| 摘要 |
PURPOSE:To shorten a time from start of instruction of starting transmission until a data transmission is actually started by performing a DMA transfer to a buffer memory and a previous processing of the transmission in parallel. CONSTITUTION:When an address of a data length of a transmitting data stored in a memory are designated by a communication control device according to an input and output command, an input and output command decoding circuit 1 decodes them and instructs DMA transfer circuit 3 to be activated to transfer through a signal line 2. At the same time, by an input and output command, a start of the transmission is instructed, so that the input and output command circuit 1 decodes it and instructs a transmission pretreatment circuit 5 to activate through a signal line 5. The transmission pre-treatment circuit 5 waits for an information of a completion of the DMA transfer of the DMA transfer circuit 3fed after the DMA transfer through a signal line 15 and instructs a transmitting circuit 7 to activate to transmit through a signal line 6. Thus, the transmitting circuit 7 starts to transmit a data to a communication line. |
