ADXL345 driver for chirimen.

adxl345.js

function changeToSignedInt(number) {
	if (number >> 15) {
		ret = 65536 - number; 
		return ret * -1;
	} else {
		return number;
	}
}

var adxl345 = {
	init:function initAccelerometer(port, address) {
		port.setDeviceAddress(address);
		return new Promise(function(resolve, reject) {
			// Select range.
			port.write8(0x31, 0x03);
			// Set measure mode.
			port.write8(0x2d, 0x08);
		});
	},

	// read acceleration value.
	read:function readAcceleration(port, address) {
		port.setDeviceAddress(address);
		return new Promise(function(resolve, reject) {
			Promise.all([
				port.read8(0x32, true),
				port.read8(0x33, true),
				port.read8(0x34, true),
				port.read8(0x35, true),
				port.read8(0x36, true),
				port.read8(0x37, true)
			]).then(function(v) {
				console.log(v);
				var x = changeToSignedInt(((v[1] << 8) | v[0]));
				var y = changeToSignedInt(((v[3] << 8) | v[2]));
				var z = changeToSignedInt(((v[5] << 8) | v[4]));
				console.log("x:" + x + " y:" + y + " z:" + z);
				var temp = [x, y, z];
				resolve(temp);
			}, function() {
				console.log("error");
				reject();
			});
		});
	},
	// Write a value to address
	write:function writeAcceleration(port, devAddress, regAddress, value) {
		port.setDeviceAddress(devAddress);
		return new Promise(function(resolve, reject) {
			Promise.all([
				port.write8(regAddress, value);
			]).then(function(v) {
				console.log("writing " + value + " to " + regAddress + " success");
				resolve(value);
			}, function() {
				console.log("error");
				reject();
			});
		});
	}
};