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Working of Scrolling text Message Display Led Matrix

When power supply is turned on, a message “FIRMCODE” is displayed on the Led Matrix. after that all text displayed is shifted from right to left , F disappear from left and S appears from right. Shifting of data continues till complete “FIRMCODES DEVELOPER” is displayed on LCD. After that above process is repeated again and again.

Components used

LPC2148 IC
74LS138
74HC595
Led Matrix
Power Supply

Working of 74LS138 (3 Line to 8 Line Decoder )

74LS138 IC is 3 line to 8 line Decoder means input are three bit and output is 8 bit. Input can be provided through A,B,C and output taken from Y0 to Y7 .Figure below explain, how input and output are related to each other.

Working of 74HC595(Shift Register)

The use of shift register 74HC595 minimizes the number of I/O pins required to drive the columns of the LED matrix. For driving 16 columns separately, we need 16 I/O pins of microcontroller, however, with the use of 74HC595 ICs, this number is reduced to 3. This device contains an 8-bit serial-in, parallel-out shift register that feeds an 8-bit D-type storage register. The storage register has 8 number of 3-STATE outputs. Separate clocks are provided for both the shift register and the storage register. The shift register has a direct-overriding clear, serial input, and serial output (standard) pins for cascading. Both the shift register and storage register use positive-edge triggered clocks. If both clocks are connected together, the shift register state will always be one clock pulse ahead of the storage register. The 74HC logic family is speed, function, and pin-out compatible with the standard 74LS logic family. All inputs are protected from damage due to static discharge by internal diode lamps to Vcc and ground.

Why we require 74LS138 & 74HC595 IC ?

When the project is made without these ICs then 64 pin is required to control 7 Led Matrix and as the Led Matrix increases pin requirement is also increase. So to reduce the pin requirement these ICs are used. After using these ICs only 6 pin is required to operate 7 Led Matrix and if Led Matrix increases no extra pin is required, only some program change is required .

Application

This project can be used for Advertising or for providing information at various places like schools, colleges, government offices, shops, hospitals, railway stations.

1. Circuit Diagram of Scrolling text Message Display Led Matrix using LPC2148

1. Program of Scrolling text Message Display Led Matrix using LPC2148

/******************************************************
IDE :- Keil
DEVELOPED BY:- FIRMWARE DEVELOPER (www.firmcodes.com)
WHAT PROGRAM DO:- Program of Scrolling text Message Display Led Matrix using LPC2148
WITH ARM(LPC2148) CONTROLLER
******************************************************/

#include<lpc21xx.h>

void delay_fv(unsigned int x,int y); // delay function

void pulse();   // this fuction give pulse to 74HC595 ic

void data_m(int);  // this fuction give input to 74LS138

void input();   // this fuction display the data on led matrix

void shift_b(int);   // thuis fuction shift the data

/* this fuction reverse the order of data
eg 10110010=0xb2 after reversing it become 01001101=0x4d*/

#define DISPLAY_DATA(x) (((0x80 & x)>>7)|((0x40 & x)>>5)|((0x20 & x)>>3)|((0x10 & x)>>1)  |   ((0x08 & x)<<1)|((0x04 & x)<<3)|((0x02 & x)<<5)|((0x01 & x)<<7))

