| XC3000 | XC4000E | XC4000X | XC5200 | XC9000 | Spartan | SpartanXL | Virtex |
|---|---|---|---|---|---|---|---|
| Primitive | Primitive | Primitive | Primitive | N/A | Primitive | Primitive | Primitive |
A UPAD allows the use of any unbonded IOBs in a device. It is used the same way as a IOPAD except that the signal output is not visible on any external device pins.
