Circuitry that may be added to an integrated circuit to provide access to on-chip Test Access Ports (TAPs) specified by IEEE Std 1149.1 is described in this standard. The circuitry uses IEEE Std 1149.1 as its foundation, providing complete backward compatibility, while aggressively adding features to support test and applications debug. It defines six classes of IEEE 1149.7 Test Access Ports (TAP....