| 摘要 |
PROBLEM TO BE SOLVED: To compose and display an image in real time even when portable electronic equipment uses an MPU having low processing capability. SOLUTION: This display composing circuit is equipped with frame buffers 32 to 34 which store image data DTAW and DTRW and composition logic data DTCW and a composite circuit 46. Data buses and address buses of the frame buffers 32 and 34 can be controlled by the MPU on a time-division basis independently of those of the frame buffer 33. Respective frames of the image data DTRW are stored in the frame buffer 33 in synchronism with a vertical synchronizing signal and respective frames of the image data DTAW and composition logic data DTCW are stored in the frame buffers 32 and 34 by the MPU independently in storage periods of corresponding frames of the image data DTRW. The composite circuit 46 puts the image data DTAR and DTBR together, pixel by pixel, in a specified period of a vertical blanking period according to the composition logic data DTCR. COPYRIGHT: (C)2003,JPO
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