JTAG

Introduction

A JTAG interface is designed for on-chip debugging. It can also be used to flash your firmware if you do not have a means to upload software via USB already. For short, if you want to upload your own software or want to do serious paparazzi development work, the you need a JTAG adapter like this.

See also:

• firmware flashing via JTAG
• debugging with JTAG

JTAG Adapters

There are multiple Paparazzi-compatible devices available that support JTAG.

Below you find a list of JTAG devices that you can use in combination with e.g. a Paparazzi Lisa/M board.

FLOSS JTAG

The FLOSS JTAG is based on an FTDI chip that allows two simultaneous USB connections, which means that FLOSS JTAG allows JTAG and UART/COM connections.

Let's take a look at upper side of the board. It contains JTAG connector (which is connected on photo) and two sets of RX/TX LEDs for JTAG and UART/COM interface separately. The JTAG connector is 2x5 pins, 0.05-inch pitch, and is compatible with the Samtec FFSD-05-D-06.00-01-N-RW-R ribbon cable.

On the other side of the board there is 4 pin UART/COM connector, which contains (from top to bottom in the image below): Ground (black), RX (orange), TX (yellow), and +5V (red)

Usage of board is pretty simple: JTAG can be used to upload firmware into the board and/or repair board with broken bootloader, and UART/COM interfaced can be used to make "COM port style" connection to the board. COM connection can be used for example for telemetry debug.

More info available on the randomprojects.org wiki.

Black Magic Probe

Some additional info about the Black Magic Probe is available at the Black Sphere Technology website.

To use Black Magic Probe instead of FLOSS-JTAG or Luftboot for firmware flashing, append the following string to the upload command:

On Linux:

FLASH_MODE=JTAG_BMP BMP_PORT=/dev/ttyACM0

On Mac OS:

FLASH_MODE=JTAG_BMP BMP_PORT=/dev/cu.usbmodem<serial>

To make this the default flash method add this in the airframe file firmware section:

   <configure name="FLASH_MODE" value="JTAG_BMP"/>
   <configure name="BMP_PORT" value="/dev/ttyACM0"/>

See the FirmwareFlashing page for other methods.

Benefits

There are good reasons to use the Black Magic Probe Mini instead of FLOSS-JTAG:

• Lower cost
• No need for OpenOCD as BMPM has a built in GDB server
• Orders of magnitude faster as all the high speed protocol logic happens on the built-in STM32
• Supports Serial Wire Debug (SWD)
• Supports tracing using the SWD trace pin
• No need for loading and unloading of FTDI drivers on Mac OS X

UART port

The pinout for the UART port on the back side of the BMP as seen on the image above and starting from the top is ground,rx,tx,3.3v . You can use this for receiving telemetry.

Upgrade BMP firmware

Check firmware version:

$ sudo /usr/bin/arm-none-eabi-gdb
(gdb)  target extended-remote /dev/ttyACM0
(gdb)  monitor version

To upgrade the brain of your Black Magic Probe, a.k.a. its firmware:

- Download the compiled firmware from http://blacksphere.co.nz/builds/  (more info at https://github.com/blacksphere/blackmagic/wiki/Frequently-Asked-Questions)
- Download and run the stm32_mem.py script:
  $ git clone git://blackmagicdebug.git.sourceforge.net/gitroot/blackmagicdebug/blackmagicdebug
  $ cd blackmagicdebug/src/scripts
  $ ./stm32_mem.py blackmagic-XXXX.bin   (this is the .bin file you downloaded in previous step)

FT2232H Mini Module

Use ftdi prog to change the Description String into: FLOSS-JTAG.
More information for this board at Serial_Adapter.