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/*----------------------------------------------------------------------*
* MCP79412RTC.cpp - Arduino library for the Microchip MCP7941x *
* Real-Time Clocks. 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 MCP7941x 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 MCP7941x. *
* *
* Jack Christensen 29Jul2012 *
* *
* 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, 171 Second Street, Suite 300, *
* San Francisco, California, 94105, USA. *
*----------------------------------------------------------------------*/
#include "MCP79412RTC.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. *
*----------------------------------------------------------------------*/
MCP79412RTC::MCP79412RTC()
{
i2cBegin();
}
/*----------------------------------------------------------------------*
* Read the current time from the RTC and return it as a time_t value. *
* Returns a zero value if RTC not present (I2C I/O error). *
*----------------------------------------------------------------------*/
time_t MCP79412RTC::get(void)
{
tmElements_t tm;
if ( read(tm) )
return( makeTime(tm) );
else
return 0;
}
/*----------------------------------------------------------------------*
* Set the RTC to the given time_t value. *
*----------------------------------------------------------------------*/
void MCP79412RTC::set(time_t t)
{
tmElements_t tm;
breakTime(t, tm);
write(tm);
}
/*----------------------------------------------------------------------*
* Read the current time from the RTC and return it in a tmElements_t *
* structure. Returns false if RTC not present (I2C I/O error). *
*----------------------------------------------------------------------*/
boolean MCP79412RTC::read(tmElements_t &tm)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite((uint8_t)TIME_REG);
if (i2cEndTransmission() != 0) {
return false;
}
else {
//request 7 bytes (secs, min, hr, dow, date, mth, yr)
i2cRequestFrom(RTC_ADDR, tmNbrFields);
tm.Second = bcd2dec(i2cRead() & ~_BV(ST));
tm.Minute = bcd2dec(i2cRead());
tm.Hour = bcd2dec(i2cRead() & ~_BV(HR1224)); //assumes 24hr clock
tm.Wday = i2cRead() & ~(_BV(OSCON) | _BV(VBAT) | _BV(VBATEN)); //mask off OSCON, VBAT, VBATEN bits
tm.Day = bcd2dec(i2cRead());
tm.Month = bcd2dec(i2cRead() & ~_BV(LP)); //mask off the leap year bit
tm.Year = y2kYearToTm(bcd2dec(i2cRead()));
return true;
}
}
/*----------------------------------------------------------------------*
* Set the RTC's time from a tmElements_t structure. *
*----------------------------------------------------------------------*/
void MCP79412RTC::write(tmElements_t &tm)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite((uint8_t)TIME_REG);
i2cWrite((uint8_t)0x00); //stops the oscillator (Bit 7, ST == 0)
i2cWrite(dec2bcd(tm.Minute));
i2cWrite(dec2bcd(tm.Hour)); //sets 24 hour format (Bit 6 == 0)
i2cWrite(tm.Wday | _BV(VBATEN)); //enable battery backup operation
i2cWrite(dec2bcd(tm.Day));
i2cWrite(dec2bcd(tm.Month));
i2cWrite(dec2bcd(tmYearToY2k(tm.Year)));
i2cEndTransmission();
i2cBeginTransmission(RTC_ADDR);
i2cWrite((uint8_t)TIME_REG);
i2cWrite(dec2bcd(tm.Second) | _BV(ST)); //set the seconds and start the oscillator (Bit 7, ST == 1)
i2cEndTransmission();
}
/*----------------------------------------------------------------------*
* Write a single byte to RTC RAM. *
* Valid address range is 0x00 - 0x5F, no checking. *
*----------------------------------------------------------------------*/
void MCP79412RTC::ramWrite(byte addr, byte value)
{
ramWrite(addr, &value, 1);
}
/*----------------------------------------------------------------------*
* Write multiple bytes to RTC RAM. *
* Valid address range is 0x00 - 0x5F, no checking. *
