| 摘要 |
<p>PURPOSE:To reduce the number of I/O signal lines by forming a circuit for switching and connecting I/O signal lines from respective I/O devices in a main device to a processor unit on the external device side. CONSTITUTION:When the external device 200 is not connected to the main device 100 and a switch SW1 is opened, the 2nd inputs of an AND1 and an AND2 are ''1'' respectively, the 2nd inputs of an AND3 and an AND4 are ''0'' and the main device 100 integrates output pulses from a sensor 14 and sends the integrated result to a display circuit 16. When the device 200 is connected to the main device 100 and the SW1 is closed, the 2nd inputs of the AND1 and AND2 are turned to ''0'' and an input from the sensor 14 to the processor unit 10 and an output from the unit 10 to the circuit 16 are cut off, the I/O terminals of the units 10, 20 are connected with each other and the unit 20 writes/reads out data in/from an EEPROM13 through the unit 10.</p> |
