code: func (a *MAX7219Driver) All(address byte, data byte) {
  	a.pinCS.Off()
  	var c uint
  	for c = 0; c < a.count; c++ {
  		a.send(address)
  		a.send(data)
  	}
  	a.pinCS.On()
  }
docs: // All sends the same data to all the modules