ADSP-BF537 Blackfin Processor Hardware Reference
7-23
Parallel Peripheral Interface
Programming Model
The following sections describe the PPI programming model.
DMA Operation
The PPI must be used with the processor’s DMA engine. This section dis-
cusses how the two interact. For additional information about the DMA
engine, including explanations of DMA registers and DMA operations,
please refer to
Chapter 5, “Direct Memory Access”
The PPI DMA channel can be configured for either transmit or receive
operation, and it has a maximum throughput of
(PPI_CLK) x
(16 bits/transfer)
. In modes where data lengths are greater than 8 bits,
only one element can be clocked in per
PPI_CLK
cycle, and this results in
reduced bandwidth (since no packing is possible). The highest throughput
is achieved with 8-bit data and
PACK_EN = 1
(packing mode enabled).
Note for 16-bit packing mode, there must be an even number of data
elements.
Configuring the PPI’s DMA channel is a necessary step toward using the
PPI interface. It is the DMA engine that generates interrupts upon com-
pletion of a row, frame, or partial-frame transfer. It is also the DMA
engine that coordinates the origination or destination point for the data
that is transferred through the PPI.
The processor’s 2D DMA capability allows the processor to be interrupted
at the end of a line or after a frame of video has been transferred, as well as
if a DMA error occurs. In fact, the specification of the
DMAx_XCOUNT
and
DMAx_YCOUNT
MMRs allows for flexible data interrupt points. For example,
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 ...