File content as of revision 6:a517fee06e2e:

/// @file TimeUtilities.cpp contains a real time clock interface for the mbed
///
/// APIs for showing the time from the RTC, or from a passed in value.
/// Also supports setting the clock, timezone offsets and calibration
/// of the RTC subsystem.
///
/// @note Copyright &copr; 2011 by Smartware Computing, all rights reserved.
///     Individuals may use this application for evaluation or non-commercial
///     purposes. Within this restriction, changes may be made to this application
///     as long as this copyright notice is retained. The user shall make
///     clear that their work is a derived work, and not the original.
///     Users of this application and sources accept this application "as is" and
///     shall hold harmless Smartware Computing, for any undesired results while
///     using this application - whether real or imagined.
///
/// @author David Smart, Smartware Computing
///
#ifndef WIN32
// embedded build
#include "mbed.h"
#endif

#define VERSION "1.04"

#include "TimeUtilities.h"
#include <time.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

#ifdef WIN32
// Fake it out for Win32 development and testing
struct LPC {
    unsigned long CCR;          // Clock Control register
    unsigned long GPREG0;       // General Purpose Register #0 - 32-bit Battery backed
    unsigned long GPREG1;       // General Purpose Register #1 - 32-bit Battery backed
    unsigned long CALIBRATION;  // Calibration Register
};
struct LPC X;
struct LPC * LPC_RTC = &X;
#define set_time(x) (void)x
#endif

static int tzOffsetHr = 0;       ///!< time zone offset hours to print time in local time
static int tzOffsetMin = 0;      ///!< time zone offset minutes to print time in local time


static const char ver[] = VERSION;

static int SignOf(const int i) {
    return (i >= 0) ? 1 : -1;
}


RealTimeClock::RealTimeClock() {
    GetTimeOffsetStore();
}


RealTimeClock::~RealTimeClock() {
}

const char * RealTimeClock::GetVersion() {
    return ver;
}

time_t RealTimeClock::GetTimeValue() {
    return time(NULL);
}


void RealTimeClock::GetTimeString(char *buf, time_t tValue) {
    GetTimeOffsetStore();       // Load the time zone offset values from the battery ram
    GetTimeString(buf, tValue, tzOffsetHr, tzOffsetMin);
}


void RealTimeClock::GetTimeString(char *buf, int hOffset, int mOffset) {
    GetTimeString(buf, 0, hOffset, mOffset);
}


void RealTimeClock::GetTimeString(char *buf, time_t tValue, int hOffset, int mOffset) {
    time_t ctTime;

    if (tValue == 0)
        tValue = time(NULL);
    ctTime = tValue + hOffset * 3600 + SignOf(hOffset) * mOffset * 60;
    strcpy(buf, ctime(&ctTime));
    buf[strlen(buf)-1] = '\0';   // remove the \n
    sprintf(buf + strlen(buf), " (tzo: %2i:%02i)", hOffset, mOffset);
}


int32_t RealTimeClock::GetTimeCalibration() {
    int32_t calvalue = LPC_RTC->CALIBRATION & 0x3FFFF;

    if (calvalue & 0x20000) {
        calvalue = -(calvalue & 0x1FFFF);
    }    
    return calvalue;
}


void RealTimeClock::SetTimeCalibration(int32_t calibration) {
    if (calibration) {
        if (calibration < 0) {
            calibration = (-calibration & 0x1FFFF) | 0x20000;
        }
        LPC_RTC->CCR = 0x000001; //(LPC_RTC->CCR & 0x0003);   // Clear CCALEN to enable it
    } else {
        LPC_RTC->CCR = 0x000011; //(LPC_RTC->CCR & 0x0003) | 0x0010;   // Set CCALEN to disable it
    }
    LPC_RTC->CALIBRATION = calibration;
}


void RealTimeClock::SetTimeOffset(int offsetHour, int offsetMinute) {
    tzOffsetHr = offsetHour;
    tzOffsetMin = offsetMinute;
    SetTimeOffsetStore();
}


void RealTimeClock::SetTimeOffsetStore() {
    LPC_RTC->GPREG0 = tzOffsetHr * 256 + tzOffsetMin;
}


void RealTimeClock::GetTimeOffsetStore() {
    tzOffsetHr = (int32_t)LPC_RTC->GPREG0 / 256;
    tzOffsetMin = (LPC_RTC->GPREG0 & 0xFF);
}

void RealTimeClock::SetTimeLastSet(time_t t) {
    LPC_RTC->GPREG1 = t;
}

time_t RealTimeClock::GetTimeLastSet() {
    return LPC_RTC->GPREG1;
}

// MM/DD/YYYY HH:MM:SS [(+/-hh:mm)]
bool RealTimeClock::SetTime(char * timestring) {
    bool success = false;
    char * p;
    time_t seconds = time(NULL);
    struct tm *t = localtime(&seconds);
    int _oH, _oM;
    
    p = strtok(timestring," /");
    if (p != NULL) {
        t->tm_mon = atoi(p) - 1;
        p = strtok(NULL, " /");
        if (p != NULL) {
            t->tm_mday = atoi(p);
            p = strtok(NULL, " /");
            if (p != NULL) {
                t->tm_year = atoi(p) - 1900;
                p = strtok(NULL, " :");
                if (p != NULL) {
                    t->tm_hour = atoi(p);
                    p = strtok(NULL, " :");
                    if (p != NULL) {
                        t->tm_min = atoi(p);
                        p = strtok(NULL, " (:");
                        if (p != NULL) {
                            t->tm_sec = atoi(p);
                            success = true;         // if we get to here, we're good
                            p = strtok(NULL, " (:");
                            if (p != NULL) {
                                success = false;    // but can't accept a partial tzo
                                _oH = atoi(p);
                                p = strtok(NULL, " (:)");
                                if (p != NULL) {
                                    _oM = atoi(p);
                                    success = true; // but a whole tzo is ok
                                    SetTimeOffset(_oH, _oM);
                                }   
                            }
                            seconds = mktime(t);
                            seconds = seconds - (time_t)(tzOffsetHr * 3600 + tzOffsetMin * 60);
                            set_time(seconds);
                            SetTimeLastSet(seconds);
                        }
                    }
                }
            }
        }
    }
    return success;
}

bool RealTimeClock::AdjustBySeconds(int32_t adjustSeconds) {
    time_t lastSet = GetTimeLastSet();
    
    if (lastSet != 0) {
        time_t seconds = time(NULL);    // get "now" according to the rtc
        int32_t delta = seconds - lastSet;
        int32_t curCal = GetTimeCalibration();
        int32_t calMAX = 131071;
        int32_t secPerDay = 86400;
        float errSecPerDay;
                
        // Convert the current calibration and the adjustment into
        // the new calibration value
        // assume it is +10sec and it has been 2days, then the adjustment
        // needs to be +5 sec per day, or one adjustment every 1/5th 
        // of a day, or 1 adjustment every 86400/5 counts.
        // delta = now - then (number of elapsed seconds)
        if (adjustSeconds != 0 && delta != 0) {
            int32_t calFactor;

            // Make the clock correct
            seconds = seconds + adjustSeconds;
            set_time(seconds);
            SetTimeLastSet(seconds);
            // Compute the calibration factor
            errSecPerDay = (float)adjustSeconds / ((float)(delta)/secPerDay);
            calFactor = (int32_t)((float)secPerDay/errSecPerDay);
            if (abs(calFactor) < calMAX)
                SetTimeCalibration(calFactor);
        }
        return true;
    } else {
        return false;
    }
}