Method and apparatus to provide fixed latency early response in a system with multiple clock domains with fixable clock ratios

Abstract

A system and method for transferring data using an early response signal to indicate subsequent transmission of data after a fixed latency, wherein the signal and data are transferred from a first clock domain to a second clock domain using a clock skipping technique. In one embodiment, an early response signal is transmitted by a first device k clock pulses prior to transmission of the data. The receiving device, which is operating at a higher clock rate, receives the early response signal and delays the signal by the number of skipped pulses which will occur in the second clock domain before the occurrence of the k valid pulse. The second device employs a skip pattern generator to generate a signal indicative of this number of skipped pulses and provides the number to a delay circuit which delays the early response signal for an this number of clock pulses. The delayed early response signal is then output to the appropriate logic to indicate the latency of the subsequent data transfer.