![Analog Devices Blackfin ADSP-BF537 Скачать руководство пользователя страница 356](http://html.mh-extra.com/html/analog-devices/blackfin-adsp-bf537/blackfin-adsp-bf537_hardware-reference-manual_2939700356.webp)
Functional Description
7-16
ADSP-BF537 Blackfin Processor Hardware Reference
No Frame Syncs
These modes cover the set of applications where periodic frame syncs are
not generated to frame the incoming data. There are two options for start-
ing the data transfer, both configured by the
PPI_CONTROL
register.
• External trigger: An external source sends a single frame sync (tied
to
PPI_FS1
) at the start of the transaction, when
FLD_SEL = 0
and
PORT_CFG = b#11
.
• Internal trigger: Software initiates the process by setting
PORT_EN = 1
with
FLD_SEL = 1
and
PORT_CFG = b#11
.
All subsequent data manipulation is handled via DMA. For example, an
arrangement could be set up between alternating 1K memory buffers.
When one fills up, DMA continues with the second buffer, at the same
time that another DMA operation is clearing the first memory buffer for
reuse.
L
Due to clock domain synchronization in RX modes with no frame
syncs, there may be a delay of at least 2
PPI_CLK
cycles between
when the mode is enabled and when valid data is received. There-
fore, detection of the start of valid data should be managed by
software.
1, 2, or 3 External Frame Syncs
The frame syncs are level-sensitive signals. The 1-sync mode is intended
for Analog-to-Digital Converter (ADC) applications. The top part of
shows a typical illustration of the system setup for this mode.
The 3-sync mode shown at the bottom of
supports video appli-
cations that use hardware signalling (
HSYNC
,
VSYNC
,
FIELD
) in accordance
with the ITU-R 601 recommendation. The mapping for the frame syncs
in this mode is
PPI_FS1 = HSYNC
,
PPI_FS2 = VSYNC
,
PPI_FS3 = FIELD
.
Please refer to
“Frame Synchronization in GP Modes” on page 7-20
more information about frame syncs in this mode.
Содержание Blackfin ADSP-BF537
Страница 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...