Some LCD modules include a built-in controller. This type of LCD module has a parallel interface for connection to a host MCU such as an Intel 80 or Motorola 68K (8- or 16-bits). The majority of the 3” and smaller size displays are of this type. These displays tend to provide the most compact form factor and are widely used in handheld applications using a single chip solution LCD controller to interface with the glass. The controller has integrated high voltage gate drivers, additional digital logic and usually one page of image buffer. Additionally, the graphics library is tied to the LCD controller. Therefore, LCD modules from two different vendors using same LCD controller chip should be able to use both displays without any change in firmware. If the LCD controller changes while migrating between LCD modules, then the LCD driver needs to be changed in order to use the proper graphics library. All color displays require some kind of back light for operation. Smaller displays use an LED backlight, most of the time more than one LED, simplifying the back light power supply. Using multiple backlight LEDs in series may require a higher voltage then if they are connected in parallel. Almost all LCD controllers operate at 3 or 3.3V which will allow one supply to power parallel backlight LEDs while the series LED configuration will require a higher voltage.  Bigger displays may use different a CCFL backlight which may require an inverter to generate high voltage. The PIC24 devices have a Parallel Master Port (PMP) module which is a highly configurable parallel interface. It can be configured for the Intel 80 or Motorola 68K interface, 8- or 16-bit versions. Microchip also provides a free graphics library with all Microsoft Windows objects to simplify design. Also, if using a touch screen, it is very easy to interface a resistive touch screen with a PIC.