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REAL TIME CLOCK DISPLAY USING GRAPHICAL LCD
Abstract
AIM:
To display the real time on graphical LCD
DESCRIPTION:
The aim of this project is to interface the graphical LCD to display the data in different graphical formats and to display time in addition to text and numeric formats on the graphical LCD. This project gives details of a simple interface technique between a display graphic and a micro-controller.
We had used Atmega-8515 which is 8-bit microcontroller and JHD12864E Graphical LCD to display the graphical Images. The Graphical LCD we have used is 128 X 64 on which we can display any type of images. The display is split logically in two half’s. It contains two controllers with controller 1 (Chip select 1) controlling the left half of the display and controller 2 (Chip select 2) controlling the right half. Each controller must be addressed independently. The page addresses, 0-7, specify one of the 8 horizontal pages which are 8 bits (1 byte) high. To display the image on the LCD we should configure the pixel by selecting the particular half (right half /left half) and page (form 0 to 7), we are using DS1307 and AT24C08 to display the clock in Graphical LCD.
The purpose of using controller is to clear the display, move the cursor, to give the data to be displayed and controlling the Graphic LCD operations. It is used to display soft font text, line drawing; graphic symbol and icon display, pixel setting etc. Using this graphic LCD we can create images which we can’t create by using normal LCD display. Using normal LCD we can display only characters and symbols. The Graphical LCD often require more initial time and effort to get them running than alphanumeric LCD’s but they do not have the character limits of such LCD displays. Here we can create images using pixels like in our C programming.
To prepare data that can be embedded in our program so that we can display a specific image on the LCD we need to prepare the data for each pixel on the LCD which can be done manually or by using some modern software’s that translates a bitmap file to display data.
REQUIREMENTS:
HARDWARE REQUIREMENTS:
 MICROCONTROLLER
 GRAPHICAL LCD
 DS1307
 SWITCHES
 PCB and Connecting wires
SOFTWARE REQUIREMENTS:
 Functionality of all above components
 Embedded c programming
Chapter 1
INTRODUCTION
1.1CIRCUIT DESCRIPTION
DESIGNING:
Since the main intension of this project is to design a real time clock display on graphical this application there are few steps that has been performed i.e.
1) Designing the power supply for the entire circuitry.
2) Selection of microcontroller that suits our application.
Selection LCD.
3) In order to fulfill of RTC
4) Selection of LCD.
Complete studies of all the above points are useful to develop this project.
SELECTION OF MICROCONTROLLER:
We are selecting Atmega 8515 AVR microcontroller
There are minimum five requirements for proper operation of microcontroller.
Those are:
1) power supply section
2) pull-ups for ports
3) Reset circuit
4) Crystal circuit
5) ISP circuit (for program dumping)
SELECTION OF RTC:
Here in this project I selected i2c protocol based DS1307 RTC. 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.RTC contains particular memory locations to store the seconds, minutes, hours, date of the month, month, day of the week whenever power up these locations will count. By using push button switches we can change these locations to set the current time.
CONNECTIONS OF RTC:
In this application we are using i2c protocol based IC DS1307.The 5th 6th pin’s of IC is connected to the PC.0, PC.7 of microcontroller respectively.
CIRCUIT OPERATION:
The main aim of the project is to interface the graphical LCD and DS1307 (RTC) to the controller .Here our application program is reading the data from DS1307 through I2c protocol. And displaying on the graphical LCD and 4 switches are for adjusting the time.
1.2 EMBEDDED SYSTEMS
Embedded systems are electronic devices that incorporate microprocessors with in their implementations. The main purposes of the microprocessors are to simplify the system design and provide flexibility. Having a microprocessor in the device helps in removing the bugs, making modifications, or adding new features are only matter of rewriting the software that controls the device. Or in other words embedded computer systems are electronic systems that include a microcomputer to perform a specific dedicated application. The computer is hidden inside these products. Embedded systems are ubiquitous. Every week millions of tiny computer chips come pouring out of factories finding their way into our everyday products.
Embedded systems are self-contained programs that are embedded within a piece of hardware. Whereas a regular computer has many different applications and software that can be applied to various tasks, embedded systems are usually set to a specific task that cannot be altered without physically manipulating the circuitry. Another way to think of an embedded system is as a computer system that is created with optimal efficiency, thereby allowing it to complete specific functions as quickly as possible.
Embedded systems designers usually have a significant grasp of hardware technologies. They use specific programming languages and software to develop embedded systems and manipulate the equipment. When searching online, companies offer embedded systems development kits and other embedded systems tools for use by engineers and businesses.
Embedded systems technologies are usually fairly expensive due to the necessary development time and built in efficiencies, but they are also highly valued in specific industries. Smaller businesses may wish to hire a consultant to determine what sort of embedded systems will add value to their organization.
1.3 CHARACTERISTICS:
Two major areas of differences are cost and power consumption. Since many embedded systems are produced in tens of thousands to millions of units range, reducing cost is a major concern. Embedded systems often use a (relatively) slow processor and small memory size to minimize costs.
The slowness is not just clock speed. The whole architecture of the computer is often intentionally simplified to lower costs. For example, embedded systems often use peripherals controlled by synchronous serial interfaces, which are ten to hundreds of times slower than comparable peripherals used in PCs. Programs on an embedded system often run with real-time constraints with limited hardware resources: often there is no disk drive, operating system, keyboard or screen. A flash drive may replace rotating media, and a small keypad and LCD screen may be used instead of a PC's keyboard and screen.
Firmware is the name for software that is embedded in hardware devices, e.g. in one or more ROM/Flash memory IC chips. Embedded systems are routinely expected to maintain 100% reliability while running continuously for long periods, sometimes measured in years. Firmware is usually developed and tested too much harsher requirements than is general-purpose software, which can usually be easily restarted if a problem occurs.

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