Module GPIO
Raspberry Pi GPIO binding for Lua.
A Lua binding to the (Python) library by Ben Croston to use the GPIO from Lua.
Info:
- Copyright: (c) 2012-2014; Ben Croston for the original Python library, Andre Simon for the initial Lua binding, Thijs Schreijer for the extensions of the Lua binding
- Author: Ben Croston,Andre Simon,Thijs Schreijer
Functions
-
cleanup ()
-
Cleans up the modules' running operations. It will set all pins configured before to input.
-
gpio_function (channel)
-
Gets the configuration of a pin.
Parameters:
- channel
channel/pin to be reported (see setmode )
Returns:
Pin configuration, being IN, OUT, I2C, PWM, SERIAL, SPI or UNKNOWN.
-
input (channel)
-
Reads the pin value. For pins configured as output, it returns the current output value.
Parameters:
- channel
channel/pin to be read (see setmode )
Returns:
Boolean true for a HIGH value, or false for a LOW value
-
output (channel, value)
-
Sets the output of a pin.
Parameters:
- channel
channel/pin to be changed (see setmode )
- value
(boolean) Use a truthy value to set the pin out to
HIGH, or falsy to set to LOW. NOTE: a numeric '0' is also considered falsy! for compatibility with the original Python code.
-
setmode (mode)
-
Sets the pin numbering scheme to be used.
Parameters:
- mode
(optional) either
BCM (chip numbering) or BOARD (Rpi connector numbering)
Returns:
currently set mode, being BCM, BOARD, or UNKNOWN.
-
setup_channel (channel, direction, pull_up_down, initial)
-
Sets a channel up on the GPIO interface.
Parameters:
- channel
channel/pin to be setup (see setmode )
- direction
Sets the direction of the pin, either
IN or OUT
- pull_up_down
(optional, only for inputs) Should the builtin pullup/down resistor be used. Either
PUD_OFF, PUD_DOWN, or PUD_UP
- initial
(boolean, optional, only for outputs) Should an initial value be set? set to truthy value to set the pin out to
HIGH, or falsy to set to LOW. NOTE: a numeric '0' is also considered falsy! for compatibility with the original Python code.
-
setwarnings (mode)
-
Turns warnings on or off.
Parameters:
- mode
if
nil or false turns warnings off, or on otherwise
Tables
-
constants
-
Constants in the module table
Fields:
- RPI_REVISION
Revision of the Raspberry Pi board as detected (either 1 or 2)
- VERSION
Version of the Lua module
- HIGH
for setting outputs and reading inputs (see output and input )
- LOW
for setting outputs and reading inputs (see output and input )
- OUT
Pin configuration, see setup_channel and gpio_function
- IN
Pin configuration, see setup_channel and gpio_function
- PWM
Pin configuration, see gpio_function
- SERIAL
Pin configuration, see gpio_function
- I2C
Pin configuration, see gpio_function
- SPI
Pin configuration, see gpio_function
- UNKNOWN
Pin and pinmode configuration, see gpio_function and setmode
- BOARD
Pinmode configuration, see setmode
- BCM
Pinmode configuration, see setmode
- RISING
Event edge-type detection, see event functions
- FALLING
Event edge-type detection, see event functions
- BOTH
Event edge-type detection, see event functions
PWM object
PWM has been implemented as software PWM. Hardware PWM is not available.
-
ChangeDutyCycle (self, dutycycle)
-
Sets the dutycycle for a PWM object.
Parameters:
- self
PWM object to operate on
- dutycycle
Dutycycle to use for the object, from 0 to 100 %
Returns:
PWM object
-
ChangeFrequency (self, freq)
-
Sets the frequency for a PWM object.
Parameters:
- self
PWM object to operate on
- freq
Frequency to use for the object, in Hz.
Returns:
PWM object
-
newPWM (channel, freq)
-
Creates a software PWM object.
Parameters:
- channel
channel/pin to use for WPM (see setmode )
- freq
Frequency for the PWM object (in Hz)
Returns:
PWM object.
Usage:
local gpio = require("rpi-gpio")
local gpio.setmode(gpio.BOARD)
local Pin, Hz, Duty = 11, 100, 50
gpio.setup_channel(Pin, gpio.OUT, gpio.HIGH)
local pwm = gpio.newPWM(Pin, Hz):start(Duty)
-
start (self, dutycycle)
-
Starts the PWM mode.
Parameters:
- self
PWM object to operate on
- dutycycle
Dutycycle to use for the object, from 0 to 100 %
Returns:
PWM object
-
stop (self)
-
Stops the PWM mode.
Parameters:
- self
PWM object to operate on
Returns:
PWM object
Event detection
Using event detection, the rising or falling edges of the GPIO pins can be detected. Either blocking, non-blocking or asynchroneous.
-
add_event_callback (channel, callback, bouncetime)
-
Adds an event callback function. Using this function requires the helper library
darksidesync (async callback support).
Parameters:
- channel
channel/pin for which to call the callback (see setmode )
- callback
Callback function to call (a single parameter, the channel number, will be passed to the callback)
- bouncetime
(optional) minimum time between two callbacks in milliseconds (intermediate events will be ignored)
-
add_event_detect (channel, edge, callback, bouncetime)
-
Adds event detection for a pin. Using this function with a callback (which is optional) requires the helper library
darksidesync (async callback support).
Parameters:
- channel
channel/pin to detect events for (see setmode )
- edge
What type of edge to catch events for. Either
RISING, FALLING or BOTH.
- callback
(optional) Callback function to call on the event (a single parameter, the channel number, will be passed to the callback). More can be added using add_event_callback .
- bouncetime
(optional) minimum time between two callbacks in milliseconds (intermediate events will be ignored)
-
event_detected (channel)
-
Reads events detected (non-blocking). Pins must first be configured using add_event_detect , events will be queued,
so event_detected will not miss events.
Parameters:
- channel
channel/pin to check for events (see setmode )
Returns:
boolean, true if an event was detected, false otherwise
-
remove_event_detect (channel)
-
Removes event detection for a pin.
Parameters:
- channel
channel/pin to stop detecting events for (see setmode )
-
wait_for_edge (channel, edge)
-
Wait for an event (blocking).
Parameters:
- channel
channel/pin to check for events (see setmode )
- edge
What type of edge to wait for. Either
RISING, FALLING or BOTH.