CAN->CCD Bus Translator V2

I am designing an interface for my current engine swap project in my Jeep. I am starting with a 1998 Jeep Cherokee, 4.0L I6, AX15 manual transmission, and a NP242 transfer case, and I am replacing the engine with a VW TDI from a 2005 VW Passat (2.0L 8v, code: BHW) and a 6 speed manual from a late model TJ Rubicon (NSG370).

This project is made up of two parts:

• a board designed to interface with the Jeep CCD protocol and VW CAN v2.0
• a event driven application to handle the needed events to translate between buses

Things needed to get started:

• KiCAD
• PlatformIO
• MinGW or GCC installed and on your $PATH (for tests)

Hardware Concept

• Teensy 3.2 at the core - extra I/O available for further expansion
• dedicated CCD interface IC - CDP68HC68S1
• CAN handled by teensy/MPC2551
• I/O for all circuits missing from engine/Jeep
• BOM at Mouser

The VW ECU expects a handful of things the Jeep does not handled

• fuel level (leters)
• speed at 8200 pulses/mile (need to confirm voltage EDC expects)
• cruise control is array of switches
• alternator is monitored by gauge cluster

Likewise, the Jeep expects a couple things the VW ECU does not provide

• speed at 8000 pulses/mile from VSS, CCD expects 8388 bits/mile for odometer
• oil pressure (PSI)
• fuel level (%)
• cruise control is resistor bus
• glow plug lamp needs CAN->physical output translation

Software Concept

• Unit tests are written in unity syntax
• Events are handled by Eventually
• Arduino API does hardware interface, with TeensyDuino additions
• Each interface gets its own class: CCD, CAN, distance/speed, fuel level... etc.

To run tests, run pio test -e native To compile ELF for teensy, run pio run

I'm a web developer so this is gonna be MVCish.

• Model: Holds some state
• View: Puts state, I.E. does the actual interface with HW
• Controller: translates between model and view, and viceversa

The counter class implements logic to read the hardware model, so by this definition it is a Controller. The VehicleState class is just a holder of state, so it is squarely a Model. The CCD hardware interface gets/sets values on the HardwareSerial interface, so it is a view.

This will likely morph.

TODO

• implement CAN class
• implement fuel level
• translate cruise buttons
• rewrite CCD class to respect bus status (currently it blindly transmits)
• write tests so they can run on teensy