Answers Database

XC4000/XC5200: PROGRAM pin designed to ignore glitches <50nS)


Record #508

Product Family:  Hardware

Product Line:  4000

Problem Title:
XC4000/XC5200: PROGRAM pin designed to ignore glitches <50nS)


Problem Description:
Urgency: Standard

Keywords: PROG pin, configuration, XC4000, XC5200

The Program pin designed to ignore glitches less than 50ns.
Glitches on the PROGRAM pin of the XC4000 can potentially
initiate an unwanted reconfiguration.  To help avoid this,
the chips are designed to ignore pulses which are shorter
than 50ns.  Note, however, that this is NOT a tested parameter.

NOTE: the minimum pulse width to guarantee a reconfiguration
is 300ns.


Solution 1:

If operating in a noisy environment where glitches of roughly
50ns occur, the user can add external circuitry for additional
RC filtering on the input of Program.



End of Record #508