Serial LCD Library

Overview

This project can be used with a standard Hitachi HD44780 (or compatible) controller chip to control it through only 2 wires. There is a variety of shapes and sizes available. Line lengths of 8, 16, 20, 24, 32 and 40 characters are all standard, in one, two or four-line versions.

The problem was that these LCDs required at least 4 data wires and 2 control wires. With this project you can communicate with the LCD through only 2 wires.

Working on the circuit

First the shift register is cleared by clocking in six 0’s
Then a 1 is clocked in. This will pull E high after another 5 bits are clocked in
Now clock in the RS bit followed by the 4bit command
Repeat this again to clock in the whole 8 bit data
The lcd should now display the character that was clocked in

Circuit diagram

Example program

program SerialLcdExample;
uses
  libSerialLCD;

begin
  SerialLCD_Init(PortB, 0, 1);
  SerialLCD_Cmd(_LCD_Clear);
  SerialLCD_Out(1, 1, 'Serial LCD Test');
  SerialLCD_Out(2, 2, 'riecktron.co.za');
end.