https://github.com/pioreactor/rpi_hardware_pwm

Access the hardware PWM of a Raspberry Pi
https://github.com/pioreactor/rpi_hardware_pwm

gpio hardware python raspberry-pi raspberrypi

Last synced: about 1 month ago
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Access the hardware PWM of a Raspberry Pi

• Host: GitHub
• URL: https://github.com/pioreactor/rpi_hardware_pwm
• Owner: Pioreactor
• License: other
• Created: 2021-05-05T13:31:43.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2024-03-06T03:04:05.000Z (9 months ago)
• Last Synced: 2024-10-11T16:43:28.095Z (about 1 month ago)
• Topics: gpio, hardware, python, raspberry-pi, raspberrypi
• Language: Python
• Homepage:
• Size: 36.1 KB
• Stars: 61
• Watchers: 5
• Forks: 14
• Open Issues: 6
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# rpi hardware pwm

![CI status](https://github.com/pioreactor/rpi_hardware_pwm/actions/workflows/ci.yaml/badge.svg)

[![PyPI version](https://badge.fury.io/py/rpi-hardware-pwm.svg)](https://badge.fury.io/py/rpi-hardware-pwm)

Access the hardware PWM of a Raspberry Pi with Python. More lightweight than alternatives.

### Installation

1. On the Raspberry Pi, add `dtoverlay=pwm-2chan` to `/boot/config.txt`. This defaults to `GPIO_18` as the pin for `PWM0` and `GPIO_19` as the pin for `PWM1`.

    - Alternatively, you can change `GPIO_18` to `GPIO_12` and `GPIO_19` to `GPIO_13` using `dtoverlay=pwm-2chan,pin=12,func=4,pin2=13,func2=4`.

    - On the Pi 5, use channels 0 and 1 to control GPIO_12 and GPIO13, respectively; use channels 2 and 3 to control GPIO_18 and GPIO_19, respectively

    - On all other models, use channels 0 and 1 to control GPIO-18 and GPIO_19, respectively

2. **Reboot your Raspberry Pi**.

    - You can check everything is working on running `lsmod | grep pwm` and looking for `pwm_bcm2835`

3. Install this library: `sudo pip3 install rpi-hardware-pwm`

### Examples

> For Rpi 1,2,3,4, use chip=0; For Rpi 5, use chip=2

```python

from rpi_hardware_pwm import HardwarePWM

pwm = HardwarePWM(pwm_channel=0, hz=60, chip=0)

pwm.start(100) # full duty cycle

pwm.change_duty_cycle(50)

pwm.change_frequency(25_000)

pwm.stop()

```

### History

The original code is from [jdimpson/syspwm](https://github.com/jdimpson/syspwm), We've updated it to Python3 and

made it look like the `RPi.GPIO` library's API (but more Pythonic than that.), and we use it in [Pioreactor](https://pioreactor.com) bioreactor system.