I made a seven segments clock display with ds1307 RTC. It feature an 8-digit hh-mm-ss with adjustment and alarm setting. Due to a design and PCB fabrication difficulties, I decided to divide two distinct board, one’s for the main controller board and another one is a display board that stack on the main controller board. The schematic below is the main controller board powered by PIC16F876A.
A 7-segments display board stack above the main board.
Making the PCB for this project by hands could spend a lot times etching, drilling and soldering. The user could select a PCB service from a PCB supplier.
PIC16F876A is an 8-bit PIC microcontroller with 28-pin package. its package is also come with a DIP version suitable for hobbyist projects and experiment.
This device is fairly fit to this project referring to the numbers of I/O pins requirement, RAM and ROM space.
An I2C peripheral is also require because it needs to read/write timing data between the DS1307 real time clock chip.
The CPU uses its timer0 timer ticks to multiplex an 8-digits 7-segments display. The display made from eight individual 0.8 inch hi-read common cathode display.
I put some buttons to adjust the HH:MM:SS and also the alarm setting. An output active buzzer beeps any time the alarm time is reached. Buttons and buzzer active time is implemented using the timer0 timer ticks method.
MPLABX XC8 is a compiler of choice for this project. Using this free compiler, the coder can access all the registers definition of the SFR just like one’s the the assembly language programming.
Source code and completed PCB project could be get from GitHub.
https://github.com/BongPeav/xc8/raw/master/SSD_CLOCK.X.rar
MPLABX XC8 source code lists below:
#include <xc.h>
#include "config.h"
#include "defination.h"
#include "i2c.h"
unsigned char T0Cnt;
unsigned char T1Cnt;
unsigned char ssdCnt;
unsigned char _time[3];
unsigned char _timeAlarm[3];
unsigned char modeSel;
unsigned char buzTimer;
unsigned char _PORTB;
unsigned int ssdBlink;
bit blink;
bit swOn;
void T0Init(void);
void timersTick(void);
void T1Init(void);
void ioInit(void);
void varInit(void);
void clockSetup(void);
void clockAdj(void);
void alarmSet(void);
void alarmCheck(void);
void SSDout(unsigned char hrs,unsigned char mns,unsigned char scs);
unsigned char getDate(unsigned char add);
unsigned char bcd2dec(unsigned char bcd);
unsigned char dec2bcd(unsigned char dec);
void rtcInit(void);
unsigned char eeRead(unsigned char add);
void eeCommand(void);
void eeWrite(unsigned char add,unsigned char dat);
void alarmLoad(void);
__EEPROM_DATA(12,30,10,0,0,0,0,0);
void interrupt ISR(void){
if(TMR0IF&&TMR0IE){
T0Cnt++;
TMR0=-78;
TMR0IF=0;
}
if(TMR1IF&&TMR1IE){
T1Cnt++;
TMR1IF=0;
}
}
void main(){
ioInit();
T0Init();
i2cMasterInit(100000);
varInit();
alarmLoad();
rtcInit();
T1Init();
while(1){
timersTick();
SSDout(_time[2],_time[1],_time[0]);
if(modeSel==0) clockAdj();
clockSetup();
alarmCheck();
}
}
void T0Init(void){
T0CS=0;
