| 摘要 |
<p>PURPOSE:To control an EEPROM without requiring the addition or the like of an I/O address by controlling the EEPROM and commanding a sub-CPU capable of executing command processing for data erasing/reading/writing from a main CPU. CONSTITUTION:The sub-CPU 2 built in a keyboard 5 to execute the key scanning control of the keyboard 5 is provided with a function for erasing/reading/ writing data from/in the read-only memory(EEPROM) 1 and the function is an interface to be attained by applying a command from the main CPU 3. The main CPU 3 controlled by a program stored in the memory 4 outputs commands for erasing/reading/writing data from/in the EEPROM 1 to the sub- CPU (keyboard controller) 2 built in the keyboard 5 to indirectly control the EEPROM 1. Consequently, it is unnecessary to especially increase the number of I/O ports and logic can be reduced.</p> |
