
14 13
12 11
10
9
8
7
6
5
4
3
2
1
0
B1
G0
R1
B0
B4
B2
B3
G1
G2
G3
G4
G5
15
R2
R3
R4
R0
dss-T055
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R1
R2
R3
R4
R0
R2
R3
R4
G0
G1
G2
G3
G4
G5
G5 G4
B1 B0
B4
B2
B3
B3 B2
B4
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23
22
21
20
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18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R1
R2
R3
R4
R0
0
0
0
G0
G1
G2
G3
G4
G5
0
0
B1 B0
B4
B2
B3
0
0
0
dss-T057
Public Version
Display Subsystem Functional Description
www.ti.com
The palette is bypassed in 12, 16, and 24 BPP, allowing up to 2
24
= 16,777,216 colors to be displayed.
7.4.2.2.2.2 Gamma Table
In the gamma curve mode, the selected encoded pixel values based on the color keys from the video or
graphics paths are sent to the gamma curve table. The mode is available only if the color look-up palette
is not used for graphics. The output of the gamma curve processing is always sent to the LCD output. It is
not available on digital output.
Each component of encoded pixel value is used as a pointer to index 1 out of 256 24-bit gamma curve
entries in the table. Each 8-bit component is replaced with the 8-bit table value corresponding to an R, G,
or B component. The format of one of the gamma curve values in the memory is as follows:
•
24-BPP Data Memory Organization (Little or Big Endian)
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Unused
Gamma-R
Gamma-G
Gamma-B
7.4.2.2.2.2.1 Replication Logic
The replication logic increases the color depth of the graphics and video encoded pixels (from true color
RGB 12-, and 16-BPP to 24-BPP). The encoded value is shifted to the 24-bit alignment. The MSB bits are
copied to the LSB missing ones. Then the graphics are merged with the video data based on the
transparency color keys. When the replication logic is not selected, the encoded pixel values are shifted to
the MSB boundary of the 24-bit format. The missing bit values are filled up with 0s.
This is an example for RGB16 extension:
•
Original 16-BPP data:
•
If replication logic is ON:
•
If replication logic is OFF:
7.4.2.3
Video Pipeline
The video pipeline is connected to the video FIFO controller for the input port and to the two overlay
managers (LCD and digital). It consists of the Re-Sampling unit, the Color Space Conversion Unit, and
some programmable replication logic. The replication logic is used to convert the RGB pixels, excluding
the RGB24 format, into RGB24 format based on user programming (replication of the MSBs for the
RGB24 LSBs or use of 0s). The first unit connected to the input port of the video pipeline is the
Re-Sampling Unit, then the replication logic used for RGB pixels, then the Color Space Conversion Unit
for YUV4:2:2 pixels.
7.4.2.3.1 Video Memory Formats
The display subsystem supports the following formats for the video layer: YUV2, UYVY, RGB12, RGB16,
RGB24 (non-packed and packed formats), ARGB16 (video channel 2 only), ARGB32 (video channel 2
only), and RGBA32 (video channel 2 only).
1640
Display Subsystem
SWPU177N – December 2009 – Revised November 2010
Copyright © 2009–2010, Texas Instruments Incorporated