PSA=0;
OPTION_REGbits.PS=0x05; // 1:64
GIE=1;
TMR0IE=1;
TMR0IF=0;
}
void timersTick(void){
if(T0Cnt>=2){
ssdCnt++;
ssdBlink++;
T0Cnt=0;
}
if(ssdBlink>=blinkRate){
blink^=1;
if(modeSel==0)
for(int i=0;i<3;i++){
_time[i]=getDate(i);
_time[i]=bcd2dec(_time[i]);
}
buzTimer++;
ssdBlink=0;
}
if(T1Cnt>=7){
swOn^=1;
T1Cnt=0;
}
}
void ioInit(void){
TRISA=0xFC;
TRISB=0x00;
TRISC=0x00;
PORTB=0;
ADCON1bits.PCFG=0x06; // all digital
CMCONbits.CM=0x07; // comparator off
}
void varInit(void){
T0Cnt=0;
ssdCnt=0;
ssdBlink=0;
modeSel=0;
T1Cnt=0;
buzTimer=0;
}
void SSDout(unsigned char hrs,unsigned char mns,unsigned char scs){
// COMMON CATHODE
const unsigned char SEG[10]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F};
unsigned char hrs10,hrs1,mns10,mns1,scs10,scs1;
/*
hrs10=hrs>>4;
hrs1=hrs&0x0F;
mns10=mns>>4;
mns1=mns&0x0F;
scs10=scs>>4;
scs1=scs&0x0F;
*/
hrs10=hrs/10;
hrs1=hrs%10;
mns10=mns/10;
mns1=mns%10;
scs10=scs/10;
scs1=scs%10;
switch(ssdCnt){
case 1 :
PORTA=0x00;
PORTC=0x00;
PORTB=SEG[hrs10]|_PORTB;
D1=1;
break;
case 2 :
PORTA=0x00;
PORTC=0x00;
PORTB=SEG[hrs1]|_PORTB;
D2=1;
break;
case 3 :
PORTA=0x00;
PORTC=0x00;
if(blink){
PORTB=64|_PORTB;
D3=1;
}
break;
case 4 :
PORTA=0x00;
PORTC=0x00;
PORTB=SEG[mns10]|_PORTB;
D4=1;
break;
case 5 :
PORTA=0x00;
PORTC=0x00;
PORTB=SEG[mns1]|_PORTB;
D5=1;
break;
case 6 :
PORTA=0x00;
PORTC=0x00;
if(blink){
PORTB=64|_PORTB;
D6=1;
}
break;
case 7 :
PORTA=0x00;
PORTC=0x00;
PORTB=SEG[scs10]|_PORTB;
D7=1;
break;
case 8 :
PORTA=0x00;
PORTC=0x00;
PORTB=SEG[scs1]|_PORTB;
D8=1;
break;
case 9 :
PORTA=0x00;
PORTC=0x00;
ssdCnt=0;
break;
}
}
unsigned char getDate(unsigned char add){
unsigned char _time;
i2cMasterStart();
i2cMasterWrite(ds1307_W);
i2cMasterWrite(add);
i2cMasterRepeatedStart();
i2cMasterWrite(ds1307_R);
_time=i2cMasterRead(0);
i2cMasterStop();
return _time;
}
unsigned char bcd2dec(unsigned char bcd){
unsigned char dec;
dec=10*(bcd>>4)+(bcd&0x0F);
return dec;
}
unsigned char dec2bcd(unsigned char dec){
unsigned char bcd,bcd10,bcd1;
bcd10=dec/10;
bcd1=dec%10;
bcd=(bcd10<<4)+bcd1;
return bcd;
}
void clockSetup(void){
if(mSel==0&&swOn==1){
modeSel++;
swOn=0;
}
switch(modeSel){
case 1 :
alarmSet();
break;
case 2 :
modeSel=0;
break;
}
}
void rtcInit(void){
i2cMasterStart();
i2cMasterWrite(ds1307_W);
i2cMasterWrite(0x07); // Select Control Register
i2cMasterWrite(0x10); // 1Hz
i2cMasterStop();
}
void clockAdj(void){
unsigned char temp;
if(sAdj==0&&swOn==1){
_time[0]++;
if(_time[0]==60) _time[0]=0;
temp=dec2bcd(_time[0]);
i2cMasterStart();
i2cMasterWrite(ds1307_W);
i2cMasterWrite(0x00);
i2cMasterWrite(temp);
i2cMasterStop();
swOn=0;
}
if(mAdj==0&&swOn==1){
_time[1]++;
if(_time[1]==60) _time[1]=0;
temp=dec2bcd(_time[1]);
i2cMasterStart();
i2cMasterWrite(ds1307_W);
i2cMasterWrite(0x01);
i2cMasterWrite(temp);
i2cMasterStop();
swOn=0;
}
if(hAdj==0&&swOn==1){
_time[2]++;
if(_time[2]==24) _time[2]=0;
temp=dec2bcd(_time[2]);
i2cMasterStart();
i2cMasterWrite(ds1307_W);
i2cMasterWrite(0x02);
