JTAG

JTAG interface is designed for on-chip debugging, which means it can program and debug chips that do not have a bootloader. There are multiple Paparazzi-compatible devices available that support JTAG.

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: Ground (black), TX (yellow), RX (orange) 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.

Black Magic Probe

Full 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, append the following string to the upload command:

On Linux:

FLASH_MODE=JTAG BMP_PORT=/dev/ACM0

On Mac OS:

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

Esden's reasons to use Black Magic Probe Mini instead of FLOSS-JTAG:

• 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

FT2232 Dev Board

use ftdi prog to change the Description String into: FLOSS-JTAG

Related articles

• DevGuide/JTAG-Debug - Developer's guide JTAG debugging
• Dev/Debugging - General debugging information

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