Answers Database

Configuration/Reprogram fails: INIT goes low timely unrelated to frames


Record #2645

Product Family:  Hardware

Product Line:  5200

Problem Title:
Configuration/Reprogram fails: INIT goes low timely unrelated to frames


Problem Description:
A configuration or reprogram fails and INIT goes low again.
Init goes low in the middle of a frame, even before the first
CCLK edge was sent (no CRC related error).


Solution 1:

During the time when INIT is low, the 4000 and 5200 fpgas are
sensible on their bounary scan pins. Activity on this pins
can cause the described behavior.

There are some ways to prevent this to happen:
1. do not use TCK as user IO
2. use TCK as output only, no other driver can toggle this pin.
3. set TMS = High during configuration. That keeps the
   boundary scan state machine in the TEST-LOGIC-RESET state.



End of Record #2645