Programming Examples
7-36
ADSP-BF537 Blackfin Processor Hardware Reference
L
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 3 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 synchro-
nize to the start of the very first frame after the PPI is enabled. It is
subsequently ignored.
When using RX mode with 3 external frame syncs, and only 2
syncs are needed, configure the PPI for three-frame-sync operation
and provide an external pull-down to
GND
for the
PPI_FS3
pin.
Programming Examples
As shown in the data transfer scenario in
PPI can be configured to receive data from a video source in several RX
modes. The following programming examples (
) describe the ITU-R 656 entire field input mode.
Figure 7-17. Lines Per Frame Register
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
0xFFC0 1010
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...