* Number of bytes (nBytes) must be between 1 and 31 (Wire library *
* limitation). *
*----------------------------------------------------------------------*/
void MCP79412RTC::ramWrite(byte addr, byte *values, byte nBytes)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite(addr);
for (byte i=0; i<nBytes; i++) i2cWrite(values[i]);
i2cEndTransmission();
}
/*----------------------------------------------------------------------*
* Read a single byte from RTC RAM. *
* Valid address range is 0x00 - 0x5F, no checking. *
*----------------------------------------------------------------------*/
byte MCP79412RTC::ramRead(byte addr)
{
byte value;
ramRead(addr, &value, 1);
return value;
}
/*----------------------------------------------------------------------*
* Read multiple bytes from RTC RAM. *
* Valid address range is 0x00 - 0x5F, no checking. *
* Number of bytes (nBytes) must be between 1 and 32 (Wire library *
* limitation). *
*----------------------------------------------------------------------*/
void MCP79412RTC::ramRead(byte addr, byte *values, byte nBytes)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite(addr);
i2cEndTransmission();
i2cRequestFrom( (uint8_t)RTC_ADDR, nBytes );
for (byte i=0; i<nBytes; i++) values[i] = i2cRead();
}
/*----------------------------------------------------------------------*
* Write a single byte to Static RAM. *
* Address (addr) is constrained to the range (0, 63). *
*----------------------------------------------------------------------*/
void MCP79412RTC::sramWrite(byte addr, byte value)
{
ramWrite( (addr & (SRAM_SIZE - 1) ) + SRAM_START_ADDR, &value, 1 );
}
/*----------------------------------------------------------------------*
* Write multiple bytes to Static RAM. *
* Address (addr) is constrained to the range (0, 63). *
* Number of bytes (nBytes) must be between 1 and 31 (Wire library *
* limitation). *
* Invalid values for nBytes, or combinations of addr and nBytes *
* that would result in addressing past the last byte of SRAM will *
* result in no action. *
*----------------------------------------------------------------------*/
void MCP79412RTC::sramWrite(byte addr, byte *values, byte nBytes)
{
#if defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
if (nBytes >= 1 && (addr + nBytes) <= SRAM_SIZE) {
#else
if (nBytes >= 1 && nBytes <= (BUFFER_LENGTH - 1) && (addr + nBytes) <= SRAM_SIZE) {
#endif
ramWrite( (addr & (SRAM_SIZE - 1) ) + SRAM_START_ADDR, values, nBytes );
}
}
/*----------------------------------------------------------------------*
* Read a single byte from Static RAM. *
* Address (addr) is constrained to the range (0, 63). *
*----------------------------------------------------------------------*/
byte MCP79412RTC::sramRead(byte addr)
{
byte value;
ramRead( (addr & (SRAM_SIZE - 1) ) + SRAM_START_ADDR, &value, 1 );
return value;
}
/*----------------------------------------------------------------------*
* Read multiple bytes from Static RAM. *
* Address (addr) is constrained to the range (0, 63). *
* Number of bytes (nBytes) must be between 1 and 32 (Wire library *
* limitation). *
* Invalid values for nBytes, or combinations of addr and *
* nBytes that would result in addressing past the last byte of SRAM *
* result in no action. *
*----------------------------------------------------------------------*/
void MCP79412RTC::sramRead(byte addr, byte *values, byte nBytes)
{
#if defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
if (nBytes >= 1 && (addr + nBytes) <= SRAM_SIZE) {
#else
if (nBytes >= 1 && nBytes <= BUFFER_LENGTH && (addr + nBytes) <= SRAM_SIZE) {
#endif
ramRead((addr & (SRAM_SIZE - 1) ) + SRAM_START_ADDR, values, nBytes);
}
}
/*----------------------------------------------------------------------*
