Patent ID: 7710136

Claim:
An integrated circuit comprising: a monitor operable to produce monitor data in dependence upon a measured parameter of the integrated circuit; and a self test controller connected to receive monitor data from the monitor, and operable to output self test data from the integrated circuit through a single communication wire, wherein the monitor includes an output shift register and is operable to output monitor data through the shift register, at least one additional monitor having a corresponding output shift register, the shift registers of the monitors and the controller being connected together in series to form a shift register loop in which each shift register, except the last in the loop, is connected to the next shift register in the loop, the controller being connected in series between the first and last shift registers of the loop; wherein data is transferred around the loop in either direction controlled by the controller and the data is transferred around the loop bi-directionally; and wherein a clocking of the data is synchronized around the loop to avoid conflicts of the data.