Programming Examples
20-34
ADSP-BF50x Blackfin Processor Hardware Reference
However, the PPI still automatically reinitializes to count to the value pro-
grammed in
PPI_FRAME
, and data transfer continues.
In ITU-R 656 modes, a frame start detect happens on the falling
edge of
F
, the field indicator. This occurs at the start of field 1.
In RX mode with three external frame syncs, a frame start detect
refers to a condition where a
PPI_FS2
assertion is followed by an
assertion of
PPI_FS1
while
PPI_FS3
is low. This occurs at the start
of field 1. Note that
PPI_FS3
only needs to be low when
PPI_FS1
is
asserted, not when
PPI_FS2
asserts. Also,
PPI_FS3
is only used to
synchronize to the start of the very first frame after the PPI is
enabled. It is subsequently ignored.
When using RX mode with three external frame syncs, and only
two syncs are needed, configure the PPI for 3-frame-sync operation
and provide an external pull-down to
GND
for the
PPI_FS3
pin.
Programming Examples
The PPI can be configured to receive data from a video source in several
RX modes. The following programming examples (
Listing 20-1
through
Listing 20-5
) describe the ITU-R 656 entire field input mode.
Figure 20-17. PPI Lines Per Frame Register
PPI Lines Per Frame Register (PPI_FRAME)
15 14
13 12
11 10
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
PPI_FRAME[15:0]
Reset = 0x0000
Holds the number of lines
expected per frame of data
Содержание EZ-KIT Lite ADSP-BF506F
Страница 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 132: ...Unique Information for the ADSP BF50x Processor 4 22 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 342: ...Unique Information for the ADSP BF50x Processor 7 106 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 484: ...Unique Information for the ADSP BF50x Processor 10 60 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 493: ...ADSP BF50x Blackfin Processor Hardware Reference 11 9 Core Timer Unique Information for the ADSP BF50x Processor None ...
Страница 494: ...Unique Information for the ADSP BF50x Processor 11 10 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 506: ...Unique Information for the ADSP BF50x Processor 12 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 544: ...Unique Information for the ADSP BF50x Processor 13 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 712: ...Unique Information for the ADSP BF50x Processor 16 62 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 972: ...Unique Information for the ADSP BF50x Processor 20 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...