
Description of Operation
7-8
ADSP-BF59x Blackfin Processor Hardware Reference
the pin. When using a particular peripheral interface, pins required for the
peripheral must be individually enabled. Keep the related function enable
bit cleared if a signal provided by the peripheral is not required by your
application. This allows it to be used in GPIO mode.
General-Purpose I/O Modules
The processor supports 32 bidirectional or general-purpose I/O (GPIO)
signals. These 32 GPIOs are managed by two different GPIO modules,
which are functionally identical. One is associated with port F, and one is
associated with port G. Port F and port G each consist of 16 GPIOs
(
PF15–0
and
PG15–0
), respectively.
Each GPIO can be individually configured as either an input or an output
by using the GPIO direction registers (
PORTxIO_DIR
).
When configured as output, the GPIO data registers (
PORTFIO
,
PORTGIO
,
and
PORTHIO
) can be directly written to specify the state of the GPIOs.
The GPIO direction registers are read-write registers with each bit posi-
tion corresponding to a particular GPIO. A logic 1 configures a GPIO as
an output, driving the state contained in the GPIO data register if the
peripheral function is not enabled by the function enable registers. A logic
0 configures a GPIO as an input.
Note when using the GPIO as an input, the corresponding bit
should also be set in the GPIO input enable register. Otherwise,
changes at the input pins will not be recognized by the processor.
The GPIO input enable registers (
PORTFIO_INEN
and
PORTGIO_INEN
) are
used to enable the input buffers on any GPIO that is being used as an
input. Leaving the input buffer disabled eliminates the need for pull-ups
and pull-downs when a particular
PFx
or
PGx
pin is not used in the system.
By default, the input buffers are disabled.
Содержание ADSP-BF59x Blackfin
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