/* data to display on led matrix*/

char ar[27][7]={0xE0,0xEF,0xEF,0xE3,0xEF,0xEF,0xEF,	 // F
               	0xF1,0xFB,0xFB,0xFB,0xFB,0xFB,0xF1,	 // I
				0xE1,0xEE,0xEE,0xE1,0xEB,0xED,0xEE,	 // R
			    0xEE,0xE4,0xEA,0xEA,0xEE,0xEE,0xEE,	 // M
				0xF1,0xEE,0xEF,0xEF,0xEF,0xEE,0xF1,	 // C
				0xF1,0xEE,0xEE,0xEE,0xEE,0xEE,0xF1,	 // O
				0xE1,0xF6,0xF6,0xF6,0xF6,0xF6,0xE1,  // D
				0xE0,0xEF,0xEF,0xE3,0xEF,0xEF,0xE0,  // E
				0xF1,0xEE,0xEF,0xF1,0xFE,0xEE,0xF1,	 // S
				0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,	 // space
				0xE1,0xF6,0xF6,0xF6,0xF6,0xF6,0xE1,  // D
				0xE0,0xEF,0xEF,0xE3,0xEF,0xEF,0xE0,  // E
				0xEE,0xEE,0xEE,0xF5,0xF5,0xFB,0xFB,  // V  
				0xE0,0xEF,0xEF,0xE3,0xEF,0xEF,0xE0,  // E
				0xEF,0xEF,0xEF,0xEF,0xEF,0xEF,0xE0,  // L
				0xF1,0xEE,0xEE,0xEE,0xEE,0xEE,0xF1,  // O
				0xE1,0xEE,0xEE,0xE1,0xEF,0xEF,0xEF,  // P
				0xE0,0xEF,0xEF,0xE3,0xEF,0xEF,0xE0,  // E
				0xE1,0xEE,0xEE,0xE1,0xEB,0xED,0xEE,	 // R
               	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,	 // space
               	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,	 // space
               	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,	 // space	
				0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,	 // space
               	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,	 // space
               	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,	 // space	
				0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,	 // space	
				0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,	 };	// space

unsigned int data,y;  // globle varible decelaration
							 
int main()
{
	unsigned int k;
  	PINSEL0=0X00000000;   // select the GPIO mode of PIN0.0 TO PIN0.15 
  	PINSEL1=0X00000000;   // select the GPIO mode of PIN0.16 TO PIN0.31 
  	IO0DIR =0X00000fff;   // PIN0.0 TO PIN0.11 work as output and PIN0.12 to PIN0.31 work as input mode
  	PINSEL2=0X00000000;   // select the GPIO mode of PIN1.16 TO PIN1.31
  	IO1DIR=0X0000000F;    // PIN1.16 to PIN0.19 work as output
  	while(1)
   	{ 
     
		input();  // display the text on led matrix
   	}

}

// thuis fuction shift the data

void shift_b(int x)
{
    int i;
	for(i=0;i<x;i++)
	{
		IO0CLR=(0<<3);
		pulse();	
	}
}

// this fuction give pulse to 74HC595 ic

void pulse()
{
  IO0SET=(3<<1);
  IO0CLR=(3<<1);
}

// this fuction give input to 74LS138
void data_m(int x)
{
 	switch(x)
 	{
  	case 1:
  		IO1CLR=(1<<16);
  		IO1CLR=(1<<17);
  		IO1CLR=(1<<18);
  		break;
  	case 2:
  		IO1SET=(1<<16);
  		break;
  	case 3:
 		IO1CLR=(1<<16);
  		IO1SET=(1<<17);
  		break;
  	case 4:
   		IO1SET=(1<<16);
    	IO1SET=(1<<17);
		break;
  	case 5:
   		IO1CLR=(1<<16);
  		IO1CLR=(1<<17);
  		IO1SET=(1<<18);
  		break;
  	case 6:
   		IO1SET=(1<<16);
   		break;
   	case 7:
   		IO1CLR=(1<<16);
   		IO1SET=(1<<17);
   		break;
   	case 8:
    	IO1SET=(1<<16);
    	IO1SET=(1<<17);
		break;
	}

}

// display the text on led matrix
void input()
{
	int i,j,k,l,m,n,x;
  	for(l=0;l<19;l++)
  	{
		for(m=0;m<9;m++)
		{
		    for(n=0;n<15;n++)
			{
  				for(i=0;i<7;i++)
  				{
    				data_m(i+1);
    				IO0CLR=(1<<0);
    				IO0SET=(1<<0);
    				for(j=l;j<7+l;j++)
					{
	   					x=DISPLAY_DATA(~ar[j][i]);
	   					for(k=0;k<8;k++)
	   					{
	      					IO0SET=((x>>k)<<3);
          					pulse();
          					IO0CLR=((x>>k)<<3);  
	   					}
					}
					shift_b(m);
					delay_fv(15,33);
  				}
			}
		}
	}
}

void delay_fv(unsigned int x,int y)
{
 unsigned int i,j;
 for(i=0;i<x;i++)
 for(j=0;j<y;j++);
}

PROTEUS File for SIMULATION(Password Of RAR file is :-firmcodes.com)

Coming soon…

Scrolling text Message Display Led Matrix using LPC2148