| 摘要 |
PURPOSE:To quickly return malfunction of a microcomputer to a normal operation, by constituting a device so that a readout data is made to coincide with an instruction for returning the microcomputer to its normal operation when an open address has been accessed. CONSTITUTION:In a microcomputer whose CPU2 reads out an instruction in order from a memory 3 and operates it, when the CPU2 has accessed other address (open address) than an address of a data stored in the memory3 due to malfunction, its readout data is made to coincide with an instruction for returning the microcomputer to its normal operation. That is to say, data buses 6 (D0-D7) for exchanging the information between the CPU2 and the memory 3 connect a resistance whose other terminal is connected to an electric power supply or earth, to the same pattern as a return instruction. As a result, when the open address is accessed due to malfunction, the memory 3 does not output a data but becomes a high resistance state, the return instruction is accessed, and the microcomputer is returned to its normal operation. |
