Answers Database

PPR 5.2: Defining point-to-point timespecs in cst file


Record #409

Product Family:  Software

Product Line:  FPGA Core

Problem Title:
PPR 5.2: Defining point-to-point timespecs in cst file


Problem Description:



Solution 1:




It is possible to define point to point timespecs in a constraint
file for PPR 5.0.  Here is an example:

	in1						out1
|ipad>-------|ibuf>-----+-----{comb logic}-----|obuf>--------<opad|
			|
			|   ____   q1		   _____   q2	     out2
			+--|DFF	|------{logic}----|DFF	|------|obuf>----<opad|
			    ----		   -----

Constraint file:

timegrp="ned=pads(in1)";	# assign TNM of ned to ipad driving in1
timegrp="fred=pads(out1)";	# assign TNM of fred to opad loading out1
timegrp="ted=pads(out2)";	# assign TNM of ted to opad loading out2
timegrp="jon=ffs(q1)";		# assign TNM of jon to DFF driving q1
timegrp="don=ffs(q2)";		# assign TNM of don to DFF driving q2

timespec="TS01=FROM:ned:TO:fred=25";	# define p2p of 25ns
timespec="TS02=FROM:ned:TO:jon=15";	# define p2s of 15ns
timespec="TS03=FROM:jon:TO:don=30";	# define c2s of 30ns
timespec="TS04=FROM:don:TO:ted=10";	# define c2p of 10ns




End of Record #409