HD44780 LCD on a Raspberry Pi controlled by node.js with onoff and sleep.

hd44780-lcd.js

var Gpio = require('onoff').Gpio;
var sleep = require('sleep');

var displayPorts = {
  RS:   7,
  E:    8,
  D4:   25,
  D5:   24,
  D6:   23,
  D7:   18,
	
  CHR: 1,
  CMD: 0
};

function LCD(displayConfig) {
	displayConfig = displayConfig || {};
	
	this._displayConfig = {
		width: displayConfig.width || 16,
		line1: 0x80,
		line2: 0xc0,
		
		pulse: displayConfig.pulse || 0.0001,
		delay: displayConfig.delay || 0.0001
	};
	
	this._ports = {
		rs:	null,
		e:	null,
		d4:	null,
		d5:	null,
		d6:	null,
		d7:	null
	};
}

LCD.prototype._sleep = function (seconds) {
	sleep.usleep(seconds * 1000000);
};

LCD.prototype._initDisplay = function () {
	this.writeByte(0x33, displayPorts.CMD);
	this.writeByte(0x32, displayPorts.CMD);
	this.writeByte(0x28, displayPorts.CMD);
	this.writeByte(0x0C, displayPorts.CMD);
	this.writeByte(0x06, displayPorts.CMD);
	this.writeByte(0x01, displayPorts.CMD);
};

LCD.prototype.init = function (callback) {
	this._ports.d4 = new Gpio(displayPorts.D4, 'out');
	this._ports.d5 = new Gpio(displayPorts.D5, 'out');
	this._ports.d6 = new Gpio(displayPorts.D6, 'out');
	this._ports.d7 = new Gpio(displayPorts.D7, 'out');
	
	this._ports.rs = new Gpio(displayPorts.RS, 'out');
	this._ports.e  = new Gpio(displayPorts.E,  'out');

	this._initDisplay();
	callback.call(this);
};

LCD.prototype._clean = function () {
	for (var key in this._ports) {
		this._ports[key].unexport();
	}
};

LCD.prototype.shutdown = function () {
	// this.writeString("\n");
	this._clean();
};

LCD.prototype.writeString = function (string) {
	var parts = string.split("\n");
	var lines = [this._displayConfig.line1, this._displayConfig.line2];
	
	for (var key in parts) {
		this.writeByte(lines[key], displayPorts.CMD);
		
		for (var i = 0; i != this._displayConfig.width; i++) {
			var c = parts[key].charCodeAt(i) || 0x20;
			
			this.writeByte(c, displayPorts.CHR);
		}
	}
};

LCD.prototype.writeByte = function (bits, mode) {
	this._ports.rs.writeSync(mode);
	this._ports.d4.writeSync(0);
	this._ports.d5.writeSync(0);
	this._ports.d6.writeSync(0);
	this._ports.d7.writeSync(0);
	
	if ((bits & 0x10) == 0x10) {
		this._ports.d4.writeSync(1);
	}
	
	if ((bits & 0x20) == 0x20) {
		this._ports.d5.writeSync(1);
	}
	
	if ((bits & 0x40) == 0x40) {
		this._ports.d6.writeSync(1);
	}
	
	if ((bits & 0x80) == 0x80) {
		this._ports.d7.writeSync(1);
	}
	
	this._sleep(this._displayConfig.delay);
	this._ports.e.writeSync(1);
	this._sleep(this._displayConfig.pulse);
	this._ports.e.writeSync(0);
	this._sleep(this._displayConfig.delay);
	
	this._ports.d4.writeSync(0);
	this._ports.d5.writeSync(0);
	this._ports.d6.writeSync(0);
	this._ports.d7.writeSync(0);
	
	if ((bits & 0x1) == 0x1) {
		this._ports.d4.writeSync(1);
	}
	
	if ((bits & 0x2) == 0x2) {
		this._ports.d5.writeSync(1);
	}
	
	if ((bits & 0x4) == 0x4) {
		this._ports.d6.writeSync(1);
	}
	
	if ((bits & 0x8) == 0x8) {
		this._ports.d7.writeSync(1);
	}
	
	this._sleep(this._displayConfig.delay);
	this._ports.e.writeSync(1);
	this._sleep(this._displayConfig.pulse);
	this._ports.e.writeSync(0);
	this._sleep(this._displayConfig.delay);
};

var lcd = new LCD();

lcd.init(function () {
	lcd.writeString("Hello World!\nFeelin' fine.");
	lcd.shutdown();
});

Check out my implementation here: http://myimages.eu/photos/single/313yta.html