| 摘要 |
PROBLEM TO BE SOLVED: To efficiently access a nonvolatile memory and to reduce the communication data amount between CPUs, in an electronic control unit for sharing one nonvolatile memory by the plural CPUs. SOLUTION: This ECU 10 is provided with a first CPU 11, a second CPU 12 and an EEPROM 13 and the respective CPUs 11 and 12 are connected through general purpose ports 14 and 15. The respective CPUs 11 and 12 and the EEPROM 13 respectively share a chip select line 16, a clock line 17 and an SCI line 18 and are connected to each other through the respective lines. For instance, the fact that it is not during access by the second CPU 12 is confirmed before the first CPU 11 accesses (read or write) the EEPROM 13 and that effect of accessing the EEPROM 13 is notified to the second CPU 12 when it is not during the access. Also, after the access to the EEPROM 13 is ended, the notification of that effect that it is during the access is cancelled.
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