gopi-hw

This repository contains hardware implementations and hardware components for gopi and some example programs in the cmd folder. The repository depends on golang version 1.11 and above (in order to support modules). For Linux support, Raspbian GNU/Linux v9 has been tested and for Mac support.

Components

The gopi components provided by this repository are:

Component Path	Plaform/Tag	Description	Conforms to
sys/filepoll	linux	Watch for read & write changes to files
sys/fsnotify	darwin	Watch for changes to files and folders	hw.FSNotify
sys/gpio	linux,rpi	General Purpose Hardware Input/Output	gopi.GPIO
sys/hw	linux,rpi,darwin	Hardware information, capabilities	gopi.Hardware
sys/i2c	linux	I2C interface	gopi.I2C
sys/lirc	linux	Linux IR control (LIRC) interface	gopi.LIRC
sys/mmal	rpi	Multimedia Abstraction Layer	hw.MMAL
sys/pwm	rpi	Pulse Wide Modulation (PWM) interface	gopi.PWM
sys/spi	linux	SPI interface	gopi.SPI

Bindings

In addition to these general interfaces, the repository contains golang bindings for underlying libraries:

Package	Description
rpi	Raspberry Pi bindings for DispmanX, MMAL, Videocore
egl	Bindings for Khronos Group OpenEGL
freetype	Bindings for Freetype2

Building and installing examples

In order to build, pkg-config is required. For the Raspberry Pi, the configuration files are located under /opt/vc/lib/pkg-config so set the environment variable as follows:

bash% PKG_CONFIG_PATH="/opt/vc/lib/pkgconfig"
bash% go install -tags rpi ./cmd/...

There is a makefile which can be used for testing and installing bindings and examples, on a per-platform basis:

bash% make linux   # makes for generic linux
bash% make darwin  # makes for MacOS
bash% make rpi     # makes for Raspberry Pi

The resulting binaries are as follows. Use the -help flag to see the different options for each:

• hw_list Provide information on hardware capabilities
• gpio_ctrl Control the GPIO interface
• i2c_detect Detect I2C devices
• lirc_receive Display IR pulses from an IR device
• pwm_ctrl Control PWM signals on the GPIO interface
• spi_ctrl Control SPI communication
• mmal_camera_preview Preview the camera output on the screen
• mmal_encode_image Demonstrates image decoding and encoding using the GPU
• mmal_video_preview Demonstrates playback of a H264 video on the screen using the GPU
• fsnotify List file & folder changes under one or more folders

Construction Ahead

More information about the individual components implemented in this repository will be forthcoming later!