Method and apparatus for accelerating detection of serial bus device speed signals
View Patent ↗A method and apparatus for accelerating detection of speed code signals, and in particular S 400 signals, for IEEE Standard 1394-1995 serial bus devices. The present invention validates S 400 mode immediately after detecting an S 400 speed signal, or immediately after detecting an S 400 speed signal following a first S 200 speed signal. The invention further provides S 200 and S 100 mode validation according to current implementations. Additionally, the invention does not require RX_DATA_PREFIX as a pre-requisite for signal detection.
1. A computer-readable medium containing instructions which, when executed by a computer, administer a serial bus, by
receiving a first speed signal by a speed signal register, the first speed signal indicating a first speed code;
receiving a second speed signal by the speed signal register, the second speed signal indicating a second speed code; and
validating a speed mode based on the order in which the speed signals were received.
2. The computer readable medium of claim 1 , wherein the first speed signal is a S 200 signal and the second speed signal is an S 400 signal, and the speed mode validated is an S 400 speed mode.
3. The computer-readable medium of claim 1 , further comprising instructions that execute to clear the speed signal register after transmission of a plurality of packets has concluded.
4. The computer-readable medium of claim 1 , further comprising instructions that execute to clear the speed signal register after a chip reset has occurred.
5. The computer-readable medium of claim 1 , further comprising instructions that execute to clear the speed signal register after a self-ID speed signal trap has occurred.