Combined wireless and wired access to memory unit
According to one embodiment, a communication device includes a first interface, a wireless communication unit, and a memory unit. The memory unit includes a first region used for first access from the first interface and a second region used for second access from the wireless communication unit. Writing to the second region by the first access and writing to the first region by the second access are inhibited.
1. A communication device comprising:
a first interface;
a wireless communication unit;
a memory unit including a first region used for first access from the first interface and a second region used for second access from the wireless communication unit; and
a controller that arbitrates between the first and second accesses to perform the first access to write data to the first region and perform the second access to write data to the second region,
wherein writing to the second region by the first access and writing to the first region by the second access are inhibited.
2. The device according to claim 1 , wherein the first and second regions respectively include tables which manage information in the first and second regions using a file system.
3. The device according to claim 1 , wherein the memory unit further includes a third region which holds information indicating that the first and second regions are contained in the memory unit.
4. The device according to claim 1 , wherein the controller converts at least one of addresses when the first and second accesses are simultaneously made to the same address.
5. The device according to claim 1 , wherein the first and second accesses are made using an SD command encapsulating a protocol which performs file control.
6. The device according to claim 5 , wherein the SD command is a CMD 56 in an SD interface standard, and the protocol is at least one of Server Message Block (SMB), File Transfer Protocol (FTP) and Web-based Distributed Authoring and Versioning (WebDAV).
7. The device according to claim 5 , wherein the first interface is an SD interface and the file system controller extracts the protocol from the received first and second accesses and issues an instruction to the memory unit according to the protocol.
8. The device according to claim 1 , wherein information on the first and second regions is managed by the same table according to the file system.
9. The device according to claim 2 , wherein the file system is a file allocation table (FAT) system.
10. A method for controlling a communication device, comprising:
reading first information indicating that a memory unit includes first and second partitions from a first region of the memory unit;
causing a first host to read a first table which manages the first partition according to a file system from the first partition based on the first information; and
causing a second host with a wireless communication function to read a second table which manages the second partition according to a file system from the second partition based on the first information.
11. The method according to claim 10 , wherein the first host is perimitted to write data in the first partition and is inhibited from writing data in the second partition, and the second host is permitted to write data in the second partition and is inhibited from writing data in the first partition.
12. A method for controlling a communication device, comprising:
receiving write access to a first address region in a memory unit from a first host;
receiving write access to the first address region from a second host with a wireless communication function; and
changing a write destination from the first address region to a second address region different from the first address region for the write access from at least one of the first and second hosts.
13. The method according to claim 12 , wherein information on the first and second address regions are managed by the same table according to a file system.
14. The method according to claim 12 , wherein the write accesses from the first and second hosts are made using an SD command encapsulating a protocol which performs file control.
15. The method according to claim 14 , wherein the SD command is a CMD 56 in an SD interface standard, and the protocol is at least one of Server Message Block (SMB), File Transfer Protocol (FTP) and Web-based Distributed Authoring and Versioning (WebDAV).
16. The method according to claim 14 , wherein the first interface is an SD interface and the file system controller extracts the protocol from the received first and second accesses and issues an instruction to the memory unit according to the protocol.
17. The method according to claim 10 , wherein the file system is a FAT system.
18. The method according to claim 13 , wherein the file system is a FAT system.