File content as of revision 2:941a59078507:

#include "MCP7940.h"

    MCP7940::MCP7940(PinName sda, PinName scl):Clock(sda, scl){
            _addr = 0xDE;   //  1101 111x
            Clock.frequency(100000);
            _YearStart = 2000;
        }
    MCP7940::MCP7940(PinName sda, PinName scl, int StartYear):Clock(sda, scl){
            _addr = 0xDE;   //  1101 111x
            Clock.frequency(100000);
            _YearStart = StartYear;
        }
        
    char MCP7940::IntToBCD(char Data){
            char Tens  =  Data / 10;
            char Units = Data % 10;
            char BCD = (Tens << 4 | Units); 
            return(BCD);
        }
    char MCP7940::BCDtoInt(char Data){
            char Value;
            Value = (((Data & 0xF0 ) >> 4) * 10) + (((Data & 0x0F )));
            return(Value);
        }
    
    int MCP7940::setTime(int Year, int Month, int Day, int Hour, int Mins){
         return(setTime(Year, Month, Day, Hour, Mins, 0, 0));
        }     
    int MCP7940::setTime(int Year, int Month, int Day, int Hour, int Mins, int Secs){
         return(setTime(Year, Month, Day, Hour, Mins, Secs, 0));
        }        
    int MCP7940::setTime(int Year, int Month, int Day, int Hour, int Mins, int Secs, int MiliSecs){
        return(setTime(Year, Month, Day, Hour, Mins, Secs, 0,1));
        }
    int MCP7940::setTime(int Year, int Month, int Day, int Hour, int Mins, int Secs, int MiliSecs, int DayOfWeek){
        _Day = Day;
        _Month = Month;
        _Year = Year;
        _Hour = Hour;
        _Minutes = Mins;
        _Seconds = Secs;
        _MilliSeconds = MiliSecs;
        _DayOfWeek = DayOfWeek;
        return(setTime());
        }
    void MCP7940::StartClock(){
        char cmd[8];
        cmd[0] = 0x00; // The start register
        cmd[1] = 0x00;
   
        Clock.start();  
        Clock.write(_addr,cmd,1) ;
        Clock.read(_addr, cmd, 1);
        
        //Cmd 0 now contains the value of the seconds regsiter
        cmd[1] = cmd[0] & 0x7F; //Move the seconds register value and clear the top bit
        cmd[0] = 0x00;         //Set write location
       // Clock.write(_addr,cmd,2);
        cmd[1] = cmd[1] | 0x80 ; //Now set the top bit 
        Clock.write(_addr,cmd,2);   //Write to Reg 0x00 the value with top bit set
        Clock.stop();
        
        }
    int MCP7940::setDefaultTime(){
        _Day = 1;
        _Month = 10;
        _Year = 2015;
        _Hour = 1;
        _Minutes = 0;
        _Seconds = 0;
        _MilliSeconds = 0;
        _DayOfWeek = 1;
        return(setTime());
        }        
    int MCP7940::setTime(){
        //Write time to the Device
        char cmd[8];
        cmd[0] = 0x00; // The start register
        cmd[1] = IntToBCD(_Seconds);
        cmd[2] = IntToBCD(_Minutes);
        cmd[3] = IntToBCD(_Hour);
        cmd[4] = IntToBCD(_DayOfWeek) | 0x80;  //NB this will clear the PWR Fail and set VBat Enable
        cmd[5] = IntToBCD(_Day);
        cmd[6] = IntToBCD(_Month);
        cmd[7] = IntToBCD(_Year - _YearStart);
    
        Clock.start();    
        Clock.write(_addr, cmd, 8);
        Clock.stop();
        
        return(1);
        }
    int MCP7940::getTime(){
        
        char cmd[7];
        cmd[0] = 0x00;
        
        Clock.start();
        //Set the position to Reg 0x00
        Clock.write(_addr, cmd, 1);
        //Read 7 bytes from 0x00
        Clock.read(_addr, cmd, 7);
        Clock.stop();
        
        //printf("%i %i %i %i %i %i %i\r\n", cmd[0], cmd[1],cmd[2],cmd[3],cmd[4], cmd[5], cmd[6]);
        
        //Convert into numbers - note have to mask out the configuration bits as well
        _Day = BCDtoInt(cmd[4] & 0x3F);
        _Month = BCDtoInt(cmd[5] & 0x1F);
        _Year = BCDtoInt(cmd[6] & 0xFF) + _YearStart;
        _Hour = BCDtoInt(cmd[2] & 0x3F);            //Should handle 12 or 24 hour here.
        _Minutes = BCDtoInt(cmd[1] & 0x7F);
        _Seconds = BCDtoInt(cmd[0] & 0x7F);
        _DayOfWeek = BCDtoInt(cmd[3] & 0x07); 
        _MilliSeconds = 0;
        //printf("Day: %i Month: %i Year: %i Hour: %i Minute: %i Second: %i\r\n", _Day, _Month,_Year,_Hour,_Minutes, _Seconds);
        return(0);
    }
    char * MCP7940::TimeStamp(){
        TimeStamp(_TimeStamp);
        return(_TimeStamp);
        }
    void MCP7940::TimeStamp(char * buf){
        getTime();
        sprintf(buf,"%04i-%02i-%02iT%02i:%02i:%02i",_Year, _Month,_Day,_Hour,_Minutes,_Seconds);
    }
    void MCP7940::niceTimeStamp(char * buf){
        getTime();
        sprintf(buf,"%02i/%02i/%04i %02i:%02i:%02i",_Day, _Month,_Year,_Hour,_Minutes,_Seconds);
        }
    void MCP7940::niceDate(char * buf){
        getTime();
        sprintf(buf,"%02i-%02i-%04i",_Day, _Month,_Year);
        }
    void MCP7940::niceTime(char * buf){
        getTime();
        sprintf(buf,"%02i:%02i:%02i",_Hour,_Minutes,_Seconds);
        }
    
    int MCP7940::Day(){
        return(_Day);
        }
    int MCP7940::Month(){
        return(_Month);
        }
    int MCP7940::Year(){
        return(_Year);
        }
    int MCP7940::Hour(){
        return(_Hour);
        }
    int MCP7940::Minutes(){
        return(_Minutes);
        
        }
    int MCP7940::Seconds(){
        return(_Seconds);
        }
        int MCP7940::MilliSeconds(){
            return(_MilliSeconds);
            }
    int MCP7940::DayOfWeek(){
        return(_DayOfWeek);
    }