| 摘要 |
PURPOSE:To transfer a data at high speed by returning a system bus occupied by a DMA controller to a central processing unit at the time of detecting a line terminating code so as to reduce the number of times of bus arbitration of the system bus. CONSTITUTION:When a compression decoding circuit 12 starts its operation by the command of a central processing unit 16, a prescribed transfer request signal is sent and given, and a raw picture data is transferred between a read/ write circuit 11 and the circuit 12 and a compressed picture data is transferred between a memory section 14 and the circuit 12 respectively. In detecting the line terminating code EOL outputted at the section of a compressed picture data at every line during direct transfer by a line terminating code detection section 17, after the response of a prescribed signal, the central processing unit 16 is returned and connected to a system bus 13. Thus, if the transfer of a raw picture data is intermitted and the data transfer request is intermitted, since the central processing unit 16 occupies the system bus 13, the program is executed. |
