Abstract: A testing device uses an input signature register to conduct “at speed” testing of asynchronous circuit responses in an effort to determine the operability of a monitored circuit. Upon receiving an enable signal, the input signature register quickly measures, compresses, and transmits the tested circuit responses so that the responses can be compared with a set of anticipated responses to determine whether the circuit is functioning properly. The enabled input signature register, such as a MISR or a SISR, generates an output signature, which contains the compressed responses of the monitored circuit and helps the testing device analyze circuit performance.

Abstract: A testing device uses an input signature register to conduct “at speed” testing of asynchronous circuit responses in an effort to determine the operability of a monitored circuit. Upon receiving an enable signal, the input signature register quickly measures, compresses, and transmits the tested circuit responses so that the responses can be compared with a set of anticipated responses to determine whether the circuit is functioning properly. The enabled input signature register, such as a MISR or a SISR, generates an output signature, which contains the compressed responses of the monitored circuit and helps the testing device analyze circuit performance.