156 lines
2.6 KiB
Markdown
156 lines
2.6 KiB
Markdown
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# PWM Module
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| Since | Origin / Contributor | Maintainer | Source |
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| :----- | :-------------------- | :---------- | :------ |
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| 2014-12-22 | [Zeroday](https://github.com/funshine) | [Zeroday](https://github.com/funshine) | [pwm.c](../../app/modules/pwm.c)|
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## pwm.close()
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Quit PWM mode for the specified GPIO pin.
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#### Syntax
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`pwm.close(pin)`
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#### Parameters
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`pin` 1~12, IO index
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#### Returns
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`nil`
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#### See also
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[pwm.start()](#pwmstart)
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## pwm.getclock()
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Get selected PWM frequency of pin.
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#### Syntax
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`pwm.getclock(pin)`
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#### Parameters
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`pin` 1~12, IO index
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#### Returns
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`number` PWM frequency of pin
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#### See also
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[pwm.setclock()](#pwmsetclock)
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#### See also
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[pwm.getduty()](#pwmgetduty)
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## pwm.getduty()
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Get selected duty cycle of pin.
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#### Syntax
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`pwm.getduty(pin)`
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#### Parameters
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`pin` 1~12, IO index
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#### Returns
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`number` duty cycle, max 1023
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#### See also
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[pwm.setduty()](#pwmsetduty)
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## pwm.setclock()
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Set PWM frequency.
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**Note:** Setup of the PWM frequency will synchronously change other setups as well if there are any. Only one PWM frequency can be allowed for the system.
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#### Syntax
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`pwm.setclock(pin, clock)`
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#### Parameters
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- `pin` 1~12, IO index
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- `clock` 1~1000, PWM frequency
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#### Returns
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`nil`
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#### See also
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[pwm.getclock()](#pwmgetclock)
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## pwm.setduty()
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Set duty cycle for a pin.
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#### Syntax
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`pwm.setduty(pin, duty)`
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#### Parameters
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- `pin` 1~12, IO index
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- `duty` 0~1023, pwm duty cycle, max 1023 (10bit)
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#### Returns
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`nil`
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#### Example
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```lua
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-- D1 is connected to green led
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-- D2 is connected to blue led
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-- D3 is connected to red led
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pwm.setup(1, 500, 512)
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pwm.setup(2, 500, 512)
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pwm.setup(3, 500, 512)
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pwm.start(1)
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pwm.start(2)
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pwm.start(3)
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function led(r, g, b)
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pwm.setduty(1, g)
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pwm.setduty(2, b)
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pwm.setduty(3, r)
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end
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led(512, 0, 0) -- set led to red
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led(0, 0, 512) -- set led to blue.
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```
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## pwm.setup()
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Set pin to PWM mode. Only 6 pins can be set to PWM mode at the most.
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#### Syntax
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`pwm.setup(pin, clock, duty)`
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#### Parameters
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- `pin` 1~12, IO index
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- `clock` 1~1000, pwm frequency
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- `duty` 0~1023, pwm duty cycle, max 1023 (10bit)
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#### Returns
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`nil`
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#### Example
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```lua
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-- set pin index 1 as pwm output, frequency is 100Hz, duty cycle is half.
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pwm.setup(1, 100, 512)
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```
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#### See also
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[pwm.start()](#pwmstart)
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## pwm.start()
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PWM starts, the waveform is applied to the GPIO pin.
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#### Syntax
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`pwm.start(pin)`
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####Parameters
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`pin` 1~12, IO index
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#### Returns
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`nil`
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#### See also
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[pwm.stop()](#pwmstop)
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## pwm.stop()
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Pause the output of the PWM waveform.
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#### Syntax
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`pwm.stop(pin)`
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#### Parameters
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`pin` 1~12, IO index
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#### Returns
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`nil`
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#### See also
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[pwm.start()](#pwmstart)
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