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Visitor dkurniaw
Visitor
9,274 Views
Registered: ‎11-11-2008

Can't Identify JTAG chain

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I'm trying to bring up a new board.

 

It's using a Spartan-6 LX25, running Master Serial Mode with M25P40 SPI flash.

 

When I try to "Initialize Chain" on Impact, I get this:

PROGRESS_START - Starting Operation.
Identifying chain contents...done.
ERROR:iMPACT - A problem may exist in the hardware configuration. Check that the cable, scan chain, and power connections are intact, that the specified scan chain configuration matches the actual hardware, and that the power supply is adequate and delivering the correct voltage.

 

I'm using Impact 14.7 with DLC9G USB programmer.

 

This design is very similar to a previous board we did, although that was using a Spartan-6 LX9.  And that worked.

 

Another difference is the VCCAUX.  On the old board, we used 2.5V, but on this board it's 3.3V (All of our VCCO are 3.3V here).

 

I measured all the JTAG pins and they're all 3.3V *except* for TDI, which is 2.1V.  Which I find weird. 

 

Any idea what might be wrong?  Or what I can do to further debug?

 

Thanks!

 

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1 Solution

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Teacher drjohnsmith
Teacher
17,902 Views
Registered: ‎07-09-2009

Re: Can't Identify JTAG chain

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Do you have a scope ?

 

thats idea, 

 

in ISE you can put the JTAG chain into debug mode, 

   which puts out a constant stream, 

 

you can then chase the signals TDI through to TDO, and TMS , TCK, 

     see where they stop. 

 

2.1v, is worng assuming you have 3v3 TTL. 

    Start checking power supplies and the required pull up's.

 

JTAG is simple enough, its a chain , so just follow it through... 

   methodical and you will find it.

 

     

<== If this was helpful, please feel free to give Kudos, and close if it answers your question ==>

View solution in original post

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2 Replies
Teacher drjohnsmith
Teacher
17,903 Views
Registered: ‎07-09-2009

Re: Can't Identify JTAG chain

Jump to solution

Do you have a scope ?

 

thats idea, 

 

in ISE you can put the JTAG chain into debug mode, 

   which puts out a constant stream, 

 

you can then chase the signals TDI through to TDO, and TMS , TCK, 

     see where they stop. 

 

2.1v, is worng assuming you have 3v3 TTL. 

    Start checking power supplies and the required pull up's.

 

JTAG is simple enough, its a chain , so just follow it through... 

   methodical and you will find it.

 

     

<== If this was helpful, please feel free to give Kudos, and close if it answers your question ==>

View solution in original post

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369 Views
Registered: ‎10-15-2018

Re: Can't Identify JTAG chain

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hi dkurniaw;

    i met that same thing about JTAG chain ,and  Another difference is the VCCAUX. On the  board, it change to  1.4V, but on this board it's 1.8V (All of our VCCO are 1.8V here),i check  all condition that i  guess,but all doesn't work ,so do you have solve this problem ?   please share with me . thanks

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