Functional Description
7-12
ADSP-BF537 Blackfin Processor Hardware Reference
Control byte sequence information is always logged. The user specifies the
number of total lines (active plus vertical blanking) per frame in the
PPI_FRAME
MMR.
Note the VBI is split into two regions within each field. From the PPI’s
standpoint, it considers these two separate regions as one contiguous
space. However, keep in mind that frame synchronization begins at the
start of field 1, which doesn’t necessarily correspond to the start of vertical
blanking. For instance, in 525/60 systems, the start of field 1 (F = 0) cor-
responds to line 4 of the VBI.
ITU-R 656 Output Mode
The PPI does not explicitly provide functionality for framing an ITU-R
656 output stream with proper preambles and blanking intervals. How-
ever, with the TX mode with 0 frame syncs, this process can be supported
manually. Essentially, this mode provides a streaming operation from
memory out through the PPI. Data and control codes can be set up in
memory prior to sending out the video stream. With the 2D DMA
engine, this could be performed in a number of ways. For instance, one
line of blanking (H + V) could be stored in a buffer and sent out N times
by the DMA controller when appropriate, before proceeding to DMA
active video. Alternatively, one entire field (with control codes and blank-
ing) can be set up statically in a buffer while the DMA engine transfers
only the active video region into the buffer, on a frame-by-frame basis.
Frame Synchronization in ITU-R 656 Modes
Synchronization in ITU-R 656 modes always occurs at the falling edge of
F, the field indicator. This corresponds to the start of field 1. Conse-
quently, up to two fields might be ignored (for example, if field 1 just
started before the PPI-to-camera channel was established) before data is
received into the PPI.
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 ...