HD66740 Datasheet, PDF (60/95 Pages) Hitachi Semiconductor – 112 x 80-dot Graphics LCD Controller/Driver

HD66740
one line can be used to achieve continuous smooth vertical scroll even in a 9-line or less display. Here,
after the 10th line is displayed, the first line is displayed again. When the 10th line is fully displayed, all
one-line display data must be rewritten immediately after scrolling because there is no non-displayed
area. Additionally, when display areas of a graphics icon such as a pictogram or a menu bar are partially
fixed-displayed, the remaining areas can be displayed. For details, see the Partial Smooth Scroll Display
Function section.
Specifically, this function is controlled by incrementing or decrementing the value in the display-start
line bits (SL2 to SL0) and display-start raster-row bits (SN3 to SN0) by 1. For example, to smoothly
scroll up, first set line bits SN3 to SN0 to 0000, and increment SL2 to SL0 by 1 from 000 to 111 to scroll
seven raster-rows. Then increment line bits SN3 to SN0 to 0001, and again increment SL2 to SL0 by 1
from 000 to 111. If the vertical double-height display is at the top of the line, scrolling is done by each
two raster-row.
When the response speed of the liquid crystal is low or when high-speed scrolling is needed, two- to
four-raster-row scrolling is recommended.
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