Abstract: An interface for implementing a loopback configuration which offers improved calibration and/or testing of an electronic system is disclosed. More specifically, embodiments provide a bi-directional interface with at least two portions or partitions capable of communicating data in opposite directions and implementing a loopback configuration between components of an electronic system, thereby enabling more flexible, efficient and effective calibration and/or testing of the electronic system using a single interface. The loopback of the partitioned bi-directional interface may be used to perform data link training and/or electronic system testing. In one embodiment, the loopback configuration of the interface may be reversible. Additionally, the looped or coupled end of the partitions may be switched from one component to another, thereby reversing the configuration of the loopback in one embodiment.

Abstract: A method of receiving data. A plurality of data signals and clocking signals are received over a source synchronous communication channel. The plurality of data signals is strobed with the clocking signal at a plurality of coarse time offset delays (e.g., time offset delays spanning over a data bit period). The plurality of error rates associated with the strobing at the plurality of coarse time offset delays is determined. Strobing design of a transmitting component (e.g., edge-strobed, center-strobed, etc.) may be determined based on the plurality of error rates. The error rates of the plurality of data signals strobed with a plurality of time offset delays close to the determined strobing design of the transmitting component is calculated. A time offset delay is selected based on the error rates. The plurality of data signals can be strobed with the selected time offset delay to recover the transmitted data signals.

Abstract: A data sampling apparatus and associated method are provided, including a first inverter receiving a data signal, and inverting the data signal to produce a trigger signal, a first flip-flop receiving the trigger signal, and outputting an output signal, a second flip-flop and a third-flop flop each receiving the output signal from the first flip-flop, the second flip-flop further receiving a strobe signal, and a second inverter inverting the strobe signal, and outputting the inverted strobe signal to the third flip-flop. An output of the second flip-flop indicates a value of the output signal output from the first flip-flop when the strobe signal is of a first state and an output of the third flip-flop indicates a value of the output signal output from the first flip-flop when the strobe signal is of a second state.

Abstract: Embodiments for positioning rising and/or filling edges of data strobe signals are disclosed. One example embodiment may comprise receiving a data signal, positioning an edge of a first delayed data strobe signal associated with the data signal by a first programmable amount, and positioning an edge of a second delayed data strobe signal associated with the data signal by a second programmable amount, wherein the second delayed data strobe signal is shifted approximately one bit-time in relation to the first delayed data strobe signal.

Abstract: Techniques and circuits for ensuring one or more circuit components are not subjected to voltage levels above their rated voltage tolerance due to core logic and I/O logic supply voltages reaching final voltage levels at different times are provided. According to some embodiments, an internal voltage supply sense circuit may monitor a level of a voltage supply that powers core logic that generates control signals used to program a voltage regulator. In response to determining the core logic voltage supply is below a predetermined level, the sense circuit may generate one or more regulated voltage signals to override regulated voltage signals generated by the voltage regulator.

Abstract: Embodiments for providing a plurality of bias voltages to input/output circuitry are disclosed.

Abstract: Circuits, methods, and apparatus for training a phase shift circuit to provide a phase shift for improved data recovery. A specific embodiment of the present invention provides a variable delay cell. A delay through the variable delay cell is changed while training patterns are received. The presence of errors in the received data pattern is tracked, and from the presence or absence of errors a preferred delay is selected and used for receiving data.

Abstract: Techniques and circuits for ensuring undefined control signals are not inadvertently driven onto a bus due to core logic and I/O logic supply voltages reaching final voltage levels at different times are provided. According to some embodiments, an internal voltage supply sense circuit may monitor a level of a voltage supply that powers core logic that generates control signals to be driven on I/O pads. The sense circuit may generate one or more control signals used to keep I/O pads in a high impedance state.

Abstract: A method of receiving data. A plurality of data signals and clocking signals are received over a source synchronous communication channel. The plurality of data signals is strobed with the clocking signal at a plurality of coarse time offset delays (e.g., time offset delays spanning over a data bit period). The plurality of error rates associated with the strobing at the plurality of coarse time offset delays is determined. Strobing design of a transmitting component (e.g., edge-strobed, center-strobed, etc.) may be determined based on the plurality of error rates. The error rates of the plurality of data signals strobed with a plurality of time offset delays close to the determined strobing design of the transmitting component is calculated. A time offset delay is selected based on the error rates. The plurality of data signals can be strobed with the selected time offset delay to recover the transmitted data signals.

Abstract: Circuits, methods, and apparatus for training a phase shift circuit to provide a phase shift for improved data recovery. A specific embodiment of the present invention provides a variable delay cell. A delay through the variable delay cell is changed while training patterns are received. The presence of errors in the received data pattern is tracked, and from the presence or absence of errors a preferred delay is selected and used for receiving data.

Abstract: Methods and apparatuses that enable memory devices to inform graphical processing systems about the results of WRITE de-skew training. A WRITE-TRAINING mode is added to a memory device. When the WRITE-TRAINING mode is asserted the memory data mask (DM) pin is converted to an output port. Incoming WRITE data is strobed-into the memory device and the resulting data pattern is compared to a desired pattern. If the incoming WRITE data and strobed-in data match, that result is sent to the graphical processing system by setting the DM pin HIGH. If the incoming WRITE data and the strobed-in data do not match, that result is sent to the graphical processing system by setting the DM pin LOW. Beneficially, the incoming data and the desired pattern are derived from pseudo random bit sequence (PRBS) sources.

Abstract: Embodiments for controlling pre-emphasis driver circuits for electrical signal interconnects within a computer system are disclosed.

Abstract: Circuits, methods, and apparatus for training a phase shift circuit to provide a phase shift for improved data recovery. A specific embodiment of the present invention provides a variable delay cell. A delay through the variable delay cell is changed while training patterns are received. The presence of errors in the received data pattern is tracked, and from the presence or absence of errors a preferred delay is selected and used for receiving data.