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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