johnny-five/lib/shiftregister.js

var Board = require("./board");
var Collection = require("./mixins/collection");
var util = require("util");
var priv = new Map();

function ShiftRegister(opts) {
  if (!(this instanceof ShiftRegister)) {
    return new ShiftRegister(opts);
  }

  if (Array.isArray(opts)) {
    // [Data, Clock, Latch, Reset]
    opts = {
      pins: {
        data: opts[0],
        clock: opts[1],
        latch: opts[2],
        reset: opts.length === 4 ? opts[3] : null,
      }
    };
  } else if (typeof opts.pins === "object" && Array.isArray(opts.pins)) {
    opts.pins = {
      data: opts.pins[0],
      clock: opts.pins[1],
      latch: opts.pins[2],
      reset: opts.pins.length === 4 ? opts.pins[3] : null,
    };
  }

  Board.Component.call(
    this, opts = Board.Options(opts)
  );

  this.size = opts.size || 1;
  this.pins.reset = typeof opts.pins.reset !== "undefined" ? opts.pins.reset : null;

  var isAnode = typeof opts.isAnode !== "undefined" ? opts.isAnode : false;
  var clear = isAnode ? 255 : 0;
  var state = {
    isAnode: isAnode,
    value: new Array(this.size).fill(clear),
    encoded: encoded[isAnode ? "anode" : "cathode"],
    clear: clear,
  };

  priv.set(this, state);

  Object.defineProperties(this, {
    isAnode: {
      get: function() {
        return isAnode;
      }
    },
    value: {
      get: function() {
        return state.value;
      }
    },
  });
}

var encoded = {
  cathode: [63, 6, 91, 79, 102, 109, 125, 7, 127, 103],
  anode: [64, 121, 36, 48, 25, 18, 2, 120, 0, 24],
};

/**
 * Print a digit on a seven segment display, or several
 * digits across several displays.
 */
ShiftRegister.prototype.display = function(value) {
  var state = priv.get(this);
  var chars;

  if (typeof value === "number") {
    // 1, 20, etc.
    return this.display(String(value));
  }

  if (typeof value === "string") {
    var matches = value.match(/([0-9]{1}\.*)/g);

    if (matches && matches.length) {
      chars = matches.map(function(char) {
        // "1"
        if (char.length === 1) {
          return state.encoded[char] | (1 << 7);
        }
        // "1.?.?"
        return state.encoded[char[0]];
      });
    }
  }

  this.send(chars);

  state.value = chars;

  return this;
};

/**
 * Send one or more values to the shift register.
 * @param {...number} value Value to send
 * @returns {ShiftRegister}
 */
ShiftRegister.prototype.send = function(value) {
  var state = priv.get(this);
  var args = Array.from(arguments);

  if (args.length === 1) {
    args = [value];
  }

  if (Array.isArray(value)) {
    args = value;
  }

  // open latch to fill register with data
  this.io.digitalWrite(this.pins.latch, this.io.LOW);

  args.forEach(function(arg) {
    if (typeof arg === "string") {
      arg = arg.charCodeAt(0);
    }
    if (this.isAnode &&
      (arg !== 255 && !state.encoded.includes(arg) && !state.encoded.includes(arg & ~(1 << 7)))) {

      var index = encoded.anode.findIndex(function(value) {
        return value === arg;
      });

      if (index !== -1) {
        arg = encoded.cathode[index];
      }
    }
    this.board.shiftOut(this.pins.data, this.pins.clock, true, arg);
  }, this);

  // close latch to commit bits into register.
  this.io.digitalWrite(this.pins.latch, this.io.HIGH);

  state.value = args;

  return this;
};

/**
 * Clear the shift register by replacing each value with a 0.
 * @type {ShiftRegister}
 */
ShiftRegister.prototype.clear = function() {
  var state = priv.get(this);
  return this.send(Array(this.size).fill(state.clear));
};

ShiftRegister.prototype.reset = function() {
  if (this.pins.reset === null) {
    throw new Error("ShiftRegister was not initialized with a reset pin");
  }
  this.io.digitalWrite(this.pins.clock, this.io.LOW);
  this.io.digitalWrite(this.pins.reset, this.io.LOW);
  this.io.digitalWrite(this.pins.clock, this.io.HIGH);
  this.io.digitalWrite(this.pins.reset, this.io.HIGH);

  return this;
};




/**
 * ShiftRegisters()
 * new ShiftRegisters()
 */
function ShiftRegisters(numsOrObjects) {
  if (!(this instanceof ShiftRegisters)) {
    return new ShiftRegisters(numsOrObjects);
  }

  Object.defineProperty(this, "type", {
    value: ShiftRegister
  });

  Collection.call(this, numsOrObjects);
}

util.inherits(ShiftRegisters, Collection);


/*
 * ShiftRegisters, display(...)
 *
 * eg. array.display(...);

 * ShiftRegisters, send(...)
 *
 * eg. array.send(...);

 * ShiftRegisters, clear()
 *
 * eg. array.clear();

 * ShiftRegisters, reset()
 *
 * eg. array.reset();
 */

Collection.installMethodForwarding(
  ShiftRegisters.prototype, ShiftRegister.prototype
);

// Assign ShiftRegisters Collection class as static "method" of ShiftRegister.
ShiftRegister.Collection = ShiftRegisters;

/* istanbul ignore else */
if (!!process.env.IS_TEST_MODE) {
  ShiftRegister.purge = function() {
    priv.clear();
  };
}

module.exports = ShiftRegister;