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_A1F     0x01
00115 #define DS3231_bit_A2F     0x02
00116 #define DS3231_bit_BSY     0x04
00117 #define DS3231_bit_EN32kHz 0x08
00118 #define DS3231_bit_OSF     0x80
00119 
00120 #define DS3231_Aging_Offset     0x10
00121 #define DS3231_MSB_Temp         0x11
00122 #define DS3231_LSB_Temp         0x12
00123 
00124 /* Interface to MAXIM DS3231 RTC */
00125 class DS3231
00126     {public :
00127      /** Create an instance of the DS3231 connected to specfied I2C pins
00128      *
00129      * @param sda The I2C data pin
00130      * @param scl The I2C clock pin
00131      */
00132      DS3231(PinName sda, PinName scl);
00133      
00134      /** set I2C bus speed
00135      * @param frequency : I2C clocl frequenct (Hz)
00136      */
00137      void setI2Cfrequency(int frequency);
00138      
00139      /** Read the temperature
00140      *
00141      * @return The temperature
00142      */
00143      float readTemp();
00144      
00145      /** Read the time registers
00146      * @param hours
00147      * @param minutes
00148      * @param seconds
00149      */
00150      void readTime(int *hours, int *minutes, int *seconds);
00151      
00152      /** force temperature conversion
00153      * 
00154      */
00155      void convertTemperature();
00156      
00157      /** Set the time registers
00158      * @param hours
00159      * @param minutes
00160      * @param seconds
00161      */
00162      void setTime(int hours, int minutes, int seconds);
00163      
00164      /** Read the date registers
00165      * @param date
00166      * @param month
00167      * @param year
00168      */
00169      void readDate(int *date, int *month, int *year);
00170      
00171      /** Set the date registers
00172      * @param dayOfWeek : day of week
00173      * @param date
00174      * @param month
00175      * @param year
00176      */
00177      void setDate(int dayOfWeek, int date, int month, int year);
00178      
00179      /** Read the date and time registers
00180      * @param dayOfWeek : day of week
00181      * @param date
00182      * @param month
00183      * @param year
00184      * @param hours
00185      * @param minutes
00186      * @param seconds
00187      */
00188      void readDateTime(int *dayOfWeek, int *date, int *month, int *year, int *hours, int *minutes, int *seconds);
00189      
00190      /** Read a register
00191      * @param reg : register address
00192      * @return The register content
00193      */     
00194      int readRegister(char reg);
00195      
00196      /** Write to a register
00197      * @param reg : register address
00198      * @param The register content
00199      */       
00200      void writeRegister(int reg,char byte);
00201      
00202      /** set OSF (Oscillator Stop Flag) bit to 0 in Control Status register
00203      * should be done just after power up DS3231
00204      * OSF bit is automaticaly set to 1 when on power up or when the DS3231 oscillator stops
00205      */
00206      void eraseOSF();
00207      
00208      /** Return OSF bit. If true the oscillator stopped or the DS3231 just powered up
00209      * @return The OSF bit
00210      */
00211      bool OSF();
00212      
00213      /** returns a c-string timestamp
00214      * @return character pointer
00215      */
00216      char* getTimestamp();
00217      
00218      /**
00219      *  Tells if the RTC has lost power recently.
00220      *  @return False if battery power has been lost
00221      *  @return True if battery power has been maintained.
00222      */
00223      bool checkClockIntegrity();
00224      
00225      bool error;
00226      
00227      private :
00228      I2C i2c;
00229      int bcd2dec(int k); // bcd to decimal conversion
00230      int dec2bcd(int k); // decimal to bcd conversion
00231      void decodeTime(int regHours, int regMinutes, int regSeconds,int *Hours, int *Minutes, int *Seconds);
00232      void decodeDate(int regDate,int regMonth, int regYear, int *date, int *month, int *year);
00233      char charbuf[20];
00234      bool powerFailure;
00235     };
00236 
00237 
00238 #endif