[51] 8051 based rtc circuit

[tapu]

Dear all
I want to design an alarm clock.with 8051 & 4 digit led display.I have RTC code but I want to know how to multiplex rtc data to 4 digit led display.& what are essential components to run circuit efficiently. Please give reply.

 

[shaiko]

Post the data sheet of the 7 seg

 

[Venkadesh_M]

https://www.circuitstoday.com/interfacing-seven-segment-display-to-8051

 

[tapu]

Dear all,
I replied too late becouse i was using buffers & decoders for each display.but which is very costly method.now i want to multiplex.I have tried above circuit but it does not run properly on proteus.& shows error ''simulation does not run in real time due to excessive load of cpu''.please reply.

 

[welove8051]

dont use buffers and decoders, the circuit given above is simple try it. or else give your code here

 

[Venkadesh_M]

Post your proteus file and code..

 

[tapu]

Here is a code for multiplexing 7 segment displays. In proteus I make circuit as given above but shows error in simulation.I did not make actual hardware yet.

#include<reg51.h>

sbit e1=P2^0;   //for display1
sbit e2=P2^1;   //for display2
sbit e3=P2^2;    //for display3
sbit e4=P2^3;   //for display4
                      // P3 is a data port.
void delay_ms(unsigned int ms_count);
void delay_us(unsigned int us_count);


void main()
	
{
P2=0x00;       //turning off all displays(common cathod)

 while(1)
 {
 
 P3=0x40;   
	e1=1; //enable display1
	 delay_ms(2);
e1=0;
	P3=0xf9;
	 e2=1;
	 delay_ms(2);
   e2=0;
	 
	P3=0x24;
	 e3=1;
	 delay_ms(2);
	 e3=0;

	P3=0x30;
	 e4=1;
	 delay_ms(2);
	 e4=0;
  }
  }


 void delay_ms(unsigned int ms_count)
 {
        while(ms_count!=0)
         {
            delay_us(112);   //delay_us is called to generate 1ms delay
             ms_count--;
            }
   }
 

  void delay_us(unsigned int us_count)
 {  
    while(us_count!=0)
      {
         us_count--;
       }												   
   }

 

[Venkadesh_M]

What errors ?

post the screen shot..

 

[arun_190175]

use timmer for display update

 

[welove8051]

common cathode display with out driver for 8051 is not ideal. use common anode.

the code seems to be okay. increase delay to 8ms.
sorry, i dont have proteus to check this code

 

[tapu]

Dear All.
I have added delay by 8ms and more but problom remains same.here is a circuit

 

[milan.rajik]

Can you use mikroC PRO 8051 Compiler ? Is it ok if I provide RTC DS1307 mikroC PRO 8061 code. mikroC PRO 8051 has software I2C library. I will write RTC code using it.

Have you checked the I2C and DS1307 projects based on 8051 at saeedsolutions.blogspot.com

They work fine.

 

[tapu]

Dear all,
saeeds blog has lcd interfacing.here i want to multiplex 4 seven segment led's for clock project(i shown only multiplex code).
Is Microc compiler easy for keil user?becouse i use keil.

 

[arun_190175]

[ATTACH=CONFIG]114651._xfImport[/ATTACH]#include<reg51.h>
unsigned char  DSPL_RAM[4]={1,2,3,4};//this is for rtc data like HH MM 
unsigned char code image[10]={0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};
void main()
{
	TMOD=0x01; //timer 0 in 16bit timer
	TH0=0xEF;//for 4ms so refresh rate 4x4=16ms==60Hz
	TL0=0xBA;
	ET0=1;//enable timer 0
	EA=1;//globle enable
	TR0=1;//timer run
	while(1)
	{
		//do your task for read rtc and update DSPL_RAM
	}
}
void ISR() interrupt 1
{
	static unsigned char i;//for digit counter
	TH0=0xEF; //reload timer for next segment
	TL0=0xBA;
	P2|=0x0F;//OFF ALL SEGMENT
	P0=image[DSPL_RAM[i]];
	P2&=~(1<<i); //ON CROSPOND SEMENT
	if(i++>=3)
		i=0;
}

=31
i think this help you if you use 8ms delay so total time 8x4=32ms that refresh rate is 1/32~31Hz this is not good for view