When I implement a XC9500 design, a warning message similar to the following occurs:
"WARNING:Cpld:158 - We have detected that a large number of internal signals may be switching at the same time. To avoid potential simultaneous switching/ground bounce issues, please contact Xilinx Customer Support for more information."
You can use one of the following methods to minimize ground bounce issues:
- Place some equations in low-power mode.
- Place some outputs in slow-slew mode.
Both of these methods include adding delay to signals. This delay helps keep all of the signals from switching simultaneously, and as a result, minimizes any ground bounce issues.