Electrical computers and digital processing systems: support – Synchronization of clock or timing signals – data – or pulses
Reexamination Certificate
2005-01-04
2005-01-04
Lee, Thomas (Department: 2115)
Electrical computers and digital processing systems: support
Synchronization of clock or timing signals, data, or pulses
C365S220000
Reexamination Certificate
active
06839856
ABSTRACT:
A bus interface circuit and method for reliable data capture in the presence of bus-master changeovers and/or for synchronizing received data to an internal clock signal, wherein the received data includes a strobe. Since the strobe may have a delay that is unknown (due to varying distances from the driver, clock jitter, and/or other causes), it is important to re-synchronize to the internal clock, and to do so with the smallest delay possible. This synchronization is provided in a way that also eliminates potential problems due to bus-master changeover, and in a way that minimizes time-critical signal generation. One aspect provides a method and/or apparatus for reliable data capture. The method includes: providing an N-stage latch including a first stage latch and a second stage latch, wherein N is two or larger; loading every Nth word of a data stream into the first stage latch using a first signal based on a strobe passed in the data stream; loading every N+1st word of the data stream into the second stage latch using a second signal based on the strobe passed in the data stream; unloading every Nth word from the first stage latch using a third signal based on an internal bus clock; and unloading every N+1st word from the second stage latch using a fourth signal based on the internal bus clock. In some embodiments, the first signal and the second signal are further based on a first stage selector and on a data_ready signal passed in the data stream.
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Fromm Eric C.
Ruesch Rodney
Connolly Mark
Lee Thomas
Schwegman Lundberg Woessner & Kluth P.A.
Silicon Graphics Inc.
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