Revision 0:11dfd7ac4188, committed 2012-12-22

Comitter:

cromda

Date:

Sat Dec 22 19:23:19 2012 +0000

Child:

1:84ccc64067d8

Commit message:

MAXIM DS3231 RTC

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DS3231.cpp	Sat Dec 22 19:23:19 2012 +0000
@@ -0,0 +1,132 @@
+#include "DS3231.h"
+
+DS3231::DS3231(PinName sda, PinName scl) : i2c(sda, scl)
+    {
+    } 
+    
+    
+// BCD to decimal conversion    
+int DS3231::bcd2dec(int k)
+    {return(((k&0xF0)>>4)*10+(k&0x0F));}
+    
+    
+// decimal to BCD conversion    
+int DS3231::dec2bcd(int k)
+    {return((k/10)*16+(k%10));}      
+    
+void DS3231::setI2Cfrequency(int frequency)
+    {i2c.frequency(frequency);
+    }
+    
+// read temperature from DS3231    
+float DS3231::readTemp()
+    {char buf[2];
+     buf[0]=DS3231_MSB_Temp;
+     int w=i2c.write(DS3231_Address,buf,1);
+     int r=i2c.read(DS3231_Address,buf,2);
+     error=((w!=0)||(r!=0));   
+     return(buf[0]+buf[1]/256.0);}   
+
+// decode time registers     
+void DS3231::decodeTime(int regHours, int regMinutes, int regSeconds,int *Hours, int *Minutes, int *Seconds)
+    {*Hours=bcd2dec(regHours);
+     *Minutes=bcd2dec(regMinutes);
+     *Seconds=bcd2dec(regSeconds);
+    }      
+     
+     
+// read time registers dand decode them to decimal     
+void DS3231::readTime(int *hours, int *minutes, int *seconds)
+    {char buf[3];
+     buf[0]=DS3231_Seconds;
+     int w=i2c.write(DS3231_Address,buf,1);
+     int r=i2c.read(DS3231_Address,buf,3);
+     decodeTime(buf[2],buf[1],buf[0],hours,minutes,seconds);    
+     error=((w!=0)||(r!=0));
+    }  
+    
+// set time register    
+void DS3231::setTime(int hours, int minutes, int seconds)
+    {writeRegister(DS3231_Seconds,dec2bcd(seconds));
+     writeRegister(DS3231_Minutes,dec2bcd(minutes));
+     writeRegister(DS3231_Hours,dec2bcd(hours));
+    }    
+    
+// decode date registers
+void DS3231::decodeDate(int regDate,int regMonth, int regYear, int *date, int *month, int *year)
+    {*date=bcd2dec(regDate);
+     int century=regMonth&128;
+     *month=bcd2dec(regMonth&127);
+     *year=bcd2dec(regYear);
+     if (century==0)         // only XXth and XXIst centuries allowed
+        {*year=*year+1900;}
+     else
+        {*year=*year+2000;}
+    }         
+    
+// read date registers    
+void DS3231::readDate(int *date, int *month, int *year)
+    {char buf[3];
+     buf[0]=DS3231_Date;
+     int w=i2c.write(DS3231_Address,buf,1);
+     int r=i2c.read(DS3231_Address,buf,3);
+     decodeDate(buf[0],buf[1],buf[2],date,month,year);            
+     error=((w!=0)||(r!=0));         
+    }     
+    
+// set the date registers
+void DS3231::setDate(int dayOfWeek, int date, int month, int year)
+    {writeRegister(DS3231_Date,dec2bcd(date));
+     writeRegister(DS3231_Day,dayOfWeek);
+     int century=0; // only XXth and XXIst centuries allowed
+     if (year<1900){year=1900;}
+     if (year>2099){year=2099;}
+     if (year<2000)
+        {year=year-1900;}
+     else
+        {year=year-2000;century=1;}   
+     writeRegister(DS3231_Month_Century,dec2bcd(month)+128*century);   
+     writeRegister(DS3231_Year,dec2bcd(year));
+    }     
+    
+// read date and time registers    
+void DS3231::readDateTime(int *dayOfWeek, int *date, int *month, int *year, int *hours, int *minutes, int *seconds)
+    {char buf[7];
+     buf[0]=DS3231_Seconds;
+     int w=i2c.write(DS3231_Address,buf,1);
+     int r=i2c.read(DS3231_Address,buf,7);
+     decodeTime(buf[2],buf[1],buf[0],hours,minutes,seconds);
