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Diffstat (limited to 'docs/library/machine.Timer.rst')
| -rw-r--r-- | docs/library/machine.Timer.rst | 124 |
1 files changed, 14 insertions, 110 deletions
diff --git a/docs/library/machine.Timer.rst b/docs/library/machine.Timer.rst index ef46f9dd7..b16ad52d5 100644 --- a/docs/library/machine.Timer.rst +++ b/docs/library/machine.Timer.rst @@ -21,6 +21,9 @@ Timer callbacks. :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 ------------ @@ -32,129 +35,30 @@ Constructors Methods ------- -.. only:: port_wipy +.. method:: Timer.init(\*, mode=Timer.PERIODIC, period=-1, callback=None) - .. method:: Timer.init(mode, \*, width=16) + Initialise the timer. Example:: - 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 - tim.init(Timer.PERIODIC) # periodic 16-bit timer - tim.init(Timer.ONE_SHOT, width=32) # one shot 32-bit timer + Keyword arguments: - 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.PWM`` - Output a PWM signal on a pin. + - ``mode`` can be one of: - - ``width`` must be either 16 or 32 (bits). For really low frequencies < 5Hz - (or large periods), 32-bit timers should be used. 32-bit mode is only available - for ``ONE_SHOT`` AND ``PERIODIC`` modes. + - ``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. -.. only:: port_wipy - - .. method:: Timer.channel(channel, \**, freq, period, polarity=Timer.POSITIVE, duty_cycle=0) - - 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. - -.. only:: port_wipy - - class TimerChannel --- setup a channel for a timer - ================================================== - - Timer channels are used to generate/capture a signal using a timer. - - TimerChannel objects are created using the Timer.channel() method. - - Methods - ------- - - .. method:: timerchannel.irq(\*, trigger, priority=1, handler=None) - - The behavior of this callback is heavily dependent on the operating - mode of the timer channel: - - - If mode is ``Timer.PERIODIC`` the callback is executed periodically - with the configured frequency or period. - - If mode is ``Timer.ONE_SHOT`` the callback is executed once when - the configured timer expires. - - If mode is ``Timer.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 ``Timer.TIMEOUT`` when the operating mode is either ``Timer.PERIODIC`` or - ``Timer.ONE_SHOT``. In the case that mode is ``Timer.PWM`` then trigger must be equal to - ``Timer.MATCH``. - - Returns a callback object. - -.. only:: port_wipy - - .. method:: timerchannel.freq([value]) - - Get or set the timer channel frequency (in Hz). - - .. method:: timerchannel.period([value]) - - Get or set the timer channel period (in microseconds). - - .. method:: timerchannel.duty_cycle([value]) - - 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. - Constants --------- .. data:: Timer.ONE_SHOT -.. data:: Timer.PERIODIC + Timer.PERIODIC Timer operating mode. |