STMicroelectronics STM32F405 - Page 505

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)