HD66760 Datasheet, PDF (62/105 Pages) Hitachi Semiconductor – 104 X 80-dot Graphics LCD Controller/Driver for 256 Colors

HD66760
Grayscale Palette
The HD66760 incorporates a grayscale palette to simultaneously display 256 of the 4,096 possible colors.
The R and G grayscales consist of eight four-bit palettes, and the B grayscale consists of four four-bit palettes.
The 16-stage grayscale levels can be selected from the four-bit palette data.
For the display data of R and G, the three-bit data in the GRAM written from the microcomputer is used. For
the display data of B, the two-bit data in the GRAM is used.
In this palette, a curtailed frame grayscale system, which has low charging current in the LCD panel, is used.
Although the system is the same for each color, the curtailed frame timing is adjusted between adjacent dots
to reduce flickering.
Graphics RAM (GRAM)
MSB
LSB
Display data R2 R1 R0 G2 G1 G0 B1 B0
3
Palette R
"000" RK03 RK02 RK01 RK00
"001" RK13 RK12 RK11 RK10
"010" RK23 RK22 RK21 RK20
"011" RK33 RK32 RK31 RK30
"100" RK43 RK42 RK41 RK40
"101" RK53 RK52 RK51 RK50
"110" RK63 RK62 RK61 RK60
"111" RK73 RK72 RK71 RK70
3
Palette G
"000" GK03 GK02 GK01 GK00
"001" GK13 GK12 GK11 GK10
"010" GK23 GK22 GK21 GK20
"011" GK33 GK32 GK31 GK30
"100" GK43 GK42 GK41 GK40
"101" GK53 GK52 GK51 GK50
"110" GK63 GK62 GK61 GK60
"111" GK73 GK72 GK71 GK70
2
Palette B
"00" BK03 BK02 BK01 BK00
"01" BK13 BK12 BK11 BK10
"10" BK23 BK22 BK21 BK20
"11" BK33 BK32 BK31 BK30
4
16-grayscale control
<R>
LCD driver
4
16-grayscale control
<G>
LCD driver
4
16-grayscale control
<B>
LCD driver
RG B
LCD
Figure 42 Grayscale Palette Control