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DS1307 RTC Interfacing with ATmega32 and 7-Segment Display

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Real Time Clocks, as the name suggests are clock modules. They are available as integrated circuits (ICs) and manages timing like a clock. Some RTC ICs also manages date like a calendar. The main advantage is that they have a system of battery backup which keeps the clock/ca lender running even in case of power failure. A very small current is required for keeping the RTC alive. This in most case is provided by a miniature 3V lithium coin cell. So even if the embedded system with RTC is powered off the RTC module is up and running by the backup cell. This same technique is used in PC timing also. If you have opened your computer case you will notice a small coin cell in the mother board. 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(TWI Communication Protocol). 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.

In this project, we will learn How to interface a DS1307 Real Time Clock(RTC) with AVR ATmega32 microcontroller and 7-Segment Display. Here, we will read time(Hour, Minute and Second) from the DS1307 RTC and we will display the hour and minute values in 4 7-segment displays. The second value of DS1307 RTC is used to blink the dot (.) of the middle 7-segment. The data communication between DS1307 RTC and AVR ATmega32 microcontroller takes place using TWI(Two Wire Interface) communication protocol. But before reading the DS1307 RTC, the DS1307 RTC needs to be initialized with hour, second and minute values. The DS1307 RTC is initialized only once. We will initialize the hour, minute and second values of the DS1307 RTC with of 5, 0 and 0(Clock will start with 5 hour(PM), 0 minute and 0 second). You can change the initialization values according to your need by changing the initialization values in the DS1307 write section of the code. After initialization of DS1307 RTC, the AVR ATmega32 microcontroller will read the hour, minute and second values from the DS1307 continuously through two wire interface communication and it will display those hour and minute values in the 4 7-segment displays. The microcontroller will use the second value to blink the dot (.) of the middle 7-segment display.

Softwares Required

• AVR Studio 4 Software
• WinAVR 2010 Software
• SinaProg Hex Downloader Software
• USBasp Driver

Hardwares Required

Name	Quantity
AVR Trainer Board-100 with ATmega32	1pc
AVR USB Programmer	1pc
12V, 1A DC SMPS Adaptor	1pc
EEPROM & RTC Board with AT24C02	1pc
Quad 7-Segment Display Board	1pc
1 to 1 Connector-Female to Female	4pc
10 to 10 FRC Female to Female Connector	3pc

Video

Connection Guide

The step-by-step connection guide for DS1307 RTC Interfacing with ATmega32 and 7-Segment Display is as follows