When the SelectMAP32 configuration setting is used on a Virtex-4 device, what are the software settings required for this feature?
There is a MANDATORY constraint that must be applied to all designs using SelectMAP32. This is the CONFIG MODE constraint and is documented in the Constraints Guide. What the Constraints Guide does not outline are the constraints for the SelectMAP32 settings.
The basic UCF syntax is:
CONFIG CONFIG_MODE=<pick one of the two items below>;
S_SELECTMAP32 - Slave SelectMAP32 Mode
S_SELECTMAP32+READBACK - Slave SelectMAP Mode with Persist set to support
Readback and Reconfiguration.
These constraints allow for proper padding to be added to the bit file and, if desired, allow the configuration pins to persist.