Patent ID: 7145977
Filing Date: 2006-12-05
Classification: G11C

Abstract:
1. A circuit for observing and restoring data of a shift register without altering logical values of said data, said circuit comprising: a wiring loop connecting the input of said shift register with the output of said shift register; and a control device connected to said wiring loop, wherein said control device is adapted to use said wiring loop to cause said data to be continually transferred from said output of said shift register to said input of said shift register and through said shift register in a circular manner, wherein said control device includes a data output accessible from outside said circuit, wherein said control device outputs data appearing on said wiring loop as said data is circulated through said shift register to permit said data of said shift register to be observed outside said circuit without altering logical values of said data of said shift register, and wherein said control device includes a shift register length control unit adapted to limit the circular transfer of data within said wiring loop and said shift register such that all of said data is circulated through said wiring loop a single time, and such that said data is at the same position of said shift register before and after said circular transfer of said data.