MCP7940N RTC Library for ESP8266

This library is intended to make use of the MCP7940N RTC under the Arduino environment for the ESP8266, ESP01, ESP12E & all other derivative hardware.

It's been based on the DS1307RTC library and its main purpose is to be used in conjuction with the Time library.

Usage:

First of all object should be created by passing the SDA & SCL pin numbers to its contructor:

const uint8_t SCLPIN = 12;
const uint8_t SDAPIN = 14;

MCP7940NRTC RTC = MCP7940NRTC(SDAPIN, SCLPIN);

Once the object has been created you can now invoke its methods normally. They are as follows:

//Acquire data from hardware and return time_t
//Returns 0 if there is a comms issue or oscillator is halted
time_t get();
//Sets the HW clock to the time given in time_t format
//Returns false if there was a communication error
bool set(time_t t);
//Returns the HW time in tmElements_t format
//False if theres a comms issue or oscillator is halted
bool read(tmElements_t &tm);
//Writes the given data to the HW registers
//Returns false if there was a comms error
bool write(tmElements_t &tm);
//This is set to true when no communication errors exist
bool chipPresent();
//Checks the oscillator running bit
bool isRunning();
//Checks the external battery status
bool getBatteryStatus() const;
//Sets the external battery
void enableBattery();
void disableBattery();

Please see attached examples folder to get an idea of it's basic usage.

Not implemented:

• Calibration procedure
• Retrieving of power down/up status bit and timestamps
• Alarm functionality
• Internal SRAM