+     *dayOfWeek=buf[3];
+     decodeDate(buf[4],buf[5],buf[6],date,month,year);
+     error=((w!=0)||(r!=0));     
+    }    
+    
+// read a register    
+int DS3231::readRegister(char reg)
+    {char buf[1];
+     buf[0]=reg;
+     int w=i2c.write(DS3231_Address,buf,1);
+     int r=i2c.read(DS3231_Address,buf,1);
+     error=((w!=0)||(r!=0));  
+     return(buf[0]);
+    }   
+
+// write a register    
+void DS3231::writeRegister(int reg,char byte)
+    {char buf[2];
+     buf[0]=reg;
+     buf[1]=byte;
+     int w=i2c.write(DS3231_Address,buf,2); 
+     error=(w!=0);   
+    }      
+    
+void DS3231::eraseOSF()
+    {int reg=readRegister(DS3231_Control_Status);
+     reg=reg&0x7F;
+     writeRegister(DS3231_Control_Status,reg);
+    }     
+    
+bool DS3231::OSF()
+    {int reg=readRegister(DS3231_Control_Status);
+    return(reg&DS3231_bit_OSF);
+    }
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DS3231.h	Sat Dec 22 19:23:19 2012 +0000
@@ -0,0 +1,216 @@
+/** mbded library for driving the PMAXIM DS3231 Real Time Clock
+* datasheet link : http://datasheets.maximintegrated.com/en/ds/DS3231.pdf
+* breakout       : MACETECH ChronoDot V2.1 High Precision RTC
+* remi cormier 2012
+* WARNING : sda and sdl should be pulled up with 2.2k resistor
+*/
+
+/** Example code
+* @code
+// DS3231 Library test program
+// remi cormier 2012
+
+#include "mbed.h"
+#include "DS3231.h"
+
+Serial pc(USBTX, USBRX);
+
+int hour;
+int minute;
+int second;
+
+int dayOfWeek;
+int date;
+int month;
+int year;  
+   
+DS3231 RTC(p28,p27);
+
+
+int main()
+    {printf("\r\n\nDS3231 Library test program\r\nremi cormier 2012\r\n\n");
+    
+     RTC.setI2Cfrequency(400000);
+    
+     //RTC.writeRegister(DS3231_Aging_Offset,0); // uncomment to set Aging Offset 1LSB = approx. 0.1 ppm according from datasheet = 0.05 ppm @ 21 °C from my measurments
+      
+     int reg=RTC.readRegister(DS3231_Aging_Offset);
+     if (reg>127)
+        {reg=reg-256;}
+     pc.printf("Aging offset : %i\r\n",reg);
+         
+     pc.printf("OSF flag : %i",RTC.OSF());
+     pc.printf("\r\n");
+     
+     RTC.readDate(&date,&month,&year);
+     pc.printf("date : %02i-%02i-%02i",date,month,year);
+     pc.printf("\r\n");
+     
+     //RTC.setTime(19,48,45); // uncomment to set time
+     
+     RTC.readTime(&hour,&minute,&second);
+     pc.printf("time : %02i:%02i:%02i",hour,minute,second);
+     pc.printf("\r\n");
+     
+     //RTC.setDate(6,22,12,2012); // uncomment to set date
+     
+     RTC.readDateTime(&dayOfWeek,&date,&month,&year,&hour,&minute,&second);
+     pc.printf("date time : %i / %02i-%02i-%02i %02i:%02i:%02i",dayOfWeek,date,month,year,hour,minute,second);
+     pc.printf("\r\n");
+     
+     pc.printf("temperature :%6.2f",RTC.readTemp());
+     pc.printf("\r\n");
+    }
+* @endcode
+*/
+
+
+#include "mbed.h"
+
+#ifndef MBED_DS3231_H
+#define MBED_DS3231_H
+
+//DS3231 8 bit adress
+#define DS3231_Address          0xD0
+
+//DS3231 registers
+#define DS3231_Seconds          0x00
+#define DS3231_Minutes          0x01
+#define DS3231_Hours            0x02
+// DS3231 Hours bits
+#define DS3231_bit_AM_PM        0x20
+#define DS3231_bit_12_24        0x40
+
+#define DS3231_Day              0x03
+#define DS3231_Date             0x04
+#define DS3231_Month_Century    0x05
+#define DS3231_Year             0x06
+#define DS3231_Alarm1_Seconds   0x07
+#define DS3231_Alarm1_Minutes   0x08
+#define DS3231_Alarm1_Hours     0x09
+#define DS3231_Alarm1_Day_Date  0x0A
+#define DS3231_Alarm2_Minutes   0x0B
