Abstract: A method for quickly calibrating a memory interface circuit from time to time in conjunction with operation of a functional circuit is described. The method uses controlling the memory interface circuit with respect to read data capture for byte lanes, including controlling CAS latency compensation for the byte lanes. In the method control settings for controlling CAS latency compensation are determined and set according to a dynamic calibration procedure performed from time to time in conjunction with functional operation of a circuit system containing one or more memory devices connected to the memory interface circuit. In the method, determining and setting the control settings for controlling CAS latency compensation is performed independently and parallely in each of the byte lanes.

Abstract: Circuits and methods for implementing a continuously adaptive timing calibration training function in an integrated circuit interface are disclosed. A mission data path is established where a data bit is sampled by a strobe. A similar reference data path is established for calibration purposes only. At an initialization time both paths are calibrated and a delta value between them is established. During operation of the mission path, the calibration path continuously performs calibration operations to determine if its optimal delay has changed by more than a threshold value. If so, the new delay setting for the reference path is used to change the delay setting for the mission path after adjustment by the delta value. Circuits and methods are also disclosed for performing multiple parallel calibrations for the reference path to speed up the training process.

Abstract: A method for calibrating a DDR memory controller is described. The method provides an optimum delay for a core clock delay element to produce an optimum capture clock signal. The method issues a sequence of read commands so that a delayed version of a dqs signal toggles continuously. The method delays a core clock signal to sample the delayed dqs signal at different delay increments until a 1 to 0 transition is detected on the delayed dqs signal. This core clock delay is recorded as “A.” The method delays the core clock signal to sample the core clock signal at different delay increments until a 0 to 1 transition is detected on the core clock signal. This core clock delay is recorded as “B.” The optimum delay value is computed from the A and B delay values.

Abstract: A DDR memory controller is described wherein a core domain capture clock is created by programmably delaying the core clock of the memory controller. The delay of this capture clock is typically calibrated during a power on the initialization sequence in concert with a DDR memory in a system environment, thereby minimizing the effects of system delays and increasing both device and system yield. An additional embodiment also includes programmably delaying the incoming dqs signal. To compensate for voltage and temperature variations over time during normal operation, a runtime dynamic calibration mechanism and procedure is also provided.

Abstract: A method for calibrating a DDR memory controller is described. The method provides an optimum delay for a core clock delay element to produce an optimum capture clock signal. The method issues a sequence of read commands so that a delayed version of a dqs signal toggles continuously. The method delays a core clock signal to sample the delayed dqs signal at different delay increments until a 1 to 0 transition is detected on the delayed dqs signal. This core clock delay is recorded as “A.” The method delays the core clock signal to sample the core clock signal at different delay increments until a 0 to 1 transition is detected on the core clock signal. This core clock delay is recorded as “B.” The optimum delay value is computed from the A and B delay values.

Abstract: A DDR memory controller is described wherein a core domain capture clock is created by programmably delaying the core clock of the memory controller. The delay of this capture clock is calibrated during a power on the initialization sequence in concert with a DDR memory in a system environment, thereby minimizing the effects of system delays and increasing both device and system yield. An additional embodiment also includes programmably delaying the incoming dqs signal.