Abstract: A data processing system comprises a plurality of sub-circuits, a clock generator provided with a control circuit, a pool of oscillator circuits comprising at least three oscillator circuits, and a multiplexing circuit coupled between the pool and clock inputs of the sub-circuits. The multiplexing circuit has a control input coupled to a control output of the control circuit. The multiplexing circuit is configured to couple any selectable one of the oscillator circuits in the pool to a clock input of each of the sub-circuits. The control circuit is configured to set the frequencies of respective ones of the clock circuit by controlling the multiplexing circuit to supply clock signals derived from selected ones of the oscillator circuits to the sub-circuits.

Abstract: The invention relates to a controlled shut-down of an electronic circuit or circuits such that the electrical power consumption of that circuit or circuits is minimized and that each said circuit is at a status which is a pre-determined state (42; 52) of that said circuit wherein all of its own control and messaging signals are taken to their zero level. The present invention claimed relates to the methodology of entering said circuit into this pre-determined state (42;52); where all said signal and messaging lines are taken to zero; thereby reducing power consumption within an electronic circuit when its status is defined as being shut-down or standby.

Abstract: A data processing system comprises a plurality of sub-circuits (10a, 10a, 10c), a clock generator (20) provided with a control circuit (22), a pool of oscillator circuits (24a, . . . 24f) comprising at least three oscillator circuits, and a multiplexing circuit (26) coupled between the pool and clock inputs of the sub-circuits. The multiplexing circuit has a control input (27) coupled to a control output (23) of the control circuit. The multiplexing circuit is configured to couple any selectable one of the oscillator circuits in the pool to a clock input (11a, 11b, 11c) of each of the sub-circuits. The control circuit (22) is configured to set the frequencies of respective ones of the clock circuit by controlling the multiplexing circuit to supply clock signals derived from selected ones of the oscillator circuits to the sub-circuits.

Abstract: The invention relates to a controlled shut-down of an electronic circuit or circuits such that the electrical power consumption of that circuit or circuits is minimized and that each said circuit is at a status which is a pre-determined state (42; 52) of that said circuit wherein all of its own control and messaging signals are taken to their zero level. The present invention claimed relates to the methodology of entering said circuit into this pre-determined state (42;52); where all said signal and messaging lines are taken to zero; thereby reducing power consumption within an electronic circuit when its status is defined as being shut-down or standby.

Abstract: A testing approach involves selective application of clock signals to target circuitry. In an example embodiment (300), a target circuit (332) having logic circuitry that processes data in response to an operational clock signal (308) having at least one clock period, is analyzed for delay faults. Test signals are applied to the logic circuitry while the logic circuitry is clocked with a high-speed test clock (309) having several clock-state transitions that occur during at least one clock period of the operational clock (308). An output from the logic circuitry is analyzed for its state (e.g., as affected by delay in the circuitry). Delay faults are detected as a difference in state of the output of the logic circuitry. With this approach, circuits are tested using conventional testers (340) that operate at normal (e.g., slow) speeds while selectively clocking selected portions of the circuit at higher speeds for detecting speed-related faults therein.

Abstract: A Gray Code counter includes first translator logic, binary incrementing/decrementing logic, second translator logic, and a clocked storage device. The first translator logic receives at an input a Gray Code number, I.sub.gray ?n:0! which the first translator translates into a binary number, I.sub.bin ?n:0!. The binary incrementing/decrementing logic either increments or decrements the binary number I.sub.bin ?n:0! to produce an incremented/decremented binary number, Z.sub.bin ?n:0!. The second translator logic translates the incremented/decremented binary number Z.sub.bin ?n:0! into an incremented/decremented Gray Code number, Z.sub.gray ?n:0!. The clocked storage device stores the incremented/decremented Gray Code number, Z.sub.gray ?n:0!. The clocked storage device also feeds the incremented/decremented Gray Code number, Z.sub.gray ?n:0!, to the input of the first translator logic.