BME280 driver for CHIRIMEN

i2c-BME280.js

// BME280 driver for CHIRIMEN WebI2C
// ported from https://github.com/SWITCHSCIENCE/BME280/blob/master/Python27/bme280_sample.py
// by Satoru Takagi

var BME280 = function(i2cPort,slaveAddress){
	this.digT = [];
	this.digP = [];
	this.digH = [];
	this.t_fine = 0;
	this.i2cPort = i2cPort;
	this.i2cSlave = null;
	if (slaveAddress){
		this.slaveAddress = slaveAddress;
	} else {
		this.slaveAddress = 0x77;
	}
};

BME280.prototype = {
	init: function(){
		return new Promise((resolve, reject)=>{
			this.i2cPort.open(this.slaveAddress).then(async (i2cSlave)=>{
				this.i2cSlave = i2cSlave;
				console.log("init ok:"+this.i2cSlave);
				await this.setup();
				await this.getCalibParam();
				resolve();
			},(err)=>{
				reject(err);
			});
		});
	},
	read: function(){
		return new Promise(async (resolve, reject)=>{
			if(this.i2cSlave == null){
				reject("i2cSlave Address does'nt yet open!");
			}else{
				var MSB = await this.i2cSlave.read8(0x00);
				var LSB = await this.i2cSlave.read8(0x01);
				var data = ((MSB << 8) + LSB)/128.0;
				resolve(data);
			}
		});  
	},
	getCalibParam: async function(){
		var calib = [];
		var dat;
		for ( var ra = 0x88 ; ra <= 0x88+24 ; ra++ ){
			dat = await this.i2cSlave.read8(ra);
			calib.push(dat);
		}
		for ( var ra = 0xE1 ; ra <= 0xE1+7 ; ra++ ){
			dat = await this.i2cSlave.read8(ra);
			calib.push(dat);
		}
		console.log(calib);
		var digT = this.digT;
		var digP = this.digP;
		var digH = this.digH;
		var getSVal = this.getSVal;
		digT.push((calib[1] << 8) | calib[0]); // uint
		digT.push(getSVal((calib[3] << 8) | calib[2]));
		digT.push(getSVal((calib[5] << 8) | calib[4]));
		digP.push((calib[7] << 8) | calib[6]); // uint
		digP.push(getSVal((calib[9] << 8) | calib[8]));
		digP.push(getSVal((calib[11]<< 8) | calib[10]));
		digP.push(getSVal((calib[13]<< 8) | calib[12]));
		digP.push(getSVal((calib[15]<< 8) | calib[14]));
		digP.push(getSVal((calib[17]<< 8) | calib[16]));
		digP.push(getSVal((calib[19]<< 8) | calib[18]));
		digP.push(getSVal((calib[21]<< 8) | calib[20]));
		digP.push(getSVal((calib[23]<< 8) | calib[22]));
		digH.push(getSVal( calib[24] ));
		digH.push(getSVal((calib[26]<< 8) | calib[25]));
		digH.push(getSVal( calib[27] ));
		digH.push(getSVal((calib[28]<< 4) | (0x0F & calib[29])));
		digH.push(getSVal((calib[30]<< 4) | ((calib[29] >> 4) & 0x0F)));
		digH.push(getSVal( calib[31] ));
		console.log(digT,digP,digH);
//		console.log(getSVal(digT[1]),getSVal(digT[2]),getSVal(digP[1]),getSVal(digP[2]),getSVal(digP[3]),getSVal(digP[4]),getSVal(digP[5]),getSVal(digP[6]),getSVal(digP[7]),getSVal(digP[8]));
	},
	getSVal: function(val){
		if ( val & 0x8000 ){
			return (( -val ^ 0xFFFF) + 1);
		} else {
			return ( val );
		}
	},
	setup: async function(){
		var osrs_t = 1; //Temperature oversampling x 1
		var osrs_p = 1; //Pressure oversampling x 1
		var osrs_h = 1; //Humidity oversampling x 1
		var mode   = 3; //Normal mode
		var t_sb   = 5; //Tstandby 1000ms
		var filter = 0; //Filter off
		var spi3w_en = 0; //3-wire SPI Disable

		var ctrl_meas_reg = (osrs_t << 5) | (osrs_p << 2) | mode;
		var config_reg    = (t_sb << 5) | (filter << 2) | spi3w_en;
		var ctrl_hum_reg  = osrs_h;
		
		await this.i2cSlave.write8(0xF2,ctrl_hum_reg);
		await this.i2cSlave.write8(0xF4,ctrl_meas_reg);
		await this.i2cSlave.write8(0xF5,config_reg);
	},
	compensate_P: function(adc_P){
		var t_fine = this.t_fine;
		var digP = this.digP;
		var pressure = 0.0;
		
