MAX7219.js
function(brightness, callback) {
    if (brightness < 0 || brightness > 15) {
      throw "Invalid brightness number";
    }
    this._shiftOut(MAX7219._Registers.Intensity, brightness, callback);
  }
function(brightness, callback) {
    if (brightness < 0 || brightness > 15) {
      throw "Invalid brightness number";
    }
    this._shiftOut(MAX7219._Registers.Intensity, brightness, callback);
  }
function ( brightness , callback ) { if ( brightness < 0 || brightness > 15 ) { throw "Invalid brightness number" ; } this . _shiftOut ( MAX7219 . _Registers . Intensity , brightness , callback ) ; }
Sets digital control of display brightness.

@param number brightness
The brightness from 0 (dimmest) up to and including 15 (brightest).

@param function callback [optional]
Invoked once the write to the SPI device finishes.
Sets digital control of display brightness .