HD66750 Datasheet, PDF (64/96 Pages) Hitachi Semiconductor – 128 x 128-dot Graphics LCD Controller/Driver with Four-grayscale Functions

HD66750/1
Four-grayscale Display Function
The HD66750/1 supports the four-grayscale monochrome display function. The four-grayscale
monochrome display is used for the display data of the two-bit pixel set sent to the CGRAM. There are four
grayscale levels: always unlit, weak middle level, strong middle level, and always lit. In the weak
middle-level grayscale display, the GS bit can select the 1/3 or 1/2 level.
The frame rate control (FRC) method is used for grayscale control.
Table 23 Relationships between the CGRAM Data and the Display Contents
Upper Bit
Lower Bit
Liquid Crystal Display
0
0
Non-selected (unlit)
0
1
GS = 0: 1/3-level grayscale (one frame lit during a three-frame period)
GS = 1: 1/2-level grayscale (one frame lit during a two-frame period)
1
0
2/3-level grayscale (two frames lit during a three-frame period)
1
1
Selected (lit)
Note: Upper bits: DB15, DB13, DB11, DB9, DB7, DB5, DB3, and DB1
Lower bits: DB14, DB12, DB10, DB8, DB6, DB4, DB2, and DB0
L SB
DB0
MSB LSB
DB15 DB0
MSB
DB15
0 01 0 0 1 1 1 1 1 0 1 1 0 0 0 0 0 0 0 1 0 1 0 0 1 0 1 1 1 1 1
CGRAM
Grayscal e
c ontrol circuit
LCD panel display
Figure 42 Four-grayscale Monochrome Display
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