Double interface CF card

A method for operating a double interface CF card, which supports a CF interface and a USB interface connected to a system end at different times with a single micro controller controlling a plurality of erasable memories therein and transmitting and exchanging data with any of the CF and the USB interfaces, comprising the following procedures:

• starting a power source;
• converting the power source to an internal voltage suitable for the CF card and cutting off and isolating another interface circuit;
• switching to and starting a CF bus interface circuit or a USB bus interface circuit based on a system detected with an interface detection and selection circuit;
• and
• according to an interface specification of the detected system, the micro controller accepting instruction codes transmitted from the system end and treating the instruction codes with a response.

A double interface flash memory card, comprising:

• a plurality of erasable memories;
• a CF interface, complying with a CF interface specification;
• a USB interface, complying with a USB interface specification;
• a power source transfer and protection circuit, converting a power source into an internal voltage suitable for the CF and switching off another interface;
• an interface detection and selection circuit, being coupled with the power transfer and protection circuit to detecting a system end of the CF interface or the USB interface and switching the CF interface circuit or the USB interface circuit as the correct working mode;
• and
• a control chip, being built with a micro controller, a CF bus interface circuit and a USB bus interface circuit;
• wherein, the micro controller accepts instruction codes transmitted from a system end and treats the instruction codes with necessary response based on a system specification after switching.