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 important constraints 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 instead of this class.
Constructors¶
-
class
machine.Timer(id, ...)¶ Construct a new timer object of the given id. Id of -1 constructs a virtual timer (if supported by a board).
See
initfor parameters of initialisation.
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:
modecan 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.