AR# 774: XC5200: Mode pins M0, M1, M2 are bidirectional, but library MD0, MD1, MD2 are unidirectional.
AR# 774
XC5200: Mode pins M0, M1, M2 are bidirectional, but library MD0, MD1, MD2 are unidirectional.
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 library 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.
解决方案
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 symbol to the appropiate mode pin.