XC9500 device (any density) fails to configure (load) properly immediately following
power-up. What could be causing this?
Check the power supply ramp rate. Xilinx CPLDs, as well as all other CPLDs, will
configure properly only with a monotonic power supply. Xilinx has prepared an
application note titled 'XAPP144: Designing CPLD Multi-voltage Systems' which
completely reviews proper power-up requirements for the XC9500 device family. This
application note can be found at : http://www.xilinx.com/xapp/xapp144.pdf
Xilinx has found that some earlier XC9500 devices (with a date code prior to 0017)
have exhibited an additional sensitivity to non-monotonic power supplies. This
increased sensitivity, combined with the duration, profile, and monotonicity of the
power supply could cause the device to configure incorrectly. Devices with a date
code of 0017 or greater do not exhibit this additional sensitivity.
If you are experiencing configuration problems with any XC9500 device, please
contact your local Xilinx salesperson for appropriate device dispositioning and/or