Answers Database
Virtex: Configuration -- DONE goes high, but IO never goes active
Record #7426
Problem Title:
Virtex: Configuration -- DONE goes high, but IO never goes active
Problem Description:
Keywrods: Virtex, DONE, Configuration, Pullup
Urgency: standard
Problem Description
In Virtex parts, a problem has been seen where configuration appears
to have completed successfully, but the IOs never go active (or some
other part of the startup sequence does not complete).
Solution 1:
The reason for this problem is that the external pullup on the DONE pin
is not strong enough to pull up the DONE line fast enough when the
FPGA releases the DONE pin. If a 4.7K resistor is used, this may be
the case.
An appropriate value for the DONE pullup is a 330 ohm resistor.
Replacing a 4.7K with a 330 usually fixes this problem.
End of Record #7426 - Last Modified: 09/17/99 11:20 |
