| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of times how many a USB host controller is turned to be a bus master. SOLUTION: A USB host controller 100 is provided with a storage part 108 for storing an ED and a TD, and when an OHCI master interface 107 acquires an ED or a TD from an external storage device 112, an ED/TD identification part 106 compares the ED or the TD of the storage part 108, and when they are matched, the ED or the TD is acquired from the storage part 108, and when they are not matched, the ED or the TD is acquired from the external storage device 112, and USB-transferred. After the USB-transfer, when a reply from USB equipment is NAK based on USB specifications, the ED and TD acquired from the external storage device 112 are stored in the storage part 108. COPYRIGHT: (C)2005,JPO&NCIPI
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