micro controller assignment 3

8/6/2019 Micro Controller Assignment 3

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5th sem ,ASSIGNMENT 3 ,HANJI VISHAL RAJENDRA,1MS07EC033

7.EXPLAIN THE REGISTERS AND PINS OF LCD PANEL AND WRITE AN 8051 ALP DISPLAY MESSAGE

MSRIT ON THE LCD PANEL.

ANS:

REGISTERS OF THE LCD PANEL:

a)command code register:It is used when command is sent to LCD panel

b)data register:It is used when data to be displayed is sent.

LCD command codes:

Code Command to LCD instruction register

1 Clear display screen

2 Return home4 Decrement cursor(shiftr cursor to left)

6 Increment cursor(shift cursor to right)

5 Shift display right

7 Shift display left

8 Display off,cursor off

A Display off ,cursor on

C Display on, cursor off

E Display on,cursor blinking

F Display on,cursor blinking

10 Shift cursor position to left

14 Shift cursor position to right

18 Shift entire display to left

1c Shift entire display to right

80 Force cursor to beginning if 1st line

C0 Force cursor to beginning if 2nd line

38 2 lines and 5x7 matrix

Pin details:

i.RS,register select

If RS=0,the instruction command code register is selected,allowing user to send a command such as

clear display, cursorvat home etc.

If RS=1,data register is selected to send data data to be displayed on LCD.

ii.R/W,read /write

R/W input allows user to write information to LCD or read information from it,when R/W=1 when

reading,R/w=0 when writing.

iii.E,enable


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Enable pin is used by LCD to latch information presented to it by data pins.When data is supplied to

data pins,a high to low pulse must be applied to this pin in ordr for the LCD to latch it.This pulse

must be a minimum of 450ns wide.

iv.D0-D7

The 8 bit data pins D0-D7 are used to send information to the LCD or read the contents of the LCDsinternal registers.To display letters and numbers ,we send ASCII values to these pins with RS=1.There

are also instruction command codes that can be sent to the display or force the cursor to home

position or blink the cursor.

With RS=0,busy flag is checked to see if LCD is ready to receive information.The busy flag is D7 and

can be read when R/W=1 and RS=0.When D7=1,LCD is is busy and will not accept any new

information.When RS=0,ready to receive to new information.Busy flag should be checked before

writing to the LCD.

Pin descriptions of LCD.

Pin Symbol I/O Description

1 Vss - GROUND

2 Vcc - +5V power supply

3 Vee - Power supply to control contrast

4 RS I RS=0 to select command register

RS=1 to select data register

5 R/W I R/W=1 for write,R/W=1 for read

6 E I/O Enable

7 DB0 I/O THE 8-bit data bus









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ALP to display MSRIT:

ORG 0

MOV DPTR,#MYCOM

C1: CLR A

MOVC A,@A+DPTR

ACALL COMNWRT ;call command subroutine

ACALL DELAY ;give LCD some delay

JZ SEND_DAT

INC DPTR

SJMP C1

SEND_ DAT:

MOV DPTR,#MYDATAD1: CLR A

MOVC A,@A+DPTR

RS

R/W

E

D0

D1

:

:

:

D7

P2.0

P2.1

P2.2

P1.0

P1.1

:

:

:

P1.7

LCD PANEL 8051 MICROCONTROLLER


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ACALL DATAWRT ;call command subroutine

ACALL DELAY ;give LCD some elay

INC DPTR

JZ AGAIN

SJMP D1

AGAIN: SJMP AGAIN ;stay here

COMNWRT : ;send command LCD

MOV P1,A ;send command to P1

CLR P2.0 ;RS=0 for command

CLR P2.1 ;R/W=0 for command

SETB P2.2 ;E=1 for high pulse

SETB P2.2 ;give LCD some time

ACALL DELAY ;E=0 for H-t0-L

CLR P2.2

ACALL DELAY

CLR P2.2

RET

DATAWRT:

MOV P1,A ;send data to p1

SETB P2.0 ;RS=1 for data

CLR P2.1 ;R/W=0 for write

SETB P2.2 ;E=1 for high pulse

ACALL DELAY ;give LCD some time

CLR P2.2 ;E=0 for H-to-l pulse

RET

DELAY: MOV R3,#250 ;long delay for fast CPUs

HERE2: MOV R4,#255


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HERE: DJNZ R4,#255

DJNZ R3,HERE2

RET

ORG 300H

MYCOM: DB 38H,0EH,01H,06H,80H,0 ;command and null

MYDATA: DB MSRIT,0 ;data nd null

END

8.DRAW 8051 CONNECTION T0 DAC0808 AT PORT P1 AND WRITE A C PROGRAM TO GENERATE

SINE WAVE.

ANS: +5V

8051 DAC0808 +5V

5K

Vout=0 to10V

.1uF

5K

.1uF

-12

In DAC 808 the digital unputs are converted to current (Iout) and by connecting a resistor to the Iout

pin we convert the result to voltage.Iout is a function of digital inputs and reference current as

below.

P1.0

P1.1

:

:

:

P1.7

RD VCC

WR Vref(+)

D0 OUT

D1

:

: Vref( -)

:

D7

VEE COMP GND

1K


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Iout=Iref( )The Iref current is generally 2mA.The maximum output current,if all inputs to DAC are high is

1.99mA from figure above.

GENERATING SINE WAVE:

Full scale output of DAC is achieved when all data inputs of DAC are high.Therefore, to achieve

fullscale output we use the following equation.

Vout=5V+(5xsin@).

Vout for DAC for various angles is calculated as below at increment of 30 degrees.

Angle @

(degrees)

sin@ Vout(voltage mag)

5V+(5VXsin@)

Values sent to DAC(decimal)

(Voltage magX25.6)0 0 5 128

30 0.5 7.5 192

60 0.866 9.33 238

90 1.0 10 255

120 0.866 9.33 238

150 0.5 7.5 192

180 0 5 128

210 -0.5 2.5 64

240 -0.866 0.669 17

270 -1.0 0 0

300 -0.866 0.699 17

330 -0.5 2.5 64360 0 5 128

C program to generate sine wave:

#include

sfr DACDATA =P1;

void main()

{

Unsigned char wavevalue[12]={128,192,238,255,238,192,128,64,17,0,17,64};

Unsigned char x;

while(1)

{


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for(x=0;x


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0 1 DC motor moves moderately(50% duty cycle)

1 0 DC motor moves fast(75% duty cycle)

1 1 DC motor moves very fast(100% duty cycle)

#include

sbit mtr=P1^0;

void msdelay(unsigned int value);

void main()

{

Unsigned char x;

P2=0xFF;

z=P2;

z=z&0x03;

mtr =0;

while (1)

{

switch (z)

{

case(0):

{

mtr=1;

msdelay(25);

mtr=0;

msdelay(75);

break;

}

case(1):

{

mtr=1;

msdelay(50);


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mtr=0;

msdelay(50);

break;

}

case(2):

{

mtr=1;

msdelay(75);

mtr=0;

msdelay(25);

break;

}

default:

mtr=1;

}

}

micro controller assignment 3

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