Appendix A

XST Naming Conventions

This appendix discusses net naming and instance naming conventions.

Net Naming Conventions

These rules are listed in order of naming priority.

1. External pin names maintained.

2. Keep hierarchy in signal names, using underscores as hierarchy designators.

3. Output signal names of registers, including state bits, will be maintained. Use the hierarchical name from the level where the register was inferred.

4. Output signals of clock buffers get _clockbuffertype (like _BUFGP or _IBUFG) following the clock signal name.

5. Input nets to registers and tristates maintain their names.

6. Output net names of IBUFs are named net_name_IBUF. For example, for an IBUF with an output net name of DIN, the output IBUF net name is DIN_IBUF.

   Input net names to OBUFs are named net_name_OBUF. For example, for an OBUF with an input net name of DOUT, the input OBUF net name is DOUT_OBUF.

Instance Naming Conventions

These rules are listed in order of naming priority.

1. Keep hierarchy in instance names, using underscores as hierarchy designators.

2. Register instances, including state bits, will be named for the output signal.

3. Clock buffer instances are named _clockbuffertype (like _BUFGP or _IBUFG) after the output signal.

4. Instantiation instance names of black boxes are maintained.

5. Instantiation instance names of library primitives are maintained.

6. Input and output buffers are named _IBUF or _OBUF after the pad name.

7. Output instance names of IBUFs are named instance_name_IBUF.

   Input instance names to OBUFs are named instance_name_OBUF.