obniz/parts/Display/MatrixLED_MAX7219/index.js

obniz sdk for javascript

class MatrixLED_MAX7219 {
  constructor() {
    this.keys = ['vcc', 'gnd', 'din', 'cs', 'clk'];
    this.requiredKeys = ['din', 'cs', 'clk'];
  }

  static info() {
    return {
      name: 'MatrixLED_MAX7219',
    };
  }

  wired(obniz) {
    this.cs = obniz.getIO(this.params.cs);
    // logich high must 3.5v <=
    if (obniz.isValidIO(this.params.vcc)) {
      obniz.getIO(this.params.vcc).output(true);
    }
    if (obniz.isValidIO(this.params.gnd)) {
      obniz.getIO(this.params.gnd).output(false);
    }

    // max 10Mhz but motor driver can't
    this.params.frequency = this.params.frequency || 10 * 1000 * 1000;
    this.params.mode = 'master';
    this.params.mosi = this.params.din;
    this.params.drive = '3v';
    this.spi = this.obniz.getSpiWithConfig(this.params);

    // reset a onece
    this.cs.output(true);
    this.cs.output(false);
    this.cs.output(true);
  }

  init(width, height) {
    this.width = width;
    this.height = height;
    this.preparevram(width, height);
    this.initModule();
  }

  initModule() {
    this.write([0x09, 0x00]); // Code B decode for digits 3-0 No decode for digits 7-4
    this.write([0x0a, 0x05]); // brightness 9/32 0 to f
    this.write([0x0b, 0x07]); // Display digits 0 1 2 3 4 567
    this.write([0x0c, 0x01]); // Shutdown to normal operation
    this.write([0x0f, 0x00]);
    this.passingCommands();
    this.obniz.wait(10);
  }

  test() {
    this.write([0x0f, 0x00]); // test command
    this.passingCommands();
  }

  passingCommands() {
    for (let i = 8; i < this.width; i += 8) {
      // this needed for number of unit
      this.write([0x00, 0x00]);
    }
  }

  brightness(val) {
    this.write([0x0a, val]); // 0 to 15;
    this.passingCommands();
  }

  preparevram(width, height) {
    this.vram = [];
    for (let i = 0; i < height; i++) {
      let dots = new Array(width / 8);
      for (let ii = 0; ii < dots.length; ii++) {
        dots[ii] = 0x00;
      }
      this.vram.push(dots);
    }
  }

  write(data) {
    this.cs.output(false);
    this.spi.write(data);
    this.cs.output(true);
  }

  writeVram() {
    for (let line_num = 0; line_num < this.height; line_num++) {
      let addr = line_num + 1;
      let line = this.vram[line_num];
      let data = [];
      for (let col = 0; col < line.length; col++) {
        data.push(addr);
        data.push(line[col]);
      }
      this.write(data);
    }
  }

  clear() {
    for (let line_num = 0; line_num < this.height; line_num++) {
      let line = this.vram[line_num];
      for (let col = 0; col < line.length; col++) {
        this.vram[line_num][col] = 0x00;
      }
      this.writeVram();
    }
  }

  draw(ctx) {
    const imageData = ctx.getImageData(0, 0, this.width, this.height);
    const data = imageData.data;

    for (let i = 0; i < data.length; i += 4) {
      let brightness = 0.34 * data[i] + 0.5 * data[i + 1] + 0.16 * data[i + 2];
      let index = parseInt(i / 4);
      let line = parseInt(index / this.width);
      let col = parseInt((index - line * this.width) / 8);
      let bits = parseInt(index - line * this.width) % 8;
      if (bits === 0) this.vram[line][col] = 0x00;
      if (brightness > 0x7f) this.vram[line][col] |= 0x80 >> bits;
    }

    this.writeVram();
  }
}

if (typeof module === 'object') {
  module.exports = MatrixLED_MAX7219;
}