The project is discussed in two parts.
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.
Fig. 2: Circuit set up of LCD Module built using AVR controller and 16×2 alphanumeric LCD display
Part2: Interfacing the LCD module using any other microcontroller.
In part two the controller used is in our project is another AVR chip. The data send to the LCD module via serial transmission pin (TXD-15).A switch demonstrated in our project give the input to the controller.
Fig. 3: Interfacing the LCD module with second AVR microcontroller for
A predefined text is transmitted to the LCD module upon every press of the switch. Whatever the text sends, the data will be scrolled in the LCD module.
Fig. 4: Data communication between LCD Module and AVR via serial transmission circuit setup on breadboard
From this demonstration it can be noticed that 8 data pins and 3 control pins of the microcontroller can be saved. Those saved pins can be used for any other purpose.
Connections of LCD with ATmega16 are shown in circuit diagram. In 4-bit mode, the Data lines must be connected with D4, D5, D6 and D7 pins of LCD module.