VGA

case class Vga (rgbConfig: RgbConfig) extends Bundle with IMasterSlave{
  val vSync = Bool
  val hSync = Bool

  val colorEn = Bool  //High when the frame is inside the color area
  val color = Rgb(rgbConfig)

  override def asMaster() = this.asOutput()
}

case class VgaTimingsHV(timingsWidth: Int) extends Bundle {
  val colorStart = UInt(timingsWidth bit)
  val colorEnd = UInt(timingsWidth bit)
  val syncStart = UInt(timingsWidth bit)
  val syncEnd = UInt(timingsWidth bit)
}

case class VgaTimings(timingsWidth: Int) extends Bundle {
  val h = VgaTimingsHV(timingsWidth)
  val v = VgaTimingsHV(timingsWidth)

   def setAs_h640_v480_r60 = ...
   def driveFrom(busCtrl : BusSlaveFactory,baseAddress : Int) = ...
}

case class VgaCtrl(rgbConfig: RgbConfig, timingsWidth: Int = 12) extends Component {
  val io = new Bundle {
    val softReset = in Bool
    val timings   = in(VgaTimings(timingsWidth))

    val frameStart = out Bool
    val pixels     = slave Stream (Rgb(rgbConfig))
    val vga        = master(Vga(rgbConfig))

    val error      = out Bool
  }
  // ...
}