GPIO(3lua)

GPIO(3lua) | 3lua | GPIO(3lua)

# NAME

gpio — access gpio(4) pins from Lua

# SYNOPSIS

local gpio = require 'gpio'

gpiodev = gpio.open(path)
pins = gpio.info(gpiodev)
gpio.close(gpiodev)
gpio.set(gpiodev, pin, flags)
gpio.unset(gpiodev, pin)
state = gpio.read(gpiodev, pin)
oldstate = gpio.write(gpiodev, pin, state)
gpio.toggle(gpiodev, pin)
gpio.attach(gpiodev, driver, offset, mask [, flags])

# DESCRIPTION

The gpio Lua binding provides access to a gpio(4) device using the ioctl(2) interface.

gpiodev = gpio.open(path)
  Open the gpio device and return an object to access its pins.

pins = gpio.info(gpiodev)
  Returns the number of pins. As with all remaining functions, this can also be called using the : notation, i.e. as gpiodev:info().

gpio.close(gpiodev)
  Close the gpio device.

gpio.set(gpiodev, pin, flags)
  Set gpio pin flags. Note that the pin number in this and all remaining functions is zero based and not one based, this to avoid confusion with tools like gpioctl(8) which also number pins starting at zero. The following flags are defined:

  gpio.PIN_INPUT
    Pin is an input.

  gpio.PIN_OUTPUT
    Pin is an output.

  gpio.PIN_INOUT
    Pin is birectional.

  gpio.PIN_OPENDRAIN
    Pin is an open-drain output.

  gpio.PIN_PUSHPULL
    Pin is a push-pull output.

  gpio.PIN_TRISTATE
    Pin is tri-state (output disabled).

  gpio.PIN_PULLUP
    Pin has an internal pull-up enabled.

  gpio.PIN_PULLDOWN
    Pin has an internal pull-down enabled.

  gpio.PIN_INVIN
    Invert input.

  gpio.PIN_INVOUT
    Invert output.

  gpio.PIN_USER
    Pin accessible by users.

  gpio.PIN_PULSATE
    Pulsate pin at a hardware set frequency.

  gpio.PIN_SET
    Pin is set.

gpio.unset(gpiodev, pin)
  Unset gpio pin.

stat = gpio.read(gpiodev, pin)
  Read the current pin state.

oldstate = gpio.write(gpiodev, pin, state)
  Write the pin state returning the old state. The following states are defined:

  gpio.PIN_LOW
    Pin is in the low state.

  gpio.PIN_HIGH
    Pin is in the high state.

gpio.toggle(gpiodev, pin)
  Toggle pin state.

gpio.attach(gpiodev, driver, offset, mask [, flags])
  Attach a device driver with offset, mask, and optional flags at a pin.

# EXAMPLES

The following example code opens /dev/gpio0 and prints all pin values:

    local gpio = require 'gpio'

    gpiodev = gpio.open('/dev/gpio0')

    local npins = gpiodev:info()

    for n = 1, npins do
    	print('pin ' .. n .. ': ' .. gpiodev:read(n - 1))
    end

# SEE ALSO

lua(1), luac(1), intro(3lua), gpio(4)

# HISTORY

A gpio manual appeared in NetBSD 7.0.

# AUTHORS

The gpio Lua binding was written by Marc Balmer <mbalmer@NetBSD.org>.

Januar 7, 2014 | NetBSD 7.0