Interface Overview
10-4
ADSP-BF537 Blackfin Processor Hardware Reference
External Interface
Most of the SPI signals are accessible through Port F. The five most
important signals (
SCK
,
MISO
,
MOSI
,
SPISS
, and
SPISSEL1
) are not multi-
plexed with other peripherals. However, by default they function as
GPIOs and are individually enabled by the respective bits in the
PORTF_FER
register.
Port F features three additional slave select signals that are multiplexed
with the timer signals. They can be enabled on an individual basis using
the
PFS4E
,
PFS5E
, and
PFS6E
bits in the
PORT_MUX
Port J also provides three slave select signals. These signals cannot func-
tion as normal GPIOs and therefore do not need to be enabled by any
function enable bits. However, these outputs are multiplexed with CAN
and SPORT0 signals and require
PJSE = 1
, or
PJCE = 10
.
Serial Peripheral Interface Clock Signal (SCK)
The
SCK
signal is the serial clock signal. This control signal is driven by the
master and controls the rate at which data is transferred. The master may
transmit data at a variety of bit rates. The
SCK
signal cycles once for each
bit transmitted. It is an output signal if the device is configured as a mas-
ter, and an input signal if the device is configured as a slave.
The
SCK
is a gated clock that is active during data transfers only for the
length of the transferred word. The number of active clock edges is equal
to the number of bits driven on the data lines. Slave devices ignore the
serial clock if the
SPISS
input is driven inactive (high).
The
SCK
is used to shift out and shift in the data driven on the
MISO
and
MOSI
lines. The data is always shifted out on active edges of the clock and
sampled on inactive edges of the clock. Clock polarity and clock phase rel-
ative to data are programmable in the
SPI_CTL
register and define the
transfer format.
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 ...