Data transfer control system, electronic instrument, and data transfer control method

A data transfer control system for transferring data through a bus, comprising:

• a command processing section which receives a command packet transferred through a first bus and issues a command included in the command packet to a device connected with a second bus;
• and
• a Direct Memory Access (DMA) transfer instruction section which sets a fixed DMA data length irrespective of type of the issued command and instructs start of DMA transfer to or from the device connected with the second bus,
• wherein the DMA transfer instruction section sets a value greater than a data length which is capable of being designated by a command included in the command packet as the fixed DMA data length.

A data transfer control system for transferring data through a bus, comprising:

• a command processing section which receives a command packet transferred through a first bus and issues a command included in the command packet to a device connected with a second bus;
• and
• a Direct Memory Access (DMA) transfer instruction section which sets a fixed DMA data length irrespective of type of the issued command and instructs start of DMA transfer to or from the device connected with the second bus,
• wherein the first bus is a bus through which data is transferred according to the IEEE1394 standard and the second bus is a bus through which data is transferred according to the AT Attachment (ATA)/ATA Packet Interface (ATAPD standard, and
• wherein the command packet is an ORB packet defined by the Serial Bus Protocol-2 (SBP-2).

A data transfer control method for transferring data through a bus, the method comprising:

• receiving a command packet transferred through a first bus and issuing a command included in the command packet to a device connected with a second bus;
• and
• setting a fixed Direct Memory Access (DMA) data length irrespective of type of the issued command and instructing start of DMA transfer to or from the device connected with the second bus,
• wherein the device connected with the second bus is a device which writes data transferred through the second bus in a storage or reads data to be transferred through the second bus from the storage, and
• wherein the method further comprises setting a value greater than a storage capacity of the storage as the fixed DMA data length.

A data transfer control method for transferring data through a bus, the method comprising:

• receiving a command packet transferred through a first bus and issuing a command included in the command packet to a device connected with a second bus;
• and
• setting a fixed Direct Memory Access (DMA) data length irrespective of type of the issued command and instructing start of DMA transfer to or from the device connected with the second bus,
• wherein the first bus transfers data conforming to the IEEE1394 standard and the second bus transfers data conforming to the AT Attachment (ATA)/ATA Packet Interface (ATAPI) standard, and
• wherein the command packet is an operation request block (ORB) packet defined by the Serial Bus Protocol-2 (SBP-2).

A data transfer control system for transferring data through a bus, comprising:

• a command processing section which receives a command packet transferred through a first bus and issues a command included in the command packet to a device connected with a second bus;
• and
• a Direct Memory Access (DMA) transfer instruction section which sets a fixed DMA data length irrespective of type of the issued command and instructs start of DMA transfer to or from the device connected with the second bus,
• wherein the command processing section omits decode processing of a command for calculating a size of a DMA data length and issues the command to the device connected with the second bus, the command being included in the command packet which is transferred through the first bus,
• wherein the first bus is a bus through which data is transferred according to the IEEE1394 standard and the second bus is a bus through which data is transferred according to the AT Attachment (ATA)/ATA Packet Interface (ATAPI) standard, and
• wherein the command packet is an ORB packet defined by the Serial Bus Protocol-2 (SBP-2).

A data transfer control method for transferring data through a bus, the method comprising:

• receiving a command packet transferred through a first bus and issuing a command included in the command packet to a device connected with a second bus;
• setting a fixed Direct Memory Access (DMA) data length irrespective of type of the issued command and instructing start of DMA transfer to or from the device connected with the second bus;
• and
• omitting decode processing of a command for calculating a sizes of a DMA data length and issuing the command to the device connected with the second bus, the command being included in the command packet which is transferred through the first bus,
• wherein the first bus transfers data conforming to the IEEE1394 standard and the second bus transfers data conforming to the AT Attachment (ATA)/ATA Packet Interface (ATAPI) standard, and
• wherein the command packet is an operation recluest block (ORB) packet defined by the Serial Bus Protocol-2 (SBP-2).