Using PWM in MaixCAM MaixPy
2024-12-05
Introduction
To use PWM
in MaixPy (v4), first set the pin function to PWM
using pinmap
.
Each PWM
corresponds to a specific pin, as shown in the pin diagram of MaixCAM:
We recommend using PWM6
and PWM7
.
For MaixCAM
, since WiFi
uses all pins of SDIO1
, PWM4~9
can only be used alternatively with WiFi
.
TODO: Provide a method to disable WiFi (requires disabling the WiFi driver in the system, which is quite complex)
Using PWM to Control a Servo in MaixPy
Here we take controlling a servo as an example, using PWM7
and the A19
pin of MaixCAM
:
from maix import pwm, time, pinmap
SERVO_PERIOD = 50 # 50Hz 20ms
SERVO_MIN_DUTY = 2.5 # 2.5% -> 0.5ms
SERVO_MAX_DUTY = 12.5 # 12.5% -> 2.5ms
# Use PWM7
pwm_id = 7
# !! set pinmap to use PWM7
pinmap.set_pin_function("A19", "PWM7")
def angle_to_duty(percent):
return (SERVO_MAX_DUTY - SERVO_MIN_DUTY) * percent / 100.0 + SERVO_MIN_DUTY
out = pwm.PWM(pwm_id, freq=SERVO_PERIOD, duty=angle_to_duty(0), enable=True)
for i in range(100):
out.duty(angle_to_duty(i))
time.sleep_ms(100)
for i in range(100):
out.duty(angle_to_duty(100 - i))
time.sleep_ms(100)
This code controls the servo to rotate from the minimum angle to the maximum angle and then back to the minimum angle.