JTAG

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Revision as of 12:05, 18 April 2012 by Jkg (talk | contribs) (added info about JTAG connector/cable)
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JTAG interface was designed for on chip debug. That means, it can debug chips that has no bootloader at all. The board provided by JobyRobotics is based on FTDI chip that allows two simultaneous USB connections. For us it 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.

Jtag-up.jpg

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)

Jtag-down.jpg

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.

Alternative

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

AlternativeFlossJtag.png

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