Electronic device with card interface
View Patent ↗When initializing a card-shaped device inserted in a card interface, operation mode acquiring means incorporated in an electronic device acquires operation mode information, stored in a register file incorporated in the card-shaped device, by a predetermined procedure using a predetermined pin. Operation mode setting means incorporated in the electronic device executes signal assignment on a plurality of data pins peculiar to an operation mode indicated by the acquired operation mode information, thereby switching a data transfer width, and allowing the card-shaped device to operate in the operation mode.
1. A card-shaped device to be used by an electronic device having a card interface, comprising:
a connector having connector pins that include data pins, a command pin, and a power signal pin, the connector being connectable to the electronic device via the card interface;
a register file pre-storing operation mode information of the card-shaped device, the operation mode information indicating one of first and second operation modes;
a transmitter configured to transmit the operation mode information stored in the register file to the electronic device via one of the connector pins, when a first command that requests reading of the operation mode information is received from the electronic device via the command pin; and
a data transfer unit configured to execute data transfer between the card-shaped device and the electronic device, the data transfer unit transferring data using the data pins to which signal assignment was performed by the electronic device according to the operation mode information, wherein:
the data transfer unit uses all of the data pins for data transfer in the first operation mode;
the data transfer unit uses one of the data pins for data transfer in the second operation mode;
the register file stores an operation voltage information indicating an operation voltage of the card-shaped device; and
the transmitter transmits the operation voltage information stored in the register file to the electronic device via the command pin, when a second command that requests reading of the operation voltage information is received from the electronic device via the command pin.
2. The card-shaped device according to claim 1 , wherein the connector receives a power voltage information indicating a power voltage supplied from the electronic device via the power signal pin.
3. The card-shaped device according to claim 2 , wherein the transmitter transmits a response indicating a ready state if the card-shaped device can be operated by the power voltage.
4. The card-shaped device according to claim 3 , wherein:
the register file stores a card address pre-assigned to the card-shaped device; and
the transmitter transmits the card address stored in the register file to the electronic device, via the command pin, when a third command that requests reading of the card address is received from the electronic device via the command pin.
5. The card-shaped device according to claim 4 , wherein:
the connector receives a fourth command for selecting the card-shaped device, the fourth command including a card address indicating a card-shaped device to be selected; and
the card-shaped device shifts to a selected state if the card address included in the fourth command is identical to the card address stored in the register file.
6. The card-shaped device according to claim 5 , wherein:
the register file stores a card ID, the card ID identifying data peculiar to the card-shaped device; and
the transmitter transmits the card ID stored in the register file to the electronic device via the command pin, when a fifth command that requests reading of the card ID is received from the electronic device via the command pin.
7. The card-shaped device according to claim 6 , wherein the card-shaped device shifts from a Ready State to an Identification State after the transmitter transmits the card ID to the electronic device.
8. The card-shaped device according to claim 3 , wherein the transmitter transmits a response indicating a busy state if the card-shaped device can not be operated by the power voltage.
9. The card-shaped device according to claim 6 , further comprising a non-volatile programmable memory.
10. The card-shaped device according to claim 6 , wherein the data transfer unit uses at least one of the data pins for informing a state of the electronic device in the second mode.
11. The card-shaped device according to claim 7 , wherein the connector pins further include a plurality of ground signal pins for transferring ground voltage from the electronic device to the card-shaped device.
12. The card-shaped device according to claim 11 , wherein the connector pins further include a clock pin for transferring a clock signal from the electronic device to the card-shaped device.