Patent ID: 7085855

Claim:
A data transfer control device for transferring data among a plurality of nodes that are connected to a bus, the data transfer control device comprising: a control circuit which starts transfer processing when a processing unit issues a start command for data transfer, and resumes transfer processing when the processing unit issues a resume command for data transfer; a transfer execution circuit which executes processing for dividing transfer data into a series of packets and transferring the divided series of packets continuously, when the processing unit issues the start command for data transfer; a cancellation circuit which cancels an execution of one of the start command and the resume command, when the processing unit issues one of the start command and the resume command, respectively, during a period of a reset that clears node topology information; and a circuit which informs the processing unit that command execution has been canceled by the reset, wherein the cancellation circuit receives a reset period signal which becomes active during the period of the reset and makes a command signal corresponding to one of the issued start command and the issued resume command not to be transferred to the control circuit when the reset period signal becomes active, and wherein the control circuit performs one of transfer starting and transfer resuming when the processing unit issues one of the start command and the resume command during a period other than the period of the reset.