MICRO CONTROLLER AND MICRO PROCESSER

PROJECT REPORT:

Frequency meter

Submitted to :

Ma’am Maria

Submitted by :

Aroosa

Sheher

Sidra Ali

Objective:

Measuring frequency is one of the prime requirements for many applications. The most

obvious method of measuring frequency is using CRO (or now a days using DSO). But

this instrument is not handheld or available with all the students or hobbyists at any

time. It is actually laboratory instrument and not the portable one. Also it is costlier. Also

conventional CRO does not give the direct frequency value read out. One has to first set

the waveform then find time/division and finely calculate time period and frequency. So

it’s a long process that takes time. Another way is use frequency counter that will give

us direct digital readout of frequency. In this no need of first adjusting the waveform into

screen then find time / division and then calculate time period and frequency such as

CRO. Just apply the signal input and get the read out of frequency. That’s why

frequency counters finding their own place in measuring instruments.

Component Details:

AT89C51 Microcontroller:

AT89S51 is an 8-bit microcontroller and belongs to Atmel's 8051 family. AT89S51 has 4KB of Flash programmable and erasable read only memory (PEROM) and 128 bytes of RAM. It can be erased and program to a maximum of 1000 times.

In 40 pin AT89C51, there are four ports designated as P1, P2, P3 and P0. All these ports are 8-bit bi-directional ports, i.e., they can be used as both input and output ports. Except P0 which needs external pull-ups, rest of the ports have internal pull-ups. When 1s are written to these port pins, they are pulled high by the internal pull-ups and can be used as inputs. These ports are also bit addressable and so their bits can also be accessed individually.

LCD:

LCD (Liquid Crystal Display) screen is an electronic display module and find a wide range of

applications. A 16x2 LCD display is very basic module and is very commonly used in various

devices and circuits.A 16x2 LCD means it can display 16 characters per line and there are 2 such

lines. In this LCD each character is displayed in 5x7 pixel matrix. This LCD has two registers,

namely, Command and Data.

Crystal Oscilator

Implementation on proteus:

CODE EXPLANATION:

Our project consist of six functions :

Description of each of the function is given below:

void delay(unsigned int time)

void One_Sec_Delay()

void lcd_initilize()

void lcd_command(unsigned char cmd)

void lcd_string(unsigned char str[])

void lcd_int(unsigned int i)

void delay(unsigned int time):

This function will generated delay every time before any byte is sent to LCD

unsigned int i,j;

for(i=0;i<time;i++)

for(j=0;j<255;j++);

void One_Sec_Delay():

This function will calculate number of frequencies per second and set the timers initial

value.from where the timer will start..

TH1 = 0x3C; // for 50 ms delay

TL1 = 0xB0;

void lcd_initilize():

lcd_command(0x38); Function Set: 8-bit, 2 Line, 5x7 Dots

lcd_command(0x0E); Display on Cursor on

lcd_command(0x06); During write operation only shift cursor right (increment cursor)

lcd_command(0x01); Clear Display (also clear DDRAM content)

lcd_command(0x80); it will select top line(first line)

void lcd_command(unsigned char cmd):

function sends command byte to be displayed on LCD.In this command register is selected. and data is

write on the LCD to micro controller. and LCD is enable Now data will start execute

LCD_DATA = cmd;

RS=0;

RW=0;

EN=1;

delay(2);

EN=0;

void lcd_string(unsigned char str[]):

for(i=0 ; str[i] ; i++)

LCD_DATA=str[i];

RS=1;

RW=0;

EN=1;

delay(1);

EN=0;

void lcd_int(unsigned int i):

This function takes two arguments. It converts HEX numbers into decimal and then decimal to

ASCII so that they can be displayed on screen .

unsigned char ascii[6];

ascii[5] = 0; // = NULL

ascii[4] = i % 10 | 0x30 ; i = i / 10;

ascii[3] = i % 10 | 0x30 ; i = i / 10;

ascii[2] = i % 10 | 0x30 ; i = i / 10;

ascii[1] = i % 10 | 0x30 ; i = i / 10;

ascii[0] = i % 10 | 0x30 ; i = i / 10;

lcd_string(ascii);