Design of electronic clock based on 51 single chip microcomputer

be based on 51 Design of electronic clock of single chip microcomputer

0 Function is introduced

1、 from DS1302 Read time display in

2、 altogether 4 A button , Key 1 Press to enter the modify time mode , Press again to switch the modified time variable , This is the time 2 and 3 The first key is the key to modify the time variable , After modification , Click the key 4 Confirm the change

3、 Not in modify mode , Press the button 2, You can switch the display of time and date

4、 In modify mode , The corresponding modified time variable will flash

1 Software platform and open source code

Simulation software ：Proteus 8.9

Code writing ：Keil5

Baidu network disk link ：

link ：https://pan.baidu.com/s/1RP_8MkZIqHt7WFPc6na3sQ
Extraction code ：y2fn
– From Baidu network disk super member V4 The share of

Gitee link ：

51 Single chip project learning : This warehouse is used to keep some 51 Single chip project learning (gitee.com)

2 Simulation hardware selection

DS1302 Get the current time ,8 Bit common cathode digital tube ,74HC138 Make a choice ,74HC573 Make segment selection ,4 A button .

3 Code writing

3.1 The overall design idea

​ from DS1302 Read out the current time display , When modifying the time , First save the current time into a cache , Then modify the data in the cache , Wait until the modification is completed , Then write the data in the cache DS1302 in .

3.2 Software code design

3.2.1 The nixie tube shows

​ The display of the nixie tube will be placed in a 5ms In the timer of , every other 5ms, Change the display order , adopt 74HC138 To achieve the change of display bit .segCode It is the stored digital tube segment code , cache ,segBuff What is the actual value of , Is whose segment code , If the value is 10, I set it up. segCode by 0x00, That is, do not show .

void SegShow()
{
    
	static u8 segSelectCount = 0;// Bit select variable 
	
	segSelectCount ++;
	if(segSelectCount > 7)
		segSelectCount = 0;

	SEG = 0x00;// Blanking 
	switch (segSelectCount)
	{
    
		case 0: HCC = 0;HCB = 0;HCA = 0;SEG = segCode[segBuff[0]];break;
		case 1: HCC = 0;HCB = 0;HCA = 1;SEG = segCode[segBuff[1]];break;
		case 2: HCC = 0;HCB = 1;HCA = 0;SEG = 0x40               ;break;
		case 3: HCC = 0;HCB = 1;HCA = 1;SEG = segCode[segBuff[2]];break;
		case 4: HCC = 1;HCB = 0;HCA = 0;SEG = segCode[segBuff[3]];break;
		case 5: HCC = 1;HCB = 0;HCA = 1;SEG = 0x40               ;break;
		case 6: HCC = 1;HCB = 1;HCA = 0;SEG = segCode[segBuff[4]];break;
		case 7: HCC = 1;HCB = 1;HCA = 1;SEG = segCode[segBuff[5]];break;
		default:HCC = 0;HCB = 0;HCA = 0;SEG = segCode[segBuff[0]];break;
	}
}

3.2.2 DS1302 Data processing in

Go to DS1302 Write value in register

void ds1302write(u8 addre,u8 dat)
{
    
	u8 i;
	RST=0;
	_nop_();
	SCK=0;
	_nop_();
	RST=1;
	_nop_();
	for (i=0;i<8;i++)
	{
    
		IO=addre&0x01;
		addre>>=1;
		SCK=1;
		_nop_();
		SCK=0;
		_nop_();
	}
	for (i=0;i<8;i++)
	{
    
		IO=dat&0x01;
		dat>>=1;
		SCK=1;
		_nop_();
		SCK=0;
		_nop_();
	}
	RST=0;
}

from DS1302 Medium reading value

u8 ds1302read(u8 addre)
{
    
	u8 i,dat1,dat;
	RST=0;
	_nop_();
	SCK=0;
	_nop_();
	RST=1;
	_nop_();
	for (i=0;i<8;i++)
	{
    
		IO=addre&0x01;
		addre>>=1;
		SCK=1;
		_nop_();
		SCK=0;
		_nop_();
	}
	_nop_();
	for (i=0;i<8;i++)
	{
    
		dat1=IO;
		dat=(dat>>1)|(dat1<<7);
		SCK=1;
		_nop_();
		SCK=0;
		_nop_();
	}
	RST=0;
	_nop_();
	SCK=1;
	_nop_();
	IO=1;
	_nop_();
	IO=0;
	_nop_();
	return dat;
}

DS1302 The initialization , If defined at the beginning of the file FIRST_WRITE The value of is 1, Then it will go to DS1302 writes time[] Time set in , You can open this code for the first time , You can close it later .

