The BIST emulator can be run in two modes: BILBO and CSTP. The mode is chosen by -simul option. Use -simul bilbo for BILBO mode and -simul cstp for CSTP mode. The BIST configuration can be defined by user or generated randomly by the emulator. For random configuration use -rand flag and specify the length of the TPG (by -glen) and the SA (by -alen). By default, the emulator generates 1000 vectors and stops. A very useful option -optimize forces the generator to truncate the sequence at that point where the fault coverage stops growing. This helps us to identify the useful length of the test sequence. Look at the example of usage below:
 
 

prompt> bist -rand -glen 36 -alen 25 -optimize -simul bilbo c17
Design : c17 Reading SSBDD-model file c17.agm... OK Allocating test patterns... OK Simulating generated vectors... OK Executing BILBO analyzer... OK Writing test patterns file c17.tst... OK Test vectors : 11 Fault coverage (without aliasing): 100.000000% Time, used by process: 0.050000 Deleting SSBDD-model from memory... OK

For larger designs longer test sequences are needed. Use -count option to specify the desired test length.

 

prompt> bist -rand -glen 36 -alen 25 -optimize -simul bilbo -count 10000 c1908.agm
Design : c1908 Reading SSBDD-model file c1908.agm... OK Allocating test patterns... OK Simulating generated vectors... OK Executing BILBO analyzer... OK Writing test patterns file c1908.tst... OK Test vectors : 4034 Fault coverage (without aliasing): 99.480370% Time, used by process: 25.350000 Deleting SSBDD-model from memory... OK

When a good random BIST configuration has been found it can be observed in <design>.tst file. A fragment of c17.tst file is given below:

.GENERATOR	*TPG section*
.INITIAL_STATE 110000100110101000001100111000111110 .POLYNOMIAL 101011011100100110111101011100001001	*TPG seed* *TPG architecture*
.ANALYZER	*SA section*
.INITIAL_STATE 0010010001001010011111011 .POLYNOMIAL 1101000010010010110001110 .SIGNATURE 1011011011100100100010010	*SA seed* *SA architecture*

To apply custom configuration to the BIST emulator it has to be specified in command line by -ginit <TPG seed> -gpoly <TPG polynomial> -ainit <SA seed> -apoly <SA polynomial> switches: