Input switching arrangement for a semiconductor circuit and test method for unidirectional input drivers in semiconductor circuits

摘要

Unidirectional input switching arrangements or pad circuits are supplemented by transfer switching devices employed to route an internal test signal to the input of an input driver in the unidirectional input switching arrangement and to couple it to an internal switching logic unit. The transfer switching devices are controlled via a multiplexer unit, which for its part can be programmed directly using boundary scan registers. The present invention allows all unidirectional pad circuits or input drivers to be tested in the course of a reduced I/O test method for semiconductor circuits, in which testing internal circuits in the semiconductor circuit involves only a subset of the signal connections associated with the input drivers being coupled to a test apparatus.