You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
Luke Palmer d3d8c0c5c6 Merge pull request #79 from fd0/rpi3-kernel-4.9 4 years ago
controller Initial support for rfm69 radio 5 years ago
convertors Fix typo 6 years ago
embd cli: print the rev number in hex 7 years ago
host make fork ready for merge-back 5 years ago
interface interface: add an abstraction layer for character displays 7 years ago
motion/servo unified servo and analog output support for pwms 8 years ago
samples Println doesn't accept formatting. 6 years ago
sensor gpio: provide an api to allow performance timing of pulses 8 years ago
util add test for Map 8 years ago
.gitignore bring in the idea of a hardware abstraction layer 8 years ago
.travis.yml fix travis 5 years ago
AUTHORS added support for us020 ultra sonic range finder 8 years ago
CONTRIBUTING.md doc: how to contribute 8 years ago
CONTRIBUTORS update contributors 5 years ago
LICENSE initial commit 8 years ago
README.md README update 5 years ago
ROADMAP.md doc: add roadmap 8 years ago
descriptor.go spi: added spi feature for all bbb and rpi 8 years ago
detect.go Correctly detect Raspberry Pi 3 on Kernel 4.9 5 years ago
detect_test.go simplify package structure 8 years ago
doc.go revert some gratuitous whitespace changes 5 years ago
gpio.go minor documentation addition 5 years ago
gpiodriver.go gpio: added pinmap accessor for introspection usage 7 years ago
gpiodriver_test.go gpio: added missing function in fakeDigitalPin 7 years ago
i2c.go removing failed Stat use 6 years ago
i2cdriver.go host specific drivers can now be loaded separately 8 years ago
led.go allow lazy initialisation of the drivers 8 years ago
leddriver.go host specific drivers can now be loaded separately 8 years ago
pin.go gpio: CapNormal -> CapAnalog 8 years ago
pin_test.go gpio: CapNormal -> CapAnalog 8 years ago
spi.go Fix typo 6 years ago
spidriver.go Support SPI minor devices >255 (PR #33) 5 years ago
update_contributors.sh rename update_contibutors.sh 5 years ago
utils.go host specific drivers can now be loaded separately 8 years ago

README.md

embd Build Status GoDoc

embd is a hardware abstraction layer (HAL) for embedded systems.

It allows you to start your hardware hack on easily available hobby boards (like the Raspberry Pi, BeagleBone Black, C.H.I.P., etc.) by giving you straight-forward access to the board's capabilities as well as a plethora of sensors (like accelerometers, gyroscopes, thermometers, etc.) and controllers (PWM generators, digital-to-analog convertors) for which it includes drivers. If you move to custom designed boards you have to throw away your code: you carry forward the effort where the HAL abstraction of EMBD will save you precious time.

The overall strategy used in embd is to use Linux device drivers to access gpio pins, SPI and I2C buses, as well as interrupts. This makes it easy to port from one platform to another and it enables kernel code to handle the devices as efficiently as possible. What embd then adds is first a Golang library interface on top of the various Linux devices and then another layer of user-level drivers for specific sensors and controllers that are connected to gpio pins or one of the buses.

Development supported and sponsored by SoStronk and ThoughtWorks.

Also, you might be interested in: Why Golang?

Blog post introducing EMBD

Getting Started

Install Go version 1.6 or later to make compiling for ARM easy. The set up your GOPATH, and create your first .go file. We'll call it simpleblinker.go.

package main

import (
	"time"

	"github.com/kidoman/embd"
	_ "github.com/kidoman/embd/host/rpi" // This loads the RPi driver
)

func main() {
	for {
		embd.LEDToggle("LED0")
		time.Sleep(250 * time.Millisecond)
	}
}

Then install the EMBD package:

$ go get github.com/kidoman/embd

Build the binary for linux/ARM:

$ export GOOS=linux
$ export GOARCH=arm
$ go build simpleblinker.go

Copy the cross-compiled binary to your RaspberryPi*:

$ scp simpleblinker pi@192.168.2.2:~

Then on the rPi run the program with sudo*:

$ sudo ./simpleblinker

You will now see the green LED (next to the always on power LED) blink every 1/4 sec.

