Difference between revisions of "JTAG"

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(rough draft -- is this pinout good?)
 
(JTAG information on other wiki)
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== external links ==
 
== external links ==
  
 +
* [http://openjtag.net/ the OpenJTAG wiki] ( http://openjtag.net/ )
 
* [http://www.arm.com/support/faqdev/1336.html "When designing development boards what style JTAG connector should I use?"] The 20-pin JTAG connector.
 
* [http://www.arm.com/support/faqdev/1336.html "When designing development boards what style JTAG connector should I use?"] The 20-pin JTAG connector.
 
* [http://www.embedded.com/story/OEG20021028S0049 "Introduction to JTAG"] by Rob Oshana 2002
 
* [http://www.embedded.com/story/OEG20021028S0049 "Introduction to JTAG"] by Rob Oshana 2002
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* [http://www.interfacebus.com/Design_Connector_JTAG_Bus.html "JTAG Bus Description"]
 
* [http://www.interfacebus.com/Design_Connector_JTAG_Bus.html "JTAG Bus Description"]
 
* [http://en.wikipedia.org/wiki/JTAG Wikipedia:JTAG]
 
* [http://en.wikipedia.org/wiki/JTAG Wikipedia:JTAG]
 +
* [http://wiki.openwrt.org/OpenWrtDocs/Customizing/Hardware/JTAG_Cable OpenWRT wiki: JTAG Cables]
 +
* [http://jtag-arm9.sourceforge.net/ the Jtag-Arm9 project at Sourceforge] gives instructions and photographs of a [http://jtag-arm9.sourceforge.net/hardware.html Home made JTAG interface] (also shows an example of prototyping using SMT IC)

Revision as of 00:04, 18 May 2007

The Joint Test Action Group (JTAG) standardized a 5 pin boundary-scan test port as IEEE Std. 1149.1, "Standard Test Access Port and Boundary-Scan Architecture".

While originally intended for boundary-scan testing of PCB assemblies, to replace bed-of-nails testing, the JTAG port included in many popular microprocessors is also often used for programming and debugging.

"If you have information on how to connect a JTAG probe to a Nokia phone, please let me know."

There are five pins:

  • TCK/clock
  • TMS/mode select
  • TDI/data in
  • TDO/data out
  • TRST/reset (optional), when driven low, resets the internal state machine.

Except for TCK, all other JTAG lines should be pulled high via a resistor.


WARNING: unconfirmed pinout. Please add links to pinout standard.

20 Pin JTAG PinOut

   Pin Function Pin Function
   1   TRST     2   GND
   3   TDO      4   GND
   5   TDI      6   GND
   7   TMS      8   GND
   9   TCK     10   GND
   11  VPP_E   12   GND
   13  A/W     14   GND
   15  User 0  16   GND
   17  Rdy/Bsy 18   GND
   19  User 1  20   Vcc

external links