gluaperiphery

README

Periphery for GopherLua

A native Go implementation of lua-periphery for the GopherLua VM.

Feature Status

• I²C
• GPIO
• SPI
• MMIO
• Serial

Using

Loading Modules

import (
	"github.com/nubix-io/gluaperiphery"
)

// Bring up a GopherLua VM
L := lua.NewState()
defer L.Close()

// Preload periphery modules
gluaperiphery.Preload(L)

Blinking an LED via a GPIO pin

The following code blinks an LED connected to GPIO18 (header J8 pin #12) of a Raspberry Pi 3 B+:

import (
	"github.com/nubix-io/gluaperiphery"
	"github.com/nubix-io/gluasocket"
)

L := lua.NewState()
defer L.Close()
gluaperiphery.Preload(L)
gluasocket.Preload(L)
L.DoString(`
	local periphery = require 'periphery'
	local socket = require 'socket'
	local gpio18 = periphery.GPIO(18, 'out')
	for j=1,10 do
		gpio18:write(true)
		socket.sleep(.5)
		gpio18:write(false)
		socket.sleep(.5)
	end`)

Reading a GPIO pin

Using a Raspberry Pi 3 B+ with a jumper bridge between GPIO17 and GPIO18, the following code sets a high and low state at GPIO18 used as an output, then reads the state back using GPIO17 used as an input.

import (
	"github.com/nubix-io/gluaperiphery"
)

L := lua.NewState()
defer L.Close()
gluaperiphery.Preload(L)
L.DoString(`
	local periphery = require 'periphery'
	local gpio17 = periphery.GPIO(17, 'in')
	local gpio18 = periphery.GPIO(18, 'out')
	
	gpio18:write(false)
	assert(gpio17:read() == false)
	
	gpio18:write(true)
	assert(gpio17:read() == true)
`)

Opening an I²C bus device

import (
	"github.com/nubix-io/gluaperiphery"
)

L := lua.NewState()
defer L.Close()
gluaperiphery.Preload(L)
L.DoString(`
	local periphery = require 'periphery';
	local i2c = periphery.I2C('/dev/i2c-1');
	return i2c`)
i2c := L.CheckUserData(-1)

Using with lua-bme280

import (
	"github.com/nubix-io/gluaperiphery"
)

L := lua.NewState()
defer L.Close()
gluaperiphery.Preload(L)
L.DoString(`package.preload['bme280'] = function(...)
	(... full inline contents of https://github.com/nubix-io/lua-bme280/blob/0.1.0/src/bme280.lua ...)
end`)
L.DoString(`
	local bme280 = require 'bme280'
	local periphery = require 'periphery'
	local i2c = periphery.I2C('/dev/i2c-1')
	local coeff = bme280.readCoefficients(i2c)
	local tempC = bme280.readTemperatureC(i2c, bme280.AccuracyMode.STANDARD, coeff)
	local pressPa = bme280.readPressurePa(i2c, bme280.AccuracyMode.STANDARD, coeff)
	local humRH = bme280.readHumidityRH(i2c, bme280.AccuracyMode.STANDARD, coeff)
	return tempC, pressPa, humRH`)
tempC, pressPa, humRH := L.CheckNumber(-3), L.CheckNumber(-2), L.CheckNumber(-1)

Testing

$ dep ensure
$ go test -v github.com/nubix-io/gluaperiphery...
=== RUN   TestModuleTableExportsI2C
--- PASS: TestModuleTableExportsI2C (0.00s)
PASS
ok  	github.com/nubix-io/gluaperiphery	(cached)
=== RUN   TestBME280
--- SKIP: TestBME280 (0.00s)
	bme280_test.go:16: A BME280 is not detected
=== RUN   TestLoader
--- PASS: TestLoader (0.00s)
=== RUN   TestConstantExports
--- PASS: TestConstantExports (0.00s)
=== RUN   TestOpenMalformedDevice
--- PASS: TestOpenMalformedDevice (0.00s)
=== RUN   TestOpenNonExistentDevice
--- PASS: TestOpenNonExistentDevice (0.00s)
PASS
ok  	github.com/nubix-io/gluaperiphery/i2c	0.021s

Documentation

Index

• func Loader(L *lua.LState) int
• func Preload(L *lua.LState)

Functions

func Loader

func Loader(L *lua.LState) int

func Preload

func Preload(L *lua.LState)