rpi-gpio3

API (Error-first)

The default API uses the node-style error-first callbacks to perform asynchronous functions. Most of these methods take a callback, and that callback should check for an error in its first argument. It is important to check for an error after each command, else your code will continue to run and will likely fail in hard to understand ways.

$3

#### setup(channel [, direction, edge], callback)
Sets up a channel for read or write. Must be done before the channel can be used.
* channel: Reference to the pin in the current mode's schema.
* direction: The pin direction, pass either DIR_IN for read mode or DIR_OUT for write mode. You can also pass DIR_LOW or DIR_HIGH to use the write mode and specify an initial state of 'off' or 'on' respectively. Defaults to DIR_OUT.
* edge: Interrupt generating GPIO chip setting, pass in EDGE_NONE for no interrupts, EDGE_RISING for interrupts on rising values, EDGE_FALLING for interrupts on falling values or EDGE_BOTH for all interrupts.
Defaults to EDGE_NONE.
* callback: Provides Error as the first argument if an error occurred.

#### read(channel, callback)
Reads the value of a channel.
* channel: Reference to the pin in the current mode's schema.
* callback: Provides Error as the first argument if an error occured, otherwise the pin value boolean as the second argument.

#### write(channel, value [, callback])
Writes the value of a channel.
* channel: Reference to the pin in the current mode's schema.
* value: Boolean value to specify whether the channel will turn on or off.
* callback: Provides Error as the first argument if an error occured.

#### setMode(mode)
Sets the channel addressing schema.
* mode: Specify either Raspberry Pi or SoC/BCM pin schemas, by passing MODE_RPI or MODE_BCM. Defaults to MODE_RPI.

#### input()
Alias of read().

#### output()
Alias of write().

#### destroy()
Tears down any previously set up channels.

#### reset()
Tears down the module state - used for testing.

$3

#### change
Emitted when the value of a channel changed
* channel
* value

API (Promises)

This API exposes a Promises interface to the module. All of the same functions are available, but do not take callbacks and instead return a Promise.

gpio.setup(7, gpio.DIR_IN, readInput);

gpio.setup(7, gpio.DIR_OUT, write);

gpio.setup(7, gpio.DIR_HIGH, write);

gpio.on('export', function(channel) {
console.log('Channel set: ' + channel);
});

gpio.setup(7, gpio.DIR_OUT);
gpio.setup(15, gpio.DIR_OUT);
gpio.setup(16, gpio.DIR_OUT, pause);

function pause() {
setTimeout(closePins, 2000);
}

var pin = 7;
var delay = 2000;
var count = 0;
var max = 3;

gpio.setup(pin, gpio.DIR_OUT, on);

function on() {
if (count >= max) {
gpio.destroy(function() {
console.log('Closed pins, now exit');
});
return;
}

setTimeout(function() {
gpio.write(pin, 1, off);
count += 1;
}, delay);
}

async.parallel([
function(callback) {
gpio.setup(7, gpio.DIR_OUT, callback)
},
function(callback) {
gpio.setup(15, gpio.DIR_OUT, callback)
},
function(callback) {
gpio.setup(16, gpio.DIR_OUT, callback)
},
], function(err, results) {
console.log('Pins set up');
write();
});

function write() {
async.series([
function(callback) {
delayedWrite(7, true, callback);
},
function(callback) {
delayedWrite(15, true, callback);
},
function(callback) {
delayedWrite(16, true, callback);
},
function(callback) {
delayedWrite(7, false, callback);
},
function(callback) {
delayedWrite(15, false, callback);
},
function(callback) {
delayedWrite(16, false, callback);
},
], function(err, results) {
console.log('Writes complete, pause then unexport pins');
setTimeout(function() {
gpio.destroy(function() {
console.log('Closed pins, now exit');
});
}, 500);
});
};

Due to the nature of this project it can be quite time-consuming to test against real hardware, so the automated test suite is all the more important. I will not accept any pull requests that cause the build to fail, and probably will not accept any that do not have corresponding test coverage.