| 摘要 |
In a typical microprocessor based computer, many peripheral and memory devices 11, 12, 14 are connected directly to the system bus 20. Consequently, energy is wasted driving bus signals to those devices during cycles not intended for those devices. Power conservation is particularly important in portable, battery-powered systems. Credit card sized PCMCIA cards 26, 27, 28 are user-installable mass storage and I/O communication options, interfaced by an interface controller 50 interposed between the host system bus 20 and the card slots 6,7,8. The invention provides the capability for the interface controller 50 to operates a quiet bus to a plurality of, or to a single, PCMCIA card slot(s) 6, 7, 8 when configured to do so. In the quiet bus mode, address signals are not passed through to the PCMCIA card until a memory or I/O card address match qualified by appropriate control signals from the microprocessor 16 are detected, indicating a bus cycle intended for the card peripheral.
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