| 摘要 |
PURPOSE:To respond quickly to the request of a device of high priority order by presetting and storing priority order set to outputting devices of different operation speed. CONSTITUTION:When a request is made from a printing device PR1, a memory MM1 is read out through a connection line b1, and its priority order, for instance, ''5'' is compared with zero by a zero comparator CMP. As it is actually not zero, the priority order is made to ''4'' by a -1 arithmetic unit DF, and ''4'' is stored in a position corresponding to PR1 in an MM2. When a new pattern data request arrives from a cathode-ray tube display unit DSP1, in the same manner as above-mentioned, the value of 2-1=1 is written in a position corresponding to DSP1 of the MM2. The CMP operates zero comparison and DF on the value read out from the MM2 and stores zero for OSP1. Then, zero comparison is made to obtain an X signal, and a request pattern data transferring section RQP transfers it to the DSP1. As for PR1, transfer to PR1 is made only when the result of comparison becomes zero.
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