| 摘要 |
PROBLEM TO BE SOLVED: To realize a simple data transmitting and receiving procedure by DMA-transferring data to a memory on a receiving-side from a memory on a transmitting side by a word unit where one word is positive integral multiple of 8 bits and transferring data of the number of bytes which is not positive integral multiple of a word length to the memory on the receiving side from the memory on the transmitting side. SOLUTION: The number of transferring bytes is set to a counter 4 from a CPU/DMAC 5 and when the number of the transferring bytes is larger than zero, the number of the transferring bytes is compared with the number of the maximum effective bytes of 1 packet. When, the number of the effective bytes is larger than 0, a data request signal DREQ is outputted to the CPU/ DMAC 5, which reads data from transmission system memories 6a and 6b to output a response signal DACK to write in a transmission buffer memory 3. When the number of the effective bytes is smaller than 0, 1 packet is sent to a network and processing is repeated from comparing processing of the number of transferring bytes again. In the case except this, processing is repeated from the deciding processing of the number of the effective bytes.
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