ADSP-BF537 Blackfin Processor Hardware Reference
7-11
Parallel Peripheral Interface
Data transfer starts immediately after synchronization to field 1 occurs,
but does not include the first EAV code that contains the F = 0
assignment.
L
Note the first line transferred in after enabling the PPI will be miss-
ing its first 4-byte preamble. However, subsequent lines and frames
should have all control codes intact.
One side benefit of this mode is that it enables a “loopback” feature
through which a frame or two of data can be read in through the PPI and
subsequently output to a compatible video display device. Of course, this
requires multiplexing on the PPI pins, but it enables a convenient way to
verify that 656 data can be read into and written out from the PPI.
Active Video Only
This mode is used when only the active video portion of a field is of inter-
est, and not any of the blanking intervals. The PPI ignores (does not read
in) all data between EAV and SAV, as well as all data present when V = 1.
In this mode, the control byte sequences are not stored to memory; they
are filtered out by the PPI. After synchronizing to the start of Field 1, the
PPI ignores incoming samples until it sees an SAV.
L
In this mode, the user specifies the number of total (active plus ver-
tical blanking) lines per frame in the
PPI_FRAME
MMR.
Vertical Blanking Interval (VBI) only
In this mode, data transfer is only active while V = 1 is in the control byte
sequence. This indicates that the video source is in the midst of the Verti-
cal Blanking Interval (VBI), which is sometimes used for ancillary data
transmission. The ITU-R 656 recommendation specifies the format for
these ancillary data packets, but the PPI is not equipped to decode the
packets themselves. This task must be handled in software. Horizontal
blanking data is logged where it coincides with the rows of the VBI.
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 ...