Mentor v8.6_4 manual Setup pin constraints nr 1

Using wdb2flex Effectively FlexTest WDB Translation Support

∙wdb2flex resolves the state of bidirectional pins as either input or output based on the state of the forces and results waveform associated with the pin. If the forces waveform has a weak strength, the bidirectional is treated as an output. If the results waveform has a weak strength, the bidirectional is treated as an input. If neither forces nor results waveforms have a weak strength and have the same logic values, the utility assumes wired behavior and treats the bidirectional as an output. If none of the above conditions prevail, the bidirectional is neither measured nor driven.

To ensure that the results of a QuickSim II simulation correspond with that of FlexTest, the FlexTest test cycle should correspond to the wdb2flex control file. You can set up the test cycle using the following steps and the example timing illustration in Figure B-2:

1.Calculate the number of timeframes in the FlexTest test cycle. The number should equal the sum of the control file input strobe times and clock strobe times.

For the example in Figure B-2, if all inputs strobe at 75ns (time t1), all clocks strobe active at 105ns (time t2), and all clocks strobe for the off-state at 205ns (time t3), then there should be three timeframes in the test cycle. The first timeframe (frame 0) corresponds to the time 0—105ns (t1,t2), the second timeframe (frame 1) corresponds to the time 105—205ns (t2,t3) and the third timeframe (frame 2) corresponds to the time 205—250ns (t3, period). The time from 0—75ns is not considered since the stable output is strobed at 95ns and all input events happen before 75ns.

2.Calculate the timeframe associated with each strobe time. In FlexTest, when a force event and strobe event occur in the same timeframe, the strobe event happens before the force event in that timeframe.

3.For all input pins, set up non-return pin constraints with an offset value equal to one less than the timeframe at which the pin changes state. For the example in Figure B-2, you would enter the following to indicate that the offset value is 0; all inputs change at the first timeframe:

setup pin constraints nr 1 0

B-8 FastScan and FlexTest Reference Manual, V8.6_4