Atmel Evaluation Kit AT91SAM9G25-EK AT91SAM9G25-EK Data Sheet
Product codes
AT91SAM9G25-EK
960
SAM9G25 [DATASHEET]
11032C–ATARM–25-Jan-13
Figure 44-6. Three Frame Buffers Application and Memory Mapping
44.4.5 Codec Path
44.4.5.1 Color Space Conversion
Depending on user selection, this module can be bypassed so that input YCrCb stream is directly connected to the
format converter module. If the RGB input stream is selected, this module converts RGB to YCrCb color space with the
formulas given below:
format converter module. If the RGB input stream is selected, this module converts RGB to YCrCb color space with the
formulas given below:
An example of coefficients is given below:
44.4.5.2 Memory Interface
Dedicated FIFOs are used to support packed memory mapping. YCrCb pixel components are sent in a single 32-bit word
in a contiguous space (packed). Data is stored in the order of natural scan lines. Planar mode is not supported.
in a contiguous space (packed). Data is stored in the order of natural scan lines. Planar mode is not supported.
44.4.5.3 DMA Features
Like preview datapath, codec datapath DMA mode uses linked list operation.
frame n
frame n+1
frame n+2
frame n-1
frame n+3
frame n+4
Frame Buffer 0
Frame Buffer 1
Frame Buffer 3
4:2:2 Image
Full ROI
Full ROI
ISI config Space
Codec Request
Codec Done
LCD
Memory Space
Y
C
r
C
b
C
0
C
1
C
2
C
3
C
–
4
C
–
5
C
–
6
C
–
7
C
8
R
G
B
×
Y
off
Cr
off
Cb
off
+
=
Y
0.257
R
⋅
0.504
G
0.098
B
16
+
⋅
+
⋅
+
=
C
r
0.439
R
⋅
0.368
G
⋅
–
0.071
B
128
+
⋅
–
=
C
b
0.148
R
⋅
–
0.291
G
0.439
B
128
+
⋅
+
⋅
–
=