STMicroelectronics STM32F405 Reference Manual page 504

LCD-TFT Controller (LTDC)
Bits 31:8 Reserved, must be kept at reset value
Bits 7:0 CONSTA[7:0]: Constant Alpha
16.7.20 LTDC Layerx Default Color Configuration Register (LTDC_LxDCCR)
(where x=1..2)
This register defines the default color of a layer in the format ARGB. The default color is
used outside the defined layer window or when a layer is disabled. The reset value of
0x00000000 defines a transparent black color.
Address offset: 0x9C + 0x80 x (Layerx -1), Layerx = 1 or 2
Reset value: 0x0000 0000
31 30 29 28
DCALPHA[7:0]
15 14 13 12
DCGREEN[7:0]
Bits 31:24 DCALPHA[7:0]: Default Color Alpha
Bits 23:16 DCRED[7:0]: Default Color Red
Bits 15:8 DCGREEN[7:0]: Default Color Green
Bits 7:0 DCBLUE[7:0]: Default Color Blue
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These bits configure the Constant Alpha used for blending. The Constant Alpha is divided
by 255 by hardware.
Example: if the programmed Constant Alpha is 0xFF, the Constant Alpha value is
255/255=1
27 26 25
rw
11 10 9
rw
These bits configure the default alpha value
These bits configure the default red value
These bits configure the default green value
These bits configure the default blue value
DocID018909 Rev 11
24 23 22 21
rw rw rw
8 7 6 5
rw rw rw
20 19 18 17
DCRED[7:0]
rw rw rw rw
4 3 2 1
DCBLUE[7:0]
rw rw rw rw
RM0090
16
rw
0
rw