Using https://github.com/nebrius/raspi-gpio on a Raspberry Pi to control digital pin states at 2 kHz from node. In this example a switch was placed on pin 2 and an led was hooked up to pin 0. When the switch (yellow trace) was flipped, the led turned on (blue trace) within 500 us

switch-log.js

console.log('Hello Pi')

var raspi = require('raspi')
var gpio = require('raspi-gpio')
var NanoTimer = require('nanotimer')
var fs = require('fs')
var now = require('performance-now')
var path = require('path')

var timer = new NanoTimer()

var interval = process.argv[2]
var repeats = process.argv[3]

var filename = path.basename(process.argv[1], '.js')
var ws = fs.createWriteStream('./logs/' + filename + '-' + interval + '-' + repeats +'.log' )

var iteration = 0

raspi.init(function() {
  obj = {
    'board': true,
    'date': new Date(),
    'time': now().toFixed(3)
  }
  console.log(JSON.stringify(obj))
//  ws.write(JSON.stringify(obj))

  var input = new gpio.DigitalInput(2)
  var output = new gpio.DigitalOutput(0)

  var curTime = 0
  var prevTime = 0
  var value = 0

timer.setInterval(function() {
  curTime = now()
  for (i=0; i<repeats; i++) {
    value = input.read()   
  }
  for (i=0; i<repeats; i++) {
    output.write(value)
  }
 
  obj = {
    'sw': value,
    'it': iteration,
    'ts': curTime.toFixed(3),
    'df': (curTime - prevTime).toFixed(3)
   }
  prevTime = curTime
  iteration++
//  console.log(JSON.stringify(obj))
  ws.write(JSON.stringify(obj) + '\n')
 }, '', interval)
})

$sudo node switch-multi.js '500u' 20

$sudo node switch-multi.js '500u' 20

$sudo node switch-multi.js '500u' 20
20 pin read, 20 pin writes, and a block of JSON at 2 kHz controlling the switching on and off of an LED