Making precise at-speed timing measurements via boundary-scan

IEEE 1149.1 Boundary-Scan has traditionally been used for continuity and low speed functional testing of integrated circuits. The boundary-scan RUNBIST instruction allows Built-In Self Test for functional testing at full clock speeds. This paper describes an approach that uses the RUNBIST instruction to make timing measurements with a resolution 32 times smaller than the clock period while doing at-speed testing. Measurement commands and results are transmitted via boundary-scan.