| 摘要 |
PURPOSE:To continue processing operation without running-out with a microcomputer even when an undisirable condition is generated by connecting a signal supplying means, which supplies a specified signal, to a bus which connects the microcomputer and a peripheral device. CONSTITUTION:A processing circuit 4 executes the processing of a main program, which is stored in a ROM 5, and continues the processing operation with moving to a sub-program, which is stored in a ROM 6, according to a jump instruction in the process of the processing. At such a time, when a connecting condition between buses b0-b7 and buses B0-B7 is canceled or the power source of a peripheral device 2 is interrupted, a buffer 3 is interrupted and the buses B0-B7 go to a high impedance condition. Then, the buses B0-B7 go to a high level or a low level and accordingly, a return instruction in read to the processing circuit 4. Thus, the processing circuit 4 can return to the main program, which is stored in the ROM 5, and continue the processing operation without being run-out. |
