Answers Database


JTAG - How to use EXTEST instruction before configuration in a XC4K/XC5K device?


Record #194

Problem Title:
JTAG - How to use EXTEST instruction before configuration in a XC4K/XC5K device?


Problem Description:
Urgency: standard

General Description:

How to execute the EXTEST instruction before configuration?


Solution 1:

If the /PROGRAM pin is held low, the Boundary Scan registers for EXTEST
will reset and not work. Releasing /PROGRAM, but holding the INIT low will halt configuration just at the start. With the INIT signal held low, you may then
execute the EXTEST instruction.

The only other way to use the EXTEST instruction is to do so after
configuration has completed.




End of Record #194 - Last Modified: 01/10/00 22:09

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