Data communication on a serial bus using an initial protocol which being executed in a transaction layer

A data communication method for performing data communication on a serial bus, said method comprising the steps of:

• returning capability information to a host device in response to a request using an initial protocol, which is executed in a transaction layer of an OSI model, from the host device;
• setting a communication protocol to be used in data communication, in accordance with an instruction from the host device based on the capability information;
• and
• performing data communication with the host device based on the set communication protocol.

A data communication apparatus for performing data communication on a serial bus, said apparatus comprising:

• communication means corresponding to an initial protocol, which is executed in a transaction layer of an OSI model, and a plurality of communication protocols for data communication;
• storage means in which capability information including information indicative of the plurality of communication protocols is stored;
• and
• setting means for setting a communication protocol of said communication means, wherein
• said communication means sends the capability information stored in said storage means based on a request by using the initial protocol from a host device, and
• said setting means sets the communication protocol of said communication means in accordance with an instruction by using the initial protocol from the host device.

A data communication system for performing data communication on a serial bus, said system comprising:

• at least one host device;
• and
• at least one target device, wherein
• data communication is performed between said at least one host device and said at least one target device based on a set communication protocol,
• said at least one host device obtains capability information of a usable communication protocol of said at least one target device by communication using an initial protocol, which is executed in a transaction layer of an OSI model,
• said at least one target device sets a communication protocol that can be used in data communication based on the obtained capability information, and
• said at least one host device performs the data communication with said at least one target device based on the set communication protocol.

A computer program product of a computer-readable medium with computer program codes for executing data communication on a serial bus, said product comprising:

• acquisition process procedure codes for acquiring capability information of a target device by communication using an initial protocol, which is executed in a transaction layer of an OSI model;
• setting process procedure codes for having the target device set a communication protocol that can be used in data communication, based on the acquired capability information;
• and
• communication process procedure codes for performing the data communication with the target device based on the set communication protocol.

A computer program product of a computer-readable medium with computer program codes for executing data communication on a serial bus, said product comprising:

• response process procedure codes for returning capability information to a host device in response to a request using an initial protocol, which is executed in a transaction layer of an OSI model, from the host device;
• setting process procedure codes for setting a communication protocol to be used in data communication, in accordance with an instruction from the host device, based on the capability information;
• and
• communication process procedure codes for performing data communication with the host device based on the set communication protocol.