A microcontroller is a device which has an inbuilt processor surrounded by few dedicated hardware modules. Once the microcontroller initializes them they start operating on their own. In case of an ADC it will do the sampling and digital to analog conversion all by itself and keep the converted data in its buffer so that the microcontroller can read that later. The advantage of this kind of implementation is that the microcontroller is free to do other tasks during that time and hence increase the overall efficiency. That was the case of hardware modules or peripherals inside a microcontroller which increases the processing efficiency of the built in processor. The efficiency can increase even more if the external hardware attached to the microcontroller can also does lot more tasks by their own without depending the microcontroller. The hardware may or may not contain another processor so that it can perform certain predetermined task after initialized by the microcontroller.
An example for such a device is the serial LCD scrolling display. Once the data to be displayed in scrolling manner is received from the microcontroller, it will start the operation by its own and perform the scrolling process. This project explains interfacing of LCD MODULE with any type of controller using single serial receiving pin. In this mode only one pin is used for sending data. This scrolling display mode has the advantage over the 8-bit mode as it uses only a single pin. The remaining pins of the controller are available for normal use and the valuable processing power required to scroll the data can be used for any other purpose.
Part 1: To Create LCD module
In part one LCD module is created using AVR controller and 16×2 alphanumeric LCD display. The controller ATMEGA16 controls the LCD. The programmed code dumped permanently to this atmega16 is controlling the LCD module. A single receiving pin (RXD -14) of ATMEGA16 is the only input of this LCD module. The data received by serial communication is displayed on the LCD module in a scrolling manner.
For more detail: LCD Scrolling Display Module