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--- dev:nab:v2:jtag_access [2015/11/12 12:49] – [JTAG probe: BusBlaster] redox
+++ dev:nab:v2:jtag_access [2015/11/12 13:38] (current) – removed redox
@@ Line 1: / Line 1: @@
-# JTAG access
-## Overview
-As detailed on the Schematic (released in the FCC documents), the Nabaztag:tag board breaks out the JTAG port. Let's see how to use it to access the CPU to be able to flash and debug some code !
-## Hardware
-### JTAG probe: BusBlaster
-I think you can use any JTAG probe that's 3.3v compatible, if you have one. If you don't, I recommend the [BusBlaster v3](http://dangerousprototypes.com/docs/Bus_Blaster_v3_design_overview). It's a great board, versatile and cheap; oh ! and it's also open hardware and open source ! :-)
-On of the best features of the BusBlaster is you can reconfigure the CPLD to emulate any FT2232 JTAG probe. I think it comes pre-programmed with a JTAGkey buffer logic, which should work fine for this application.
-_Note_: My BusBlaster (a v4 !) uses a KT-link buffer logic, because I needed the SWD capabilities for another application. If the following steps don't work, try to reprogram the CPLD with a KT-link buffer and try again !
-You also need some jumper wires (also called _Dupont wire_ sometimes) F/F to connect the BusBlaster to the Nabaztag
-### Nabaztag:tag
-Well, of course you need a Nabaztag:tag ( a version 2 ). You also must be ready to open it.
-Grab a small flat screwdriver and remove the four screws on the base. You can also use a triangle screwdriver if you happen to have one, I don't.
-And this is about it. the JTAG header is on the top left corner of the board.
-Pinout is the following (top to bottom):
-^ Nabaztag Pin ^ Function ^ BusBlaster pin ^
-|  1           |  3.3v    |  VTG (or NC)   |
-|  2           |  Gnd     |  GND           |
-|  3           |  nTRST   |  TRST          |
-|  4           |  TDI     |  TDI           |
-|  5           |  TMS     |  TMS           |
-|  6           |  TCK     |  TCK           |
-|  7           |  TDO     |  TDO           |
-|  8           |  RESETN  |  TSRST         |
-## Software: OpenOCD
-### Pacth and compile
-### Usage
-## Pictures
-{{.:jtag:nabjtag.jpg?250| BusBlaster connected to the Nabaztag, side view}} {{.:jtag:nabjtag_bottom.jpg?250| BusBlaster connected to the Nabaztag, bottom view}}
-## Links