Answers Database

XC5200: Mode pins M0, M1, M2 are bidirectional, but library MD0, MD1, MD2 are unidirectional.


Record #774

Product Family:  Hardware

Product Line:  5200

Problem Title:
XC5200:	Mode pins M0, M1, M2 are bidirectional, but library MD0, MD1,
MD2 are unidirectional.



Problem Description:
Keywords: MD0, MD1, MD2, IOs, 5200

Urgency: Standard

Description

The 5200 mode pins are all io's after configuration, but if you use the MD0, MD1

or MD2 library symbols to define your mode pins then you can only use the pin
as a unidirectional pin.  The reason for this is that the MD0, MD1 and MD2 libra
ry
symbols were only intended for design conversions from the XC4000 devices,
therefore these pins would not be bidirectional.

If you use these symbols as a bidirectional io then XNFPREP will issue an eror
saying that these symbols can only be used as unidirectional signals.


Solution 1:

Don't use the special MD0, MD1 and MD2 library symbols when trying to use the
mode pins as bidirectional io's.  Use a regular iopad symbol and lock that symbo
l
to the appropiate mode pin.



End of Record #774