| 摘要 |
A cable detection method is provided for detecting the existence of an 80-conductor cable used in connecting a host device to peripheral devices of a computer system. An 80-conductor cable is required for Ultra-ATA to function at data transfer rates of modes 3 or 4. In compliance with ATA/ATAPI standards and requirement, the cable detection method includes the placement of a capacitor on the PDIAG- signal at the host. A device would assert the PDIAG- signal to a low state for a predetermined length of time to discharge the capacitor, release the signal then measure the state of the signal within a window of time, thereby assuring a high state for an 80 conductor cable and a low state for a non-80 conductor cable.
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