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/*----------------------------------------------------------------------*
* DS3232RTC.cpp - Arduino library for the Maxim Integrated DS3232 *
* Real-Time Clock. This library is intended for use with the Arduino *
* Time.h library, http://www.arduino.cc/playground/Code/Time *
* *
* This library is a drop-in replacement for the DS1307RTC.h library *
* by Michael Margolis that is supplied with the Arduino Time library *
* above. To change from using a DS1307 RTC to an DS3232 RTC, it is *
* only necessary to change the #include statement to include this *
* library instead of DS1307RTC.h. *
* *
* In addition, this library implements functions to support the *
* additional features of the DS3232. *
* *
* This library will also work with the DS3231 RTC, which has the same *
* features of the DS3232 except: (1) Battery-backed SRAM, (2) Battery- *
* backed 32kHz output (BB32kHz bit in Control/Status register 0x0F), *
* and (3) Adjustable temperature sensor sample rate (CRATE1:0 bits in *
* the Control/Status register). *
* *
* Whether used with the DS3232 or DS3231, the user is responsible for *
* ensuring reads and writes do not exceed the device's address space *
* (0x00-0x12 for DS3231, 0x00-0xFF for DS3232); no bounds checking *
* is done by this library. *
* *
* Jack Christensen 06Mar2013 *
* 28Aug2013 Changed the lower level methods to return the status of *
* the I2C communication with the RTC. Thanks to *
* Rob Tillaart for the suggestion. (Fixes issue #1.) *
* *
* This work is licensed under the Creative Commons Attribution- *
* ShareAlike 3.0 Unported License. To view a copy of this license, *
* visit http://creativecommons.org/licenses/by-sa/3.0/ or send a *
* letter to Creative Commons, 444 Castro Street, Suite 900, *
* Mountain View, CA 94041. *
*----------------------------------------------------------------------*/
#include <DS3232RTC.h>
//define release-independent I2C functions
#if defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
#include <TinyWireM.h>
#define i2cBegin TinyWireM.begin
#define i2cBeginTransmission TinyWireM.beginTransmission
#define i2cEndTransmission TinyWireM.endTransmission
#define i2cRequestFrom TinyWireM.requestFrom
#define i2cRead TinyWireM.receive
#define i2cWrite TinyWireM.send
#elif ARDUINO >= 100
#include <Wire.h>
#define i2cBegin Wire.begin
#define i2cBeginTransmission Wire.beginTransmission
#define i2cEndTransmission Wire.endTransmission
#define i2cRequestFrom Wire.requestFrom
#define i2cRead Wire.read
#define i2cWrite Wire.write
#else
#include <Wire.h>
#define i2cBegin Wire.begin
#define i2cBeginTransmission Wire.beginTransmission
#define i2cEndTransmission Wire.endTransmission
#define i2cRequestFrom Wire.requestFrom
#define i2cRead Wire.receive
#define i2cWrite Wire.send
#endif
/*----------------------------------------------------------------------*
* Constructor. *
*----------------------------------------------------------------------*/
DS3232RTC::DS3232RTC()
{
i2cBegin();
}
/*----------------------------------------------------------------------*
* Read the current time from the RTC and return it as a time_t value. *
* Returns a zero value if an I2C error occurred (e.g. RTC *
* not present). *
*----------------------------------------------------------------------*/
time_t DS3232RTC::get()
{
tmElements_t tm;
if ( read(tm) ) return 0;
return( makeTime(tm) );
}
/*----------------------------------------------------------------------*
* Set the RTC to the given time_t value. *
* Returns the I2C status (zero if successful). *
*----------------------------------------------------------------------*/
byte DS3232RTC::set(time_t t)
{
tmElements_t tm;
breakTime(t, tm);
return ( write(tm) );
}
/*----------------------------------------------------------------------*
* Read the current time from the RTC and return it in a tmElements_t *
* structure. Returns the I2C status (zero if successful). *
