Loading Firmware via JTAG

Hardware

In order to load and debug the Model-T via JTAG, you will need the following:

• A 5x2 1.27mm pitch JTAG header This will need to be soldered to the controller board (schematics and layout).
• A JTAG programmer. We currently support the following (although any programmer supported by OpenOCD could be used with some small makefile tweaks):
  • Olimex ARM-USB-TINY-H programmer
  • USB-MiniJTAG J-Link
  • ST-LINK/V2
• A JTAG 20 pin to 10 pin adapter

You will need to set the JTAG environment variable to either jlink, stlink, or olimex in order to load code and debug.

Ubuntu

1. Install OpenOCD 0.8.0

• sudo apt-get install openocd

2. Set up the permissions for the programmer and buspirate (from model-t directory):

• sudo groupadd usbusers
• sudo usermod -a -G usbusers <your username>
• newgrp usbusers (This is required because new groups don't take effect until you completely log out and back in. You only need to do this until your first log out and log in)
• sudo cp scripts/40-persistent-usb.rules /etc/udev/rules.d
• sudo udevadm control --reload-rules

Windows

1. Download OpenOCD 0.8.0, extract, and add to path
2. Download Zadig
3. Connect the JTAG programmer to your computer. When Windows asks for drivers to be installed, cancel out of the dialog and do not install any recommended drivers. Run Zadig, and select your programmer from the drop down, there may be 2 listed. Select WinUSB for the driver and install for both of your devices in the dropdown.

Download

You should now be able to connect the JTAG programmer to your Model-T and through the command line or Eclipse load your custom firmware.