| 摘要 |
PURPOSE:To ensure the highly effective driving with a small-size driving circuit, by dividing the internal bus into several portions through the bus selecting circuit and without increasing the chip area. CONSTITUTION:A connection is given (as shown by broken lines) between bus selecting circuits 5-1 and 5-2 by microprocessor unit 2, and the internal bus is divided into three portions 3-1, 3-2 and 3-3 each. When the data is transferred between processor 2 and pad 4-1 connected to bus 3-2, circuit 5-1 is switched to the conduction mode by the command of processor 2 to transfer the data to pad 4-1 via only bus 3-2. And in case the data is transferred between processor 2 and pad 4-2, circuit 5-2 is switched to the conduction mode. In this case, the internal bus including the bus selecting circuit which is switched to the conduction mode is isolated from the internal bus including the bus selecting circuit which is not switched to the conduction mode to carry out the data transfer independently. |
