IO voltage properties in CPLD
The I/O standard you choose depends on what the CPLD is hooked up to. If you hook it up to a 1.8V device, you should supply 1.8V through Vccio1 and Vccio2 and select LVCMOS18 (for low voltage complementary metal oxide silicon integrated circuit chips running at 1.8V). For other I/O voltages you can choose the standard accordingly.