		var v1 = (t_fine / 2.0) - 64000.0;
		var v2 = (((v1 / 4.0) * (v1 / 4.0)) / 2048) * digP[5];
		v2 = v2 + ((v1 * digP[4]) * 2.0);
		v2 = (v2 / 4.0) + (digP[3] * 65536.0);
		v1 = (((digP[2] * (((v1 / 4.0) * (v1 / 4.0)) / 8192)) / 8)  + ((digP[1] * v1) / 2.0)) / 262144;
		v1 = ((32768 + v1) * digP[0]) / 32768;
		
		if (v1 == 0){
			return (0);
		}
		var pressure = ((1048576 - adc_P) - (v2 / 4096)) * 3125;
		if (pressure < 0x80000000){
			pressure = (pressure * 2.0) / v1;
		} else {
			pressure = (pressure / v1) * 2;
		}
		v1 = (digP[8] * (((pressure / 8.0) * (pressure / 8.0)) / 8192.0)) / 4096;
		v2 = ((pressure / 4.0) * digP[7]) / 8192.0;
		pressure = pressure + ((v1 + v2 + digP[6]) / 16.0)  ;

		console.log( "pressure : ", (pressure/100)," hPa");
		return (pressure);
	},
	compensate_T: function(adc_T){
		var  t_fine = this.t_fine;
		var digT = this.digT;
		var v1 = (adc_T / 16384.0 - digT[0] / 1024.0) * digT[1];
		var v2 = (adc_T / 131072.0 - digT[0] / 8192.0) * (adc_T / 131072.0 - digT[0] / 8192.0) * digT[2];
		t_fine = v1 + v2;
		var temperature = t_fine / 5120.0;
		console.log( "temperature : ",(temperature)," degrees celsius" );
		return (temperature);
	},
	compensate_H: function(adc_H){
		var  t_fine = this.t_fine;
		var digH = this.digH;
		var var_h = t_fine - 76800.0;
		if (var_h != 0){
			var_h = (adc_H - (digH[3] * 64.0 + digH[4]/16384.0 * var_h)) * (digH[1] / 65536.0 * (1.0 + digH[5] / 67108864.0 * var_h * (1.0 + digH[2] / 67108864.0 * var_h)));
		} else {
			return (0);
		}
		var_h = var_h * (1.0 - digH[0] * var_h / 524288.0);
		if (var_h > 100.0){
			var_h = 100.0;
		} else if ( var_h < 0.0){
			var_h = 0.0;
		}
		console.log( "humidity : ", (var_h)," %");
		return ( var_h );
	},
	readData: async function(){
		var data = [];
		var dat;
		for ( var ra =0xF7 ; ra<= 0xF7+8; ra++){
			dat = await this.i2cSlave.read8(ra);
			data.push(dat);
		}
		var pres_raw = (data[0] << 12) | (data[1] << 4) | (data[2] >> 4);
		var temp_raw = (data[3] << 12) | (data[4] << 4) | (data[5] >> 4);
		var hum_raw  = (data[6] << 8)  |  data[7];
		var temperature = this.compensate_T(temp_raw);
		var pressure = this.compensate_P(pres_raw);
		var humidity = this.compensate_H(hum_raw);
		return {
			temperature: temperature,
			pressure: pressure/100,
			humidity: humidity
		}
	}
};

index.html

<!doctype html>
<html>

<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1">
  <title>i2c-DHT12</title>
  <script src="../../polyfill/polyfill.js"></script>
  <script src="../../driversD/i2c-BME280.js"></script>
  <script src="./mainBme.js"></script>
  <style>
    table,p {
      color: blue;
      text-align: center;
      font-size: 24px;
    }

    img {
      display: block;
      margin-left: auto;
      margin-right: auto;
    }
  </style>
</head>

<body>
  <p id="head">BME-280</p>
  <table>
  <tr><td>temperature</td><td id="temp"></td></tr>
  <tr><td>pressure</td><td id="pres"></td></tr>
  <tr><td>humidity</td><td id="humi"></td></tr>
  </table>
</body>

</html>

mainBme.js

"use strict";

var head;
window.addEventListener(
	"load",
	function() {
		head = document.querySelector("#head");
		mainFunction();
	},
	false
);

async function mainFunction() {
	try {
		var i2cAccess = await navigator.requestI2CAccess();
		var port = i2cAccess.ports.get(1);
		var bme280 = new BME280(port, 0x77);
		await bme280.init();
		while (1) {
			var val = await bme280.readData();
			temp.innerHTML=val.temperature;
			pres.innerHTML=val.pressure;
			humi.innerHTML=val.humidity;
			await sleep(1000);
		}
	} catch (error) {
		console.error("error", error);
	}
}

function sleep(ms) {
	return new Promise(function(resolve) {
		setTimeout(resolve, ms);
	});
}