| 摘要 |
PURPOSE:To start video input with the waiting time of one scanning time at its maximum, by performing operations for implementing image indexes irrespectively of a video input request. CONSTITUTION:A video input interface 12 converts inputted video signals into digital image data and, at the same time, implements image indexes. Then the interface 12 transfers the implemented image index to an image memory 13 through a local bus 20. The above-mentioned operations of the video input interface 12 are always performed regardless of the presence/absence of any video input request from a CPU 17. The image memory 13 successively writes the image data in its storing area in accordance with the image indexes transferred from the video input interface 12. Therefore, the waiting time from the moment when a video input request is issued from the CPU 17 to the moment when the input is actually started can be reduced to one scanning time (about 63.5mus) at the maximum.
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