HD66421 Datasheet, PDF (26/46 Pages) Hitachi Semiconductor – (RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD)

Preliminary
Rev. 1.1E '99.02.10
HD66421
Vertical Scroll Function
The HD66421 can vertically scroll a display by
varying the top raster to be displayed. which is
specified by the display start raster register.
Figure 22 and 23 show vertical scroll examples. As
shown, when the top raster to be displayed is set to
l, data in Y address H'0 is displayed on the 100th
raster. To display another frame on the 100th
raster, therefore, data in Y address H'0 must be
modified after setting the top raster. When
display duty is less than 100, for example 1/80,
data of address H'50 is displayed after address
H'4F.
Top raster to be
displayed = 0
Y-address
H'00
H'01
H'02
H'03
H'04
H'05
H'06
H'07
H'08
H'09
H'0A
H'60
H'61
H'62
H'63
Top raster to be
displayed = 1
Y-address
H'01
H'02
H'03
H'04
H'05
H'06
H'07
H'08
H'09
H'0A
H'0B
H'61
H'62
H'63
H'00
Top raster to be
displayed = 2
Y-address
H'02
H'03
H'04
H'05
H'06
H'07
H'08
H'09
H'0A
H'0B
H'0C
H'62
H'63
H'00
H'01
Figure 22 Vertical Scroll : 1/100Duty Cycle
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