Cirrus Logic EP93xx - Manual (Page 204)

7-22 DS785UM1
Copyright 2007 Cirrus Logic
Raster Engine With Analog/LCD Integrated Timing and Interface
EP93xx User’s Guide
7
7
7
Assuming the 3 bit input pattern that represents this 50% duty cycle grayscale is 0x3 (or
011b), the values in
Table 7-7 should be used to program this pattern into the grayscale look-
up-table.
Since all patterns must be evaluated against their specific use, no more examples for half
intensity will be offered. Instead, another example will be used to make a walking distortion
more obvious.
Take the example of a one-third luminous intensity grayscale pattern. Assume a 3Hx3Vx3F
matrix for this definition. Wanting the intensity to be evenly distributed and given the three
frame interval, any cell in the matrix should only be active for one frame. The matrix could be
filled in as in
Figure 7-6 .
Figure 7-6. Programming for One-third Luminous Intensity
Table 7-7. Programming 50% Duty Cycle Into Lookup Table
Frame Vert Horz VCNT (lines)
1
1 1
1 1
1 1
1 1
0 1
0 1
0 1
0 0
1 0
1 0
1 0
1 0
0 0
0 0
0 0
0 GrySclLUT
Address *4
Ctr Ctr Ctr
HCNT
(pixels)
1
1 1
0 0
1 0
0 1
1 1
0 0
1 0
0 1
1 1
0 0
1 0
0 1
1 1
0 0
1 0
0
Frame Pixel
D18 D17 D16
Register
Address
D
1
5 D
1
4 D
1
3 D
1
2 D
1
1 D
1
0
D
9 D
8 D
7 D
6 D
5 D
4 D
3 D
2 D
1 D
0
Value
1 1 1 base + 0x0C 0 1 0 1 1 1 0 0 0 1 0 1 0 0 1 1 00 011
base + 0x2C 1 0 1 0 0 0 1 1 1 0 1 0 1 1 0 0 01 011
base + 0x4C 1 1 0 0 0 1 0 1 0 0 1 1 0 1 0 1 10 011
base + 0x6C 0 0 1 1 1 0 1 0 1 1 0 0 1 0 1 0 11 011
Frame 0 H O R Z Frame 1
V 1 0 0 0 1 0
E 0 1 0 0 0 1
R 0 0 1 1 0 0
T
Frame 2
0 0 1
1 0 0
0 1 0