jeje · March 12, 2012 10:53 · Mar 12, 2012
diff --git a/DS3231.cpp b/DS3231.cpp
@@ -0,0 +1,302 @@
+// DS3231 Class is by Seeed Technology Inc(http://www.seeedstudio.com) and used
+// in Seeeduino Stalker v2.1 for battery management(MCU power saving mode)
+// & to generate timestamp for data logging. DateTime Class is a modified
+// version supporting day-of-week.
+
+// Original DateTime Class and its utility code is by Jean-Claude Wippler at JeeLabs
+// http://jeelabs.net/projects/cafe/wiki/RTClib 
+// Released under MIT License http://opensource.org/licenses/mit-license.php
+
+#include <Wire.h>
+#include <avr/pgmspace.h>
+#include "DS3231.h"
+#include <Arduino.h>
+
+#define SECONDS_PER_DAY 86400L
+
+////////////////////////////////////////////////////////////////////////////////
+// utility code, some of this could be exposed in the DateTime API if needed
+
+static uint8_t daysInMonth [] PROGMEM = { 31,28,31,30,31,30,31,31,30,31,30,31 };
+
+// number of days since 2000/01/01, valid for 2001..2099
+static uint16_t date2days(uint16_t y, uint8_t m, uint8_t d) {
+    if (y >= 2000)
+        y -= 2000;
+    uint16_t days = d;
+    for (uint8_t i = 1; i < m; ++i)
+        days += pgm_read_byte(daysInMonth + i - 1);
+    if (m > 2 && y % 4 == 0)
+        ++days;
+    return days + 365 * y + (y + 3) / 4 - 1;
+}
+
+static long time2long(uint16_t days, uint8_t h, uint8_t m, uint8_t s) {
+    return ((days * 24L + h) * 60 + m) * 60 + s;
+}
+
+static uint8_t conv2d(const char* p) {
+    uint8_t v = 0;
+    if ('0' <= *p && *p <= '9')
+        v = *p - '0';
+    return 10 * v + *++p - '0';
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// DateTime implementation - ignores time zones and DST changes
+// NOTE: also ignores leap seconds, see http://en.wikipedia.org/wiki/Leap_second
+
+DateTime::DateTime (long t) {
+    ss = t % 60;
+    t /= 60;
+    mm = t % 60;
+    t /= 60;
+    hh = t % 24;
+    uint16_t days = t / 24;
+    uint8_t leap;
+    for (yOff = 0; ; ++yOff) {
+        leap = yOff % 4 == 0;
+        if (days < 365 + leap)
+            break;
+        days -= 365 + leap;
+    }
+    for (m = 1; ; ++m) {
+        uint8_t daysPerMonth = pgm_read_byte(daysInMonth + m - 1);
+        if (leap && m == 2)
+            ++daysPerMonth;
+        if (days < daysPerMonth)
+            break;
+        days -= daysPerMonth;
+    }
+    d = days + 1;
+}
+
+DateTime::DateTime (uint16_t year, uint8_t month, uint8_t date, uint8_t hour, uint8_t min, uint8_t sec, uint8_t wd) {
+    if (year >= 2000)
+        year -= 2000;
+    yOff = year;
+    m = month;
+    d = date;
+    hh = hour;
+    mm = min;
+    ss = sec;
+    wday = wd;
+}
+
+// A convenient constructor for using "the compiler's time":
+//   DateTime now (__DATE__, __TIME__);
+// NOTE: using PSTR would further reduce the RAM footprint
+DateTime::DateTime (const char* date, const char* time) {
+    // sample input: date = "Dec 26 2009", time = "12:34:56"
+    yOff = conv2d(date + 9);
+    // Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 
+    switch (date[0]) {