* Write a single byte to EEPROM. *
* Address (addr) is constrained to the range (0, 127). *
* Can't leverage page write function because a write can't start *
* mid-page. *
*----------------------------------------------------------------------*/
void MCP79412RTC::eepromWrite(byte addr, byte value)
{
i2cBeginTransmission(EEPROM_ADDR);
i2cWrite( addr & (EEPROM_SIZE - 1) );
i2cWrite(value);
i2cEndTransmission();
eepromWait();
}
/*----------------------------------------------------------------------*
* Write a page (or less) to EEPROM. An EEPROM page is 8 bytes. *
* Address (addr) should be a page start address (0, 8, ..., 120), but *
* is ruthlessly coerced into a valid value. *
* Number of bytes (nBytes) must be between 1 and 8, other values *
* result in no action. *
*----------------------------------------------------------------------*/
void MCP79412RTC::eepromWrite(byte addr, byte *values, byte nBytes)
{
if (nBytes >= 1 && nBytes <= EEPROM_PAGE_SIZE) {
i2cBeginTransmission(EEPROM_ADDR);
i2cWrite( addr & ~(EEPROM_PAGE_SIZE - 1) & (EEPROM_SIZE - 1) );
for (byte i=0; i<nBytes; i++) i2cWrite(values[i]);
i2cEndTransmission();
eepromWait();
}
}
/*----------------------------------------------------------------------*
* Read a single byte from EEPROM. *
* Address (addr) is constrained to the range (0, 127). *
*----------------------------------------------------------------------*/
byte MCP79412RTC::eepromRead(byte addr)
{
byte value;
eepromRead( addr & (EEPROM_SIZE - 1), &value, 1 );
return value;
}
/*----------------------------------------------------------------------*
* Read multiple bytes from EEPROM. *
* Address (addr) is constrained to the range (0, 127). *
* Number of bytes (nBytes) must be between 1 and 32 (Wire library *
* limitation). *
* Invalid values for addr or nBytes, or combinations of addr and *
* nBytes that would result in addressing past the last byte of EEPROM *
* result in no action. *
*----------------------------------------------------------------------*/
void MCP79412RTC::eepromRead(byte addr, byte *values, byte nBytes)
{
#if defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
if (nBytes >= 1 && (addr + nBytes) <= EEPROM_SIZE) {
#else
if (nBytes >= 1 && nBytes <= BUFFER_LENGTH && (addr + nBytes) <= EEPROM_SIZE) {
#endif
i2cBeginTransmission(EEPROM_ADDR);
i2cWrite( addr & (EEPROM_SIZE - 1) );
i2cEndTransmission();
i2cRequestFrom( (uint8_t)EEPROM_ADDR, nBytes );
for (byte i=0; i<nBytes; i++) values[i] = i2cRead();
}
}
/*----------------------------------------------------------------------*
* Wait for EEPROM write to complete. *
*----------------------------------------------------------------------*/
byte MCP79412RTC::eepromWait(void)
{
byte waitCount = 0;
byte txStatus;
do
{
++waitCount;
i2cBeginTransmission(EEPROM_ADDR);
i2cWrite((uint8_t)0);
txStatus = i2cEndTransmission();
} while (txStatus != 0);
return waitCount;
}
/*----------------------------------------------------------------------*
* Read the calibration register. *
* The calibration value is not a twos-complement number. The MSB is *
* the sign bit, and the 7 LSBs are an unsigned number, so we convert *
* it and return it to the caller as a regular twos-complement integer. *
*----------------------------------------------------------------------*/
int MCP79412RTC::calibRead(void)
{
byte val = ramRead(CALIB_REG);
if ( val & 0x80 ) return -(val & 0x7F);
else return val;
}
/*----------------------------------------------------------------------*
* Write the calibration register. *
* Calibration value must be between -127 and 127, others result *
* in no action. See note above on the format of the calibration value. *
*----------------------------------------------------------------------*/
