Using the DS3231 on the Pioneer600 with the Raspberry Pi

The Raspberry Pi doesn’t have an RTC chip on it but with an expansion board you can add this

A popular chip is the DS3231 , lets have a quick look at this chip

DS3231 Information

I used a Pioneer600 board which has one of these chips on it among other features

Parts

The Pioneer600 costs around $39 for many useful features

DS3231 Examples

C example using the  BCM library

[codesyntax lang=”cpp”]

#include <bcm2835.h>  
#include <stdio.h>
#include <unistd.h>

//regaddr,seconds,minutes,hours,weekdays,days,months,yeas
char  buf[]={0x00,0x00,0x22,0x06,0x27,0x12,0x19};
char  *str[]  ={"SUN","Mon","Tues","Wed","Thur","Fri","Sat"};
void pcf8563SetTime()
{
	bcm2835_i2c_write(buf,8);
}

void pcf8563ReadTime() 
{   
	buf[0] = 0x00;  
    bcm2835_i2c_write_read_rs(buf ,1, buf,7);  
} 

int main(int argc, char **argv)  
{  
	if (!bcm2835_init())return 1;  
   	bcm2835_i2c_begin();  
    bcm2835_i2c_setSlaveAddress(0x68);  
    bcm2835_i2c_set_baudrate(10000);  
    printf("DS3231 Test Program ...\n\n"); 
   	
    pcf8563SetTime(); 
    while(1)  
    {  
       	pcf8563ReadTime();
		buf[0] = buf[0]&0x7F; //sec
		buf[1] = buf[1]&0x7F; //min
		buf[2] = buf[2]&0x3F; //hour
		buf[3] = buf[3]&0x07; //week
		buf[4] = buf[4]&0x3F; //day
		buf[5] = buf[5]&0x1F; //mouth
		//year/month/day
		printf("20%02x/%02x/%02x  ",buf[6],buf[5],buf[4]);
		//hour:minute/second
		printf("%02x:%02x:%02x  ",buf[2],buf[1],buf[0]);
		//weekday
		printf("%s\n",str[(unsigned char)buf[3]]);
		bcm2835_delay(1000); 
	}  

	bcm2835_i2c_end();  
   	bcm2835_close();  
      
    return 0;  
}  

[/codesyntax]

Save the file as “ds3231.c”. Compile and run with:

gcc -Wall ds3231.c -o ds3231-lbcm2835
sudo ./ds3231

Python example

[codesyntax lang=”python”]

#!/usr/bin/python
# -*- coding: utf-8 -*-
import smbus
import time

address = 0x68
register = 0x00
#sec min hour week day mout year
NowTime = [0x00,0x00,0x22,0x06,0x27,0x12,0x19]
w  = ["SUN","Mon","Tues","Wed","Thur","Fri","Sat"];
#/dev/i2c-1
bus = smbus.SMBus(1)
def ds3231SetTime():
	bus.write_i2c_block_data(address,register,NowTime)

def ds3231ReadTime():
	return bus.read_i2c_block_data(address,register,7);

ds3231SetTime()
while 1:
	t = ds3231ReadTime()
	t[0] = t[0]&0x7F  #sec
	t[1] = t[1]&0x7F  #min
	t[2] = t[2]&0x3F  #hour
	t[3] = t[3]&0x07  #week
	t[4] = t[4]&0x3F  #day
	t[5] = t[5]&0x1F  #mouth
	print("20%x/%02x/%02x %02x:%02x:%02x %s" %(t[6],t[5],t[4],t[2],t[1],t[0],w[t[3]-1]))
	time.sleep(1)

[/codesyntax]

Save the file as “ds3231.py” and execute it with:

sudo python ds3231.py

C example using  WiringPi

[codesyntax lang=”cpp”]

#include <wiringPi.h>
#include <wiringPiI2C.h>  
#include <stdio.h>

#define DS3231_Address 0x68
//seconds,minutes,hours,weekdays,days,months,yeas
char  buf[]={0x00,0x00,0x22,0x06,0x27,0x12,0x19};
char  *str[]  ={"SUN","Mon","Tues","Wed","Thur","Fri","Sat"};
int fd,i;

void pcf8563SetTime()
{
	for(i = 0;i < 7;i++)
	{
		wiringPiI2CWriteReg8(fd,i,buf[i]);
	}
}

void pcf8563ReadTime() 
{   
	for(i = 0;i < 7;i++)
	{
		buf[i] = (char)wiringPiI2CReadReg8(fd,i);
	}
} 

int main(int argc, char **argv)  
{  
	if(wiringPiSetup() < 0)return 1;  
   	fd = wiringPiI2CSetup(DS3231_Address);
    printf("DS3231 Test Program ...\n\n"); 
   	
    pcf8563SetTime(); 
    while(1)  
    {  
       	pcf8563ReadTime();
		buf[0] = buf[0]&0x7F; //sec
		buf[1] = buf[1]&0x7F; //min
		buf[2] = buf[2]&0x3F; //hour
		buf[3] = buf[3]&0x07; //week
		buf[4] = buf[4]&0x3F; //day
		buf[5] = buf[5]&0x1F; //mouth
		//year/month/day
		printf("20%02x/%02x/%02x  ",buf[6],buf[5],buf[4]);
		//hour:minute/second
		printf("%02x:%02x:%02x  ",buf[2],buf[1],buf[0]);
		//weekday
		printf("%s\n",str[(unsigned char)buf[3]]);
		delay(1000); 
	} 
    return 0;  
}

[/codesyntax]

Save the file as “ds3231.c”. Compile and run with:

gcc -Wall ds3231.c -o ds3231-lbcm2835 -lwiringPi
sudo ./ds3231