*----------------------------------------------------------------------*/
byte DS3232RTC::read(tmElements_t &tm)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite((uint8_t)RTC_SECONDS);
if ( byte e = i2cEndTransmission() ) return e;
//request 7 bytes (secs, min, hr, dow, date, mth, yr)
i2cRequestFrom(RTC_ADDR, tmNbrFields);
tm.Second = bcd2dec(i2cRead() & ~_BV(DS1307_CH));
tm.Minute = bcd2dec(i2cRead());
tm.Hour = bcd2dec(i2cRead() & ~_BV(HR1224)); //assumes 24hr clock
tm.Wday = i2cRead();
tm.Day = bcd2dec(i2cRead());
tm.Month = bcd2dec(i2cRead() & ~_BV(CENTURY)); //don't use the Century bit
tm.Year = y2kYearToTm(bcd2dec(i2cRead()));
return 0;
}
/*----------------------------------------------------------------------*
* Set the RTC's time from a tmElements_t structure. *
* Returns the I2C status (zero if successful). *
*----------------------------------------------------------------------*/
byte DS3232RTC::write(tmElements_t &tm)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite((uint8_t)RTC_SECONDS);
i2cWrite(dec2bcd(tm.Second));
i2cWrite(dec2bcd(tm.Minute));
i2cWrite(dec2bcd(tm.Hour)); //sets 24 hour format (Bit 6 == 0)
i2cWrite(tm.Wday);
i2cWrite(dec2bcd(tm.Day));
i2cWrite(dec2bcd(tm.Month));
i2cWrite(dec2bcd(tmYearToY2k(tm.Year)));
return i2cEndTransmission();
}
/*----------------------------------------------------------------------*
* Write multiple bytes to RTC RAM. *
* Valid address range is 0x00 - 0xFF, no checking. *
* Number of bytes (nBytes) must be between 1 and 31 (Wire library *
* limitation). *
* Returns the I2C status (zero if successful). *
*----------------------------------------------------------------------*/
byte DS3232RTC::writeRTC(byte addr, byte *values, byte nBytes)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite(addr);
for (byte i=0; i<nBytes; i++) i2cWrite(values[i]);
return i2cEndTransmission();
}
/*----------------------------------------------------------------------*
* Write a single byte to RTC RAM. *
* Valid address range is 0x00 - 0xFF, no checking. *
* Returns the I2C status (zero if successful). *
*----------------------------------------------------------------------*/
byte DS3232RTC::writeRTC(byte addr, byte value)
{
return ( writeRTC(addr, &value, 1) );
}
/*----------------------------------------------------------------------*
* Read multiple bytes from RTC RAM. *
* Valid address range is 0x00 - 0xFF, no checking. *
* Number of bytes (nBytes) must be between 1 and 32 (Wire library *
* limitation). *
* Returns the I2C status (zero if successful). *
*----------------------------------------------------------------------*/
byte DS3232RTC::readRTC(byte addr, byte *values, byte nBytes)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite(addr);
if ( byte e = i2cEndTransmission() ) return e;
i2cRequestFrom( (uint8_t)RTC_ADDR, nBytes );
for (byte i=0; i<nBytes; i++) values[i] = i2cRead();
return 0;
}
/*----------------------------------------------------------------------*
* Read a single byte from RTC RAM. *
* Valid address range is 0x00 - 0xFF, no checking. *
*----------------------------------------------------------------------*/
byte DS3232RTC::readRTC(byte addr)
{
byte b;
readRTC(addr, &b, 1);
return b;
}
/*----------------------------------------------------------------------*
* Set an alarm time. Sets the alarm registers only. To cause the *
* INT pin to be asserted on alarm match, use alarmInterrupt(). *
* This method can set either Alarm 1 or Alarm 2, depending on the *
* value of alarmType (use a value from the ALARM_TYPES_t enumeration). *
* When setting Alarm 2, the seconds value must be supplied but is *
* ignored, recommend using zero. (Alarm 2 has no seconds register.) *
*----------------------------------------------------------------------*/
void DS3232RTC::setAlarm(ALARM_TYPES_t alarmType, byte seconds, byte minutes, byte hours, byte daydate)
{
uint8_t addr;
seconds = dec2bcd(seconds);
minutes = dec2bcd(minutes);
hours = dec2bcd(hours);
