Patent ID: 7240138

Claim:
A data transfer control apparatus comprising: a bus master; a bus interface connected to said bus master via a master bus; a plurality of bus slaves connected to said bus interface via a slave bus; a transfer bus which connects a first bus slave and a plurality of second bus slaves in said plurality of bus slaves, wherein said first bus slave is constituted by an external device control section for controlling an external device connected outside; a selection section which outputs a select signal for selecting one of said plurality of second bus slaves; a transfer instruction section which outputs a transfer instruction signal for instructing whether or not to execute data transfer via said transfer bus; a transfer control section which controls data transfer via said transfer bus between said second bus slave selected by said select signal and said first bus slave in response to a control signal output to said slave bus when an instruction is given by said transfer instruction signal; and a second bus interface connected to a second bus master via a second master bus, wherein said second bus master executes data transfer between one of said plurality of second bus slaves via said second bus interface concurrently with data transfer which is carried out via said transfer bus between said second bus slave selected by said select signal and said external device via said external device control section under control of said transfer control section.