obniz/parts/CompassSensor/HMC5883L/index.js

obniz sdk for javascript

class HMC5883L {
  constructor() {
    this.keys = ['gnd', 'sda', 'scl', 'i2c'];

    this.address = {};
    this.address.device = 0x1e;
    this.address.reset = [0x02, 0x00]; // Continuous Measurment Mode
    this.address.xMSB = [0x03];
  }

  static info() {
    return {
      name: 'HMC5883L',
    };
  }

  wired(obniz) {
    this.obniz = obniz;
    obniz.setVccGnd(null, this.params.gnd, '3v');

    this.params.clock = 100000;
    this.params.pull = '3v';
    this.params.mode = 'master';

    this.i2c = obniz.getI2CWithConfig(this.params);

    this.obniz.wait(500);
  }

  init() {
    this.i2c.write(this.address.device, this.address.reset);
    this.obniz.wait(500);
  }

  async get() {
    this.i2c.write(this.address.device, this.address.xMSB);
    let readed = await this.i2c.readWait(this.address.device, 2 * 3);

    let obj = {};
    let keys = ['x', 'y', 'z'];
    for (let i = 0; i < 3; i++) {
      let val = (readed[i * 2] << 8) | readed[i * 2 + 1];
      if (val & 0x8000) {
        val = val - 65536;
      }
      obj[keys[i]] = val;
    }

    return obj;
  }
}

if (typeof module === 'object') {
  module.exports = HMC5883L;
}