Patent attributes
An integrated programmable device has a plurality of signal inputs (P1, P2, P3) connected to respective ones of a plurality of switching elements (S1, S2, S3). Each switching element (S1, S2, S3) has an associated enable line (E1, E2, E3). A control circuit (15) activates one or more selected signal inputs (P1-P3) in accordance with a channel select signal (16) via these enable lines (E1, E2, E3). Feedback lines (F1, F2, F3) are connected to corresponding enable lines (E1, E2, E3) to a channel feedback indicative of which signal inputs (P1, P2, P3) is enabled. This allows determination whether the enabled signal inputs (P1, P2, P3) correspond to the channel select signal (16) and initiates an exception handling in case of a mismatch. The comparison can be performed by a compare logic circuit (40) or the channel feedback can be stored in a memory (30) accessible by a software program (60), which performs the comparison.