Patent ID: 6157210
Filing Date: 2000-12-05
Classification: G01R

Abstract:
A programmable logic device having circuitry for observing logic signals from programmable logic elements, comprising:a plurality of programmable logic elements arranged in rows and columns;a plurality of sense lines each associated with a different one of the columns of programmable logic elements and each extending past plural rows of programmable logic elements;a plurality of access transistors each associated with a different one of the programmable logic elements for connecting that programmable logic element to one of the sense lines;a plurality of access transistor control lines each associated with a different one of the rows of programmable logic elements and each connected to the access transistors in that row for controlling those access transistors;a test register to which each of the sense lines is connected; anddecoder circuitry connected to the access transistor control lines for selectively turning on the access transistors in a given row using a corresponding one of the access transistor control lines so that signals from the programmable logic elements in the given row are provided to the test register.