RTC.pdf - DS1307 64 x 8 Serial Real-Time Clock...

This preview shows page 1 - 4 out of 12 pages.

1 of 12 100101 FEATURES Real-time clock (RTC) counts seconds, minutes, hours, date of the month, month, day of the week, and year with leap-year compensation valid up to 2100 56-byte, battery-backed, nonvolatile (NV) RAM for data storage Two-wire serial interface Programmable squarewave output signal Automatic power-fail detect and switch circuitry Consumes less than 500nA in battery backup mode with oscillator running Optional industrial temperature range: -40°C to +85°C Available in 8-pin DIP or SOIC Underwriters Laboratory (UL) recognized ORDERING INFORMATION DS1307 8-Pin DIP (300-mil) DS1307Z 8-Pin SOIC (150-mil) DS1307N 8-Pin DIP (Industrial) DS1307ZN 8-Pin SOIC (Industrial) PIN ASSIGNMENT PIN DESCRIPTION V CC - Primary Power Supply X1, X2 - 32.768kHz Crystal Connection V BAT - +3V Battery Input GND - Ground SDA - Serial Data SCL - Serial Clock SQW/OUT - Square Wave/Output Driver DESCRIPTION The DS1307 Serial Real-Time Clock is a low-power, full binary-coded decimal (BCD) clock/calendar plus 56 bytes of NV SRAM. Address and data are transferred serially via a 2-wire, bi-directional 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 corrections for leap year. The clock operates in either the 24-hour or 12-hour format with AM/PM indicator. The DS1307 has a built-in power sense circuit that detects power failures and automatically switches to the battery supply. DS1307 64 x 8 Serial Real-Time Clock DS1307 8-Pin SOIC (150-mil) DS1307 8-Pin DIP (300-mil) X1 X2 V BAT GND V CC SQW/OUT SCL l 2 3 4 8 7 6 5 SDA l 2 3 4 8 7 6 5 X1 X2 V BAT GND V CC SQW/OUT SCL SDA
Image of page 1

Subscribe to view the full document.

DS1307 2 of 12 OPERATION The DS1307 operates as a slave device on the serial bus. Access is obtained by implementing a START condition and providing a device identification code followed by a register address. Subsequent registers can be accessed sequentially until a STOP condition is executed. When V CC falls below 1.25 x V BAT the device terminates an access in progress and resets the device address counter. Inputs to the device will not be recognized at this time to prevent erroneous data from being written to the device from an out of tolerance system. When V CC falls below V BAT the device switches into a low-current battery backup mode. Upon power-up, the device switches from battery to V CC when V CC is greater than V BAT + 0.2V and recognizes inputs when V CC is greater than 1.25 x V BAT . The block diagram in Figure 1 shows the main elements of the serial RTC. DS1307 BLOCK DIAGRAM Figure 1 TYPICAL OPERATING CIRCUIT
Image of page 2
DS1307 3 of 12 SIGNAL DESCRIPTIONS V CC , GND – DC power is provided to the device on these pins. V CC is the +5V input. When 5V is applied within normal limits, the device is fully accessible and data can be written and read. When a 3V battery is connected to the device and V CC is below 1.25 x V BAT , reads and writes are inhibited. However, the timekeeping function continues unaffected by the lower input voltage. As V CC falls below V BAT the RAM and timekeeper are switched over to the external power supply (nominal 3.0V DC) at V
Image of page 3

Subscribe to view the full document.

Image of page 4
  • Winter '18
  • PATEL SIR
  • Square wave, Clock signal, VCC, REAL TIME CLOCK IC

{[ snackBarMessage ]}

Get FREE access by uploading your study materials

Upload your study materials now and get free access to over 25 million documents.

Upload now for FREE access Or pay now for instant access
Christopher Reinemann
"Before using Course Hero my grade was at 78%. By the end of the semester my grade was at 90%. I could not have done it without all the class material I found."
— Christopher R., University of Rhode Island '15, Course Hero Intern

Ask a question for free

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern