International Business Machines Corporation
Reducing latency of memory read operations returning data on a read data path across multiple clock boundaries, to a host implementing a high speed serial interface

Abstract:

A calibration controller determines a latest arriving data strobe from at least one data chip at a first data buffer in a read data path between at least one memory chip and a host on a high speed interface. The calibration controller determines whether external feedback of the at least one data chip is required. The calibration controller, in response to determining that external feedback of the at least one data chip is required, aligns a chip clock distributed to a second data buffer in the read data path with the latest arriving data strobe by applying a 180 degree phase align of the chip clock through one or more latches, wherein data cross a first clock boundary from the first data buffer to the second data buffer, to minimize a latency in the read data path across the first clock boundary.