Answers Database

SPROMs (XC1700): How to program reset polarity on Xilinx SPROMs


Record #3779

Product Family:  Hardware

Product Line:  1700

Problem Title:
SPROMs (XC1700): How to program reset polarity on Xilinx SPROMs


Problem Description:
Keywords:  prom, program, reset polarity

Urgency: standard

General Description:  How do you program reset polarity on Xilinx PROMs?


Solution 1:

The RESET/OE pin on Xilinx SPROMS can be programmed to:

    1)	active High RESET/active Low Output Enable
    or
    2) active Low RESET/active High Output Enable

The only way to program this reset polarity is through a Xilinx or third party
programmer.

RESET polarity is not programmable through Makebits, Bitgen,
or any other software.

The Xilinx programming specification states that the
programmer software should prompt the user as to what
polarity he would like reset polarity programmed.
All Xilinx programmers (HW-112 and HW-130) support
reset polarity in this manner, as do most third party
programmers.

Data I/O programmers did not follow this specification
and required that you load certain address locations in
the PROM with either FF's or 00's for active High and active
Low RESET, respectively.  (See Solution 188 for more details
on this topic).




End of Record #3779