Patent ID: 7916826

Claim:
A circuit for observing and restoring data of a shift register without altering logical values of said data, said circuit comprising: a shift register comprising a single input receiving data, a plurality of latches connected in series and maintaining said data and a single output outputting said data; a wiring loop electrically connecting said output to said input; a control device operatively connected to said wiring loop between said output and said input, said control device causing said wiring loop to circulate any data, which is currently maintained in said latches of said shift register, from said output to said input and back into said latches of said shift register at least a single time such that said any data returns to a same position within said shift register; an observation wire connected to said wiring loop and said control device, said observation wire simultaneously passing said any data from said wiring loop to said control device as said any data is being circulated from said output to said input and back into said latches of said shift register, said control device further comprising an input/output port accessible from outside said circuit, said input/output port outputting said any data such that said any data is observable outside said circuit without altering any logical data values within said shift register.