+#define DS3231_Alarm2_Hours     0x0C
+#define DS3231_Alarm_2_Day_Date 0x0D
+
+#define DS3231_Control          0x0E
+// DS3231 Control bits
+#define DS3231_bit_A1IE        1
+#define DS3231_bit_A2IE        2
+#define DS3231_bit_INTCN       4
+#define DS3231_bit_SQW_1Hz     0
+#define DS3231_bit_SQW_1024Hz  8
+#define DS3231_bit_SQW_4096Hz 16
+#define DS3231_bit_SQW_8192Hz 24
+#define DS3231_bit_CONV       32
+#define DS3231_bit_BBSQW      64
+#define DS3231_bit_EOSCb     128
+
+
+#define DS3231_Control_Status   0x0F
+// DS3231 Control/Status bits
+#define DS3231_bit_BSY     0x04
+#define DS3231_bit_EN32kHz 0x08
+#define DS3231_bit_OSF     0x80
+
+#define DS3231_Aging_Offset     0x10
+#define DS3231_MSB_Temp         0x11
+#define DS3231_LSB_Temp         0x12
+
+/* Interface to MAXIM DS3231 RTC */
+class DS3231
+    {public :
+     /** Create an instance of the DS3231 connected to specfied I2C pins
+     *
+     * @param sda The I2C data pin
+     * @param scl The I2C clock pin
+     */
+     DS3231(PinName sda, PinName scl);
+     
+     /** set I2C bus speed
+     * @param frequency : I2C clocl frequenct (Hz)
+     */
+     void setI2Cfrequency(int frequency);
+     
+     /** Read the temperature
+     *
+     * @return The temperature
+     */
+     float readTemp();
+     
+     /** Read the time registers
+     * @param hours
+     * @param minutes
+     * @param seconds
+     */
+     void readTime(int *hours, int *minutes, int *seconds);
+     
+     
+     /** Set the time registers
+     * @param hours
+     * @param minutes
+     * @param seconds
+     */
+     void setTime(int hours, int minutes, int seconds);
+     
+     /** Read the date registers
+     * @param date
+     * @param month
+     * @param year
+     */
+     void readDate(int *date, int *month, int *year);
+     
+     /** Set the date registers
+     * @param dayOfWeek : day of week
+     * @param date
+     * @param month
+     * @param year
+     */
+     void setDate(int dayOfWeek, int date, int month, int year);
+     
+     /** Read the date and time registers
+     * @param dayOfWeek : day of week
+     * @param date
+     * @param month
+     * @param year
+     * @param hours
+     * @param minutes
+     * @param seconds
+     */
+     void readDateTime(int *dayOfWeek, int *date, int *month, int *year, int *hours, int *minutes, int *seconds);
+     
+     /** Read a register
+     * @param reg : register address
+     * @return The register content
+     */     
+     int readRegister(char reg);
+     
+     /** Write to a register
+     * @param reg : register address
+     * @param The register content
+     */       
+     void writeRegister(int reg,char byte);
+     
+     /** set OSF (Oscillator Stop Flag) bit to 0 in Control Status register
+     * should be done just after power up DS3231
+     * OSF bit is automaticaly set to 1 when on power up or when the DS3231 oscillator stops
+     */
+     void eraseOSF();
+     
+     /** Return OSF bit. If true the oscillator stopped or the DS3231 just powered up
+     * @return The OSF bit
+     */
+     bool OSF();
+     
+     bool error;
+     
+     private :
+     I2C i2c;
+     int bcd2dec(int k); // bcd to decimal conversion
+     int dec2bcd(int k); // decimal to bcd conversion
+     void decodeTime(int regHours, int regMinutes, int regSeconds,int *Hours, int *Minutes, int *Seconds);
+     void decodeDate(int regDate,int regMonth, int regYear, int *date, int *month, int *year);
+    };
+
+
+#endif
\ No newline at end of file