void MCP79412RTC::calibWrite(int value)
{
byte calibVal;
if (value >= -127 && value <= 127) {
calibVal = abs(value);
if (value < 0) calibVal += 128;
ramWrite(CALIB_REG, calibVal);
}
}
/*----------------------------------------------------------------------*
* Read the unique ID. *
* For the MCP79411 (EUI-48), the first two bytes will contain 0xFF. *
* Caller must provide an 8-byte array to contain the results. *
*----------------------------------------------------------------------*/
void MCP79412RTC::idRead(byte *uniqueID)
{
i2cBeginTransmission(EEPROM_ADDR);
i2cWrite(UNIQUE_ID_ADDR);
i2cEndTransmission();
i2cRequestFrom( EEPROM_ADDR, UNIQUE_ID_SIZE );
for (byte i=0; i<UNIQUE_ID_SIZE; i++) uniqueID[i] = i2cRead();
}
/*----------------------------------------------------------------------*
* Returns an EUI-64 ID. For an MCP79411, the EUI-48 ID is converted to *
* EUI-64. For an MCP79412, calling this function is equivalent to *
* calling idRead(). For an MCP79412, if the RTC type is known, calling *
* idRead() will be a bit more efficient. *
* Caller must provide an 8-byte array to contain the results. *
*----------------------------------------------------------------------*/
void MCP79412RTC::getEUI64(byte *uniqueID)
{
byte rtcID[8];
idRead(rtcID);
if (rtcID[0] == 0xFF && rtcID[1] == 0xFF) {
rtcID[0] = rtcID[2];
rtcID[1] = rtcID[3];
rtcID[2] = rtcID[4];
rtcID[3] = 0xFF;
rtcID[4] = 0xFE;
}
for (byte i=0; i<UNIQUE_ID_SIZE; i++) uniqueID[i] = rtcID[i];
}
/*----------------------------------------------------------------------*
* Check to see if a power failure has occurred. If so, returns TRUE *
* as the function value, and returns the power down and power up *
* timestamps. After returning the time stamps, the RTC's timestamp *
* registers are cleared and the VBAT bit which indicates a power *
* failure is reset. *
* *
* Note that the power down and power up timestamp registers do not *
* contain values for seconds or for the year. The returned time stamps *
* will therefore contain the current year from the RTC. However, there *
* is a chance that a power outage spans from one year to the next. *
* If we find the power down timestamp to be later (larger) than the *
* power up timestamp, we will assume this has happened, and well *
* subtract one year from the power down timestamp. *
* *
* Still, there is an assumption that the timestamps are being read *
* in the same year as that when the power up occurred. *
* *
* Finally, note that once the RTC records a power outage, it must be *
* cleared before another will be recorded. *
*----------------------------------------------------------------------*/
boolean MCP79412RTC::powerFail(time_t *powerDown, time_t *powerUp)
{
byte day, yr; //copies of the RTC Day and Year registers
tmElements_t dn, up; //power down and power up times
ramRead(DAY_REG, &day, 1);
ramRead(YEAR_REG, &yr, 1);
yr = y2kYearToTm(bcd2dec(yr));
if ( day & _BV(VBAT) ) {
i2cBeginTransmission(RTC_ADDR);
i2cWrite(PWRDWN_TS_REG);
i2cEndTransmission();
i2cRequestFrom(RTC_ADDR, TIMESTAMP_SIZE); //read both timestamp registers, 8 bytes total
dn.Second = 0;
dn.Minute = bcd2dec(i2cRead());
dn.Hour = bcd2dec(i2cRead() & ~_BV(HR1224)); //assumes 24hr clock
dn.Day = bcd2dec(i2cRead());
dn.Month = bcd2dec(i2cRead() & 0x1F); //mask off the day, we don't need it
dn.Year = yr; //assume current year
up.Second = 0;
up.Minute = bcd2dec(i2cRead());
up.Hour = bcd2dec(i2cRead() & ~_BV(HR1224)); //assumes 24hr clock
up.Day = bcd2dec(i2cRead());
up.Month = bcd2dec(i2cRead() & 0x1F); //mask off the day, we don't need it
up.Year = yr; //assume current year
*powerDown = makeTime(dn);
*powerUp = makeTime(up);
//clear the VBAT bit, which causes the RTC hardware to clear the timestamps too.
