| Element | XC3000 | XC4000E | XC4000X | XC5200 | XC9000 | Spartan | SpartanXL | Virtex |
|---|---|---|---|---|---|---|---|---|
| NOR2, NOR2B1, NOR2B2, NOR3, NOR3B1, NOR3B2, NOR3B3, NOR4, NOR4B1, NOR4B2, NOR4B3, NOR4B4 | Primitive | Primitive | Primitive | Primitive | Primitive | Primitive | Primitive | Primitive |
| NOR5, NOR5B1, NOR5B2, NOR5B3, NOR5B4, NOR5B5 | Primitive | Primitive | Primitive | Macro | Primitive | Primitive | Primitive | Primitive |
| NOR6, NOR7, NOR8, NOR9 | Macro | Macro | Macro | Macro | Primitive | Macro | Macro | Macro |
Figure 7.35 NOR Gate Representations |  |
The NOR function is performed in the Configurable Logic Block (CLB) function generators for XC3000, XC4000, XC5200, and Spartans. NOR gates of up to five inputs are available in any combination of inverting and non-inverting inputs. NOR gates of six to nine inputs are available with only non-inverting inputs. To invert some or all inputs, use external inverters. Since each input uses a CLB resource, replace gates with unused inputs with gates having the necessary number of inputs.
Refer to the “NOR12, 16” section for information on additional NOR functions for the XC5200 and Virtex.
Figure 7.36 NOR5 Implementation XC5200 | |
Figure 7.37 NOR8 Implementation XC3000 | |
Figure 7.38 NOR8 Implementation XC4000, Spartans | |
Figure 7.39 NOR8 Implementation XC5200 | |
Figure 7.40 NOR8 Implementation Virtex | |
