Electronic clock made by 51 single chip microcomputer-EEWORLD

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I have recently started researching single-chip microcomputers, using the domestically produced STC98C52 chip.

STC89C52 is a low-power, high-performance CMOS 8-bit microcontroller produced by STC, with 8K in-system programmable Flash memory. STC89C52 uses the classic MCS-51 core, but has made many improvements to give the chip functions that traditional 51 microcontrollers do not have. With a smart 8-bit CPU and in-system programmable Flash on a single chip, STC89C52 provides highly flexible and super-effective solutions for many embedded control application systems.

I bought it a long time ago but it has been lying there all the time. Today I took it out again and wrote a C++ program for an electronic clock. It uses a power bank to power it and it is pretty good as an electronic clock.

Function:

Four seven-segment digital tubes serve as the main body of the clock display, two showing hours, two showing minutes, eight LED lights flashing for seconds, and four independent buttons, namely hour+1, hour+10, minute+1, and minute+10.

Electronic clock made by 51 single chip microcomputer
Query the LED circuit, the access terminals are P1^0 to P1^7.

Electronic clock made by 51 single chip microcomputer
The digital tube uses a driver chip, and the access terminals are P2^0 to P2^3.

Electronic clock made by 51 single chip microcomputer
The access end of the button is shown in the figure.

With access to various circuits, we use Keil for programming.

/*
* Copyright (c) 2015, School of Computer Science, Yantai University
* All rights reserved.
* Author: Shao Shuai
* File: temp.c
* Completion date: May 29, 2015
*/  
#include 
#define uchar unsigned char
sbit P2_0 = P2^0;
sbit P2_1 = P2^1;
sbit P2_2 = P2^2;
sbit P2_3 = P2^3;
sbit key1=P3^5; // press the button
sbit key2=P3^4;
sbit key3=P3^3;
sbit key4=P3^2;
static unsigned char second,minute,hour;
unsigned int tcount;
unsigned char m;
uchar code table[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,
                        0xf8,0x80,0x90};

void delay(uchar i)
{
  uchar j,k;
  for(j=i;j>0;j--)
    for(k=125;k>0;k--);
}

void display()
{

   P0=table[hour/10];
   P2_0 = 0;
   delay(5);
   P2_0 = 1;

   P0=(table[hour%10]& 0x7f);
   P2_1 = 0;
   delay(5);
   P2_1 = 1;

   P0=table[minute/10];
   P2_2 = 0;
   delay(5);
   P2_2 = 1;

   P0=table[minute%10];
   P2_3 = 0;
   delay(5);
   P2_3 = 1;
   
}

void main(void)
{
    unsigned int a;
	TMOD=0x02;
    TH0=0x06;
    TL0=0x06;
    TR0=1;
    ET0=1;
    EA=1;
   
 while(1)
 {
   	if(key1==0)
		{
			if(key1==0) //Confirm that the key is pressed
			{
				while(!key1);//release detection
			     hour++;
			}
	   
		}
		if(key2==0)
		{
			if(key2==0)	 
			{
				while(!key2);
			    hour=hour+10;
			}
		}
		if(key3==0)
		{
			if(key3==0)	
			{
				while(!key3);
				minute++;
			}
		}
		if(key4==0)
		{
			if(key4==0)	  
			{
				while(!key4);
				minute=minute+10;
			}
		}	
   for(a=100;a>0;a--)
   {
     display();
   }
 
 }
}

 void t0(void) interrupt 1 using 0
  {	
  tcount++;
    if(tcount==4000)
	  {tcount=0;
	    second++;
		 if(second==60)
		  {second=0;
		   minute++;
		    if(minute==60)
			 {minute=0;
			  hour++;

			  if(hour==24)
			   {hour=0;
			   }
			 }
		  }
		P1=~P1;
	  }
	}

Package it into a hex file and burn it.

Electronic clock made by 51 single chip microcomputer

Run the microcontroller!

Electronic clock made by 51 single chip microcomputer

I originally planned to use a Xiaomi box as the outer shell, but later I found that the box was a bit small, so I just used the bare machine first. Anyway, the 5V power supply cannot reach it.

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