Nancy J Holt

US Patent:

62890654, Sep 11, 2001

Filed:

Jan 15, 1997

Appl. No.:

8/783782

Inventors:

Nancy Holt - Colorado Springs CO
Stephen M. Johnson - Colorado Springs CO

Assignee:

Hyundai Electronics America - San Jose CA

International Classification:

H04L 700
H04L 2500
G06F 1200

US Classification:

375372

Abstract:

The invention relates to data transfers between devices having asynchronous clocks. A FIFO having multiple levels holds the data while en route from a sender to a receiver. The invention monitors the FIFO. When all levels become full, the invention issues a FIFO_FULL signal. When all levels become empty, the invention issues a FIFO_EMPTY signal. In these signals, there are four events whose timing is important. (1) The ACTUATION of the FIFO_FULL is immediate; (2) the ACTUATION of the FIFO_EMPTY signal is immediate; (3) the DE-ACTUATION of the FIFO_FULL signal is synchronous with the clock of the computer reading the FIFO; (4) the DE-ACTUATION of the FIFO_EMPTY signal is synchronous with the clock of the computer writing to the FIFO. The invention allows throughput through the FIFO to proceed at a very high speed, even though the sender and receiver are asynchronous.