| 摘要 |
PURPOSE:To make it possible to easily observe the signal of an input/output port. CONSTITUTION:A CPU 1, a work memory (RAM) 2 and a peripheral device 3, and an input/output circuit 4 are integrated. This CPU 1 and the work memory (RAM) 2 and the peripheral device 3, and the input/output circuit 4 are connected each other by a data bus 5 and an address bus 6. Plural input/output ports 7 are introduced from the input/output circuit 4. In addition to it, a control bus 8 performing the control of the data bus 5, the address bus 6 and the CPU 1 is connected with an external interface 9. Further, changeover switches 10 are provided on plural input/output ports 7, respectively, these moving contacts are connected with a selector 11 and a data bus 12 from this selector 11 is connected with the external interface 9. The control terminal of the changeover switch 10 is connected with the selector 11 and a control bus 13 from this selector 11 is connected with the external interface 9. |
