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Mila
Joined: 07 May 2008
Posts: 2
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 07 May 2008 14:58 direction of JTAG signal TDI and TDO at PMC interface |
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Hallo professionals!
You have two boards: one is PMC mezzanine board and this board is placed at second (carrier board). You want use JTAG interface between this two boards.
Question is:
Is signal TDI input or output at carrier board?
At PCI and PMC standards I didn`t find explicit description of direction this signals.
Thank you very much for your help.
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FvM
Joined: 22 Jan 2008
Posts: 5161
Helped: 767
Location: Bochum, Germany
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07 May 2008 19:50 Re: direction of JTAG signal TDI and TDO at PMC interface |
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| I can only imagine that PMC board JTAG interface is controlled from an external system (through the carrier board). Then the PMC board would have TDI (and also TCK and TMS) as input and TDO as output.
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ilikebbs
Joined: 30 Nov 2002
Posts: 101
Helped: 2
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09 May 2008 3:46 direction of JTAG signal TDI and TDO at PMC interface |
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| TDI is input in any condition.
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Mila
Joined: 07 May 2008
Posts: 2
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19 May 2008 13:15 Re: direction of JTAG signal TDI and TDO at PMC interface |
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Thank you,
I have the same idea as FvM, but I need exact description at some standard and I can΄t find this.
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Google
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19 May 2008 13:15 Ads |
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sparso
Joined: 30 Dec 2006
Posts: 64
Helped: 1
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06 Jun 2008 6:48 direction of JTAG signal TDI and TDO at PMC interface |
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| Can any one explain the JTAG timing or post some material with the timing explanation?
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synq
Joined: 21 May 2001
Posts: 65
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16 Jun 2008 12:48 Re: direction of JTAG signal TDI and TDO at PMC interface |
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be more specific on Jtag timing are u trying to run an external JTAG chain ?
are you trying to initiate a JTAG scan internally?
first one need a esternal JTAg controller in which you can set appropriate frrequency in the range 100Hz to all the way up to 2M provide you interconnect system has got some good noise imunity to scan clocks...
and the joke is in a lab don't dream anything better than 10Khz ..hahaha cruel isn't it?
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stanislavb
Joined: 08 Jun 2008
Posts: 29
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28 Jun 2008 9:40 Re: direction of JTAG signal TDI and TDO at PMC interface |
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Attached JTAG timing example:
TCK Fftck Frequency 10MHz
TCK Ttckl Time low 50ns
TCK Ttckh Time high 50ns
TDI, TMS Ttsu Setup to TCK 40ns
TDI, TMS Tth Hold from TCK 40ns
TDO Ttval Valid from TCK 30ns
TDO Ttz Hi-Z from TCK 5ns 40ns
Enjoy!
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