
ADSP-BF59x Blackfin Processor Hardware Reference
13-7
SPI-Compatible Port Controller
module provides hardware support to generate up to seven slave select
enable signals automatically (depending upon the configuration of the
specific processor). See
Figure 13-14 on page 13-37
for details.
These signals are always active low in the SPI protocol. Since the respec-
tive pins are not driven during reset, it is recommended to pull them up
by a resistor.
If enabled as a master, the SPI uses the
SPI_FLG
register to enable gen-
eral-purpose port pins to be used as individual slave select lines. Before
manipulating this register, the port pins that are to be used as SPI
slave-select outputs must first be configured as such. To work as SPI out-
put pins, the port pins must be enabled for use by SPI in the appropriate
PORT_MUX
register.
In slave mode, the
SPI_FLG
bits have no effect, and each SPI uses the
SPISS
input as a slave select. Just as in the master mode case, the port pin
associated with
SPISS
must first be configured appropriately before use.
Figure 13-14 on page 13-37
shows the
SPI_FLG
register diagram.
Slave Select Inputs
If the SPI is in slave mode,
SPISS
acts as the slave select input. When
enabled as a master,
SPISS
can serve as an error detection input for the SPI
in a multimaster environment. The
PSSE
bit in
SPI_CTL
enables this
Figure 13-3. SPI Timing
T1
T2
SPISS
(TO SLAVE)
SCK
(CPOL = 1)
T4
T3
Содержание ADSP-BF59x Blackfin
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Страница 74: ...Processor Specific MMRs 2 10 ADSP BF59x Blackfin Processor Hardware Reference...
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Страница 244: ...Programming Examples 6 40 ADSP BF59x Blackfin Processor Hardware Reference...
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Страница 738: ...Boundary Scan Architecture B 8 ADSP BF59x Blackfin Processor Hardware Reference...