Method for operating a data interface circuit where a calibration controller controls both a mission path and a reference path

A method for operating a data interface circuit wherein a calibration controller controls:

• a mission path that captures and delays a data bit value in conjunction with operation of a functional circuit;
• and
• a reference path that captures and delays the data bit value, the method comprising:
• performing a first calibration operation for both reference and mission paths to establish an optimal delay setting for each path, and determining a delta value between the optimal delay settings for the reference and mission paths;
• operating the data interface circuit including operation of the mission path to capture read data during operation of the functional circuit;
• from time to time, and without interfering with operation of the functional circuit and the mission path, performing an additional calibration of the reference path to determine a new optimal delay setting for the reference path;
• if the new optimal delay setting for the reference data path differs from a previous delay setting by an amount greater than a change threshold value, and without interrupting operation of the functional circuit, setting the delay setting for the mission path to be equal to the new optimal delay setting for the reference path adjusted by the delta value;
• and
• wherein the mission path performs data capture solely for the functional circuit, and the reference path performs data capture solely for calibration purposes.

A method for operating a data interface circuit wherein a calibration controller controls:

• a mission path that captures a data bit value using a first delayed capture strobe, the mission path operating in conjunction with a functional circuit;
• and
• a reference path that captures the data bit value using a second delayed capture strobe,
• the method comprising:
• performing a first calibration operation for both reference and mission paths to establish an optimal delay setting for each path, and determining a delta value between the optimal delay settings for the reference and mission paths;
• operating the data interface circuit including operation of the mission path to capture read data during operation of the functional circuit;
• from time to time, and without interfering with operation of the functional circuit and the mission path, performing an additional calibration of the reference path to determine a new optimal delay setting for the reference path;
• if the new optimal delay setting for the reference data path differs from a previous delay setting by an amount greater than a change threshold value, and without interrupting operation of the functional circuit, setting the delay setting for the mission path to be equal to the new optimal delay setting for the reference path adjusted by the delta value;
• and
• wherein the mission path performs data capture solely for the functional circuit, and the reference path performs data capture solely for calibration purposes.

A method for operating a data interface circuit where a calibration controller controls both a mission path and a reference path that each capture a common data bit value in conjunction with operation of a functional circuit, the method comprising:

• performing a first calibration for both reference and mission paths to initially establish optimal initial delay settings for each path, and determining a delta value between the optimal delay settings of the reference and mission paths;
• operating the functional circuit including operation of the mission path;
• from time to time during operation of the functional circuit, and without interfering with operation of the functional circuit or the mission path, performing an additional calibration operation for the reference path to determine a new optimal delay setting;
• and
• wherein if a new optimal delay setting for the reference data path differs from a previous optimal delay setting for the reference path by an amount greater than a change threshold value, setting the delay setting for the mission path to a value that is equal to the new optimal delay setting for the reference path adjusted by the delta value.