//I suppose there is a risk here that the day has changed since we read it,
//but the Day of Week is actually redundant data and the makeTime() function
//does not use it. This could be an issue if someone is reading the RTC
//registers directly, but as this library is meant to be used with the Time library,
//and also because we don't provide a method to read the RTC clock/calendar
//registers directly, we won't lose any sleep about it at this point unless
//some issue is actually brought to our attention ;-)
day &= ~_BV(VBAT);
ramWrite(DAY_REG, &day , 1);
//adjust the powerDown timestamp if needed (see notes above)
if (*powerDown > *powerUp) {
--dn.Year;
*powerDown = makeTime(dn);
}
return true;
}
else
return false;
}
/*----------------------------------------------------------------------*
* Enable or disable the square wave output. *
*----------------------------------------------------------------------*/
void MCP79412RTC::squareWave(uint8_t freq)
{
uint8_t ctrlReg;
ramRead(CTRL_REG, &ctrlReg, 1);
if (freq > 3) {
ctrlReg &= ~_BV(SQWE);
}
else {
ctrlReg = (ctrlReg & 0xF8) | _BV(SQWE) | freq;
}
ramWrite(CTRL_REG, &ctrlReg, 1);
}
/*----------------------------------------------------------------------*
* Set an alarm time. Sets the alarm registers only, does not enable *
* the alarm. See enableAlarm(). *
*----------------------------------------------------------------------*/
void MCP79412RTC::setAlarm(uint8_t alarmNumber, time_t alarmTime)
{
tmElements_t tm;
uint8_t day; //need to preserve bits in the day (of week) register
alarmNumber &= 0x01; //ensure a valid alarm number
ramRead( ALM0_DAY + alarmNumber * (ALM1_REG - ALM0_REG) , &day, 1);
breakTime(alarmTime, tm);
i2cBeginTransmission(RTC_ADDR);
i2cWrite( ALM0_REG + alarmNumber * (ALM1_REG - ALM0_REG) );
i2cWrite(dec2bcd(tm.Second));
i2cWrite(dec2bcd(tm.Minute));
i2cWrite(dec2bcd(tm.Hour)); //sets 24 hour format (Bit 6 == 0)
i2cWrite( (day & 0xF8) + tm.Wday );
i2cWrite(dec2bcd(tm.Day));
i2cWrite(dec2bcd(tm.Month));
i2cEndTransmission();
}
/*----------------------------------------------------------------------*
* Enable or disable an alarm, and set the trigger criteria, *
* e.g. match only seconds, only minutes, entire time and date, etc. *
*----------------------------------------------------------------------*/
void MCP79412RTC::enableAlarm(uint8_t alarmNumber, uint8_t alarmType)
{
uint8_t day; //alarm day register has config & flag bits
uint8_t ctrl; //control register has alarm enable bits
alarmNumber &= 0x01; //ensure a valid alarm number
ramRead(CTRL_REG, &ctrl, 1);
if (alarmType < ALM_DISABLE) {
ramRead(ALM0_DAY + alarmNumber * (ALM1_REG - ALM0_REG), &day, 1);
day = ( day & 0x87 ) | alarmType << 4; //reset interrupt flag, OR in the config bits
ramWrite(ALM0_DAY + alarmNumber * (ALM1_REG - ALM0_REG), &day, 1);
ctrl |= _BV(ALM0 + alarmNumber); //enable the alarm
}
else {
ctrl &= ~(_BV(ALM0 + alarmNumber)); //disable the alarm
}
ramWrite(CTRL_REG, &ctrl, 1);
}
/*----------------------------------------------------------------------*
* Returns true or false depending on whether the given alarm has been *
* triggered, and resets the alarm "interrupt" flag. This is not a real *
* interrupt, just a bit that's set when an alarm is triggered. *
*----------------------------------------------------------------------*/
boolean MCP79412RTC::alarm(uint8_t alarmNumber)
{
