machine.Timer.rst

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 behavior (which thus won't be portable to other boards).

See discussion of 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 micropython.alloc_emergency_exception_buf for how to get around this limitation.

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

Constructors

Construct a new timer object of the given id. Id of -1 constructs a virtual timer (if supported by a board).

Methods

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.

Timer.deinit()

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

Constants

Timer.ONE_SHOT Timer.PERIODIC

Timer operating mode.