Patent ID: 7043592

Claim:
An external bus controller that controls transfer of data between an internal bus and an external bus, comprising: a first exchange, that converts a width of first data input thereto from the internal bus so as to coincide with a data width of an external device connected to the external bus, and outputs the converted first data, and that converts a width of second data from the external bus so as to coincide with a data width of the internal bus; a recognition circuit, that recognizes for each of the external devices, which signal lines of the external bus are connected to input/output terminals of the external devices; a selector, that selects the signal lines to be used by the external bus according to a recognition result of said recognition circuit and a device specification signal; and a second exchange, that outputs the converted first data input from said first exchange to the signal lines of the external bus selected by said selector, and that outputs the second data input from the signal lines of the external bus to said first exchange.