Abstract: An apparatus is provided that compensates for misalignment on a synchronous data bus. The apparatus includes a replica radial distribution element, a bit lag control element, and a synchronous lag receiver that is configured to receive one of a plurality of radially distributed strobes and a data bit, and that is configured to delay registering of the data bit by a propagation time. The replica radial distribution element is configured to receive a first signal, and is configured to generate a second signal, where the replica radial distribution element comprises replicated propagation path lengths, loads, and buffering of a radial distribution network for a strobe. The bit lag control element is configured to measure a propagation time beginning with assertion of the first signal and ending with assertion of the second signal, and is configured to generate a value on a lag bus that indicates the propagation time.

Abstract: A method that compensates for misalignment on a synchronous data bus. The method includes: replicating propagation path lengths, loads, and buffering of a radial distribution network for a strobe, receiving a lag pulse signal, and generating a replicated strobe signal by employing the replicated propagation path loads lengths, and buffering; measuring the time between assertion of the lag pulse signal and assertion of the replicated strobe signal; on a lag bus, generating a value that indicates the time; within a synchronous lag receiver, receiving a first one of a plurality of radially distributed strobes and a data bit, and delaying registering of the data bit by the time.

Abstract: A method for aligning signals on a bus, including: replicating propagation path lengths, loads, and buffering of a radial distribution network for a strobe; receiving a first signal, and generating a second signal by employing the replicated propagation path lengths, loads, and buffering; receiving control information over a standard JTAG bus, wherein the control information indicates an amount to adjust a propagation time; and measuring the propagation time beginning with assertion of the first signal and ending with assertion of the second signal, said measuring comprising: selecting one of a plurality of successively delayed versions of the first signal that coincides with assertion of the second signal; adjusting the propagation time by the amount prescribed by the control information to yield an adjusted propagation time; and gray encoding the adjusted propagation time to generate a value on a lag bus.

Abstract: An apparatus having a bit lag control element that measures a propagation time beginning with assertion of a first signal and ending with assertion of a second signal, and that generates a first value indicating an adjusted propagation time. The control element includes delay lock control, adjust logic, and a gray encoder. The delay lock control selects one of a plurality of successively delayed versions of the first signal that coincides with the assertion the second signal, and generates a second value on a lag select bus that indicates the propagation time. The adjust logic is coupled to a circuit and to the lag select bus, and adjusts the second value by an amount prescribed by the circuit to yield a third value that is output to an adjusted lag bus. The gray encoder gray encodes the third value to generate the first value on the lag bus.

Abstract: An apparatus that compensates for misalignment on a synchronous data bus. The apparatus includes a replica distribution network, a bit lag control element, and a synchronous lag receiver. The replica distribution network receives a first signal, and generates a second signal, where the replica distribution network comprises replicated propagation characteristics of a radial distribution network for a strobe. The bit lag control element is configured to measure a propagation time beginning with assertion of the first signal and ending with assertion of the second signal, and is configured to generate a value on a lag bus that indicates the propagation time. The synchronous lag receiver is coupled to the bit lag control element, and is configured to receive a first one of a plurality of radially distributed strobes and a data bit, and is configured to delay registering of the data bit by the propagation time.

Abstract: An apparatus is provided that compensates for misalignment on a synchronous data bus. The apparatus includes a bit lag control element and a synchronous lag receiver. The bit lag control element is configured to measure a propagation time beginning with assertion of a strobe and ending with assertion of a first one of a plurality of radially distributed strobes corresponding to the strobe, and is configured to generate a value on a lag bus that indicates the propagation time. The synchronous lag receiver is coupled to the bit lag control element, and is configured to receive the first one of the plurality of radially distributed strobes and a data bit, and is configured to delay registering of the data bit by the propagation time.

Abstract: An apparatus having a bit lag control element that measures a propagation time beginning with assertion of a first signal and ending with assertion of a second signal, and that generates a first value indicating an adjusted propagation time. The control element includes delay lock control, adjust logic, and a gray encoder. The delay lock control selects one of a plurality of successively delayed versions of the first signal that coincides with the assertion the second signal, and generates a second value on a lag select bus that indicates the propagation time. The adjust logic is coupled to a circuit and to the lag select bus, and adjusts the second value by an amount prescribed by the circuit to yield a third value that is output to an adjusted lag bus. The gray encoder gray encodes the third value to generate the first value on the lag bus.

