit messages, call ftcan_transmit()
5. When a message is received, ftcan_msg_received_cb() is called. It has a default empty implementation, which you can simply override.

Enabling CAN in STM32CubeMX

This isn't specific to can-halal, but for completeness sake is included here.

bxCAN (e.g. STM32F3xx)

1. Enable the CAN peripheral
   
2. Setup the bit timings.
   Note: the baud rate depends on your system clock, so make sure that is setup correctly first!
   
3. Make sure the CAN_RX0 interrupt is enabled
   

FDCAN (e.g. STM32H7xx)

1. Enable the CAN peripheral
   
2. Setup the frame format, nominal SJW, filters, and FIFOs. The numbers for filters/FIFOs in the screenshot are examples.
   Note: You need to tell can-halal about the number of filters by defining FTCAN_NUM_FILTERS (see above).
   
3. Setup the bit timings. We only use CAN in classic mode, not FD mode, so we only need to worry about the nominal bit timings
   Note: the baud rate depends on your system clock, so make sure that is setup correctly first!
   
4. Make sure the interrupts are enabled