Answers Database

XABEL 5.1/EPLD designs: FOE pins are active high


Record #543

Product Family:  Software

Product Line:  Data I/O

Problem Title:
XABEL 5.1/EPLD designs: FOE pins are active *high*


Problem Description:

LONG DESCRIPTION:

PROBLEM:

Customer assigns a pin in XABEL/ABEL to a FOE (Fast Output Enable) pin, but
when the design is compiled, the pin assigned to the FOE pin is assigned to
a different pin.


Solution 1:


CAUSE:

The user defined in ABEL/XABEL code a FOE pin, but the FOE signal was
defined as active-low in the code.

SOLUTION:

The FOE are active high by architecture.  The only way to get an active low
FOE is to reroute the signal through the AND-array and a macrocell.  So, the
user must either allow this rerouting of the signal, or invert the FOE signal
outside of the device.











End of Record #543