| 摘要 |
<p>PURPOSE:To apparently execute horizontal scroll by displaying an image memory which is shifted in a vertical direction by as much as one screen until next horizontal preset load is executed in the case that a horizontal address is over a maximum value. CONSTITUTION:When image data is inputted in the image memory 4, the horizontal address is specified by a horizontal address counter 8 and a basic address is generated by a vertical address at a vertical address counter 2. Next, when an arithmetic enable signal is outputted by a detection means 11 constituted of a comparator 9 and an F/F 10, the basic address and the data of a vertical picture element number register 6 are added by an addition means 3 and outputted to the memory 4 as the vertical address as it is when there is no signal. When a prescribed value and the output of a horizontal A/C 8 coincide each other, a detection signal is outputted by the comparator 9 and the F/F 10 is set. Besides, the arithmetic enable signal is outputted and the output thereof is stopped simultaneously with the horizontal preset load. Thus, an image which is shifted in the vertical direction by as much as one screen is displayed and the horizontal scroll is aparently executed.</p> |
