| 摘要 |
PURPOSE:To attain the effective and economical use of a digital data circuit network by finishing the transfer of the picture data carried out by a direct memory access through a microprocessor with the end signal of the picture data supplied via a signal line different from a picture data bus. CONSTITUTION:When the picture data of the final packet is transferred to the buffer of a memory 106 from a picture data bus 101, a reader 1 detects the page end and the page end signal is produced on a control data bus 102. this end signal is written to a data buffer 104. An interruption is applied to a mcroprocessor 107 by an interruption signal 115 given from a data buffer 104 and the contents of the buffer 104 are read. The microprocessor 107 finishes the transfer of the picture data in terms of software after the page end signal is detected. then the processor 107 understands immediately the data quantity of he final packet transferred by reading the byte count value of a DMAC 103. Therefore the coded picture data can be transferred at high speed by means of the DMA transfer without using the control of software performed by a microprocessor.
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