DocID018909 Rev 11
505/1731
RM0090
LCD-TFT Controller (LTDC)
511
16.7.21 LTDC Layerx Blending Factors Configuration Register (LTDC_LxBFCR)
(where x=1..2)
This register defines the blending factors F1 and F2.
The general blending formula is: BC = BF1 x C + BF2 x Cs
•
BC = Blended color
•
BF1 = Blend Factor 1
•
C = Current layer color
•
BF2 = Blend Factor 2
•
Cs = subjacent layers blended color
Address offset: 0xA0 + 0x80 x (
Layerx
-1),
Layerx
= 1 or 2
Reset value: 0x0000 0607
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
BF1[2:0]
Reserved
BF2[2:0]
rw
rw
rw
rw
rw
rw
Bits 31:11 Reserved, must be kept at reset value
Bits 10:8
BF1[2:0]
: Blending Factor 1
These bits select the blending factor F1
000: Reserved
001: Reserved
010: Reserved
011: Reserved
100: Constant Alpha
101: Reserved
110: Pixel Alpha x Constant Alpha
111:Reserved
Bits 7:3 Reserved, must be kept at reset value
Bits 2:0
BF2[2:0]
: Blending Factor 2
These bits select the blending factor F2
000: Reserved
001: Reserved
010: Reserved
011: Reserved
100: Reserved
101: 1 - Constant Alpha
110: Reserved
111: 1 - (Pixel Alpha x Constant Alpha)