Patent ID: 7265578

Claim:
A programmable device comprising: (a) non-dedicated, programmable resources including programmable logic; (b) dedicated circuitry; (c) a Joint Test Action Group (JTAG) interface adapted to selectively interchange signals with the programmable logic via the dedicated circuitry; and (d) a Serial Peripheral Interface (SPI) adapted to (1) selectively interchange signals with the programmable logic via the dedicated circuitry and (2) selectively interchange signals with the JTAG interface via the dedicated circuitry, wherein the dedicated circuitry comprises: (i) one or more muxes, each adapted to selectively transfer to the SPI interface either (1) a signal from the JTAG interface or (2) a signal from the programmable logic; (ii) at least one other mux; and (iii) at least one demux adapted to selectively transfer a signal from the SPI interface to either (1) the at least one other mux or (2) the programmable logic, wherein: the at least one other mux is adapted to selectively transfer to the JTAG interface either (1) the signal from the at least one demux or (2) a signal from the programmable logic.