Real Time Clock (RTC) DS1307 IC

The DS1307 is a low power Full Binary (BCD) Real Time Clock (RTC) IC with 56 bytes of SVRAM that communicates through I2C Protocol. The IC can work from directly supply on Vcc and switch to Battery automatically when required. Pin Configuration Pin Number Pin Name Description 1,2 X1 , X2 Crystal Oscillator should be connected to these pins 3 V-Bat Connected to Positive terminal of the battery 4 Ground Ground pin of the IC 5,6 SCL and SDA Pins for I2C communication with CPU 7 SQW / Out Square wave output driver pin to obtain square wave frequencies. 8 Vcc Powers the IC typically 5V DS1307 Specifications I2C Interface RTC IC Operating Voltage: 5V Less than 500nA current when operating with battery 56bytes SVRAM Operates in power or battery mode Programmable square wave output pin Available in PDIP and SO package How to use DS1307 The DS1307 is a 8-pin IC which operates on 5V and communicates with CPU though I2C protocol. A typical application circuit for the DS1307 from DS1307 datasheet is shown below. As you can see the IC has SCL (Serial Clock) and SDA (Serial Data) pins using which it communicates to the CPU, both these pins has to be pulled high using a resistor. The IC can be powered by providing 5V on the Vcc pin, when the power fails it will automatically switch to battery operated mode in which it will obtain power with Lithium cell connected to pin Vbat and ground. The pins X1 and X2 are used to connect the crystal oscillator; typically a 32.7KHz Quartz crystal is used. The SQW pin is used to provide a PWM square wave of programmable frequencies in the range of 1Hz, 4KHz, 8KHZ or 32KHz. This pin also requires a pull up resistor. Data between the CPU and RTC IC is exchanged only though the I2C protocol. Both Read and write happens through this communication. The IC can provide details like Real-Time Clock Counts Seconds, Minutes, Hours, Date of the Month, Month, Day of the Week, and Year with Leap-Year Compensation Valid Up to 2100. Applications · Robotics · Gaming · Servers · Computer Peripherals · GPS · Utility power meters 2D-Model (PDIP 8-pin) DS1307 Datasheet

The DS1307N+ is a 64 x 8, serial, I2C real-time clock (RTC) in 8 pin DIP package. It is a low power, full binary coded decimal (BCD) clock/calendar with 56bytes of NV SRAM. It has a supply voltage range from 4.5V to 5.5V, active supply current of 1.5mA and standby current of 200µA. Address and data are transferred serially through an I2C bidirectional bus. The clock/calendar provides seconds, minutes, hours, day, date, month and year information. The end of the month date is automatically adjusted for months with fewer than 31 days including leap year compensation valid up to 2100. The clock operates in either 24 hours or 12-hour format with AM/PM indicator. The DS1307 has built-in power sense circuit that detects power failures and automatically switches to backup supply. Timekeeping operation continues while the device operates from the backup supply. Features: UL recognized Operating temperature range from -40°C to 85°C Automatic power fail to detect and switch circuitry Timekeeping current of 300nA Completely manages all timekeeping functions 56byte, battery backed, general purpose RAM with unlimited writes A programmable square wave output signal Simple serial port interfaces to most microcontrollers Low power operation extends battery backup runtime Consumes less than 500nA in battery backup mode with oscillator running Applications: Clock & Timing