void ds1302init()
{
    
#if FIRST_WRITE == 1
	u8 i;
	ds1302write(0x8e,0x00);
	for (i=0;i<7;i++)
	{
    
		ds1302write(writeaddre[i],time[i]);
	}
	ds1302write(0x8e,0x80);
#endif
}

DS1302 Read time , Take data from DS1302 Read it from the register , Then make another one BCD Transcoding 10 Base conversion .

void ds1302readtime()
{
    
	u8 i;
	for (i=0;i<7;i++)
	{
    
		time[i]=ds1302read(readaddre[i]);
	}
	second = (time[0]/16)*10+(time[0]&0x0f);
	minute = (time[1]/16)*10+(time[1]&0x0f);
	hour   = (time[2]/16)*10+(time[2]&0x0f);
	day    = (time[3]/16)*10+(time[3]&0x0f);
	month  = (time[4]/16)*10+(time[4]&0x0f);
	week   = (time[5]/16)*10+(time[5]&0x0f);
	year   = (time[6]/16)*10+(time[6]&0x0f);
}

DS1302 Write time , Do the variable to be written first 10 Turn into the system BCD code , Then write the corresponding register .

void ds1302writetime()
{
    
	u8 i;
	ds1302write(0x8e,0x00);
	time[0] = (((secondTemp/10)<<4) + (secondTemp%10));
	time[1] = (((minuteTemp/10)<<4) + (minuteTemp%10));
	time[2] = (((hourTemp/10)<<4)   + (hourTemp%10));
	time[3] = (((dayTemp/10)<<4)    + (dayTemp%10));
	time[4] = (((monthTemp/10)<<4)  + (monthTemp%10));
	time[5] = (((weekTemp/10)<<4)   + (weekTemp%10));
	time[6] = (((yearTemp/10)<<4)   + (yearTemp%10));
	
	for (i=0;i<7;i++)
	{
    
		ds1302write(writeaddre[i],time[i]);
	}
	ds1302write(0x8e,0x80);
}

3.2.3 Key scan

​ Key scan reference punctual atom writing , But my delay is not according to his use delay Time delay , It is the timer delay used , The advantage of this is that the delay does not occupy CPU resources .

void KeyScan(u8 mode)
{
    
    static int keyCount = 0;
    static int keyState = 0;
    if(mode == 1) keyState=0;
    if (keyState == 0 && (KEY0 == 0||KEY1 == 0||KEY2 == 0||KEY3 == 0))
    {
    
        keyCount++;
        if(keyCount>2)
        {
    
            keyState = 1;
            keyCount=0;
            if(KEY0 == 0) isKey0 = 1;
            else if(KEY1 == 0) isKey1 = 1;
			else if(KEY2 == 0) isKey2 = 1;
			else if(KEY3 == 0) isKey3 = 1;
        }
    } else if (KEY0 == 1 && KEY1 == 1 && KEY2 == 1 && KEY3 == 1)
    {
    
        keyState = 0;
    }
}

3.2.4 Modify the display variables according to the display mode

According to the display status variable , Modify the current display variable

void SegBuffChange()
{
    
	if(showMode == 0)
	{
    
		segBuff[5] = second%10;
		segBuff[4] = second/10;
		segBuff[3] = minute%10;
		segBuff[2] = minute/10;
		segBuff[1] = hour%10;
		segBuff[0] = hour/10;
	}else if(showMode == 1)
	{
    
		segBuff[5] = day%10;
		segBuff[4] = day/10;
		segBuff[3] = month%10;
		segBuff[2] = month/10;
		segBuff[1] = year%10;
		segBuff[0] = year/10;
	}else if(showMode == 2)
	{
    
		segBuff[5] = secondTemp%10;
		segBuff[4] = secondTemp/10;
		segBuff[3] = minuteTemp%10;
		segBuff[2] = minuteTemp/10;
		segBuff[1] = hourTemp%10;
		segBuff[0] = hourTemp/10;
	}else if(showMode == 3)
	{
    
		segBuff[5] = dayTemp%10;
		segBuff[4] = dayTemp/10;
		segBuff[3] = monthTemp%10;
		segBuff[2] = monthTemp/10;
		segBuff[1] = yearTemp%10;
		segBuff[0] = yearTemp/10;
	}
}

3.2.5 Flicker function

​ In the key modification mode , Set the flashing status value 1, Because this function is placed in segBuff After the modification , So before the actual display , What is changed here will be the actual display , You can achieve a flashing effect .

