/*----------------------------------------------------------------------*

* MCP79412RTC.h - 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. *

*----------------------------------------------------------------------*/

#ifndef MCP79412RTC_h

#define MCP79412RTC_h

#include <Time.h>

#if defined(ARDUINO) && ARDUINO >= 100

#include <Arduino.h>

#else

#include <WProgram.h>

#endif

#ifndef _BV //Macro is defined in AVR libraries not present in SAMD21

#define _BV(bit) (1 << (bit)) //if the macro isn't defined, define it

#endif

//MCP7941x I2C Addresses

#define RTC_ADDR 0x6F

#define EEPROM_ADDR 0x57

//MCP7941x Register Addresses

#define TIME_REG 0x00 //7 registers, Seconds, Minutes, Hours, DOW, Date, Month, Year

#define DAY_REG 0x03 //the RTC Day register contains the OSCON, VBAT, and VBATEN bits

#define YEAR_REG 0x06 //RTC year register

#define CTRL_REG 0x07 //control register

#define CALIB_REG 0x08 //calibration register

#define UNLOCK_ID_REG 0x09 //unlock ID register

#define ALM0_REG 0x0A //alarm 0, 6 registers, Seconds, Minutes, Hours, DOW, Date, Month

#define ALM1_REG 0x11 //alarm 1, 6 registers, Seconds, Minutes, Hours, DOW, Date, Month

#define ALM0_DAY 0x0D //DOW register has alarm config/flag bits

#define PWRDWN_TS_REG 0x18 //power-down timestamp, 4 registers, Minutes, Hours, Date, Month

#define PWRUP_TS_REG 0x1C //power-up timestamp, 4 registers, Minutes, Hours, Date, Month

#define TIMESTAMP_SIZE 8 //number of bytes in the two timestamp registers

#define SRAM_START_ADDR 0x20 //first SRAM address

#define SRAM_SIZE 64 //number of bytes of SRAM

#define EEPROM_SIZE 128 //number of bytes of EEPROM

#define EEPROM_PAGE_SIZE 8 //number of bytes on an EEPROM page

#define UNIQUE_ID_ADDR 0xF0 //starting address for unique ID

#define UNIQUE_ID_SIZE 8 //number of bytes in unique ID

//Control Register bits

#define OUT 7 //sets logic level on MFP when not used as square wave output

#define SQWE 6 //set to enable square wave output

#define ALM1 5 //alarm 1 is active

#define ALM0 4 //alarm 0 is active

#define EXTOSC 3 //set to drive the RTC registers from an external oscillator instead of a crystal

#define RS2 2 //RS2:0 set square wave output frequency: 0==1Hz, 1==4096Hz, 2==8192Hz, 3=32768Hz

#define RS1 1

#define RS0 0

enum {SQWAVE_1_HZ, SQWAVE_4096_HZ, SQWAVE_8192_HZ, SQWAVE_32768_HZ, SQWAVE_NONE};

//Other Control Bits

#define ST 7 //Seconds register (TIME_REG) oscillator start/stop bit, 1==Start, 0==Stop

#define HR1224 6 //Hours register (TIME_REG+2) 12 or 24 hour mode (24 hour mode==0)

#define AMPM 5 //Hours register (TIME_REG+2) AM/PM bit for 12 hour mode

#define OSCON 5 //Day register (TIME_REG+3) oscillator running (set and cleared by hardware)

#define VBAT 4 //Day register (TIME_REG+3) set by hardware when Vcc fails and RTC runs on battery.

//VBAT is cleared by software, clearing VBAT also clears the timestamp registers

#define VBATEN 3 //Day register (TIME_REG+3) VBATEN==1 enables backup battery, VBATEN==0 disconnects the VBAT pin (e.g. to save battery)

#define LP 5 //Month register (TIME_REG+5) leap year bit

//Alarm Control Bits

#define ALMPOL 7 //Alarm Polarity: Defines the logic level for the MFP when an alarm is triggered.

#define ALMC2 6 //Alarm configuration bits determine how alarms match. See ALM_MATCH defines below.

#define ALMC1 5

#define ALMC0 4

#define ALMIF 3 //Alarm Interrupt Flag: Set by hardware when an alarm was triggered, cleared by software.

enum {ALM_MATCH_SECONDS, ALM_MATCH_MINUTES, ALM_MATCH_HOURS, ALM_MATCH_DAY, ALM_MATCH_DATE, ALM_RESERVED_5, ALM_RESERVED_6, ALM_MATCH_DATETIME, ALM_DISABLE};

//Note ALM_MATCH_DAY triggers alarm at midnight

#define ALARM_0 0 //constants for calling functions

#define ALARM_1 1

class MCP79412RTC

{

public:

MCP79412RTC();

static time_t get(void);

static void set(time_t t);

static boolean read(tmElements_t &tm);

static void write(tmElements_t &tm);

void sramWrite(byte addr, byte value);

void sramWrite(byte addr, byte *values, byte nBytes);

byte sramRead(byte addr);

void sramRead(byte addr, byte *values, byte nBytes);

void eepromWrite(byte addr, byte value);

void eepromWrite(byte addr, byte *values, byte nBytes);

byte eepromRead(byte addr);

void eepromRead(byte addr, byte *values, byte nBytes);

int calibRead(void);

void calibWrite(int value);

void idRead(byte *uniqueID);

void getEUI64(byte *uniqueID);

boolean powerFail(time_t *powerDown, time_t *powerUp);

void squareWave(uint8_t freq);

void setAlarm(uint8_t alarmNumber, time_t alarmTime);

void enableAlarm(uint8_t alarmNumber, uint8_t alarmType);

boolean alarm(uint8_t alarmNumber);

void out(boolean level);

void alarmPolarity(boolean polarity);

boolean isRunning(void);

void vbaten(boolean enable);

private:

static void ramWrite(byte addr, byte value);

static void ramWrite(byte addr, byte *values, byte nBytes);

static byte ramRead(byte addr);

static void ramRead(byte addr, byte *values, byte nBytes);

static byte eepromWait(void);

static uint8_t dec2bcd(uint8_t num);

static uint8_t bcd2dec(uint8_t num);

};

#ifdef RTC // From Paul Stoffregen's DS1307RTC library

#undef RTC // workaround for Arduino Due/Zero, which defines "RTC"...

#endif

extern MCP79412RTC RTC;

#endif