System for reverse data transmission flow control wherein command is transferred by asynchronous transfer mode while data is transferred by isochronous transfer mode

A data transmission apparatus connected to a serial bus, which is capable of transfer by an isochronous transfer mode and an asynchronous transfer mode, said apparatus comprising:

• a generator, arranged to generate a command to reverse subsequent data transfer by a device connected to the serial bus;
• and
• a transmitter, arranged to reliably transmit the generated command to the device by using the asynchronous transfer mode while data is currently being transferred by the isochronous transfer mode.

A data transmission apparatus connected to a serial bus, which is capable of transfer by an isochronous transfer mode and an asynchronous transfer mode, said apparatus comprising:

• a receiver, arranged to receive a command, which is reliably transferred by the asynchronous transfer mode while data is transferred by the isochronous transfer mode, from a device connected to the serial bus;
• and
• a transfer unit, arranged to reverse a data transfer based on the command received by said receiver.

A data transmission system for transferring data through a serial bus, which is capable of transfer by an isochronous transfer mode and an asynchronous transfer mode, said system comprising:

• a command issuer, arranged to issue a command to a first device connected to the serial bus, wherein the command is reliably transferred by the asynchronous transfer mode while data is transferred by the isochronous transfer mode;
• and
• a controller, arranged to reverse a data transfer by a second device connected to the serial bus, based on the command issued by said command issuer.

A data transmission method for a data transmission system that transfers data between devices connected by a serial bus, which is capable of transfer by an isochronous transfer mode and an asynchronous transfer mode, the data transfer, started by first and second devices, being performed based on device information of the first and second devices provided in advance,

• wherein, in a case where the second device has not a flow control function, a direction of the data transfer is reversed by a command issued by the first device and reliably transferred by the asynchronous transfer mode while the data is transferred by the isochronous transfer mode, and
• wherein the data is transferred from the second device to the first device after the direction is reversed.

A data transmission apparatus connected to a serial bus, which is capable of transfer by an isochronous transfer mode and an asynchronous transfer mode, said apparatus comprising:

• a transmitter, arranged to reliably transmit a command, for reversing a direction of data transfer by using the asynchronous transfer mode while data is transferred by the isochronous transfer mode, to a device connected to the serial bus;
• and
• a receiver, arranged to receive the data after the command has been transmitted.

A computer program product comprising a computer-readable medium storing computer program codes for executing data transmission of devices connected to a serial bus, which is capable of transfer by an isochronous transfer mode and an asynchronous transfer mode, said product comprising:

• issuance process procedure code for issuing a command to perform a flow control, from a first device to a second device, wherein the command is reliably transferred by the asynchronous transfer mode while data is transferred by the isochronous transfer mode;
• and
• reception process procedure code for receiving data sent from the second device by the first device, in accordance with the command.

A computer program product comprising a computer-readable medium storing computer program codes for executing data transmission of devices connected to a serial bus, which is capable of transfer by an isochronous transfer mode and an asynchronous transfer mode, said product comprising:

• reception process procedure code for receiving a command issued from a first device and reliably transferred by the asynchronous transfer mode while dada is transferred by the isochronous transfer mode to perform a flow control, by a second device;
• and
• reverse process procedure code for reversing the data transfer by the second device, in accordance with the command.