Spartan 3 JTAG problems

[Mike Perkins]

Has anyone come across an issue where an XC3S200 is recognised in
Impact; "Right Click to Add Device or Initialize JTAG chain", and then
can't read the device ID, status or indeed do anything else.

Power supplies on the board look good. Changed device and still the same
problem.

Will investigate more later, but any ideas? It can only be something
stupid!!

--
Mike Perkins
Video Solutions Ltd
www.videosolutions.ltd.uk

 

[Adam Górski]

W dniu 2014-04-17 12:50, Mike Perkins pisze:

Has anyone come across an issue where an XC3S200 is recognised in
Impact; "Right Click to Add Device or Initialize JTAG chain", and then
can't read the device ID, status or indeed do anything else.

Power supplies on the board look good. Changed device and still the same
problem.

Will investigate more later, but any ideas? It can only be something
stupid!!

Like too long jtag cable together with too fast jtag clock speed. You
must ensure good clock edge quality.

Best regards

Adam

 

[Mike Perkins]

On 17/04/2014 11:50, Mike Perkins wrote:

Has anyone come across an issue where an XC3S200 is recognised in
Impact; "Right Click to Add Device or Initialize JTAG chain", and then
can't read the device ID, status or indeed do anything else.

Power supplies on the board look good. Changed device and still the same
problem.

Will investigate more later, but any ideas? It can only be something
stupid!!

Yes - very stupid. It seems you can initialise a chain without TDI
connected.

Connected TDI and all's well.


--
Mike Perkins
Video Solutions Ltd
www.videosolutions.ltd.uk