daydate = dec2bcd(daydate);
if (alarmType & 0x01) seconds |= _BV(A1M1);
if (alarmType & 0x02) minutes |= _BV(A1M2);
if (alarmType & 0x04) hours |= _BV(A1M3);
if (alarmType & 0x10) hours |= _BV(DYDT);
if (alarmType & 0x08) daydate |= _BV(A1M4);
if ( !(alarmType & 0x80) ) { //alarm 1
addr = ALM1_SECONDS;
writeRTC(addr++, seconds);
}
else {
addr = ALM2_MINUTES;
}
writeRTC(addr++, minutes);
writeRTC(addr++, hours);
writeRTC(addr++, daydate);
}
/*----------------------------------------------------------------------*
* Set an alarm time. Sets the alarm registers only. To cause the *
* INT pin to be asserted on alarm match, use alarmInterrupt(). *
* This method can set either Alarm 1 or Alarm 2, depending on the *
* value of alarmType (use a value from the ALARM_TYPES_t enumeration). *
* However, when using this method to set Alarm 1, the seconds value *
* is set to zero. (Alarm 2 has no seconds register.) *
*----------------------------------------------------------------------*/
void DS3232RTC::setAlarm(ALARM_TYPES_t alarmType, byte minutes, byte hours, byte daydate)
{
setAlarm(alarmType, 0, minutes, hours, daydate);
}
/*----------------------------------------------------------------------*
* Enable or disable an alarm "interrupt" which asserts the INT pin *
* on the RTC. *
*----------------------------------------------------------------------*/
void DS3232RTC::alarmInterrupt(byte alarmNumber, boolean interruptEnabled)
{
uint8_t controlReg, mask;
controlReg = readRTC(RTC_CONTROL);
mask = _BV(A1IE) << (alarmNumber - 1);
if (interruptEnabled)
controlReg |= mask;
else
controlReg &= ~mask;
writeRTC(RTC_CONTROL, controlReg);
}
/*----------------------------------------------------------------------*
* Returns true or false depending on whether the given alarm has been *
* triggered, and resets the alarm flag bit. *
*----------------------------------------------------------------------*/
boolean DS3232RTC::alarm(byte alarmNumber)
{
uint8_t statusReg, mask;
statusReg = readRTC(RTC_STATUS);
mask = _BV(A1F) << (alarmNumber - 1);
if (statusReg & mask) {
statusReg &= ~mask;
writeRTC(RTC_STATUS, statusReg);
return true;
}
else {
return false;
}
}
/*----------------------------------------------------------------------*
* Enable or disable the square wave output. *
* Use a value from the SQWAVE_FREQS_t enumeration for the parameter. *
*----------------------------------------------------------------------*/
void DS3232RTC::squareWave(SQWAVE_FREQS_t freq)
{
uint8_t controlReg;
controlReg = readRTC(RTC_CONTROL);
if (freq >= SQWAVE_NONE) {
controlReg |= _BV(INTCN);
}
else {
controlReg = (controlReg & 0xE3) | (freq << RS1);
}
writeRTC(RTC_CONTROL, controlReg);
}
/*----------------------------------------------------------------------*
* Checks the OSF bit in the status register which indicates that the *
* oscillator is or was stopped. *
*----------------------------------------------------------------------*/
boolean DS3232RTC::oscStopped(void)
{
return ( readRTC(RTC_STATUS) & _BV(OSF) );
}
/*----------------------------------------------------------------------*
* Returns the temperature in Celsius times four. *
*----------------------------------------------------------------------*/
int DS3232RTC::temperature(void)
{
union int16_byte {
int i;
byte b[2];
} rtcTemp;
rtcTemp.b[0] = readRTC(TEMP_LSB);
rtcTemp.b[1] = readRTC(TEMP_MSB);
return rtcTemp.i >> 6;
}
/*----------------------------------------------------------------------*
* Decimal-to-BCD conversion *
*----------------------------------------------------------------------*/
uint8_t DS3232RTC::dec2bcd(uint8_t n)
{
return n + 6 * (n / 10);
}
/*----------------------------------------------------------------------*
* BCD-to-Decimal conversion *
*----------------------------------------------------------------------*/
uint8_t __attribute__ ((noinline)) DS3232RTC::bcd2dec(uint8_t n)
{
return n - 6 * (n >> 4);
}
DS3232RTC RTC = DS3232RTC(); //instantiate an RTC object