+        case 'J': m = date[1] == 'a' ? 1 : m = date[2] == 'n' ? 6 : 7; break;
+        case 'F': m = 2; break;
+        case 'A': m = date[2] == 'r' ? 4 : 8; break;
+        case 'M': m = date[2] == 'r' ? 3 : 5; break;
+        case 'S': m = 9; break;
+        case 'O': m = 10; break;
+        case 'N': m = 11; break;
+        case 'D': m = 12; break;
+    }
+    d = conv2d(date + 4);
+    hh = conv2d(time);
+    mm = conv2d(time + 3);
+    ss = conv2d(time + 6);
+}
+
+long DateTime::get() const {
+    uint16_t days = date2days(yOff, m, d);
+    return time2long(days, hh, mm, ss);
+}
+
+static uint8_t bcd2bin (uint8_t val) { return val - 6 * (val >> 4); }
+static uint8_t bin2bcd (uint8_t val) { return val + 6 * (val / 10); }
+
+////////////////////////////////////////////////////////////////////////////////
+// RTC DS3231 implementation
+
+uint8_t DS3231::readRegister(uint8_t regaddress)
+{
+    Wire.beginTransmission(DS3231_ADDRESS);
+    Wire.write(regaddress);
+    Wire.endTransmission();
+
+    Wire.requestFrom(DS3231_ADDRESS, 1);
+    return Wire.read();
+}
+
+void DS3231::writeRegister(uint8_t regaddress,uint8_t value)
+{
+    Wire.beginTransmission(DS3231_ADDRESS);
+    Wire.write(regaddress);
+    Wire.write(value);
+    Wire.endTransmission();
+}
+
+uint8_t DS3231::begin(void) {
+
+  unsigned char ctReg=0;
+  ctReg |= 0b00011100; 
+  writeRegister(DS3231_CONTROL_REG, ctReg);     //CONTROL Register Address
+  delay(10);
+
+  // set the clock to 24hr format  
+  uint8_t hrReg = readRegister(DS3231_HOUR_REG);
+  hrReg &= 0b10111111;
+  writeRegister(DS3231_HOUR_REG, hrReg);       
+
+  delay(10);
+
+  return 1; 
+}
+
+//Adjust the time-date specified in DateTime format
+//writing any non-existent time-data may interfere with normal operation of the RTC
+void DS3231::adjust(const DateTime& dt) {
+
+  Wire.beginTransmission(DS3231_ADDRESS);
+  Wire.write((uint8_t) DS3231_SEC_REG);  //beginning from SEC Register address
+
+  Wire.write(bin2bcd(dt.second())); 
+  Wire.write(bin2bcd(dt.minute()));
+  Wire.write(bin2bcd((dt.hour()) & 0b10111111)); //Make sure clock is still 24 Hour
+  Wire.write(dt.dayOfWeek());
+  Wire.write(bin2bcd(dt.date()));
+  Wire.write(bin2bcd(dt.month()));
+  Wire.write(bin2bcd(dt.year() - 2000));  
+  Wire.endTransmission();
+
+}
+
+//Read the current time-date and return it in DateTime format
+DateTime DS3231::now() {
+  Wire.beginTransmission(DS3231_ADDRESS);
+  Wire.write((uint8_t) 0x00);	
+  Wire.endTransmission();
+
+  Wire.requestFrom(DS3231_ADDRESS, 8);
+  uint8_t ss = bcd2bin(Wire.read());
+  uint8_t mm = bcd2bin(Wire.read());
+
+  uint8_t hrreg = Wire.read();
+  uint8_t hh = bcd2bin((hrreg & ~0b11000000)); //Ignore 24 Hour bit
+
+  uint8_t wd =  Wire.read();
+  uint8_t d = bcd2bin(Wire.read());
+  uint8_t m = bcd2bin(Wire.read());
+  uint16_t y = bcd2bin(Wire.read()) + 2000;
+
+  return DateTime (y, m, d, hh, mm, ss, wd);
+}
+
+//Enable periodic interrupt at /INT pin. Supports only the level interrupt
+//for consistency with other /INT interrupts. All interrupts works like single-shot counter
+//Use refreshINTA() to re-enable interrupt.
