VTech Alphabert s Magic Readport User Manual download pdf (Page 34)

Lab Manual of Microcontroller & Interfacing Page 34

EXPERIMENT NO. 9

AIM: Interface LCD with the microcontroller. Display your name on the LCD.

Interfacing diagram:

Pin connections:

• Data lines of LCD are connected with port P0.

• RS (Register Select) line is connected with port pin P2.0.

• R/W pin is directly connected to ground.

• Enable line is connected with port pin P2.1.

• Relay is driven by transistor SL-100. Transistor SL-100 is controlled by port pin P1.0.

• Push button switches SW1 and SW2 are connected with port Pin P3.2 and P3.3 (External

interrupts pins)

Programming steps:

• Initialize the LCD. For example send command word #38h to initialize LCD for 5⤬7

dots/character and 2 rows. Send command word #3Ch for 5⤬10 dots/character and two

rows. Send other command words like 01h to clear LCD screen, 06h to make LCD ON &

Cursor ON, 80h to start from first line and first character etc.

• Write separate routine to send command in which we will make RS=0 and after

transferring command word to port P1, we will enable LCD by sending pulse at port pin

P3.1. We will use this command routine whenever we want to issue certain commands

during initialization, to clear display, for movement of cursor to display data at particular

position etc.

• Write separate routine to send data to the LCD in which we will make RS=1 and after

transferring data to port P1, we will enable LCD to display data. We will not check

whether LCD is busy or not but we will put certain amount of delay (about 5 ms)

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VTech Alphabert s Magic Readport User Manual Page 34