machine.PWM
PWM: Pulse width modulation module, hardware-supported PWM, can specify any pin (0 to 47 pins)
Each PWM depends on a timer, that is, when the timer is bound to the PWM function, it cannot be used as an ordinary timer. Because there are 3 timers and each timer has 4 channels, that is, a maximum of 12 PWM waveforms can be generated at the same time.
1. Constructor
`python
class machine.PWM (tim, freq, duty, pin, enable = True) `
Create a new PWM object with the specified parameters
1.1. Parameters
tim: Each PWM relies on a timer to generate a waveform, so a timer object needs to be passed here. The timer ID and channel number must be specified when the timer object is initialized.freq: PWM waveform frequencyduty: PWM duty cycle, refers to the percentage of high level in the entire cycle, value: [0,100][pin]: PWM output pin. Instead of setting it, use [fm] (../ builtin_py / fm.md) to manage the pin mapping uniformly.enable: Whether to start generating the waveform immediately, the default bitTrue, and to start generating the PWM waveform on the specified pin immediately after the object is generated
2. Method
2.1. init
Constructor-like
`python
PWM.init (tim, freq, duty, pin, enable = True) `
parameters
Same as constructor
return value
no
2.2. freq
Get or set the PWM frequency
`python
PWM.freq (freq) `
parameters
freq: PWM frequency, optional parameter, if no parameter is passed, the step setting only returns the current frequency value
return value
Actual PWM frequency currently set
2.3. duty
Gets or sets the PWM duty cycle
`python
PWM.duty (duty) `
parameters
duty: PWM duty cycle is optional. If no parameter is passed, the step setting only returns the current duty cycle value.
return value
PWM duty cycle value currently set
2.4. enable
Enable PWM output to generate waveform immediately on specified pin
`python
PWM.enable () `
parameters
no
return value
no
2.5. disable
Disable PWM output, no longer generate waveforms at specified pins
`python
PWM.disable () `
parameters
no
return value
no
2.6. deinit / \ del \
Unregister the PWM hardware, release the occupied resources, and shut down the PWM clock
`python
PWM.deinit () `
parameters
no
return value
no
Examples
`python
pwm.deinit () or
`` python
del pwm
`
3. Constants
no
4. Examples
4.1. Routine 1 (breathing light)
` python
from machine import Timer, PWM
import time
from fpioa_manager import board_info
tim = Timer (Timer.TIMER0, Timer.CHANNEL0, mode = Timer.MODE_PWM)
ch = PWM (tim, freq = 500000, duty = 50, pin = board_info.LED_G)
duty = 0
dir = True
while True:
if dir:
duty + = 10
else:
duty-= 10
if duty> 100:
duty = 100
dir = False
elif duty <0:
duty = 0
dir = True
time.sleep (0.05)
ch.duty (duty)
`
4.2. Routine 2
` python
import time
import machine
from fpioa_manager import board_info
tim = machine.Timer (machine.Timer.TIMER0, machine.Timer.CHANNEL0, mode = machine.Timer.MODE_PWM)
ch0 = machine.PWM (tim, freq = 3000000, duty = 20, pin = board_info.LED_G, enable = False)
ch0.enable ()
time.sleep (3)
ch0.freq (2000000)
print ("freq:", ch0.freq ())
ch0.duty (60)
time.sleep (3)
ch0.disable ()
`