* Notes

  • Assuming your RaspberryPi has an IP address of 192.168.2.2. Substitute as necessary
  • sudo (root) permission is required as we are controlling the hardware by writing to special files
  • This sample program is optimized for brevity and does not clean up after itself. Click here to see the full version

Getting Help

Join the slack channel

Platforms Supported

The command line tool

go get github.com/kidoman/embd/embd

will install a command line utility embd which will allow you to quickly get started with prototyping. The binary should be available in your $GOPATH/bin. However, to be able to run this on a ARM based device, you will need to build it with GOOS=linux and GOARCH=arm environment variables set.

For example, if you run embd detect on a BeagleBone Black:

root@beaglebone:~# embd detect

detected host BeagleBone Black (rev 0)

Run embd without any arguments to discover the various commands supported by the utility.

How to use the framework

Package embd provides a hardware abstraction layer for doing embedded programming on supported platforms like the Raspberry Pi and BeagleBone Black. Most of the examples below will work without change (i.e. the same binary) on all supported platforms. How cool is that?

Although samples are all present in the samples folder, we will show a few choice examples here.

Use the LED driver to toggle LEDs on the BBB:

import "github.com/kidoman/embd"
import _ "github.com/kidoman/embd/host/all"
...
embd.InitLED()
defer embd.CloseLED()
...
led, err := embd.NewLED(3)
...
led.Toggle()

Even shorter when quickly trying things out:

import "github.com/kidoman/embd"
import _ "github.com/kidoman/embd/host/all"
...
embd.InitLED()
defer embd.CloseLED()
...
embd.ToggleLED(3)

3 is the same as USR3 for all intents and purposes. The driver is smart enough to figure all this out.

BBB + PWM:

import "github.com/kidoman/embd"
import _ "github.com/kidoman/embd/host/all"
...
embd.InitGPIO()
defer embd.CloseGPIO()
...
pwm, _ := embd.NewPWMPin("P9_14")
defer pwm.Close()
...
pwm.SetDuty(1000)

Control GPIO pins on the RaspberryPi / BeagleBone Black:

import "github.com/kidoman/embd"
import _ "github.com/kidoman/embd/host/all"
...
embd.InitGPIO()
defer embd.CloseGPIO()
...
embd.SetDirection(10, embd.Out)
embd.DigitalWrite(10, embd.High)

Could also do:

import "github.com/kidoman/embd"
import _ "github.com/kidoman/embd/host/all"
...
embd.InitGPIO()
defer embd.CloseGPIO()
...
pin, err := embd.NewDigitalPin(10)
...
pin.SetDirection(embd.Out)
pin.Write(embd.High)

Or read data from the Bosch BMP085 barometric sensor:

import "github.com/kidoman/embd"
import "github.com/kidoman/embd/sensor/bmp085"
import _ "github.com/kidoman/embd/host/all"
...
bus := embd.NewI2CBus(1)
...
baro := bmp085.New(bus)
...
temp, err := baro.Temperature()
altitude, err := baro.Altitude()

Even find out the heading from the LSM303 magnetometer:

import "github.com/kidoman/embd"
import "github.com/kidoman/embd/sensor/lsm303"
import _ "github.com/kidoman/embd/host/all"
...
bus := embd.NewI2CBus(1)
...
mag := lsm303.New(bus)
...
heading, err := mag.Heading()

The above two examples depend on I2C and therefore will work without change on almost all platforms.

Protocols Supported

Sensors Supported

Interfaces

Controllers

Convertors

  • MCP3008 8-channel, 10-bit ADC with SPI protocol, Datasheet

Contributing

Pull requests that follow the guidelines are very appreciated. If you find a problem but are not up to coding a fix please file an issue. Thank you!

About

EMBD is affectionately designed/developed by Karan Misra (kidoman), Kunal Powar (kunalpowar) and FRIENDS. We also have a list of CONTRIBUTORS.