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// Arduino DS3232RTC Library
// https://github.com/JChristensen/DS3232RTC
// Copyright (C) 2018 by Jack Christensen and licensed under
// GNU GPL v3.0, https://www.gnu.org/licenses/gpl.html
//
// Arduino library for the Maxim Integrated DS3232 and DS3231
// Real-Time Clocks.
// Requires PJRC's improved version of the Arduino Time Library,
// https://playground.arduino.cc/Code/Time
// https://github.com/PaulStoffregen/Time
//
// For AVR architecture, a DS3232RTC object named RTC is instantiated
// by the library and I2C initialization occurs in the constructor;
// this is for backwards compatibility.
// For other architectures, the user needs to instantiate a DS3232RTC
// object and optionally initialize the I2C bus by calling
// DS3232RTC::begin(). The constructor has an optional bool parameter
// to indicate whether I2C initialization should occur in the
// constructor; this parameter defaults to true if not given.
// 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
#include <TimeLib.h> //https://github.com/PaulStoffregen/Time
#include <DS3232RTC.h>
// DS3232 I2C Address
#define RTC_ADDR 0x68
// DS3232 Register Addresses
#define RTC_SECONDS 0x00
#define RTC_MINUTES 0x01
#define RTC_HOURS 0x02
#define RTC_DAY 0x03
#define RTC_DATE 0x04
#define RTC_MONTH 0x05
#define RTC_YEAR 0x06
#define ALM1_SECONDS 0x07
#define ALM1_MINUTES 0x08
#define ALM1_HOURS 0x09
#define ALM1_DAYDATE 0x0A
#define ALM2_MINUTES 0x0B
#define ALM2_HOURS 0x0C
#define ALM2_DAYDATE 0x0D
#define RTC_CONTROL 0x0E
#define RTC_STATUS 0x0F
#define RTC_AGING 0x10
#define RTC_TEMP_MSB 0x11
#define RTC_TEMP_LSB 0x12
#define SRAM_START_ADDR 0x14 // first SRAM address
#define SRAM_SIZE 236 // number of bytes of SRAM
// Alarm mask bits
#define A1M1 7
#define A1M2 7
#define A1M3 7
#define A1M4 7
#define A2M2 7
#define A2M3 7
#define A2M4 7
// Control register bits
#define EOSC 7
#define BBSQW 6
#define CONV 5
#define RS2 4
#define RS1 3
#define INTCN 2
#define A2IE 1
#define A1IE 0
// Status register bits
#define OSF 7
#define BB32KHZ 6
#define CRATE1 5
#define CRATE0 4
#define EN32KHZ 3
#define BSY 2
#define A2F 1
#define A1F 0
// Other
#define DS1307_CH 7 // for DS1307 compatibility, Clock Halt bit in Seconds register
#define HR1224 6 // Hours register 12 or 24 hour mode (24 hour mode==0)
#define CENTURY 7 // Century bit in Month register
#define DYDT 6 // Day/Date flag bit in alarm Day/Date registers
byte DS3232RTC::errCode; // for debug
// Constructor. Initializes the I2C bus by default, but better
// practice is to pass false in the constructor and call
// the begin() function in the setup code.
DS3232RTC::DS3232RTC(bool initI2C)
{
if (initI2C) i2cBegin();
}
// Initialize the I2C bus.
void DS3232RTC::begin()
{
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 and clear the
// oscillator stop flag (OSF) in the Control/Status register.
// 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() ) { errCode = e; 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 time from a tmElements_t structure and clear the
// oscillator stop flag (OSF) in the Control/Status register.
// 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)));
byte ret = i2cEndTransmission();
uint8_t s = readRTC(RTC_STATUS); // read the status register
writeRTC( RTC_STATUS, s & ~_BV(OSF) ); // clear the Oscillator Stop Flag
return ret;
}
// 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) daydate |= _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, bool 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.
bool 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);
}
// Returns the value of the oscillator stop flag (OSF) bit in the
// control/status register which indicates that the oscillator is or *
// was stopped, and that the timekeeping data may be invalid.
// Optionally clears the OSF bit depending on the argument passed.
bool DS3232RTC::oscStopped(bool clearOSF)
{
uint8_t s = readRTC(RTC_STATUS); // read the status register
bool ret = s & _BV(OSF); // isolate the osc stop flag to return to caller
if (ret && clearOSF) // clear OSF if it's set and the caller wants to clear it
{
writeRTC( RTC_STATUS, s & ~_BV(OSF) );
}
return ret;
}
// Returns the temperature in Celsius times four.
int16_t DS3232RTC::temperature()
{
union int16_byte {
int16_t i;
byte b[2];
} rtcTemp;
rtcTemp.b[0] = readRTC(RTC_TEMP_LSB);
rtcTemp.b[1] = readRTC(RTC_TEMP_MSB);
return rtcTemp.i / 64;
}
// 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);
}
#ifdef ARDUINO_ARCH_AVR
DS3232RTC RTC; // instantiate an RTC object
#endif
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