Allwinner A20 - Page 569

A20 User Manual (Revision 1.2) Copyright © 2013 Allwinner Technology Co., Ltd. All Rights Reserved. Page 569 / 812
Bit
Read/W
rite
Default/H
ex
Description
31:24
R/W
UDF
Alpha value
23:16
R/W
UDF
Red value
15:8
R/W
UDF
Green value
7:0
R/W
UDF
Blue value
In this mode, the sprite RAM array is used for palette lookup table, each pixel in the sprite frame
buffer is treated as an index into the RAM array to select the actual color.
The following figure shows the RAM array used for palette lookup and the corresponding colors
output.

0 R0 G0 B0

1 R1 G1 B1

254 R254 G254 B254

255 R255 G255 B255

n Rn Gn Bn
On chip SRAM array
5 38 133 28
Inputting external
frame buffer data
(8bpp)
Output color

5 R5 G5 B5

38 R38 G38 B38

133 R133 G133 B133

28 R28 G28 B28
On chip SRAM for palette lookup
5.4.4.52. PALETTE MODE
Offset:
Pipe0:0x5000-0x53FF
Pipe1:0x5400-0x57FF
Pipe palette color table SRAM block
Bit
Read/W
rite
Default/
Hex
Description
31:24
R/W
UDF
Alpha value
23:16
R/W
UDF
Red value
15:8
R/W
UDF