circuitpython/docs/library/rp2.PIO.rst

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.. currentmodule:: rp2
.. _rp2.PIO:
class PIO -- advanced PIO usage
===============================
The :class:`PIO` class gives access to an instance of the RP2040's PIO
(programmable I/O) interface.
The preferred way to interact with PIO is using :class:`rp2.StateMachine`, the
PIO class is for advanced use.
For assembling PIO programs, see :func:`rp2.asm_pio`.
Constructors
------------
.. class:: PIO(id)
Gets the PIO instance numbered *id*. The RP2040 has two PIO instances,
numbered 0 and 1.
Raises a ``ValueError`` if any other argument is provided.
Methods
-------
.. method:: PIO.add_program(program)
Add the *program* to the instruction memory of this PIO instance.
The amount of memory available for programs on each PIO instance is
limited. If there isn't enough space left in the PIO's program memory
this method will raise ``OSError(ENOMEM)``.
.. method:: PIO.remove_program([program])
Remove *program* from the instruction memory of this PIO instance.
If no program is provided, it removes all programs.
It is not an error to remove a program which has already been removed.
.. method:: PIO.state_machine(id, [program, ...])
Gets the state machine numbered *id*. On the RP2040, each PIO instance has
four state machines, numbered 0 to 3.
Optionally initialize it with a *program*: see `StateMachine.init`.
>>> rp2.PIO(1).state_machine(3)
StateMachine(7)
.. method:: PIO.irq(handler=None, trigger=IRQ_SM0|IRQ_SM1|IRQ_SM2|IRQ_SM3, hard=False)
Returns the IRQ object for this PIO instance.
MicroPython only uses IRQ 0 on each PIO instance. IRQ 1 is not available.
Optionally configure it.
Constants
---------
.. data:: PIO.IN_LOW
PIO.IN_HIGH
PIO.OUT_LOW
PIO.OUT_HIGH
These constants are used for the *out_init*, *set_init*, and *sideset_init*
arguments to `asm_pio`.
.. data:: PIO.SHIFT_LEFT
PIO.SHIFT_RIGHT
These constants are used for the *in_shiftdir* and *out_shiftdir* arguments
to `asm_pio` or `StateMachine.init`.
.. data:: PIO.JOIN_NONE
PIO.JOIN_TX
PIO.JOIN_RX
These constants are used for the *fifo_join* argument to `asm_pio`.
.. data:: PIO.IRQ_SM0
PIO.IRQ_SM1
PIO.IRQ_SM2
PIO.IRQ_SM3
These constants are used for the *trigger* argument to `PIO.irq`.