| 摘要 |
PURPOSE:To return quickly a peripheral LSI to its original state even in case a part of the peripheral LSI is reset by an electrostatic noise, by generating periodically a control signal to the peripheral LSI from a CPU, and checking the operation of the peripheral LSI. CONSTITUTION:A malfunction preventing method is operated by a command of a CPU1 in accordance with the program in a ROM3. First of all, a prescribed clock is outputted to an A/D converting circuit 11 from a programmable interface (I/F) LSI10. Subsequently, the contents of a display RAM of an I/F LSI20 are read. The contents of a ''0'' address and an 8 address of this RAM are compared, and in case they do not coincide with each, the I/F LSI20 is set to an initial mode, and in case they coincide, a clock signal is ouptutted at evey 100ms to the A/D converting circuit 11 from the LSI10. By repeating the method above mentioned even if the LSIs 10, 20 execute a malfunction by the electrostatic noise, the CPU1 can recognize it immediately, and can set them to a prescribed mode again. |