+void DS3231::enableInterrupts(uint8_t periodicity)
+{
+
+    unsigned char ctReg=0;
+    ctReg |= 0b00011101; 
+    writeRegister(DS3231_CONTROL_REG, ctReg);     //CONTROL Register Address
+
+   switch(periodicity) 
+   {
+       case EverySecond:
+       writeRegister(DS3231_AL1SEC_REG,  0b10000000 ); //set AM1
+       writeRegister(DS3231_AL1MIN_REG,  0b10000000 ); //set AM2
+       writeRegister(DS3231_AL1HOUR_REG, 0b10000000 ); //set AM3
+       writeRegister(DS3231_AL1WDAY_REG, 0b10000000 ); //set AM4
+
+       break;
+
+       case EveryMinute:
+       writeRegister(DS3231_AL1SEC_REG,  0b00000000 ); //Clr AM1
+       writeRegister(DS3231_AL1MIN_REG,  0b10000000 ); //set AM2
+       writeRegister(DS3231_AL1HOUR_REG, 0b10000000 ); //set AM3
+       writeRegister(DS3231_AL1WDAY_REG, 0b10000000 ); //set AM4
+
+       break;
+
+       case EveryHour:
+       writeRegister(DS3231_AL1SEC_REG,  0b00000000 ); //Clr AM1
+       writeRegister(DS3231_AL1MIN_REG,  0b00000000 ); //Clr AM2
+       writeRegister(DS3231_AL1HOUR_REG, 0b10000000 ); //Set AM3
+       writeRegister(DS3231_AL1WDAY_REG, 0b10000000 ); //set AM4
+
+       break;
+   }
+}
+
+//Enable HH/MM/SS interrupt on /INTA pin. All interrupts works like single-shot counter
+void DS3231::enableInterrupts(uint8_t hh24, uint8_t mm, uint8_t ss)
+{
+    unsigned char ctReg=0;
+    ctReg |= 0b00011101; 
+    writeRegister(DS3231_CONTROL_REG, ctReg);     //CONTROL Register Address
+
+    writeRegister(DS3231_AL1SEC_REG,  0b00000000 | bin2bcd(ss) ); //Clr AM1
+    writeRegister(DS3231_AL1MIN_REG,  0b00000000 | bin2bcd(mm)); //Clr AM2
+    writeRegister(DS3231_AL1HOUR_REG, (0b00000000 | (bin2bcd(hh24) & 0b10111111))); //Clr AM3
+    writeRegister(DS3231_AL1WDAY_REG, 0b10000000 ); //set AM4
+}
+
+//Disable Interrupts. This is equivalent to begin() method.
+void DS3231::disableInterrupts()
+{
+    begin(); //Restore to initial value.
+}
+
+//Clears the interrrupt flag in status register. 
+//This is equivalent to preparing the DS3231 /INT pin to high for MCU to get ready for recognizing the next INT0 interrupt
+void DS3231::clearINTStatus()
+{
+    // Clear interrupt flag 
+    uint8_t statusReg = readRegister(DS3231_STATUS_REG);
+    statusReg &= 0b11111110;
+    writeRegister(DS3231_STATUS_REG, statusReg);
+
+}
+
+//force temperature sampling and converting to registers. If this function is not used the temperature is sampled once 64 Sec.
+void DS3231::convertTemperature()
+{
+    // Set CONV 
+    uint8_t ctReg = readRegister(DS3231_CONTROL_REG);
+    ctReg |= 0b00100000; 
+    writeRegister(DS3231_CONTROL_REG,ctReg); 
+
+
+    //wait until CONV is cleared. Indicates new temperature value is available in register.
+    do
+    {
+       //do nothing
+    } while ((readRegister(DS3231_CONTROL_REG) & 0b00100000) == 0b00100000 ); 
+
+}
+
+//Read the temperature value from the register and convert it into float (deg C)
+float DS3231::getTemperature()
+{
+    int   temperatureCelsius;
+    float fTemperatureCelsius;
+    uint8_t tUBYTE  = readRegister(DS3231_TMP_UP_REG);  //Two's complement form
+    uint8_t tLRBYTE = readRegister(DS3231_TMP_LOW_REG); //Fractional part
+
+    if(tUBYTE & 0b10000000) //check if -ve number
+    {
+       tUBYTE  ^= 0b11111111;  
+       tUBYTE  += 0x1;
+       fTemperatureCelsius = tUBYTE + ((tLRBYTE >> 6) * 0.25);
+       fTemperatureCelsius = fTemperatureCelsius * -1;
+    }
+    else
+    {
+        fTemperatureCelsius = tUBYTE + ((tLRBYTE >> 6) * 0.25); 
+    }
+
+    return (fTemperatureCelsius);
+
+}
+