| 摘要 |
PURPOSE:To recognize the push of a key with simple firmware before the firmware for control of keyboard is loaded and at the same time to reduce the capacity of a firmware memory. CONSTITUTION:It is possible to understand the state (space or mark state) of a data line 7 led from a keyboard 5 with reduced quantity of firmware provided within an ROM2 before the firmware for control of keyboard is loaded. Therefore it is possible to identify the two states of the keyboard 5 by keeping the line 7 in a space or mark state. For instance, it is possible to decide a floppy disk or a large-capacity magnetic disk basing on the key pushing state of the keyboard 5 for the type of the device which is used in an initial loading mode (IPL) of the firmware when a power supply is turned on.
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