Active Video Only; Vertical Blanking Interval (Vbi) Only - Analog Devices ADSP-BF506F Hardware Reference Manual

Functional Description
but does not include the first EAV code that contains the
assignment.

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
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.

In this mode, the user specifies the number of total (active plus ver-
tical blanking) lines per frame in the

Vertical Blanking Interval (VBI) Only

In this mode, data transfer is only active while
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.
Control byte sequence information is always logged. The user specifies the
number of total lines (active plus vertical blanking) per frame in the
MMR.
PPI_FRAME
20-10 ADSP-BF50x Blackfin Processor Hardware Reference
= 0
F
MMR.
PPI_FRAME
= 1 is in the control byte
V
= 1.
V