i2cMasterWrite(temp);
i2cMasterStop();
swOn=0;
}
}
void eeWrite(unsigned char add,unsigned char dat){
// write address and data to eeprom
while(EECON1bits.WR);
EEADR=add;
EEDATA=dat;
EECON1bits.EEPGD=0; // point to data memory
EECON1bits.WREN=1; // enable write
}
unsigned char eeRead(unsigned char add){
unsigned char edata;
EEADR=add;
EECON1bits.EEPGD=0; // select data space
EECON1bits.RD=1; // read
edata=EEDATA;
return edata;
}
void eeCommand(void){
// Special Command
GIE=0;
EECON2=0x55;
EECON2=0xAA;
EECON1bits.WR=1;
GIE=1;
TMR0IE=1;
TMR0IF=0;
EECON1bits.WREN=0;
}
void alarmLoad(void){
for(int i=0;i<3;i++){
_timeAlarm[i]=eeRead(i);
}
}
void alarmSet(void){
_PORTB=0x00;
PORTB|=_PORTB;
for(int i=0;i<3;i++){
_time[i]=_timeAlarm[i];
}
if(sAdj==0&&swOn==1){
_timeAlarm[0]++;
if(_timeAlarm[0]==60) _timeAlarm[0]=0;
eeWrite(sAlarm,_timeAlarm[0]);
eeCommand();
swOn=0;
}
if(mAdj==0&&swOn==1){
_timeAlarm[1]++;
if(_timeAlarm[1]==60) _timeAlarm[1]=0;
eeWrite(mAlarm,_timeAlarm[1]);
eeCommand();
swOn=0;
}
if(hAdj==0&&swOn==1){
_timeAlarm[2]++;
if(_timeAlarm[2]==24) _timeAlarm[2]=0;
eeWrite(hAlarm,_timeAlarm[2]);
eeCommand();
swOn=0;
}
alarmLoad();
}
void T1Init(void){
T1CONbits.T1CKPS=0x02; // 1:4
T1CONbits.T1OSCEN=0;
T1CONbits.TMR1CS=0; //FOSC/4
T1CONbits.TMR1ON=1;
TMR1H=0;
TMR1L=0;
INTCONbits.PEIE=1;
PIE1bits.TMR1IE=1;
PIR1bits.TMR1IF=0;
}
void alarmCheck(void){
unsigned short long alarmSet;
unsigned short long timeRun;
alarmSet=(3600*_timeAlarm[2])+(60*_timeAlarm[1])+_timeAlarm[0];
timeRun=(3600*_time[2])+(60*_time[1])+_time[0];
if((timeRun<=alarmSet+10)&&(timeRun>=alarmSet)){
_PORTB=128;
}
else
_PORTB=0;
}
Bill of Material:
Category References Value Stock Code Unit Cost Capacitors C1 10p Maplin WX44X Capacitors C2 10p Maplin WX44X Capacitors C3 1000U Digikey P5142-ND Capacitors C4 100n Maplin BX03D Resistors R1 220R M220R Resistors R2 220R M220R Resistors R3 220R M220R Resistors R4 220R M220R Resistors R5 220R M220R Resistors R6 220R M220R Resistors R7 220R M220R Resistors R8 220R M220R Resistors R9 10k M10K Resistors R10 10k M10K Resistors R11 1k M1k Resistors R12 10k M10K Resistors R13 10k M10K Resistors R14 10k M10K Resistors R15 10k M10K Resistors R16 10k M10K Resistors R17 470R M220R Integrated Circuits U1 CONN-SIL8 Integrated Circuits U2 DD7SEG08 Integrated Circuits U3 7404 Integrated Circuits U4 7404 Integrated Circuits U5 ULN2804 Transistors Q1 2N3904 Diodes D1 CONN-SIL7 Diodes D2 LED Miscellaneous BAT1 3V Miscellaneous BUZ1 BUZZER03 Miscellaneous BUZ2 BUZZER03 Miscellaneous DP1 DD7SEG08 Miscellaneous DP2 DD7SEG08 Miscellaneous DP3 DD7SEG08 Miscellaneous DP4 DD7SEG08 Miscellaneous J1 DD7SEG08 Miscellaneous J2 CONN-SIL8 Miscellaneous J3 CONN-SIL2 Miscellaneous J4 ICSP Miscellaneous J5 CONN-SIL7 Miscellaneous J6 CONN-SIL8 Miscellaneous SW1 Miscellaneous SW2 Miscellaneous SW3 Miscellaneous SW4 Miscellaneous SW5 Miscellaneous X1 DD7SEG08 Miscellaneous X2 CRYSTAL
Click here to download full PCB project file.
DIY Electronics Projects 