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| -rw-r--r-- | docs/library/machine.PWM.rst | 79 | ||||
| -rw-r--r-- | docs/library/machine.rst | 1 |
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diff --git a/docs/library/machine.PWM.rst b/docs/library/machine.PWM.rst new file mode 100644 index 0000000000..f2273d8b45 --- /dev/null +++ b/docs/library/machine.PWM.rst @@ -0,0 +1,79 @@ +.. currentmodule:: machine +.. _machine.PWM: + +class PWM -- pulse width modulation +=================================== + +This class provides pulse width modulation output. + +Example usage:: + + from machine import PWM + + pwm = PWM(pin) # create a PWM object on a pin + pwm.duty_u16(32768) # set duty to 50% + + # reinitialise with a period of 200us, duty of 5us + pwm.init(freq=5000, duty_ns=5000) + + pwm.duty_ns(3000) # set pulse width to 3us + + pwm.deinit() + +Constructors +------------ + +.. class:: PWM(dest, \*, freq, duty_u16, duty_ns) + + Construct and return a new PWM object using the following parameters: + + - *dest* is the entity on which the PWM is output, which is usually a + :ref:`machine.Pin <machine.Pin>` object, but a port may allow other values, + like integers. + - *freq* should be an integer which sets the frequency in Hz for the + PWM cycle. + - *duty_u16* sets the duty cycle as a ratio ``duty_u16 / 65535``. + - *duty_ns* sets the pulse width in nanoseconds. + + Setting *freq* may affect other PWM objects if the objects share the same + underlying PWM generator (this is hardware specific). + Only one of *duty_u16* and *duty_ns* should be specified at a time. + +Methods +------- + +.. method:: PWM.init(\*, freq, duty_u16, duty_ns) + + Modify settings for the PWM object. See the above constructor for details + about the parameters. + +.. method:: PWM.deinit() + + Disable the PWM output. + +.. method:: PWM.freq([value]) + + Get or set the current frequency of the PWM output. + + With no arguments the frequency in Hz is returned. + + With a single *value* argument the frequency is set to that value in Hz. The + method may raise a ``ValueError`` if the frequency is outside the valid range. + +.. method:: PWM.duty_u16([value]) + + Get or set the current duty cycle of the PWM output, as an unsigned 16-bit + value in the range 0 to 65535 inclusive. + + With no arguments the duty cycle is returned. + + With a single *value* argument the duty cycle is set to that value, measured + as the ratio ``value / 65535``. + +.. method:: PWM.duty_ns([value]) + + Get or set the current pulse width of the PWM output, as a value in nanoseconds. + + With no arguments the pulse width in nanoseconds is returned. + + With a single *value* argument the pulse width is set to that value. diff --git a/docs/library/machine.rst b/docs/library/machine.rst index 18dc6f2afa..5076dc30e0 100644 --- a/docs/library/machine.rst +++ b/docs/library/machine.rst @@ -167,6 +167,7 @@ Classes machine.Pin.rst machine.Signal.rst machine.ADC.rst + machine.PWM.rst machine.UART.rst machine.SPI.rst machine.I2C.rst |