Abstract: An apparatus that compensates for misalignment on a synchronous data bus. The apparatus includes a replica distribution network, a bit lag control element, and a synchronous lag receiver. The replica distribution network receives a first signal, and generates a second signal, where the replica distribution network comprises replicated propagation characteristics of a radial distribution network for a strobe. The bit lag control element is configured to measure a propagation time beginning with assertion of the first signal and ending with assertion of the second signal, and is configured to generate a value on a lag bus that indicates the propagation time. The synchronous lag receiver is coupled to the bit lag control element, and is configured to receive a first one of a plurality of radially distributed strobes and a data bit, and is configured to delay registering of the data bit by the propagation time.

Abstract: A phase error circuit including phase difference logic and delay and register logic. The phase difference logic provides a pulse difference signal including at least one difference pulse indicative of a timing difference between selected edges of a pair of clock signals. The delay and register logic receives the pulse difference signal and provides a phase error value representing phase error between the clock signals. The delay and register logic may include a delay line with multiple delay cells and taps coupled in series in which each tap provides an output state of a delay cell. The register logic registers a state of each tap to provide delay bits in response to each trailing edge of the difference pulses. Each delay bit may remain set until reset so that the longest pulse difference signal is registered to provide the peak phase error.

Abstract: A microprocessor according to one embodiment includes a supply node providing a core voltage, a functional block, a charge node, select logic, and substrate bias logic. The functional block has multiple power modes and includes one or more semiconductor devices and a substrate bias rail routed within the functional block and coupled to a substrate connection of at least one semiconductor device. The select logic couples the substrate bias rail to the charge node when the functional block is in a low power mode and clamps the substrate bias rail to the supply node when the functional block is in a full power mode. The substrate bias logic charges the charge node to a bias voltage at an offset voltage relative to the core voltage when the functional block is in the low power mode. Semiconductor devices may be provided to clamp or otherwise couple the bias rail.

Abstract: A microprocessor including a substrate bias rail providing a bias voltage during a first operating mode, a supply node providing a core voltage, a clamp device coupled between the bias rail and the supply node, and control logic. The control logic turns on the clamp device to clamp the bias rail to the supply node during a second operating mode and turns off the clamp device during the first operating mode. The clamp devices may be implemented with P-channel and N-channel devices. Level shift and buffer circuits may be provided to control the clamp devices based on substrate bias voltage levels. The microprocessor may include a substrate with first and second areas each including separate substrate bias rails. The control logic separately turns on and off clamp devices to selectively clamp the substrate bias rails in the first and second areas based on various power modes.

Abstract: A peak phase error circuit including phase difference logic and delay and register logic. The phase difference logic provides a pulse difference signal including at least one difference pulse indicative of a timing difference between selected edges of a pair of clock signals. The delay and register logic receives the pulse difference signal and provides a peak phase error value representing peak phase error between the clock signals. The delay and register logic may include a delay line with multiple delay cells and taps coupled in series in which each tap provides an output state of a delay cell. The register logic registers a state of each tap to provide delay bits in response to each trailing edge of the difference pulses. Each delay bit remains set until reset so that the longest pulse difference signal is registered to provide the peak phase error.

Abstract: A microprocessor according to one embodiment includes a supply node providing a core voltage, a functional block, a charge node, select logic, and substrate bias logic. The functional block has multiple power modes and includes one or more semiconductor devices and a substrate bias rail routed within the functional block and coupled to a substrate connection of at least one semiconductor device. The select logic couples the substrate bias rail to the charge node when the functional block is in a low power mode and clamps the substrate bias rail to the supply node when the functional block is in a full power mode. The substrate bias logic charges the charge node to a bias voltage at an offset voltage relative to the core voltage when the functional block is in the low power mode. Semiconductor devices may be provided to clamp or otherwise couple the bias rail.

Abstract: A microprocessor including a substrate bias rail providing a bias voltage during a first operating mode, a supply node providing a core voltage, a clamp device coupled between the bias rail and the supply node, and control logic. The control logic turns on the clamp device to clamp the bias rail to the supply node during a second operating mode and turns off the clamp device during the first operating mode. The clamp devices may be implemented with P-channel and N-channel devices. Level shift and buffer circuits may be provided to control the clamp devices based on substrate bias voltage levels. The microprocessor may include a substrate with first and second areas each including separate substrate bias rails. The control logic separately turns on and off clamp devices to selectively clamp the substrate bias rails in the first and second areas based on various power modes.