AR# 38368: Spartan-6 FPGA MCB - Why are the RZQ and ZIO pins swapped when migrating from MIG v3.4 to v3.5?
Spartan-6 FPGA MCB - Why are the RZQ and ZIO pins swapped when migrating from MIG v3.4 to v3.5?
In MIGv3.5 and later version, the default RZQ and ZIO pins are swapped from previous releases.
If I change the pins back to the MIGv3.4 recommendations or change to other pins LOC options, MIG will show the warning: "The selected design's timing has not been verified with non-default RZQ/ZIO locations".
What is needed to ensure timing is met?
PIN locations from all versions satisfy the MIG requirements for RZQ and ZIO pins.
MIG v3.5 and later version pin recommendation have shown to give better results in terms of timing margin and SI simulation.
It is recommended to use the new pin locations.
However, as long as timing is met and the pin requirements for RZQ and ZIO are satisfied, the pins can be moved.