LCD-TFT Controller (LTDC)
RM0090
486/1731
DocID018909 Rev 11
Pixel input Format
The programmable pixel format is used for the data stored in the frame buffer of a layer.
Up to 8 input pixel formats can be configured for every layer through the
LTDC_LxPFCR
register
The pixel data is read from the frame buffer and then transformed to the internal 8888
(ARGB) format as follows:
•
Components which have a width of less than 8 bits get expanded to 8 bits by bit
replication. The selected bit range is concatenated multiple times until it is longer than
8 bits. Of the resulting vector, the 8 MSB bits are chosen. Example: 5 bits of an
RGB565 red channel become (bit positions): 43210432 (the 3 LSBs are filled with the 3
MSBs of the 5 bits)
The figure below describes the pixel data mapping depending on the selected format.
Table 89. Pixel Data mapping versus Color Format
ARGB8888
@+3
A
x
[7:0]
@+2
R
x
[7:0]
@+1
G
x
[7:0]
@
B
x
[7:0]
@+7
A
x+1
[7:0]
@+6
R
x+1
[7:0]
@+5
G
x+1
[7:0]
@+4
B
x+1
[7:0]
RGB888
@+3
B
x+1
[7:0]
@+2
R
x
[7:0]
@+1
G
x
[7:0]
@
B
x
[7:0]
@+7
G
x+2
[7:0]
@+6
B
x+2
[7:0]
@+5
R
x+1
[7:0]
@+4
G
x+1
[7:0]
RGB565
@+3
R
x+1
[4:0] G
x+1
[5:3]
@+2
G
x+1
[2:0] B
x+1
[4:0]
@+1
R
x
[4:0] G
x
[5:3]
@
G
x
[2:0] B
x
[4:0]
@+7
R
x+3
[4:0] G
x+3
[5:3]
@+6
G
x+3
[2:0] B
x+3
[4:0]
@+5
R
x+2
[4:0] G
x+2
[5:3]
@+4
G
x+2
[2:0] B
x+2
[4:0]
ARGB1555
@+3
A
x+1
[0]R
x+1
[4:0]
G
x+1
[4:3]
@+2
G
x+1
[2:0] B
x+1
[4:0]
@+1
A
x
[0] R
x
[4:0] G
x
[4:3]
@
G
x
[2:0] B
x
[4:0]
@+7
A
x+3
[0]R
x+3
[4:0]
G
x+3
[4:3]
@+6
G
x+3
[2:0] B
x+3
[4:0]
@+5
A
x+2
[0]R
x+2
[4:0]G
x+2
[4:
3]
@+4
G
x+2
[2:0] B
x+2
[4:0]
ARGB4444
@+3
A
x+1
[3:0]R
x+1
[3:0]
@+2
G
x+1
[3:0] B
x+1
[3:0]
@+1
A
x
[3:0] R
x
[3:0]
@
G
x
[3:0] B
x
[3:0]