Method of application memory preservation for dynamic calibration of memory interfaces

摘要

A method for calibrating a memory interface circuit is described wherein prior to a calibration operation at least a portion of application information contained in a memory circuit is moved or copied to an alternate location to preserve that information. At the completion of the calibration operation, the information is restored to the same location of the memory circuit. Thus, the calibration operation can be performed from time to time during normal operation of a system containing the memory circuit. Non-limiting examples of calibration operations are described including operations where a capture clock for a memory read circuit is calibrated, and operations where CAS latency compensation is calibrated for a DDR memory interface.

主权项

1. A method for calibrating a memory controller circuit from time to time in conjunction with functional operation of a memory circuit, comprising the steps of:
requiring a known data pattern for calibration to be located in the memory circuit, wherein if the known data pattern for calibration is not fully present in the memory circuit immediately prior to a calibration operation, at least a portion of said known data pattern for calibration is written to the memory circuit prior to the calibration operation; and wherein prior to writing said at least a portion of the known data pattern, at least a portion of functional application data located in the memory circuit is preserved by moving said at least a portion of functional application data to an alternate location.