The PRPG provides the test stimulus to the circuit, but it can only generate a finite number of care-bits from any given input seed which limits the maximum coverage that can be achieved. The only way to increase the coverage is to provide additional seed input data to the PRPG. The on-chip one time only programmable eFuse is used to store new PRPG seed data inputs and corresponding MISR output signature data for comparison. An XOR circuit option on the output of the MISR is operable to further compress the output data.