machine.Timer.rst

.. currentmodule:: machine

class Timer -- control hardware timers

Hardware timers deal with timing of periods and events. Timers are perhaps the most flexible and heterogeneous kind of hardware in MCUs and SoCs, differently greatly from a model to a model. MicroPython's Timer class defines a baseline operation of executing a callback with a given period (or once after some delay), and allow specific boards to define more non-standard behaviour (which thus won't be portable to other boards).

See discussion of :ref:`important constraints <machine_callbacks>` on Timer callbacks.

Note

Memory can't be allocated inside irq handlers (an interrupt) and so exceptions raised within a handler don't give much information. See :func:`micropython.alloc_emergency_exception_buf` for how to get around this limitation.

If you are using a WiPy board please refer to :ref:`machine.TimerWiPy <machine.TimerWiPy>` instead of this class.

Constructors

Methods

.. method:: Timer.init(*, mode=Timer.PERIODIC, period=-1, callback=None)

   Initialise the timer. Example::

       tim.init(period=100)                         # periodic with 100ms period
       tim.init(mode=Timer.ONE_SHOT, period=1000)   # one shot firing after 1000ms

   Keyword arguments:

     - ``mode`` can be one of:

       - ``Timer.ONE_SHOT`` - The timer runs once until the configured
         period of the channel expires.
       - ``Timer.PERIODIC`` - The timer runs periodically at the configured
         frequency of the channel.

.. method:: Timer.deinit()

   Deinitialises the timer. Stops the timer, and disables the timer peripheral.

Constants

.. data:: Timer.ONE_SHOT
          Timer.PERIODIC

   Timer operating mode.