Abstract: A synchronous clock generator for an integrated circuit is described in which a delay lock loop circuit may be used to delay a first input signal. A delay circuit is coupled to the delay lock loop circuit and receives a control voltage from the delay lock loop circuit, which is used to delay a second input signal. The first and second input signal may be complimentary.

Abstract: In some embodiments, the invention involves multiple integrated circuit stubs coupled in series. At least one of the integrated circuit stubs including first conductors to receive signals from a first adjacent one of the integrated circuit stubs, second conductors to provide signals to a second adjacent one of the integrated circuit stubs, and third conductors to provide signals to an integrated circuit chip. The integrated circuit stubs include first drivers and second drivers coupled to the first, second, and third conductors, wherein the first drivers receive the external signals from the first conductors and drive them onto the second conductors and the second drivers receive signals from the first conductors and drive them onto the third conductors.

Abstract: The invention provides an apparatus, method and means for capturing data. In an aspect, a differential and complementary input folded-cascode clocked amplifier is provided. In an aspect, the invention provides rail-to-rail input common-mode voltage range. In an aspect, the invention provides a setup/hold time window that is smaller than the setup/hold time window of a conventional clocked amplifier and a conventional input amplifier with a separate amplifier and latch. In an aspect, the invention provides high common-mode rejection as compared with conventional clocked sense amplifiers.

Abstract: In an electronic system having first and second logic devices, a free running on-chip clock signal is generated by the first logic device, where the signal has a frequency that is controlled to match that of a global free-running clock signal received by both devices. The on-chip clock signal is synchronized to a strobe signal received by the first device and that was transmitted in association with a data signal by the second device. A logic function is repeatedly performed as synchronized by the first clock signal, to repeatedly generate one or more bits from the data signal.

Abstract: A biased control loop for setting the impedance of an output driver includes a dummy driver having a variable output impedance, a sample and compare circuit to compare the output impedance of dummy output driver to a reference, and an up/down counter to modify the impedance. When the loop is locked, an error signal alternates positive and negative about a reference value. A digital filter produces a filtered version of the error signal with an apparent error value that does not alternate. The digital filter has a biased lock circuit that guarantees that the apparent error does not alternate. A simultaneous bidirectional port includes an output driver and the biased control loop to set the output driver impedance. When the output driver drives a bidirectional line and serves as a termination impedance for another driver, the reduced apparent error variation provides improved impedance matching.

Abstract: The invention provides, in an embodiment, an apparatus, method and means for unintrusively observing, echoing and reading signals transmitted by one of a bus and wireless communication, without disturbing electrical properties of the bus, without adding bus latency, and without adding signal discontinuities. In an aspect, a buffer having a trigger is coupled with a component that connects to a memory bus, the buffer echoes signals to an observability port, and a diagnostic device reads the echoed signals. In an aspect, the bus is one of a simultaneous bi-directional (SBD) bus having ternary logic levels, a single ended bus, a differential bus, an optically coupled bus, a chipset bus, a frontside bus, an input/output (I/O) bus, a peripheral component interface (PCI) bus, and an industry standard architecture (ISA) bus. In an aspect, the buffer echoes bus signals having frequencies between 500 MHz. and 5 GHz. In an aspect, the buffer echoes bus signals having frequencies of at least 5 GHz.

Abstract: The invention provides an apparatus, method and means for capturing data. In an aspect, a differential and complementary input folded-cascode clocked amplifier is provided. In an aspect, the invention provides rail-to-rail input common-mode voltage range. In an aspect, the invention provides a setup/hold time window that is smaller than the setup/hold time window of a conventional clocked amplifier and a conventional input amplifier with a separate amplifier and latch. In an aspect, the invention provides high common-mode rejection as compared with conventional clocked sense amplifiers.

Abstract: In an electronic system having first and second logic devices, a free running on-chip clock signal is generated by the first logic device, where the signal has a frequency that is controlled to match that of a global free-running clock signal received by both devices. The on-chip clock signal is synchronized to a strobe signal received by the first device and that was transmitted in association with a data signal by the second device. A logic function is repeatedly performed as synchronized by the first clock signal, to repeatedly generate one or more bits from the data signal.

