PPI Registers
7-26
ADSP-BF537 Blackfin Processor Hardware Reference
PPI Registers
The PPI has five memory-mapped registers (MMRs) that regulate its oper-
ation. These registers are the PPI control register (
PPI_CONTROL
), the PPI
status register (
PPI_STATUS
), the delay count register (
PPI_DELAY
), the
transfer count register (
PPI_COUNT
), and the lines per frame register
(
PPI_FRAME
).
Descriptions and bit diagrams for each of these MMRs are provided in the
following sections.
PPI_CONTROL Register
The
PPI_CONTROL
register configures the PPI for operating mode, control
signal polarities, and data width of the port. See
for a bit dia-
gram of this MMR.
The
POLC
and
POLS
bits allow for selective signal inversion of the
PPI_CLK
and
PPI_FS1
/
PPI_FS2
signals, respectively. This provides a mechanism to
connect to data sources and receivers with a wide array of control signal
polarities. Often, the remote data source/receiver also offers configurable
signal polarities, so the
POLC
and
POLS
bits simply add increased flexibility.
The
DLEN[2:0]
field is programmed to specify the width of the PPI port in
any mode. Note any width from 8 to 16 bits is supported, with the excep-
tion of a 9-bit port width. Any pins unused by the PPI as a result of the
DLEN
setting are free for use in their other functions, as detailed in
Chapter 14, “General-Purpose Ports”
.
a
In ITU-R 656 modes, the
DLEN
field should not be configured for
anything greater than a 10-bit port width. If it is, the PPI will
reserve extra pins, making them unusable by other peripherals.
The
SKIP_EN
bit, when set, enables the selective skipping of data elements
being read in through the PPI. By ignoring data elements, the PPI is able
to conserve DMA bandwidth.
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 ...