DocID018909 Rev 11
363/1731
RM0090
Chrom-Art Accelerator™ controller (DMA2D)
372
11.5.10
DMA2D background PFC control register (DMA2D_BGPFCCR)
Address offset: 0x0024
Reset value: 0x0000 0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
ALPHA[7:0]
Reserved
AM[1:0]
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CS[7:0]
Reserved
START
CCM
CM[3:0]
rw
rw
rw
rw
rw
rw
rw
rw
rc_w1
rw
rw
rw
rw
rw
Bits 31:24
ALPHA[7: 0]
: Alpha value
These bits define a fixed alpha channel value which can replace the original alpha value
or be multiplied with the original alpha value according to the alpha mode selected with
bits AM[1: 0]. These bits can only be written when data transfers are disabled. Once the
transfer has started, they are read-only.
Bits 23:18 Reserved, must be kept at reset value
Bits 17:16
AM[1: 0]
: Alpha mode
These bits define which alpha channel value to be used for the background image.
These bits can only be written when data transfers are disabled. Once the transfer has
started, they are read-only.
00: No modification of the foreground image alpha channel value
01: Replace original background image alpha channel value by ALPHA[7: 0]
10: Replace original background image alpha channel value by ALPHA[7:0] multiplied
with original alpha channel value
others: meaningless
Bits 15:8
CS[7: 0]
: CLUT size
These bits define the size of the CLUT used for the BG. Once the CLUT transfer has
started, this field is read-only.
The number of CLUT entries is equal to CS[7:0] + 1.
Bits 7:6 Reserved, must be kept at reset value