To build for the chipKIT-based Vehicle Interface, compile with the flag PLATFORM=CHIPKIT. The chipKIT is also the default platform, so the flag is optional.
The chipKIT VI supports up to 2 of the CAN1, CAN2-1 or CAN2-2 buses simultaneously.
These instructions assume your chipKIT is running the stock firmware, the avrdude bootloader.
You need to have the mini-USB port on the chipKIT connected to your computer to upload a new firmware. This is different than the micro-USB port that you use to read vehicle data - see the device connections section of the OpenXC website to make sure you have the correct cable attached.
Open a terminal run the upload_hex.sh script from the cantranslator directory, passing it the path to the .hex file you downloaded:
$ cd cantranslator
$ script/upload_hex.sh <firmware file you downloaded>.hex
The upload_hex.sh script attempts to install all required dependencies automatically, and it is tested in Cygwin, OS X Mountain Lion, Ubuntu 12.04 and Arch Linux - other operating systems may need to install the dependencies manually.
If you have more than one virtual serial (COM) port active, you may need to explicitly specify which port to use. Pass the port name as the second argument to the script, e.g. in Linux:
$ script/upload_hex.sh <firmware file you downloaded>.hex /dev/ttyUSB2
and in Windows, e.g. if you needed to use com4 instead of the default com3:
$ script/upload_hex.sh <firmware file you downloaded>.hex com4
In Windows, this command will only work in Cygwin, not the standard cmd.exe or Powershell.
If you get errors about $'\r': command not found then your Git configuration added Windows-style CRLF line endings. Run this first to ignore the CR:
$ set -o igncr && export SHELLOPTS
If the flashing script failed, you may need to install the dependencies manually.
If you are using Windows or OS X, you need to install the FTDI driver. If you didn’t need to install MPIDE, you can download the driver separately from FTDI.
In order to program the CAN translator, you need to install an AVR programmer. There are a number of free options that will work.
With MPIDE
If you have MPIDE installed, that already includes a version of avrdude. You need to set the MPIDE_DIR environment variable in your terminal to point to the folder where you installed MPIDE. Once set, you should be able to use upload_hex.sh.
Without MPIDE
If you do not already have MPIDE installed (and that’s fine, you don’t really need it), you can install a programmer seprately:
Linux - Look for avrdude in your distribution’s package manager.
OS X - Install avrdude with Homebrew.
The PIC32 avrdude bootloader is tested and working and allows flashing over USB with avrdude. All stock chipKITs are programmed with a compatible bootloader at the factory.
Once the dependencies are installed, attach the chipKIT to your computer with a mini-USB cable, cd into the src subdirectory, build and upload to the device.
$ make clean
$ make
$ make flash
If the flash command can’t find your chipKIT, you may need to set the SERIAL_PORT variable if the serial emulator doesn’t show up as /dev/ttyUSB* in Linux, /dev/tty.usbserial* in Mac OS X or com3 in Windows. For example, if the chipKIT shows up as /dev/ttyUSB4:
$ SERIAL_PORT=/dev/ttyUSB4 make flash
and if in Windows it appeared as COM4:
$ SERIAL_PORT=com4 make flash
This build process assumes your chipKIT is running the avrdude bootloader - all chipKITs come programmed with a compatible bootloader by default.
It is possible to use an IDE like Eclipse to edit and compile the project.
If you didn’t set up the environment variables from the Installation section (e.g. MPIDE_HOME), you can also do that from within Eclipse in C/C++ project settings.
There will still be some errors in the Eclipse problem detection, e.g. it doesn’t seem to pick up on the GCC __builtin_* functions, and some of the chipKIT libraries are finicky. This won’t have an effect on the actual build process, just the error reporting.
The micro-USB port on the Digilent Network Shield is used to send and receive OpenXC messages. The mini-USB cable on the Max32 itself is only used for re-programming.
On the chipKIT, UART1A is used for OpenXC output at the 230000 baud rate. Hardware flow control (RTS/CTS) is enabled, so CTS must be pulled low by the receiving device before data will be sent. There are a few tricky things to watch out for with UART (i.e. Bluetooth) output on the chipKIT, so make sure to read this entire section.
UART1A is also used by the USB-Serial connection, so in order to flash the PIC32, the Tx/Rx lines must be disconnected. Ideally we could leave that UART interface for debugging, but there are conflicts with all other exposed UART interfaces when using flow control.
UART data is sent only if pin A1 is pulled low (to ground). If you are using a Bluetooth module like the BlueSMiRF from SparkFun, you need to hard-wire GND into this pin to actually enabling UART. To disable UART, pull A1 high (hard-wire to 5v) or leave it floating.
An additional item to consider when using UART: typically you will want to rig the chipKIT to be self-powered (either from an external power source or the vehicle) if you’re going to use UART for adding Bluetooth support. There’s not much point in being wireless if you still need power from USB.
In that case, move the power jumper from the 5v input on the Network Shield to A0 (analog input 0). Instead of using 5v to power the board, the firmware can use it to detect if USB is actually attached or not. The benefit of this is that if you connect USB, then disconnect it, we can detect that in the firmware and stop wasting time trying to send data over USB. This will dramatically increase the throughput over UART.
On the chipKIT Max32, logging will be on UART2 (Pin 16 - Tx, Pin 17 - Rx) at 115200 baud (if the firmware was compiled with DEBUG=1).
The chipKIT has 1 user controllable LED. When CAN activity is detected, the LED will be enabled (it’s green).