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https://github.com/chmorgan/go-pwm-example
golang example of pwm interaction using sysfs
https://github.com/chmorgan/go-pwm-example
golang linux onion-omega2 pwm sysfs
Last synced: 5 days ago
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golang example of pwm interaction using sysfs
- Host: GitHub
- URL: https://github.com/chmorgan/go-pwm-example
- Owner: chmorgan
- License: mit
- Created: 2019-02-24T13:27:05.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2019-03-17T01:27:14.000Z (over 5 years ago)
- Last Synced: 2024-06-20T17:46:38.086Z (5 months ago)
- Topics: golang, linux, onion-omega2, pwm, sysfs
- Language: Go
- Homepage:
- Size: 7.81 KB
- Stars: 5
- Watchers: 2
- Forks: 4
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Overview
Example golang application that makes use of the hardware PWM channels.
Written as an example for the Onion Omega2 but this would serve as a good example for a number of
compute modules that have PWM hardware exposed to Linux.
# Dependencies
gobot.io's sysfs module is used to provide access to the pwm hardware
# How to build
The project has been updated to take advantage of go's new module support. This makes it
easy to build.
```
git clone https://github.com/chmorgan/go-pwm-example.git
cd go-pwm-example
go build
```
## Build for the Omega2
golang has support for a number of architectures built in, this makes it well suited for cross platform
development.
The Omega2 uses a MediaTek MT7688 SoC. This processor is a mips architecture and little endian is being used.
Therefore the architecture is 'mips' + 'le', or 'mipsle'.
```
GOOS=linux GOARCH=mipsle go build
```
You should now have a 'go-pwm-example' application in the current directory.
## Copy to your Omega2
Replace 'xxxx' with the address of your Omega.
```
scp go-pwm-example [email protected]:/root/
```
# How to run
## Pin mux configuration
Note: Pin muxing must be set appropriately for the pwm channel being used.
For example:
```
# omega2-ctrl gpiomux get
Group i2c - [i2c] gpio
Group uart0 - [uart] gpio
Group uart1 - [uart] gpio pwm01
Group uart2 - [uart] gpio pwm23
Group pwm0 - pwm [gpio]
Group pwm1 - pwm [gpio]
Group refclk - refclk [gpio]
Group spi_s - spi_s [gpio] pwm01_uart2
Group spi_cs1 - [spi_cs1] gpio refclk
Group i2s - i2s [gpio] pcm
Group ephy - [ephy] gpio
Group wled - wled [gpio]
```
Assuming we are using pwm channel 0 (GPIO18) you'll reconfigure this pin for pwm mode via:
```
# omega2-ctrl gpiomux set pwm0 pwm
set gpiomux pwm0 -> pwm
```
## Running
```
./go-pwm-example
```
And to get command line help you can pass the '-help' option:
```
# ./go-pwm-example -help
Usage of ./go-pwm-example:
-channel int
PWM channel (0, 1, 2, or 3)
-frequency float
Frequency in Hz (default 100)
```