By=pass sampling path for integrated circuit contg. complex logic - has control and observation points, and selector data transfer path contg. or by=passing shift register with series latches

摘要

The bypass sampling path in an integrated circuit contains at least one control point and one observation point for transferring and outputting observation point data. Data for selected a data transfer path and control point data are entered via a single data entry connection (201). The control point and observation point data are shifted and held by shift register (10) series latches between the data entry (201) and output (204) connections. A sampling path selector (20a) selects a data path either contg. or bypassing the shift path according to the entered selection data. USE/ADVANTAGE - For boundary scan tests in accordance with IEEE 1149.1. Reduced testing time and number of test pins.