Data transmission apparatus, system and method, and image processing apparatus

A data transmission apparatus connected to a serial bus, comprising:

• command transmission means for transmitting a command to a target device;
• reception means for receiving a response returned from the target device;
• transfer means for transferring data of a predetermined unit, which comprises a predetermined number of blocks, by isochronous transfer to the target device if it is determined, based on the response, that a transfer error has not occurred;
• and
• retransfer means for retransferring, if an occurrence of a transfer error is determined, a part of the data of the predetermined unit transferred when the transfer error occurred, based on buffer information included in the response, indicating a number of blocks received by a re-receiving buffer of the target device, regarding the data of the predetermined unit,
• wherein, in the serial bus, a first transfer method to transfer the data of the predetermined unit by the isochronous transfer, by a predetermined communication cycle, and a second transfer method to transfer the data of the predetermined unit by asynchronous transfer, in accordance with necessity, are available.

A data transmission apparatus connected to a serial bus, comprising:

• reception means for receiving a command and data sent from a host device, said reception means receiving data of a predetermined unit, which comprises a predetermined number of blocks;
• transmission means for sending a response to the host device;
• and
• detection means for inserting information indicative of occurrence of a transfer error into the response if an occurrence of a transfer error is detected in a data transfer, so that the host device retransmits a part of the data of the predetermined unit transferred when the transfer error occurred, based on buffer information included in the response indicating a number of blocks receivable by a re-receiving buffer of said reception means, regarding the data of the predetermined unit,
• wherein, in the serial bus, a first transfer method to transfer the data of the predetermined unit by isochronous transfer, by a predetermined communication cycle, and a second transfer method to transfer the data of the predetermined unit by asynchronous transfer, in accordance with necessity, are available.

A data transmission system for transferring data through a serial bus, comprising:

• communication means for sending a command from a host device to a target device, and sending a response from the target device to the host device;
• transfer means for transferring data of a predetermined unit, which comprises a predetermined number of blocks, by isochronous transfer from the host device to the target device if it is determined, based on the response, that a transfer error has not occurred, and
• retransferring, if an occurrence of a transfer error is determined, a part of the data of a predetermined unit transferred when the transfer error occurred, from the host device to the target device, based on buffer information included in the response, indicating a number of blocks receivable by a re-receiving buffer of the target device, regarding the data of the predetermined unit,
• wherein, in the serial bus, a first transfer method to transfer the data of the predetermined unit by the isochronous transfer, by a predetermined communication cycle, and a second transfer method to transfer the data of the predetermined unit by asynchronous transfer, in accordance with necessity, are available.

A data transmission method of host and target devices connected by a serial bus, said method comprising the steps of:

• sending a command from the host device to the target device;
• returning a response to the command from the target device to the host device;
• transferring data of a predetermined unit, which comprises a predetermined number of blocks, from the host device to the target device, based on the response;
• and
• retransferring, if a bus reset has occurred, a part of the data of the predetermined unit transferred when the bus reset occurred, based on buffer information included in the response, indicating a number of blocks receivable by a re-receiving buffer of the target device, regarding the data of the predetermined unit,
• wherein, in the serial bus, a first transfer method to transfer the data of the predetermined unit by isochronous transfer, by a predetermined communication cycle, and a second transfer method to transfer the data of the predetermined unit by asynchronous transfer, in accordance with necessity, are available.

A data transmission apparatus connected to a serial bus, comprising:

• command transmission means for transmitting a command to a target device;
• reception means for receiving a response to the command returned from the target device;
• transfer means for transferring data of a predetermined unit, which comprises a predetermined number of blocks, to the target device, based on the response;
• and
• retransfer means for, if a bus reset has occurred, retransferring a part of the data of the predetermined unit transferred when the bus reset occurred, based on buffer information included in the response, indicating a number of blocks receivable by a re-receiving buffer of the target device, regarding the data of the predetermined unit,
• wherein, in the serial bus, a first transfer method to transfer the data of the predetermined unit by isochronous transfer, by a predetermined communication cycle, and a second transfer method to transfer the data of the predetermined unit by asynchronous transfer, in accordance with necessity, are available.

