| 摘要 |
PURPOSE:To maintain the desired number of functions, and to decrease the number of keys by giving plural functions to a key which is operated at the time of off-line to a computer. CONSTITUTION:When a manual operating key KEY 6 is depressed after a printer has been set to off-line from a host computer, its signal is inputted to an MPU 2 and simultaneously inputted to an interruption request pulse generator IRQ 7. In a timing chart which follows the key operation, first of all, as soon as the first key is inputted, an interruption request pulse is generated from the IRQ 7, and after a prescribed time t0 has elapsed from that time, four pulses are generated at a prescribed time interval (t) from a timer. In this regard, until the generation of four continuous pulses is ended, even if the key of the second time and thereafter is inputted, the interruption request pulse is not generated.
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