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Dd January 7, 2014
Dt GPIO 3lua
Os
Sh NAME
Nm gpio
Nd access
Xr gpio 4
pins from Lua
Sh SYNOPSIS
Cd "local gpio = require 'gpio'"
Pp
Bl -tag -width XXXX -compact
It Dv gpiodev = gpio.open(path)
It Dv pins = gpio.info(gpiodev)
It Dv gpio.close(gpiodev)
It Dv gpio.set(gpiodev, pin, flags)
It Dv gpio.unset(gpiodev, pin)
It Dv state = gpio.read(gpiodev, pin)
It Dv oldstate = gpio.write(gpiodev, pin, state)
It Dv gpio.toggle(gpiodev, pin)
It Dv gpio.attach(gpiodev, driver, offset, mask [, flags])
El
Sh DESCRIPTION
The
Nm
Lua binding provides access to a
Xr gpio 4
device using the
Xr ioctl 2
interface.
Pp
Bl -tag -width XXXX -compact
It Dv gpiodev = gpio.open(path)
Open the gpio device and return an object to access its pins.
Pp
It Dv 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
Em gpiodev:info() .
Pp
It Dv gpio.close(gpiodev)
Close the gpio device.
Pp
It Dv 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
Xr gpioctl 8
which also number pins starting at zero.
The following flags are defined:
Pp
Bl -tag -width XXXX -compact
It Dv gpio.PIN_INPUT
Pin is an input.
Pp
It Dv gpio.PIN_OUTPUT
Pin is an output.
Pp
It Dv gpio.PIN_INOUT
Pin is birectional.
Pp
It Dv gpio.PIN_OPENDRAIN
Pin is an open-drain output.
Pp
It Dv gpio.PIN_PUSHPULL
Pin is a push-pull output.
Pp
It Dv gpio.PIN_TRISTATE
Pin is tri-state (output disabled).
Pp
It Dv gpio.PIN_PULLUP
Pin has an internal pull-up enabled.
Pp
It Dv gpio.PIN_PULLDOWN
Pin has an internal pull-down enabled.
Pp
It Dv gpio.PIN_INVIN
Invert input.
Pp
It Dv gpio.PIN_INVOUT
Invert output.
Pp
It Dv gpio.PIN_USER
Pin accessible by users.
Pp
It Dv gpio.PIN_PULSATE
Pulsate pin at a hardware set frequency.
Pp
It Dv gpio.PIN_SET
Pin is set.
El
Pp
It Dv gpio.unset(gpiodev, pin)
Unset gpio pin.
Pp
It Dv stat = gpio.read(gpiodev, pin)
Read the current pin state.
Pp
It Dv oldstate = gpio.write(gpiodev, pin, state)
Write the pin state returning the old state.
The following states are defined:
Pp
Bl -tag -width XXXX -compact
It Dv gpio.PIN_LOW
Pin is in the low state.
Pp
It Dv gpio.PIN_HIGH
Pin is in the high state.
El
Pp
It Dv gpio.toggle(gpiodev, pin)
Toggle pin state.
Pp
It Dv gpio.attach(gpiodev, driver, offset, mask [, flags])
Attach a device driver with offset, mask, and optional flags at a pin.
El
Sh EXAMPLES
The following example code opens
Pa /dev/gpio0
and prints all pin values:
Bd -literal
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
Ed
Sh SEE ALSO
Xr lua 1 ,
Xr luac 1 ,
Xr intro 3lua ,
Xr gpio 4
Sh HISTORY
A
Nm
manual appeared in
Nx 7.0 .
Sh AUTHORS
An -nosplit
The
Nm
Lua binding was written by
An Marc Balmer Aq Mt
[email protected] .
