CAN Bus tool for modifying the 3 busses on a Ford Fiesta Mk7.5

Provided AS-IS. License is not Free, commerial use of code not covered under other Licences is prohibited.

Uses a ATMega1284p as controller, CN340N for USB to Serial and 3x MCP2515 with TC1051 as CAN controllers and trancievers.

Planned features:

• Bus transversion, e.g. HS to ICAN data transfer
• Bus translation, e.g. converting messages to a different format (mostly MSCAN to ICAN)
• Debugging multiple busses via SLCAN protocol (extensions)
• Binary mode for better bus usage
• slcan compatible kernel driver for multiple busses

Acknowledgements

• MightyCore for the arduino compatable stuff (which makes my life easier even if I do not use arduino tools)
• The MCP_CAN_lib fork for the mcp lib. This part is under GPLv3.
• SLCAN driver as in the upstream kernel.
• can-utils
• creator of simple crc8.c file for avr.

Who this is for

This repository is the extension of my own project to get the front distance sensors working on my car. It collided with the idea of creating a translation module for Sync 4 to be fitted into Sync 3 capable vehicles. This repository is solely meant for development and debugging and not meant as a ready made tool to install and get going.

Who this is not for

• If you do not know what a CAN BUS is, this is not for you
• If you do not know how to use a micro processor, this is not for you
• If you do not know how to order PCBs, Create your own board and put it all together, this is not for you
• If you just want fancy features on "car model XXX", this is not for you
• If you do not know how to compile kernel modules and/or have the knowledge to build them from scratch, this is not for you

If you still think this is for you: Welcome, you can always create pull requests if you want to change something. Issues will be ignored.

Compile the arduino-style stuff

• Get all the needed tools: cmake, gcc-avr, avr-libc, avrdude.
• Get mightycore for the atmega1284p core files and put them in the atmega1284p/cores directory
• Get the mightycore libraries and put them into atmega1284p/libraries
• Get the standard pinout file and the avrdude config file from mightycore and put them in the atmega1284p/boards directory.

Or collect the git submodules and run the batch file to create the softlinks.

Run mkdir -p build; cd build; cmake ..

Compile the kernel module

Same as above but then make slcan_multimode and install with make install_kmod

Known issues

• There is some memoy issue which causes the device to reset on receiving data and timing out afterwards.

Additions to the original SLCAN/LAWICEL spec

• Added "B" Command which can prepend any command to a can bus which selects a bus, e.g. B1t1012FF00\r would send some stuff to bus 1 (0 is the default)
• Added "D" Command which allows the data to be send in binary format. Enable with D1\r disable with D0\r
• Sould be fully backwards compatible, timestamps are not supported.

Binary format:

• 8 bits header (0xA5)
• 2 bits bus (0b11000000)
• 1 bit rtr (0b00100000)
• 29 bits id
• 64 bits data
• 8 bits CRC8

This is a bit over half (15 vs 27) for a non timestamped frame at max size and is way easier on the microcontroller. It also has added error detection, while not great it's good enough to detect single bitflips which sometimes happen on high baudrates.

I might switch to the AUTOSAR polynomial as it would guarantee 4 bits of hamming distance which CRC8 limits to 2 for this size.