Interface Overview
10-10
ADSP-BF537 Blackfin Processor Hardware Reference
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 fea-
ture. When
PSSE = 1
, the
SPISS
input is the master mode error input.
Otherwise,
SPISS
is ignored.
Use of FLS Bits in SPI_FLG for Multiple Slave SPI Systems
The
FLSx
bits in the
SPI_FLG
register are used in a multiple slave SPI envi-
ronment. For example, if there are eight SPI devices in the system
including a processor master, the master processor can support the SPI
mode transactions across the other seven devices. This configuration
requires only one master processor in this multislave environment. For
example, assume that the SPI is the master. The seven port pins that can
be configured as SPI master mode slave-select output pins can be con-
nected to each of the slave SPI device’s
SPISS
pins. In this configuration,
the
FLSx
bits in
SPI_FLG
can be used in three cases.
In cases 1 and 2, the processor is the master and the seven microcontrol-
lers/peripherals with SPI interfaces are slaves. The processor can:
1. Transmit to all seven SPI devices at the same time in a broadcast
mode. Here, all
FLSx
bits are set.
2. Receive and transmit from one SPI device by enabling only one
slave SPI device at a time.
In case 3, all eight devices connected via SPI ports can be other
processors.
3. If all the slaves are also processors, then the requester can receive
data from only one processor (enabled by clearing the
EMISO
bit in
the six other slave processors) at a time and transmit broadcast data
to all seven at the same time. This
EMISO
feature may be available in
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 ...