void dataBlink()
{
    
	static u8  blinkCount = 0;
	static bit blinkState = 0;
	if(changeOrNormalState == 1)// In the key modification mode 
	{
    
		blinkCount++;
		if(blinkCount == 80)// every other 80*5  Flashing state value transition 
		{
    
			blinkState = !blinkState;
			blinkCount = 0;
		}
	}else
	{
    
		blinkState = 0;
	}
	if(blinkState == 1)// If the flashing status value is 1, The digit variable nixie tube does not display , I am here seg.c There are definitions. ,10 Just don't show 
	{
    
		segBuff[(2-changeCount%3)*2+1] = 10;
		segBuff[(2-changeCount%3)*2]   = 10;
	}
}

3.2.6 Press the key to execute the function

The execution function after pressing the key , You can see the code comments

void ClockChangeFunction()
{
    
	if(isKey0 == 1)
	{
    
		isKey0 = 0;
		if(changeCount == 0 && changeOrNormalState == 0)// The modified bit is 0, Seconds , At the same time, the display state is under the normal display state 
		{
    
			changeOrNormalState = 1;// Change the display status to modify the time mode 
			DataTempGet();// Get the value of the time variable before modification 
			showMode = 2;// The display mode is to display the hours, minutes and seconds under the modified time 
		}else if(changeOrNormalState == 1)// If it is in display mode 
		{
    
			changeCount++;// Press the next key ++
			if(changeCount > 5)
				changeCount = 0;
			if(changeCount > 2)// Hours, minutes and seconds are 0、1、2, Greater than 2 It is necessary to change the display of year, month and day 
				showMode = 3;// The display mode is to display the year, month and day under the modified time 
			else
				showMode = 2;
		}
	}else if(isKey1 == 1)
	{
    
		isKey1 = 0;
		if(changeOrNormalState == 1)// The display status is modified time mode 
		{
    
			dataAdd();// The corresponding bit time variable increases 
		}else // Normal display mode 
		{
    
			if(showMode == 0)// Switch the display of time and date 
				showMode = 1;
			else if(showMode == 1)
				showMode = 0;
		}
	}else if(isKey2 == 1)
	{
    
		isKey2 = 0;
		if(changeOrNormalState == 1)// Just like adding 
		{
    
			dataSub();
		}
	}else if(isKey3 == 1)
	{
    
		isKey3 = 0;
		if(changeOrNormalState == 1)// Press... In modify mode 
		{
    
			changeOrNormalState = 0;// Change to normal display mode 
			ds1302writetime();// Write the modified time 
			showMode = 0;// The display mode lasts for minutes and seconds 
			changeCount = 0;// Change the bit to zero 
		}
	}
}

3.2.7 Time variable increasing function

This part of the code , Execute in the key execution function , But because of This part is too much , So encapsulate the function , Mainly used to change time variables . The main reason is that there is a leap year , Everything else is normal .

void dataAdd()
{
    
	if(changeCount == 0)
	{
    
		secondTemp ++;
		if(secondTemp > 59)
			secondTemp = 0;
	}else if(changeCount == 1)
	{
    
		minuteTemp ++;
		if(minuteTemp > 59)
			minuteTemp = 0;
	}else if(changeCount == 2)
	{
    
		hourTemp ++;
		if(hourTemp > 23)
			hourTemp = 0;
	}else if(changeCount == 3)
	{
    
		dayTemp ++;
		if(monthTemp == 1 || monthTemp == 3 || monthTemp == 5 || monthTemp == 7 || monthTemp == 8 || monthTemp == 10 || monthTemp == 12)
		{
    
			if(dayTemp > 31)
				dayTemp = 1;
		}else if(monthTemp == 3 || monthTemp == 6 || monthTemp == 9 || monthTemp == 11)
		{
    
			if(dayTemp > 30)
				dayTemp = 1;
		}else if(monthTemp == 2)
		{
    
			if((2000+year)%400==0)
			{
    
				if(dayTemp > 29)
					dayTemp = 1;
			}
			else
			{
    
				if((2000+year)%4==0&&(2000+year)%100!=0)
				{
    
					if(dayTemp > 29)
						dayTemp = 1;
				}else
				{
    
					if(dayTemp > 28)
						dayTemp = 1;
				}
			}
		}
	}else if(changeCount == 4)
	{
    
		monthTemp ++;
		if(monthTemp > 12)
			monthTemp = 1;
	}else if(changeCount == 5)
	{
    
		yearTemp ++;
		if(yearTemp > 99)
			yearTemp = 0;
	}
}

4 summary

​ This design function is relatively simple , Maybe some places also have some small BUG, But I haven't found it yet , If anyone finds out , Welcome to exchange .