System for providing a host computer with access to a memory on a PCMCIA card in a power down mode

摘要

A wake-up system is provided to allow host computer access to a Card Information Structure (CIS) on a PCMCIA card during a SLEEP mode. The CIS is stored in a non-volatile memory accessible to a host computer via a PCMCIA bus and to PCMCIA card logic via a local bus. Arbitration logic is coupled between the PCMCIA and local buses to control access to the memory. Sleep logic prevents a fast clock signal from being supplied to the arbitration logic and the PCMCIA card logic when the PCMCIA card is switched into the SLEEP mode. A CIS read detect circuit decodes a CIS read operation on the PCMCIA bus and asserts the CIS detect signal supplied to the sleep logic. In response, the sleep logic allows the fast clock signals to be supplied to the arbitration logic and adapter card subsystem to exit from the SLEEP mode and provide the host computer with access to the memory storing the CIS information.