| 摘要 |
PURPOSE:To eliminate the change of an interface part when a logic circuit except for a module is built-in by allowing first and second buses to be mutually connectable and disconnectable through a bus switching means and allowing them to be connectable with an external bus by the bus switching means. CONSTITUTION:A custom logic circuit CLC is connected to a bus switching circuit BCC by a peripheral bus BUSI of the same specification as the external bus. Then, an internal standard bus SBP is connected through an external interface module OIM to the bus switching circuit BCC by a bus BUS2 of the same specification as the external bus. This bus switching circuit BCC changes- over a connecting condition between the bus BUS1 of the external specification and the bus BUS2 or between the BUSes 1 and 2 and the external bus according to mode selecting signals MS1 and MS2 to be supplied from an external part. Thus, when the logic circuit except for the module is built-in to the inside of the chip of the microcomputer to correspond to ASIC, the change of the interface part is eliminated and conventional testing property can be used as it is. |
