SUBMITTED BY:-
NIKLESH KUMAR

---

[attachment=12030]
DIGITAL CALENDAR
PURPOSE OF THE PROJECT
The project will display the date, month and year. In addition to this, it will also display time . We can also set the date and time.
BLOCK DIAGRAM
CIRCUIT DIAGRAM
COMPONENTS
 Microcontroller (PIC 16F873A)
 COMPONENTS
 RTC IC (DS 1307)
 COMPONENTS
 LCD Module
 COMPONENTS
 Capacitors
 Resistors
COMPONENTS
 IC 7805
 RTC Battery
 Oscillators
 Transistors
 Keys
 Connecting wires
WORKING
FOR SETTING DATE AND TIME
• Press ‘set’ key.
• Now day start blinking.
• Set day by pressing ‘increment’ and ‘decrement’ keys.
• After setting desired day, press ‘ok’ key.
• Now months start blinking. Set month , year and time in a similar way.
• Calendar is now set.
WORKING
DISPLAYING DATE AND TIME
• The calendar displays date and time as soon as the power is given.
• Even if there is power failure, the calendar displays the right date and time that it should display , when the power is back .
ADVANTAGES
 Even if there is power failure, the calendar displays the right date and time that it should display, when the power is back.
 Simplicity of the system.
 Accuracy of the system.
APPLICATIONS
Because digital calendar is very small and inexpensive devices that enhance the popularity of product designs, they are often incorporated into all kinds of devices such as
• Cars
• Radios
• Televisions
MODIFICATIONS
• ADDING ALARM
An alarm, with setting of time, will make it more effective.
• ADDING TEMPERARURE SENSOR
A temperature sensor can be used to show the temperature of the surroundings.

[attachment=12540]
INTRODUCTION
Digital calendar is very useful projects for final year students. This project replaces the Printed Calendars. It has an Inbuilt Real Time Clock which tracks over the Real Time. It displays the day/month/year and time in hh:mms format. The time and date can be changed at any Time using the keypad. The Real Time Clock is displayed on LCD display. We can set the reminders on events or alarm at a particular time and date. We can use the LED array for larger display.
BLOCK DIAGRAM
A BRIEF INTRODUCTION TO 8051 MICROCONTROLLER:
When we have to learn about a new computer we have to familiarize about the machine capability we are using, and we can do it by studying the internal hardware design (devices architecture), and also to know about the size, number and the size of the registers.
A microcontroller is a single chip that contains the processor (the CPU), non-volatile memory for the program (ROM or flash), volatile memory for input and output (RAM), a clock and an I/O control unit. Also called a "computer on a chip," billions of microcontroller units (MCUs) are embedded each year in a myriad of products from toys to appliances to automobiles. For example, a single vehicle can use 70 or more microcontrollers. The following picture describes a general block diagram of microcontroller.
AT89S52: The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of in-system programmable Flash memory. The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard 80C51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory pro-grammer. By combining a versatile 8-bit CPU with in-system programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful microcontroller, which provides a highly flexible and cost-effective solution to many, embedded control applications. The AT89S52 provides the following standard features: 8K bytes of Flash, 256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89S52 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power-down mode saves the RAM con-tents but freezes the oscillator, disabling all other chip functions until the next interrupt
The hardware is driven by a set of program instructions, or software. Once familiar with hardware and software, the user can then apply the microcontroller to the problems easily.
The pin diagram of the 8051 shows all of the input/output pins unique to microcontrollers:
The following are some of the capabilities of 8051 microcontroller.
 Internal ROM and RAM
 I/O ports with programmable pins
 Timers and counters
 Serial data communication
The 8051 architecture consists of these specific features:
 16 bit PC &data pointer (DPTR)
 8 bit program status word (PSW)
 8 bit stack pointer (SP)
 Internal ROM 4k
 Internal RAM of 128 bytes.
 4 register banks, each containing 8 registers
 80 bits of general purpose data memory
 32 input/output pins arranged as four 8 bit ports: P0-P3
 Two 16 bit timer/counters: T0-T1
 Two external and three internal interrupt sources Oscillator and clock circuits.