uint8_t day; //alarm day register has config & flag bits
alarmNumber &= 0x01; //ensure a valid alarm number
ramRead( ALM0_DAY + alarmNumber * (ALM1_REG - ALM0_REG), &day, 1);
if (day & _BV(ALMIF)) {
day &= ~_BV(ALMIF); //turn off the alarm "interrupt" flag
ramWrite( ALM0_DAY + alarmNumber * (ALM1_REG - ALM0_REG), &day, 1);
return true;
}
else
return false;
}
/*----------------------------------------------------------------------*
* Sets the logic level on the MFP when it's not being used as a *
* square wave or alarm output. The default is HIGH. *
*----------------------------------------------------------------------*/
void MCP79412RTC::out(boolean level)
{
uint8_t ctrlReg;
ramRead(CTRL_REG, &ctrlReg, 1);
if (level)
ctrlReg |= _BV(OUT);
else
ctrlReg &= ~_BV(OUT);
ramWrite(CTRL_REG, &ctrlReg, 1);
}
/*----------------------------------------------------------------------*
* Specifies the logic level on the Multi-Function Pin (MFP) when an *
* alarm is triggered. The default is LOW. When both alarms are *
* active, the two are ORed together to determine the level of the MFP. *
* With alarm polarity set to LOW (the default), this causes the MFP *
* to go low only when BOTH alarms are triggered. With alarm polarity *
* set to HIGH, the MFP will go high when EITHER alarm is triggered. *
* *
* Note that the state of the MFP is independent of the alarm *
* "interrupt" flags, and the alarm() function will indicate when an *
* alarm is triggered regardless of the polarity. *
*----------------------------------------------------------------------*/
void MCP79412RTC::alarmPolarity(boolean polarity)
{
uint8_t alm0Day;
ramRead(ALM0_DAY, &alm0Day, 1);
if (polarity)
alm0Day |= _BV(OUT);
else
alm0Day &= ~_BV(OUT);
ramWrite(ALM0_DAY, &alm0Day, 1);
}
/*----------------------------------------------------------------------*
* Check to see if the RTC's oscillator is started (ST bit in seconds *
* register). Returns true if started. *
*----------------------------------------------------------------------*/
boolean MCP79412RTC::isRunning(void)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite((uint8_t)TIME_REG);
i2cEndTransmission();
//request just the seconds register
i2cRequestFrom(RTC_ADDR, 1);
return i2cRead() & _BV(ST);
}
/*----------------------------------------------------------------------*
* Set or clear the VBATEN bit. Setting the bit powers the clock and *
* SRAM from the backup battery when Vcc falls. Note that setting the *
* time via set() or write() sets the VBATEN bit. *
*----------------------------------------------------------------------*/
void MCP79412RTC::vbaten(boolean enable)
{
uint8_t day;
ramRead(DAY_REG, &day, 1);
if (enable)
day |= _BV(VBATEN);
else
day &= ~_BV(VBATEN);
ramWrite(DAY_REG, &day, 1);
return;
}
/*----------------------------------------------------------------------*
* Decimal-to-BCD conversion *
*----------------------------------------------------------------------*/
uint8_t MCP79412RTC::dec2bcd(uint8_t n)
{
return n + 6 * (n / 10);
}
/*----------------------------------------------------------------------*
* BCD-to-Decimal conversion *
*----------------------------------------------------------------------*/
uint8_t __attribute__ ((noinline)) MCP79412RTC::bcd2dec(uint8_t n)
{
return n - 6 * (n >> 4);
}
MCP79412RTC RTC = MCP79412RTC(); //instantiate an RTC object
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