| 摘要 |
PURPOSE:To easily and surely read out varied display pattern data on a pattern display unit from a ROM at every one screen without using the management executed by a microcomputer, and to freely display the pattern, while scrolling it. CONSTITUTION:When a scroll signal is inputted to an arithmetic circuit 22, in the arithmetic circuit 22, a numerical value corresponding to the number of picture element data of a one-line portion of an image horizontal line in a pattern display unit is added. A result of this operation is synchronized with a vertical synchronizing signal and outputted to an address generating circuit 23, and in the address generating circuit 23, as well, an address generated from a result of this operation is set to the head and pattern data for showing the next one screen of the pattern display unit is read out successively from a ROM 18. In such a way, it is outputted as an address of a first line of an address pattern display which shows a second line until now, and a pattern displayed on the screen of the pattern display unit until now is shifted upward by a one-line portion of a horizontal line and displayed. |
