HD66760 Datasheet, PDF (64/105 Pages) Hitachi Semiconductor – 104 X 80-dot Graphics LCD Controller/Driver for 256 Colors

HD66760
Four-color Display Mode
The HD66760 has the four-color display mode consisting of two-bit-per-pixel data. Since the byte-wise
processing of four-pixel display data is enabled, the processing performance is four times that of the normal
256-color display. When the internal grayscale palette is used, four colors of the possible 4,096 colors can be
displayed at the same time. The two-bit display data in the GRAM written from the microcomputer is
assigned to the lower two bits of R and G; one of these bits, always 0, synthesizes the three-bit data.
Therefore, this display mode uses 000, 001, 010, 011 in grayscale palettes R and G.
MSB
C1 C0
Graphics RAM (GRAM)
LSB
C1 C0 C1 C0 C1 C0
RGB
RGB
"0"
"0"
"0"
"0"
Display data R2 R1 R0 G2 G1 G0 B1 B0
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" RK32 RK32 RK31 RK30
3
Palette G
"000" GK03 GK02 GK01 GK00
"001" GK13 GK12 GK11 GK10
"010" GK23 GK22 GK21 GK20
"011" GK33 GK32 GK31 GK30
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 43 Four-color Display Control