Package Exports

perf-gpio
perf-gpio/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (perf-gpio) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

perf-gpio

High performance GPIO tool kit for raspberry pi, including quadrature_decoder, DC motor control, soft PWM, buttons, etc. Based on c wiringpi.

install

npm install perf-gpio --save

Note: perf-gpio depend on dynamic-linked wiringPi at run-time, make sure you have wiringPi installed (/usr/local/lib/libwiringPi.so file).

API Example

https://pinout.xyz/pinout/wiringpi# is the best doc I can find for wiringpi Pin number mappings.

onoff -- simple

var onoff = require('perf-gpio').onoff;

// wiring-pi 2 = GPIO27 = PIN13
var led = onoff(2);
led.set(1);

onoff -- flash

var onoff = require('perf-gpio').onoff;

// wiring-pi 2 = GPIO27 = PIN13
var led = onoff(2);

var current = false;

setTimeout(timeout, 1000);
function timeout() {
    setTimeout(timeout, 1000);
    current = !current;
    led.set(current);
    console.log(current);
}

button -- simple read

var button = require('perf-gpio').button;

// wiring-pi 3 = GPIO22 = PIN15
var b = button(3, button.PUD_UP); // use raspberry pi build-in 50k pull-up resistor

setTimeout(timeout, 1000);
function timeout() {
    setTimeout(timeout, 1000);
    var current = b.get();
    console.log(current);
}

button -- callback

var button = require('perf-gpio').button;

// wiring-pi 3 = GPIO22 = PIN15
var b = button(3, button.PUD_UP);

b.watch(function(err, status) {
    console.log(status? 'UP' : 'DOWN');
});

inputBank (setup multiple pins, read all at once, as bit mask)

var inputBank = require('perf-gpio').inputBank();
// wiring-pi 25/24/23 = GPIO26/19/13 = PIN37/35/33
var bank = inputBank([25, 24, 23], "PUD_DOWN");

setTimeout(timeout, 1000);
function timeout() {
    setTimeout(timeout, 1000);
    var val = bank();
    // bit mask: bit 0 <= wp25, bit 1 <= wp24, bit 2 <= wp23
    console.log(val);
}

Note: inputBank support batch read, but don't support edge-triggered callback. If you need callback, consider using button.
Note: inputBank and button can share the same pin. Under the hood they are both "input" mode, thus no conflict.

quadrature_decoder

var qd = require('perf-gpio').quadrature_decoder;

// quadrature_decoder you need 2 pins, phase A and B
// wiringpi PIN 0 and 1, maps to BCM GPIO 17 and 18
var counter = qd(0,1);

timeout();

function timeout() {
    setTimeout(timeout, 1000);
    console.log(counter.getCounter());
}

led (DMA-PWM basic)

var led = require('perf-gpio').led();
var pin = led(25); // wiringPi 25, GPIO 26
pin(0.5); // 50% on

led (DMA-PWM cnt.)

var led = require('perf-gpio').led();
var pin = led(25); // wiringPi 25, GPIO 26
pin(1);

setTimeout(function() {
    pin(0.5);
    setTimeout(function() {
        pin.close(); // turn off led before quit
        led.shutdown(); // shutdown DMA device before quit
        process.exit(0);
    }, 2000);
}, 2000);

DC motor control

var motor = require('perf-gpio').motor();
// Need 2 pin to control a DC motor (forward/backword)
// you need a H-bridge module to drive a DC motor
var pin = motor(23, 25);

pin(-0.5); // anywhere range from [-1.0, +1.0]

function timeout() {
    pin.close(); // turn off motor before quit
    motor.shutdown(); // shutdown DMA device before quit
    process.exit(0);
}

setTimeout(timeout, 2000);

Note: DC motor and LED shares the same DMA channel (14 for pi2/3/zero and 7 for pi4), 5ms cycle with 2us step size.

Servo control

var servo = require('perf-gpio').servo();
var pin = servo(29); // wiringpi_25=gpio_21=Phys_40

pin(1500); // 1.5ms (mid)

setTimeout(function () {
  pin(500); // 0.5ms (min)
  setTimeout(function () {
    pin(2500); // 2.5ms (max)
    setTimeout(function () {
      pin(1500); // 1.5ms (mid)
      setTimeout(function () {
        servo.shutdown();
        process.exit(0);
      }, 500);
    }, 1000);
  }, 1000);
}, 1000);

Note: Servo runs on it's own DMA channel (13 for pi2/3/zero and 6 for pi4), 20ms cycle with 10us step size.

Clock Output

var clockOut = require('./index').clockOut();

// wiring-pi 22 = GPIO6 = PIN31
var pinNum = 22;
var pin = clockOut(pinNum);
pin.setFeq(10000); // 10kHz
.....
pin.shutdown();

Note: This hardware clock, only available from a few pin.
Note: If don't shutdown, pi continue output clock even after your programe exits!
Note: valid range from [4.7k, 19.2M] (Hz)

Why perf-gpio?

Performance is the main reason I write this library.
perf-gpio is based on c wiringPi, most of the interrupt handling is done in c code. This is especially important for quadrature_decoder, so far perf-gpio is probably the best quadrature decoder available on raspberry-pi.
The DMA-PWM is based on rpio-pwm, which is the best (if not the only) DMA-PWM solution on node.js (that's the reason I spend my time created it).
perf-gpio also supports pull-up/down resistors (which is a must-have for my project).

license

MIT