Difference between revisions of "JTAG"
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(revert to 23:13, 28 May 2007) |
(signals, not pins -the connectors have many more pins) |
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| − | The Joint Test Action Group (JTAG) standardized a 5 | + | The Joint Test Action Group (JTAG) standardized a 5 signal 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. | 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. | ||
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[http://hogyros.de/?q=node/167 "If you have information on how to connect a JTAG probe to a Nokia phone, please let me know."] | [http://hogyros.de/?q=node/167 "If you have information on how to connect a JTAG probe to a Nokia phone, please let me know."] | ||
| − | There are five | + | There are five signals: |
* TCK/clock | * TCK/clock | ||
* TMS/mode select | * TMS/mode select | ||
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== 20 Pin JTAG PinOut == | == 20 Pin JTAG PinOut == | ||
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1 +3.3 V 2 +3.3 V | 1 +3.3 V 2 +3.3 V | ||
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15 nRST 16 GND | 15 nRST 16 GND | ||
17 -- 18 GND | 17 -- 18 GND | ||
| − | 19 -- 20 GND | + | 19 -- 20 GND |
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== external links == | == external links == | ||
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* [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 | ||
| − | * [http://hri.sourceforge.net/tools/jtag_faq_org.html "JTAG FAQ"] by Stas Khirman 2004 | + | * [http://hri.sourceforge.net/tools/jtag_faq_org.html "JTAG FAQ"] by Stas Khirman 2004 includes a section on [http://hri.sourceforge.net/tools/jtag_faq_org.html#_Toc63218715 14 pin, 20 pin, and 8 pin JTAG headers] |
* [http://k9spud.com/jtag/ a parallel port JTAG Debugger circuit for Philips LPC2xxx ARM microcontrollers.] by K9JTAG (uses Schmitt trigger inverters, so it can connect 3.0 V target boards to a standard 5.0 V parallel port) | * [http://k9spud.com/jtag/ a parallel port JTAG Debugger circuit for Philips LPC2xxx ARM microcontrollers.] by K9JTAG (uses Schmitt trigger inverters, so it can connect 3.0 V target boards to a standard 5.0 V parallel port) | ||
* [http://diygadget.com/store/building-simple-jtag-cable/info_12.html parallel port JTAG "Building Simple JTAG Cable"] (resistors only) | * [http://diygadget.com/store/building-simple-jtag-cable/info_12.html parallel port JTAG "Building Simple JTAG Cable"] (resistors only) | ||
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* [http://freelabs.com/~whitis/electronics/jtag/ the JTAG protocol] by Mark Whitis | * [http://freelabs.com/~whitis/electronics/jtag/ the JTAG protocol] by Mark Whitis | ||
* [http://scienceprog.com/avrjtag-clone-in-action/ "Building AVR Jtag clone"] includes schematics and firmware. | * [http://scienceprog.com/avrjtag-clone-in-action/ "Building AVR Jtag clone"] includes schematics and firmware. | ||
| − | + | * [http://www.embecosm.com/ Embecosm] publishes a "SystemC JTAG interface specification" to simplify debugging complex chips. | |
| + | * lists a variety of [http://www.freelabs.com/~whitis/electronics/jtag/ JTAG Pinouts] | ||
| + | * [http://tree.celinuxforum.org/CelfPubWiki/ELC2009Presentations?action=AttachFile&do=get&target=DebuggingWithJtagCelf2009.pdf Debugging with JTAG (CELF presentation)] | ||
| + | * Open JTAG Project [http://www.openjtag.org Make your proper high speed JTAG] | ||
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Latest revision as of 11:47, 1 November 2011
The Joint Test Action Group (JTAG) standardized a 5 signal 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 signals:
- 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[edit]
1 +3.3 V 2 +3.3 V
3 nTRST 4 GND
5 TDI 6 GND
7 TMS 8 GND
9 TCK 10 GND
11 -- 12 GND
13 TDO 14 GND
15 nRST 16 GND
17 -- 18 GND
19 -- 20 GND
external links[edit]
- the OpenJTAG wiki ( http://openjtag.net/ )
- "When designing development boards what style JTAG connector should I use?" The 20-pin JTAG connector.
- "Introduction to JTAG" by Rob Oshana 2002
- "JTAG FAQ" by Stas Khirman 2004 includes a section on 14 pin, 20 pin, and 8 pin JTAG headers
- a parallel port JTAG Debugger circuit for Philips LPC2xxx ARM microcontrollers. by K9JTAG (uses Schmitt trigger inverters, so it can connect 3.0 V target boards to a standard 5.0 V parallel port)
- parallel port JTAG "Building Simple JTAG Cable" (resistors only)
- "JTAG Bus Description"
- Wikipedia:JTAG
- OpenWRT wiki: JTAG Cables
- the Jtag-Arm9 project at Sourceforge gives instructions and photographs of a Home made JTAG interface (also shows an example of prototyping using SMT IC)
- the JTAG protocol by Mark Whitis
- "Building AVR Jtag clone" includes schematics and firmware.
- Embecosm publishes a "SystemC JTAG interface specification" to simplify debugging complex chips.
- lists a variety of JTAG Pinouts
- Debugging with JTAG (CELF presentation)
- Open JTAG Project Make your proper high speed JTAG