A data transmission apparatus connected to a serial bus, comprising:

• command reception means for receiving a command sent from a host device;
• transmission means for transmitting a response to the command, to the host device;
• transfer means for transferring data of a predetermined unit, which comprises a predetermined number of blocks, to the host device, based on the response;
• and
• re-reception means for, if a bus reset has occurred, re-receiving a part of the data of the predetermined unit transferred when the bus reset occurred, based on buffer information included in the response, indicating a number of blocks receivable by a buffer of said re-reception means, regarding the data of the predetermined unit,
• wherein, if a bus reset has occurred, said re-reception means re-receives data received immediately before occurrence of the bus reset or data comprising the predetermined number of blocks received when the bus reset occurred.

A data transmission apparatus connected to a serial bus, comprising:

• command reception means for receiving a command sent from a host device;
• transmission means for transmitting a response to the command, to the host device;
• transfer means for transferring data of a predetermined unit, which comprises a predetermined number of blocks, to the host device, based on the response;
• and
• re-reception means for, if a bus reset has occurred, re-receiving a part of the data of the predetermined unit transferred when the bus reset occurred, based on the buffer information included in the response, indicating a number of blocks receivable by a buffer of said re-reception means, regarding the data of the predetermined unit,
• wherein, in the serial bus, a first transfer method to transfer the data of the predetermined unit by isochronous transfer, by a predetermined communication cycle, and a second transfer method to transfer the data of the predetermined unit by asynchronous transfer, in accordance with necessity, are available.

A data transmission system for transferring data through a serial bus, comprising:

• communication means for transmitting a command from a host device to a target device, and returning a response to the command from the target device to the host device;
• transfer means for transferring data of a predetermined unit, which comprises a predetermined number of blocks, between the host and target devices, based on the response;
• and
• retransfer means for, if a bus reset has occurred, retransferring a part of the data of the predetermined unit transferred when the bus reset occurred, based on buffer information included in the response, indicating a number of blocks receivable by a re-receiving buffer of the target device, regarding the data of the predetermined unit,
• wherein, in the serial bus, a first transfer method to transfer the data of the predetermined unit by isochronous transfer, by a predetermined communication cycle, and a second transfer method to transfer the data of the predetermined unit by asynchronous transfer, in accordance with necessity, are available.

A computer program product comprising a computer readable medium storing computer program codes for executing a method of data transmission between host and target devices connected by a serial bus, said product comprising process procedure codes for:

• sending a command from the host device to the target device, and sending a response from the target device to the host device;
• transferring data of a predetermined unit, which comprises a predetermined number of blocks, by isochronous transfer from the host device to the target device if it is determined, based on the response, that a transfer error has not occurred;
• and
• retransferring, if an occurrence of a transfer error is determined, a part of the data of the predetermined unit transferred when the transfer error occurred, from the host device to the target device, based on buffer information included in the response, indicating a number of blocks receivable by the re-receiving buffer of the target device, regarding the data of the predetermined unit,
• wherein, in the serial bus, a first transfer method to transfer the data of the predetermined unit by the isochronous transfer, by a predetermined communication cycle, and a second transfer method to transfer the data of the predetermined unit by asynchronous transfer, in accordance with necessity, are available.

A computer program product comprising a computer readable medium storing computer program codes for executing a method of data transmission between host and target devices connected by a serial bus, said product comprising process procedure codes for:

• transmitting a command from the host device to the target device, and returning a response to the command from the target device to the host device;
• transferring data of a predetermined unit, which comprises a predetermined number of blocks, between the host and target devices, based on the response;
• and
• retransferring, if a bus reset has occurred, a part of the data of the predetermined unit transferred when the bus reset occurred, based on buffer information included in the response, indicating a number of blocks receivable by a re-receiving buffer of the target device, regarding the data of the predetermined unit,
• wherein, in the serial bus, a first transfer method to transfer the data of the predetermined unit by isochronous transfer, by a predetermined communication cycle, and a second transfer method to transfer the data of the predetermined unit by asynchronous transfer, in accordance with necessity, are available.