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machine.TimerWiPy

Classes

TimerWiPy

Construct a new timer object of the given id. Id of -1 constructs a

timerchannel

Module Contents

class machine.TimerWiPy.TimerWiPy(id, *args, **kwargs)

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

channel(channel, *, freq, period, polarity=POSITIVE, duty_cycle=0) → Incomplete

If only a channel identifier passed, then a previously initialized channel object is returned (or None if there is no previous channel).

Otherwise, a TimerChannel object is initialized and returned.

The operating mode is is the one configured to the Timer object that was used to create the channel.

  • channel if the width of the timer is 16-bit, then must be either TIMER.A, TIMER.B. If the width is 32-bit then it must be TIMER.A | TIMER.B.

Keyword only arguments:

  • freq sets the frequency in Hz.

  • period sets the period in microseconds.

Note

Either freq or period must be given, never both.

  • polarity this is applicable for PWM, and defines the polarity of the duty cycle

  • duty_cycle only applicable to PWM. It’s a percentage (0.00-100.00). Since the WiPy doesn’t support floating point numbers the duty cycle must be specified in the range 0-10000, where 10000 would represent 100.00, 5050 represents 50.50, and so on.

Note

When the channel is in PWM mode, the corresponding pin is assigned automatically, therefore there’s no need to assign the alternate function of the pin via the Pin class. The pins which support PWM functionality are the following:

  • GP24 on Timer 0 channel A.

  • GP25 on Timer 1 channel A.

  • GP9 on Timer 2 channel B.

  • GP10 on Timer 3 channel A.

  • GP11 on Timer 3 channel B.

deinit() → None

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

init(mode, *, width=16) → None

Initialise the timer. Example:

tim.init(Timer.PERIODIC)             # periodic 16-bit timer
tim.init(Timer.ONE_SHOT, width=32)   # one shot 32-bit timer
Keyword Arguments:

  • of (- mode can be one) –

    • TimerWiPy.ONE_SHOT - The timer runs once until the configured period of the channel expires.

    • TimerWiPy.PERIODIC - The timer runs periodically at the configured frequency of the channel.

    • TimerWiPy.PWM - Output a PWM signal on a pin.

  • 32 (- width must be either 16 or) – (or large periods), 32-bit timers should be used. 32-bit mode is only available for ONE_SHOT AND PERIODIC modes.

ONE_SHOT: Incomplete
PERIODIC: Incomplete

Timer operating mode.

class machine.TimerWiPy.timerchannel
duty_cycle(value: Any | None = None) → Incomplete

Get or set the duty cycle of the PWM signal. It’s a percentage (0.00-100.00). Since the WiPy doesn’t support floating point numbers the duty cycle must be specified in the range 0-10000, where 10000 would represent 100.00, 5050 represents 50.50, and so on.

freq(value: Any | None = None) → Incomplete

Get or set the timer channel frequency (in Hz).

irq(*, trigger, priority=1, handler=None) → Callable[Ellipsis, Incomplete]

The behaviour of this callback is heavily dependent on the operating mode of the timer channel:

  • If mode is TimerWiPy.PERIODIC the callback is executed periodically with the configured frequency or period.

  • If mode is TimerWiPy.ONE_SHOT the callback is executed once when the configured timer expires.

  • If mode is TimerWiPy.PWM the callback is executed when reaching the duty cycle value.

The accepted params are:

  • priority level of the interrupt. Can take values in the range 1-7. Higher values represent higher priorities.

  • handler is an optional function to be called when the interrupt is triggered.

  • trigger must be TimerWiPy.TIMEOUT when the operating mode is either TimerWiPy.PERIODIC or TimerWiPy.ONE_SHOT. In the case that mode is TimerWiPy.PWM then trigger must be equal to TimerWiPy.MATCH.

Returns a callback object.

period(value: Any | None = None) → Incomplete

Get or set the timer channel period (in microseconds).