Class PWM – Pulse width modulation

Pulse Width Modulation (PWM) is a technique for obtaining analog results digitally.

Create object

class machine.PWM(pin, freq, duty)

Create a PWM object associated with a set pin. So you can write the analog value on that pin.

• pin pins that support PWM GPIO0、GPIO2、GPIO4、GPIO5、GPIO10、GPIO12~19、GPIO21、GPIO22、GPIO23、GPIO25~27. see more ESP32引脚功能表.
• freq frequency, 0 < freq <= 78125 Hz
• duty duty ratio, 0 ≤ duty ≤ 0x03FF (Decimal：0 ≤ duty ≤ 1023)

Important

PWM can be enabled on all output pins. But it has limitations：All must be the same frequency and only have 8 channels.

Example:

from machine import PWM, Pin

pwm = PWM (Pin(2), freq=1000,  duty=1023)    # create an PWM object

Method

PWM.init(freq, duty)

Initialize PWM，freq、duty as described above.

Example:

pwm.init(1000, 500)

PWM.freq([freq_val])

When there are no parameters, the function obtains and returns the PWM frequency. When setting parameters, the function is used to set the PWM frequency, no return value.

• freq_val PWM frequency, 0 < freq ≤ 0x0001312D（Decimal：0 < freq ≤ 78125 Hz）

Example:

print(pwm.freq())
print(pwm.freq(2000)

PWM.duty([duty_val])

Without parameters, the function obtains and returns the PWM duty cycle. When there are parameters, the function is used to set the PWM duty cycle.

• duty_val duty ratio, 0 ≤ duty ≤ 0x03FF（Decimal：0 ≤ duty_val ≤ 1023）

Example:

>>> print(pwm.duty())
50
>>> print(pwm.duty(500))
None

PWM.deinit()

Turn off PWM. After using the PWM, you need to log out deinit() 。