System and method for initiating a serial data transfer between two clock domains

摘要

A system and method for transferring a data stream between devices having different clock domains. The method initiates a serial data stream between a transmitter and a receiver. The transmitter operates according to a first clock having a first clock rate, and the receiver operates according to a second clock having a second clock rate. A ratio between the second clock rate and the first clock rate is an integer number greater than or equal to one. A first state is provided over a serial line between the transmitter and the receiver. One or more start bits are provided over the serial line. The start bits indicate a second state different from the first state. One or more ratio bits are provided over the serial line after the start bit. The ratio bits indicate the ratio between the second clock rate and the first clock rate. The start bits are received. Using a transition between the first state and the second state evident in receiving each of the start bits, the ratio bits are received. The remainder of the serial data stream is received at appropriate intervals of the second clock rate.