Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Hoja De Datos
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AT91SAM9M10-G45-EK
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SAM9M10 [DATASHEET]
6355F–ATARM–12-Mar-13
45.6.2.5
Palette
This block is used to generate the pixel gray or color information in palletized configurations. The different modes
with the palletized/non-palletized configuration can be found in
with the palletized/non-palletized configuration can be found in
. In these modes, 1, 2, 4 or 8 input bits
index an entry in the lookup table. The corresponding entry in the lookup table contains the color or gray shade
information for the pixel.
information for the pixel.
The lookup table can be accessed by the host in R/W mode to allow the host to program and check the values
stored in the palette. It is mapped in the LCD controller configuration memory map. The LUT is mapped as 16-bit
half-words aligned at word boundaries, only word write access is allowed (the 16 MSB of the bus are not used). For
the detailed memory map, see
stored in the palette. It is mapped in the LCD controller configuration memory map. The LUT is mapped as 16-bit
half-words aligned at word boundaries, only word write access is allowed (the 16 MSB of the bus are not used). For
the detailed memory map, see
The lookup table contains 256 16-bit wide entries. The 256 entries are chosen by the programmer from the 2
16
possible combinations.
For the structure of each LUT entry, see
.
In STN Monochrome, only the four most significant bits of the red value are used (16 gray shades). In STN Color,
only the four most significant bits of the blue, green and red value are used (4096 colors).
only the four most significant bits of the blue, green and red value are used (4096 colors).
In TFT mode, all the bits in the blue, green and red values are used. The LCDD unused bits are tied to 0 when TFT
palletized configurations are used (LCDD[18:16], LCDD[9:8], LCDD[2:0]).
palletized configurations are used (LCDD[18:16], LCDD[9:8], LCDD[2:0]).
45.6.2.6
Dithering
The dithering block is used to generate the shades of gray or color when the LCD Controller is used with an STN
LCD Module. It uses a time-based dithering algorithm and Frame Rate Control method.
LCD Module. It uses a time-based dithering algorithm and Frame Rate Control method.
The Frame Rate Control varies the duty cycle for which a given pixel is turned on, giving the display an appearance
of multiple shades. In order to reduce the flicker noise caused by turning on and off adjacent pixels at the same
time, a time-based dithering algorithm is used to vary the pattern of adjacent pixels every frame. This algorithm is
expressed in terms of Dithering Pattern registers (DP_i) and considers not only the pixel gray level number, but
also its horizontal coordinate.
of multiple shades. In order to reduce the flicker noise caused by turning on and off adjacent pixels at the same
time, a time-based dithering algorithm is used to vary the pattern of adjacent pixels every frame. This algorithm is
expressed in terms of Dithering Pattern registers (DP_i) and considers not only the pixel gray level number, but
also its horizontal coordinate.
Table 45-9.
Palette Configurations
Configuration
Palette
DISTYPE
PIXELSIZE
TFT
1, 2, 4, 8
Palletized
TFT
16, 24
Non-palletized
STN Mono
1, 2
Palletized
STN Mono
4
Non-palletized
STN Color
1, 2, 4, 8
Palletized
STN Color
16
Non-palletized
Table 45-10.
Lookup Table Structure in the Memory
Address
Data Output [15:0]
00
Red_value_0[4:0]
Green_value_0[5:0]
Blue_value_0[4:0]
01
Red_value_1[4:0]
Green_value_1[5:0]
Blue_value_1[4:0]
...
FE
Red_value_254[4:0]
Green_value_254[5:0]
Blue_value_254[4:0]
FF
Red_value_255[4:0]
Green_value_255[5:0]
Blue_value_255[4:0]