Memory card and host device thereof
A memory card is attached to a host device, and includes a data control circuit which transfers data with respect to the host device in synchronism with a rise edge and a fall edge of a clock signal.
1. A storage device couplable to a host, comprising:
a command line;
a plurality of data lines;
a clock line;
a nonvolatile memory; and
a controller coupled to the command line, the data lines and the clock line, wherein:
the controller is configured to receive a clock signal through the clock line;
the controller is configured to receive first data and output a first response through at least one of the data lines, in accordance with a single edge transfer based on either one of a rise edge and a fall edge of the clock signal, in a first transfer mode of the storage device;
the controller is configured to receive second data and output a second response through at least one of the data lines, in accordance with a double edge transfer based on both the rise edge and the fall edge of the clock signal, in a second transfer mode of the storage device;
the controller is configured to receive a first command and output a third response through the command line, in accordance with the single edge transfer, in the first transfer mode of the storage device;
the controller is configured to receive a second command and output a fourth response through the command line, in accordance with the single edge transfer, in the second transfer mode of the storage device;
the controller is configured to switch a transfer mode of the storage device from the first transfer mode to the second transfer mode in response to the first command; and
a transfer rate of the double edge transfer is higher than a transfer rate of the single edge transfer.
2. The storage device according to claim 1 , wherein:
the controller is configured to receive a third command and output a fifth response through the command line, in accordance with the single edge transfer; and
the controller is configured to receive the third command of the command line while transferring data of the data lines, the third command being used for informing the storage device that the host stops transferring data of the data lines.
3. The storage device according to claim 1 , wherein:
the controller is configured to receive a fourth command and output a sixth response through the command line, in accordance with the single edge transfer; and
the controller is configured to output first status data that includes information indicating that the storage device supports the second transfer mode, through the data lines in response to the fourth command.
4. The storage device according to claim 3 , wherein:
the first status data further includes data fields of a plurality of function groups; and
the second transfer mode is assigned to one of the function groups.
5. The storage device according to claim 3 , wherein:
the first status data further includes information indicating that the storage device supports an IC card function; and
the controller is configured to validate the IC card function of the storage device in response to the first command.
6. The storage device according to claim 3 , wherein the first status data further includes information on a command system.
7. The storage device according to claim 1 , wherein the controller is configured to read data from the nonvolatile memory and output the read data through the data lines.
8. The storage device according to claim 1 , wherein the nonvolatile memory is a semiconductor memory.
9. The storage device according to claim 8 , wherein the semiconductor memory is a NAND flash memory.
10. The storage device according to claim 1 , wherein the controller is configured to output second status data that includes information indicating that the storage device is set into the second transfer mode, through the data lines in response to the first command.
11. The storage device according to claim 4 , wherein the number of the function groups is six.
12. The storage device according to claim 3 , wherein the first status data further includes information on a maximum consumption current required for the second transfer mode.
13. The storage device according to claim 3 , wherein:
the controller is configured to receive data through the data lines, in accordance with the clock signal having a first frequency, in a normal bus mode;
the controller is configured to receive data through the data lines, in accordance with the clock signal having a second frequency, in a high-speed bus mode;
the second frequency is higher than the first frequency; and
the first status data further includes information indicating that the storage device supports the high-speed bus mode.
14. The storage device according to claim 1 , wherein:
the controller is configured to output data in a plurality of data blocks through the data lines; and
a CRC code is added to each of the data blocks.
15. The storage device according to claim 1 , wherein:
the controller is configured to receive data through all data lines in a first bit mode; and
the controller is configured to receive data through only one of the data lines in a second bit mode.