The CoolRunner-II data sheet does not indicate that the device is 5-volt tolerant. How can I make it 5-volt tolerant?
The CoolRunner-II CPLD is not 5-volt tolerant. However, you can use external circuits to solve this issue. For more information, see (Xilinx XAPP429): "5V Tolerance Techniques for CoolRunner-II Devices."
Xilinx CPLDs that are 5-volt tolerant (without external circuitry) are the XC9500, XC9500XL, and the CoolRunner XPLA3 family.
For other common CPLD questions, see the CPLD FAQ: (Xilinx Answer 24167).