| 摘要 |
PROBLEM TO BE SOLVED: To perform proper data writing processing in a memory, while maintaining simultaneity at execution of data writing which requires simultaneity. SOLUTION: An ECU 10 is roughly provided with a microcomputer 20, a power source IC 30, and a filter circuit 40. The microcomputer 20 is provided with a CPU 21, ROM 22, RAM 23, and SRAM 24. A voltage decrease detecting circuit 32 in the power source IC 30 fetches a fixed voltage Vcc generated by a fixed voltage circuit 31 and monitors the decrease of the fixed voltage Vcc, and outputs a voltage detection signal WI. The filter circuit 40 fetches a WI signal, and generates a WI(A) signal and a WI(B) signal, and outputs the WI(B) signal to the SRAM 24 as a signal for limiting data writing. When both the WI(A) and the WI(B) signals indicate the permission of writing, the CPU 21 permits the start of writing in the SRAM 24, and executes the writing of data for each data requiring simultaneity. |
