| 摘要 |
PROBLEM TO BE SOLVED: To prevent improper control accompanying generation of non-numerals in an electronic controller with floating point calculating function. SOLUTION: Engine control ECU 10 is provided with a microcomputer 11 and the microcomputer 11 is provided with a CPU 12, a RAM 13, a ROM 14, an FPU(floating point calculation processor) 15 and I/O 16. The FPU 15 executes arithmetic operation in a floating point system and the CPU 12 executes arithmetic operation except the one in the floating point system. The CPU 12 decides presence/absence of the non-numerals for data in the RAM 13 to store floating point type data and when the non-numerals are decided to exist, initializes RAM data. In the initialization of the RAM data, a default value without hindrance to control is written as the RAM data. In this case, the non-numerals are cleared away by initializing the RAM data in which the non-numerals exist. |
