3 mapping the display data, 4 generating grayscale tones, Mapping the display data -6 – Motorola MC68VZ328 User Manual
Page 134: Generating grayscale tones -6, Figure 8-4, Mapping memory data on the screen -6
8-6
MC68VZ328 User’s Manual
LCD Controller Operation
8.2.2.3
Mapping the Display Data
The LCD controller supports 1 or 2 bits per pixel graphics mode. In the 1-bit mode, each bit in the display
memory corresponds to a pixel in the LCD panel. The corresponding pixel on the screen is either fully on
or fully off. In 2-bit mode, each pixel is represented by two bits of display memory. To map the data to the
LCD panel, program the appropriate bit in the corresponding address of the display memory. Figure 8-4
illustrates how the system memory data in both modes are mapped.
8.2.2.4
Generating Grayscale Tones
In 2-bits-per-pixel mode, circuitry inside the LCD controller generates intermediate grayscale tones on the
LCD panel by adjusting the density
of ones and zeroes that appear over the frames. The LCD controller
can generate 16 simultaneous grayscale levels out of a palette consisting of 16 shades. The two levels
between black and white can be selected using the information in Table 8-1 on page 8-7. Use the LGPMR
registers to program the grayscale level.
Figure 8-4. Mapping Memory Data on the Screen
LCD Drivers
LCD Dr
iv
er
s
(1,0)
(2,0)
(X-1,0)
(0,0)
(0,Y-1)
(1,Y-1)
(2,Y-1)
(X-1,Y-1)
7
6
5
4
3
2
1
0
(0,0)
(1,0)
(2,0)
(3,0)
(X-4,Y-1)
(X-3,Y-1)
(X-2,Y-1)
(X-1,Y-1)
2-bits-per-pixel mode
Display
Mapping
7
6
5
4
3
2
1
0
(0,0)
(1,0)
(2,0)
(3,0)
(4,0)
(5,0)
(6,0)
(7,0)
(X-8,Y-1)
(X-7,Y-1)
(X-6,Y-1)
(X-5,Y-1)
(X-4,Y-1)
(X-3,Y-1)
(X-2,Y-1)
(X-1,Y-1)
1-bit-per-pixel mode
Display
Mapping