User guide

13-43
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Editing the timopt.cfg File
When editing the timopt.cfg file, first edit the potential sequential
device entries. Edit the potential clock signal only when you have
made no changes to the entries for sequential devices.
Editing Potential Sequential Device Entries
The following is an example of sequential devices that timopt was
not sure of:
// POTENTIAL SEQUENTIAL CELLS
// flop {jknpn} {,};
// flop {jknpc} {,};
// flop {tfnpc} {,};
You can remove the comment marks for the module definitions that
are in fact model sequential devices and which provide the clock port,
clock polarity, and optionally asynchronous ports.
A modified list might look like the following:
flop { jknpn } { CP, true};
flop { jknpc } { CP, true, CLN};
flop { tfnpc } { CP, true, CLN};
In this example CP is the clock port and the keyword true indicates
that the sequential device is triggered on the posedge of the clock
port and CLN is an asynchronous port.
If you uncomment any of these module definitions, then timopt
might identify additional clock signals that drive these sequential
devices. To enable timopt to do this: