DS3231.h

00001 /** mbded library for driving the PMAXIM DS3231 Real Time Clock
00002 * datasheet link : http://datasheets.maximintegrated.com/en/ds/DS3231.pdf
00003 * breakout       : MACETECH ChronoDot V2.1 High Precision RTC
00004 * remi cormier 2012
00005 * WARNING : sda and sdl should be pulled up with 2.2k resistor
00006 */
00007 
00008 /** Example code
00009 * @code
00010 // DS3231 Library test program
00011 // remi cormier 2012
00012 
00013 #include "mbed.h"
00014 #include "DS3231.h"
00015 
00016 Serial pc(USBTX, USBRX);
00017 
00018 int hour;
00019 int minute;
00020 int second;
00021 
00022 int dayOfWeek;
00023 int date;
00024 int month;
00025 int year;  
00026    
00027 DS3231 RTC(p28,p27);
00028 
00029 
00030 int main()
00031     {printf("\r\n\nDS3231 Library test program\r\nremi cormier 2012\r\n\n");
00032     
00033      RTC.setI2Cfrequency(400000);
00034     
00035      //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
00036      
00037      RTC.convertTemperature();
00038       
00039      int reg=RTC.readRegister(DS3231_Aging_Offset);
00040      if (reg>127)
00041         {reg=reg-256;}
00042      pc.printf("Aging offset : %i\r\n",reg);
00043          
00044      pc.printf("OSF flag : %i",RTC.OSF());
00045      pc.printf("\r\n");
00046      
00047      RTC.readDate(&date,&month,&year);
00048      pc.printf("date : %02i-%02i-%02i",date,month,year);
00049      pc.printf("\r\n");
00050      
00051      //RTC.setTime(19,48,45); // uncomment to set time
00052      
00053      RTC.readTime(&hour,&minute,&second);
00054      pc.printf("time : %02i:%02i:%02i",hour,minute,second);
00055      pc.printf("\r\n");
00056      
00057      //RTC.setDate(6,22,12,2012); // uncomment to set date
00058      
00059      RTC.readDateTime(&dayOfWeek,&date,&month,&year,&hour,&minute,&second);
00060      pc.printf("date time : %i / %02i-%02i-%02i %02i:%02i:%02i",dayOfWeek,date,month,year,hour,minute,second);
00061      pc.printf("\r\n");
00062      
00063      pc.printf("temperature :%6.2f",RTC.readTemp());
00064      pc.printf("\r\n");
00065     }
00066 * @endcode
00067 */
00068 
00069 
00070 #include "mbed.h"
00071 
00072 #ifndef MBED_DS3231_H
00073 #define MBED_DS3231_H
00074 
00075 //DS3231 8 bit adress
00076 #define DS3231_Address          0xD0
00077 
00078 //DS3231 registers
00079 #define DS3231_Seconds          0x00
00080 #define DS3231_Minutes          0x01
00081 #define DS3231_Hours            0x02
00082 // DS3231 Hours bits
00083 #define DS3231_bit_AM_PM        0x20
00084 #define DS3231_bit_12_24        0x40
00085 
00086 #define DS3231_Day              0x03
00087 #define DS3231_Date             0x04
00088 #define DS3231_Month_Century    0x05
00089 #define DS3231_Year             0x06
00090 #define DS3231_Alarm1_Seconds   0x07
00091 #define DS3231_Alarm1_Minutes   0x08
00092 #define DS3231_Alarm1_Hours     0x09
00093 #define DS3231_Alarm1_Day_Date  0x0A
00094 #define DS3231_Alarm2_Minutes   0x0B
00095 #define DS3231_Alarm2_Hours     0x0C
00096 #define DS3231_Alarm_2_Day_Date 0x0D
00097 
00098 #define DS3231_Control          0x0E
00099 // DS3231 Control bits
00100 #define DS3231_bit_A1IE        1
00101 #define DS3231_bit_A2IE        2
00102 #define DS3231_bit_INTCN       4
00103 #define DS3231_bit_SQW_1Hz     0
00104 #define DS3231_bit_SQW_1024Hz  8
00105 #define DS3231_bit_SQW_4096Hz 16
00106 #define DS3231_bit_SQW_8192Hz 24
00107 #define DS3231_bit_CONV       32
00108 #define DS3231_bit_BBSQW      64
00109 #define DS3231_bit_EOSCb     128
00110 
00111 
00112 #define DS3231_Control_Status   0x0F
00113 // DS3231 Control/Status bits
00114 #define DS3231_bit_BSY     0x04
00115 #define DS3231_bit_EN32kHz 0x08
00116 #define DS3231_bit_OSF     0x80
00117 
00118 #define DS3231_Aging_Offset     0x10
00119 #define DS3231_MSB_Temp         0x11
00120 #define DS3231_LSB_Temp         0x12
00121 
00122 /* Interface to MAXIM DS3231 RTC */
00123 class DS3231
00124     {public :
00125      /** Create an instance of the DS3231 connected to specfied I2C pins
00126      *
00127      * @param sda The I2C data pin
00128      * @param scl The I2C clock pin
00129      */
00130      DS3231(PinName sda, PinName scl);
00131      
00132      /** set I2C bus speed
00133      * @param frequency : I2C clocl frequenct (Hz)
00134      */
00135      void setI2Cfrequency(int frequency);
00136      
00137      /** Read the temperature
00138      *
00139      * @return The temperature
00140      */
00141      float readTemp();
00142      
00143      /** Read the time registers
00144      * @param hours
00145      * @param minutes
00146      * @param seconds
00147      */
00148      void readTime(int *hours, int *minutes, int *seconds);
00149      
00150      /** force temperature conversion
00151      * 
00152      */
00153      void convertTemperature();
00154      
00155      /** Set the time registers
00156      * @param hours
00157      * @param minutes
00158      * @param seconds
00159      */
00160      void setTime(int hours, int minutes, int seconds);
00161      
00162      /** Read the date registers
00163      * @param date
00164      * @param month
00165      * @param year
00166      */
00167      void readDate(int *date, int *month, int *year);
00168      
00169      /** Set the date registers
00170      * @param dayOfWeek : day of week
00171      * @param date
00172      * @param month
00173      * @param year
00174      */
00175      void setDate(int dayOfWeek, int date, int month, int year);
00176      
00177      /** Read the date and time registers
00178      * @param dayOfWeek : day of week
00179      * @param date
00180      * @param month
00181      * @param year
00182      * @param hours
00183      * @param minutes
00184      * @param seconds
00185      */
00186      void readDateTime(int *dayOfWeek, int *date, int *month, int *year, int *hours, int *minutes, int *seconds);
00187      
00188      /** Read a register
00189      * @param reg : register address
00190      * @return The register content
00191      */     
00192      int readRegister(char reg);
00193      
00194      /** Write to a register
00195      * @param reg : register address
00196      * @param The register content
00197      */       
00198      void writeRegister(int reg,char byte);
00199      
00200      /** set OSF (Oscillator Stop Flag) bit to 0 in Control Status register
00201      * should be done just after power up DS3231
00202      * OSF bit is automaticaly set to 1 when on power up or when the DS3231 oscillator stops
00203      */
00204      void eraseOSF();
00205      
00206      /** Return OSF bit. If true the oscillator stopped or the DS3231 just powered up
00207      * @return The OSF bit
00208      */
00209      bool OSF();
00210      
00211      bool error;
00212      
00213      private :
00214      I2C i2c;
00215      int bcd2dec(int k); // bcd to decimal conversion
00216      int dec2bcd(int k); // decimal to bcd conversion
00217      void decodeTime(int regHours, int regMinutes, int regSeconds,int *Hours, int *Minutes, int *Seconds);
00218      void decodeDate(int regDate,int regMonth, int regYear, int *date, int *month, int *year);
00219     };
00220 
00221 
00222 #endif