How to Interface LCD with LPC2148

lcd Interfacing With ARM7 Friendly

Tags: ARM7 LPC2148 Evaluation Board,LCD,LCD Interfacing,Step by Step Guide for Interfacing LCD with lpc2148,Interfacing LCD to Microcontroller,Interfacing LCD with LPC2148,, schematics for interfacing lcd with lpc2148, C Program to display a text in LCD using LPC2148, Source Code to display a text in LCD using LPC2148,pin details of LCD
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ARM7 LPC2148 Evaluation Board

The ARM7 LPC2148 Evaluation board is specifically designed to help students to master the required skills in the area of embedded systems. The kit is designed in such way that all the possible features of the microcontroller will be easily used by the students. The kit supports in system programming (ISP) which is done through serial port.


NXP’s ARM7 (LPC2148), ARM Evaluation Kit is proposed to smooth the progress of developing and debugging of various designs encompassing of High speed 32-bit Microcontrollers.


LCD (Liquid Crystal Display)

Liquid Crystal Display also called as LCD is very helpful in providing user interface as well as for debugging purpose. A liquid crystal display (LCD) is a flat panel display that uses the light modulating properties of liquid crystals (LCs). LCD Modules can present textual information to user.


Interfacing LCD

Fig. 1 shows how to interface the LCD to microcontroller. The 2x16 character LCD interface card with supports both modes 4-bit and 8-bit interface, and also facility to adjust contrast through trim pot. In 8-bit interface 11 lines needed to create 8-bit interface; 8 data bits (D0 – D7), three control lines, address bit (RS), read/write bit (R/W) and control signal (E).


block-diagram-for-interfacing-lcd-to-microcontroller-friendly

Fig. 1 Interfacing LCD to Microcontroller


Interfacing LCD with LPC2148

We now want to display a text in LPC2148 Evaluation Board by using LCD module. In LPC2148 Evaluation Board contains the LCD and GLCD connections in a single header.


The ARM7 LPC2148 Evaluation board has eleven numbers of LCD connections, connected with I/O Port lines (P1.20 – P1.22 && P0.16 – P0.23) to make LCD display.


Pin Assignment with LPC2148

 

GLCD/LCD

LPC2148

LCD | 128x64 GLCD Selection

CONTROL L LINES

CS1

P1.18

128x64-glcd-selection

 

 

 

CS2

P1.19

RS

P1.20

R/W

P1.21

E

P1.22

RST

P1.23

LCD – DATA LINES

DB0

P0.16

DB1

P0.17

DB2

P0.18

DB3

P0.19

DB4

P0.20

DB5

P0.21

DB6

P0.22

DB7

P0.23


 


Circuit Diagram to Interface LCD with LPC2148

circuit-diagram-to-interface-lcd-with-lpc2148-friendly


Source Code

The Interfacing LCD with LPC2148 program is very simple and straight forward, that display a text in 2 X 16 LCD module. Some delay is occurring when a single command / data is executed.


C Program to display a text in LCD using LPC2148

 

#include <lpc214x.h>

#include <stdio.h>

 

void lcd_initialize(void);

void delay(unsigned int);

void lcd_cmd(unsigned char);

void lcd_data(unsigned char);

 

const unsigned char msg[] = ("PS-ARM TYRO KITS");

const unsigned char msg1[]= (" ::LCD DEMO:: ");

const unsigned char cmd[4] = {0x38,0x0c,0x06,0x01};

 

void main(void)

{

 

           PINSEL0 = 0;

           PINSEL1 = 0;  

           IODIR0 = 0XFFFFFF00;

            delay(10);  

            lcd_initialize();

            delay(10);

 

           while(1)           //loop forever

          {  

            delay(15);      

            lcd_display();

delay(15);

while(1);

        }

      

}

 

 void lcd_initialize(void)

{

 

   int i;

   for(i=0;i<4;i++)

   {

     IOCLR0 = 0x00FF0000;

     lcd_cmd(cmd[i]);

     delay(15);

   }

 

}

 

void lcd_cmd(unsigned char data)

{

 

   IOPIN0   = data << 16;

   IOCLR0   |= 0x1000;

   IOCLR0   |= 0x2000;

   IOSET0   |= 0x4000;

   delay(15);

   IOCLR0   |= 0x4000;

 

}

 

void lcd_data(unsigned char data)

{

 

   IOPIN0   = data << 16;

   IOSET0   |= 0x1000;

   IOCLR0   |= 0x2000;

   IOSET0  |= 0x4000;

   delay(15);

   IOCLR0   |= 0x4000;

 

}

 

void delay(unsigned int n)

{

           int i,j;

 

           for(i=0;i<n;i++)

              for(j=0;j<0x2700;j++);

}  

 

void lcd_display(void)

{

 

   char i;

   IOCLR0 = 0x00FF0000;

   lcd_cmd(0x80);

   delay(15);

   i=0;

 

   while(msg[i]!='\0')

   {

IOCLR0 = 0x00FF0000;

     lcd_data(msg[i]);

             i++;

     delay(15);

            }

 

          delay(15);

   lcd_cmd(0xc0);

          delay(15);

          i=0;

 

   while(msg1[i]!='\0')

       {

             IOCLR0 = 0x00FF0000;

             lcd_data(msg1[i]);

               i++;

               delay(15);

            }

 

          delay(15);

}

 


To compile the above C code you need the KEIL software. They must be properly set up and a project with correct settings must be created in order to compile the code. To compile the above code, the C file must be added to the project.


In Keil, you want to develop or debug the project without any hardware setup. You must compile the code for generating HEX file. In debugging Mode, you want to check the port output without microcontroller Board.


The Flash Magic software is used to download the hex file into your microcontroller through UART0.


Testing the LCD Module with LPC2148

Give +3.3V power supply to LPC2148 Evaluation Board; the LCD is connected with microcontroller LPC2148 Evaluation Board. When the program is downloading into LPC2148 in Evaluation Board, the screen should show the text messages.


If you not reading any text from LCD, then you just check the jumper connections & adjust the trim pot level. Otherwise you just check it with debugging mode in Keil. If you want to see more details about debugging just see the videos in below link.



General Information

  • For proper working use the components of exact values as shown in Circuit file. Wherever possible use new components.
  • Solder everything in a clean way. A major problem arises due to improper soldering, solder jumps and loose joints.
  • Use the exact value crystal shown in schematic.
  • More instructions are available in following articles,

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