RONRIKAIRONOTESUTONISHOSURUKAIRO

摘要

A transparent shift register latch (170) includes a normal operating gate (182) and a test gate (184) for selectively connecting data to a node (180). The node (180) is input to an isolation gate (186) through an inverter (188) for connection to an output node (190). A peripheral port (172) is interfaced with the output node (190) through an isolation gate (192). The gates (186) and (192) are operable in a test mode to interface data stored on the node (180) with the output of the latch (170) and inhibit input of data from the port (172). In the normal operating mode, the isolation gate (192) is closed and the isolation gate (186) is opened. The transparent shift register latch (170) allows testing of interface lines between adjacent logic modules.