Minimization of over-masking in an on product multiple input signature register (OPMISR)

A method for implementing enhanced scan data testing with over masking minimization in an on product multiple input signature register (OPMISR) comprising:

• providing a plurality of OPMISR satellites, each of the plurality of OPMISR satellites including a multiple input signature register (MISR) for data collection and a plurality of associated scan channels;
• providing common Channel Mask Scan Registers (CMSR) data with the multiple input signature register (MISR) in each satellite;
• using an algorithm for implementing enhanced scan data testing by independently skewing scan unload shifting of selected OPMISR+ satellites by selected cycles;
• and
• providing Channel Mask Enable (CME) triggered masking on a different bit position in respective OPMISR+ satellite channels with the scan unload shifting for avoiding over masking.