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Cirrus Logic EP93xx User Manual

Page 205

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DS785UM1

7-23

Copyright 2007 Cirrus Logic

Raster Engine With Analog/LCD Integrated Timing and Interface

EP93xx User’s Guide

7

7

7

Please note that as the frame number progresses, the bit pattern in each row moves to the
right one pixel. This type of pattern shown in an area may cause diagonal lines to appear as
though they are moving to the right. As previously stated, any image distortion greatly
depends on the application. However, the pattern shown in

Figure 7-7

will have less of a

tendency to demonstrate a walking distortion.

Figure 7-7. Creating Bit Patterns that Move to the Right

Assuming that the 3-bit input pattern that represents this 33% duty cycle grayscale is 0x2 (or
010b), the values in

Table 7-8

are used to program this pattern into the grayscale look-up-

table. In this mode, the X locations are ignored by the grayscale generation.

Finally, just for demonstration purposes, a matrix with mixed 3 and 4 count axes is shown in

Figure 7-8

.

Frame 0

H O R Z

Frame 1

V

1

0

0

0

1

0

E

0

0

1

0

1

0

R

0

1

0

0

0

1

T

Frame 2

0

0

1

1

0

0

1

0

0

Table 7-8. Programming 33% Duty Cycle into the 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

Value

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

0

0

0

base + 0x08

X

X

X

X

X

0

1

0

X

1

0

0

X

0

0

1

00

010

base + 0x28

X

X

X

X

X

1

0

0

X

0

1

0

X

0

1

0

01

010

base + 0x48

X

X

X

X

X

0

0

1

X

0

0

1

X

1

0

0

10

010

base + 0x68

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

11

010