Abstract: A simultaneous bi-directional I/O circuit includes a first MUX in the reference select circuitry and a second, matching MUX in the pre-driver stage of the output buffer. In normal mode, the first MUX passes the driven data output signal, which controls the threshold of the differential receiver circuit between two different non-zero voltage levels, so that the receiver circuit can properly decode an incoming signal at the I/O node or pin. In an AC switching state or loopback test mode, the first MUX deselects the driven data output signal from controlling the receiver circuit. This allows the receiver circuit to decode outgoing data that is being looped back as incoming data. The second MUX enables the reference select circuitry to switch at a rate that matches the output slew rate in order to provide high-speed operation. Also described are an electronic system, a data processing system, and various methods of testing simultaneous bi-directional I/O circuits.

Abstract: A voltage-controlled CMOS delay cell includes a pair of inverters and a pair of load cells. The load cells are controllable by independent N and P bias control voltages to vary the delay of the delay cell. Symmetric P and N load capacitors in the delay cells, together with the N and P bias control voltages, provide effective rejection of noise on the power supply rails and enable the delay cell to generate symmetric low-going and high-going delays. The P bias control voltage is generated from the N bias control voltage by a closed-loop voltage control circuit. Also described are a voltage-controlled load cell, an integrated circuit, an electronic system, and a data processing system that incorporate one or more of the symmetric CMOS voltage-controlled delay cells.

Abstract: A frequency control unit has an input to receive a digital downstream strobe signal and an output to provide a controlled delay to the input strobe signal. A downstream latch has a data input to receive a digital downstream data signal and a clock input coupled to the output of the frequency control unit. The controlled delay is essentially equal to a set up time of the latch. A delay element coupled to the output of the frequency control unit further delays the downstream strobe signal by essentially a propagation time of the latch. Output drivers are coupled to the outputs of the latch and the delay element.

Abstract: A simultaneous bi-directional I/O circuit includes a first MUX in the reference select circuitry and a second, matching MUX in the pre-driver stage of the output buffer. In normal mode, the first MUX passes the driven data output signal, which controls the threshold of the differential receiver circuit between two different non-zero voltage levels, so that the receiver circuit can properly decode an incoming signal at the I/O node or pin. In an AC switching state or loopback test mode, the first MUX deselects the driven data output signal from controlling the receiver circuit. This allows the receiver circuit to decode outgoing data that is being looped back as incoming data. The second MUX enables the reference select circuitry to switch at a rate that matches the output slew rate in order to provide high-speed operation. Also described are an electronic system, a data processing system, and various methods of testing simultaneous bi-directional I/O circuits.

Abstract: A variable-delay circuit on an integrated circuit is used to delay a periodic strobe signal. In normal operation, the strobe signal can be shifted 90 degrees to center it within a data bit cell. In test mode, it can also be shifted up to 270 degrees in N increments to measure the effective input latch setup and hold timings. The variable-delay circuit comprises a voltage-mixing interpolator circuit to produce phase delays in N increments. The variable-delay circuit can incorporate an existing delay locked loop. Also described are an electronic system, a data processing system, and various methods of performing on-chip testing and calibration.

Abstract: Briefly, in accordance with one embodiment of the invention an integrated circuit includes: a digital feedback control circuit to adjust the impedance of an interface circuit output buffer based, at least in part, on having adjusted the impedance of a non-data signal output buffer coupled to an external impedance. Briefly, in accordance with another embodiment of the invention, a method of digitally adjusting the impedance of an interface circuit output buffer comprises: digitally adjusting the impedance of a non-data signal output buffer coupled to an external impedance, and digitally adjusting the impedance of the interface circuit output buffer based, at least in part, on the digitally adjusted impedance of the non-data signal output buffer.

Abstract: An improved 3.3 V to 5 V interface buffer comprising a solid state BiCMOS device implemented on a reduced voltage process designed to operate from 3.3 V and 5 V supplies and capable of receiving a 0-3.3 V input signal while providing a external swing signal from 0-5 V. Specifically, cross coupled PMOS and NMOS devices manufactured by a 3.3 V process are utilized with level shifting diodes for achieving a device which operates on higher voltages than conventional circuit design techniques allow for a given process technique, while providing a 0-5 V output at the sending device.