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Geode™ CS9211
Functional Description (Continued)
Table3-10isanexampleofoneofthethree32x64FRM-
Sequence tables that is addressed by the most significant
bit of the incoming pixel value. The ”n” most-significant bits
(as chosen by Offset 40Ch[6:4]) of each color component
of each incoming pixel looks up one of the 64-bit words
from this table. The number of 1’s in each 64-bit word
determines how bright the pixel will be when that word is
chosen. A word with all zeros will never illuminate the given
pixel in that color, therefore the pixel will be black. A word
with only one “1” will illuminate the given pixel one frame
out of 64, so the pixel will be as dim as possible without
being off entirely. A word with 10 “1”s will illuminate the
given pixel 10 frames out of 64. A word with 64 “1”s will illu-
minate the given pixel in each of the 64 frames, so that
pixel will be as bright as possible.
The Freq (frequency ratio) indicates the number of 0 to 1
transitions within 64 frames. This value multiplied by the
refresh rate will give the frequency of frame rate modula-
tion of a particular intensity. Higher frequency frame rate
modulation will result in better picture quality. The Int
(intensity) column indicates the duty cycle of the primary
color.
The intensity level of this FRM table starts from 0/64 and
gradually increases to 16/64 instead of jumping directly to
16/64. It seems that the human eye is less sensitive to fre-
quency variation at low intensity. As the intensity level
increases, it increases slowly from 16/64 to 48/64 to create
a smooth transition of intensities. The full scale intensity
level is truncated at 48/64 intentionally; above this point the
differences between levels start to become visible. There is
a trade-off between maximum intensity level and smooth
gradations of color.
The generation of FRM tables suitable for driving a particu-
lar display panel in a particular application requires a good
understanding of human vision and significant experimen-
tation. Good candidate patterns for these tables will have
1’s separated by equal numbers of 0’s throughout the word,
instead of clumping all the 1’s together in a particular loca-
tion. Successive values should increase monotonically. All
three tables may be identically or individually programmed.
Table 3-10. Example FRM RAM Table for One Color Component
Col Frame Count from 0 to 63 Freq Int
0 00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000 0/64 0/64
1 00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000 0/64 0/64
2 00000001,00000001,00000001,00000001,00000001,00000001,00000001,00000001 8/64 8/64
3 00000010,00001000,00010000,01000001,00000010,00001000,00010000,01000001 10/64 10/64
4 00010001,00010001,00010001,00010001,00010001,00010001,00010001,00010001 16/64 16/64
5 00010010,01001001,00100100,10010010,01001001,00100100,10010010,01001001 21/64 21/64
6 00100100,10010100,10010010,01010010,01001010,01001001,00101001,00100101 23/64 23/64
7 00100101,00100101,00100101,00100101,00100101,00100101,00100101,00100101 24/64 24/64
8 00100101,00101001,01001001,01001010,01010010,10010010,10010100,10100101 25/64 25/64
9 00101001,01001010,01010010,10010101,00101001,01001010,01010010,10010101 26/64 26/64
10 00101001,01010010,10100101,00101010,01010100,10100101,01001010,10010101 27/64 27/64
11 00101010,01010101,00101010,01010101,00101010,01010101,00101010,01010101 28/64 28/64
12 00101010,10010101,01010010,10101010,01010101,01001010,10101001,01010101 29/64 29/64
13 00101010,10101010,01010101,01010101,00101010,10101010,01010101,01010101 30/64 30/64
14 00101010,10101010,10101010,10101010,01010101,01010101,01010101,01010101 31/64 31/64
15 01010101,01010101,01010101,01010101,01010101,01010101,01010101,01010101 32/64 32/64
16 01010101,01010101,01010101,01010101,10101010,10101010,10101010,10101011 31/64 33/64
17 01010101,01010101,10101010,10101011,01010101,01010101,10101010,10101011 30/64 34/64
18 01010101,01101010,10101101,01010101,10101010,10110101,01010110,10101011 29/64 35/64
19 01010101,10101011,01010101,10101011,01010101,10101011,01010101,10101011 28/64 36/64
20 01010110,10101101,01011010,11010101,10101011,01011010,10110101,01101011 27/64 37/64
21 01010110,10110101,10101101,01101011,01010110,10110101,10101101,01101011 26/64 38/64
22 01011010,11010110,10110110,10110101,10101101,01101101,01101011,01011011 25/64 39/64
23 01011011,01011011,01011011,01011011,01011011,01011011,01011011,01011011 24/64 40/64
24 01011011,01101011,01101101,10101101,10110101,10110110,11010110,11011011 23/64 41/64
25 01011011,01101101,10110110,11011011,01011011,01101101,10110110,11011011 22/64 42/64
26 01101101,10110110,11011011,01101101,10110110,11011011,01101101,10110111 21/64 43/64
27 01101101,10110111,01101101,10110111,01101101,10110111,01101101,10110111 20/64 44/64
28 01101101,11011011,01110110,11011101,10111011,01101110,11011011,10110111 19/64 45/64
29 01101110,11011101,10111011,01110111,01101110,11011101,10111011,01110111 18/64 46/64
30 01101110,11101110,11011101,11011101,10111011,10111011,01110111,01110111 17/64 47/64
31 01110111,01110111,01110111,01110111,01110111,01110111,01110111,01110111 16/64 48/64