Shiva ES Experiments

7/31/2019 Shiva ES Experiments

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M.Tech.Sem II (ES Lab) Roll No.: 11M31D5704

Experiment No: 1

LCD INTERFACE TO 8051

Aim: To interface the LCD display with the 8051-SDK and display the requiredmessage on the LCD.

Apparatus, Equipments and Tools:

1. 12V DC, 1.5A Adaptor

2. 8051 SDK Microcontroller Development Kit

3. RS 232 serial communication cable

4. Personal Computer

5. Keil Software

6. AC Power Supply

LIQUID CRYSTAL DISPLAY (LCD)

LCD data pins are connected to Port 0, and the control pins RS (Data/Command)

pin is connected to Port3.4, RW pin is grounded and EN(Enable) pin is connected to

Port3.5.

Diagram: LCD

Department of Electronics & Communications 1Nishitha College of Engineering and Technology


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EN (Enable LCD):

EN bit is to ENABLE or DISABLE the LCD. When ever controller wants to write

some thing into LCD or READ acknowledgment from LCD it needs to enable the LCD.

EN = 0 => High Impedance

EN = 1 => Low Impedance

ACK (LCD Ready):

ACK bit is to acknowledge the MCU that LCD is free so that it can send new

command or data to be stored in its internal Ram locations

ACK = 1 => Not ACK

ACK = 0 => ACK

Hardware Explanation

LCD Diagram:

Diagram: LCD



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Block Diagram:

Hardware Connections :



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LCD ALGORITHM:

STEP1: Configure port pins for all hardware connections

STEP2: Initialize the LCD by passing the proper set of COMMANDS

STEP3: Display the DATA in LCD

STEPS FOR WRITING COMMAND TO LCD

STEP4: Write each COMMAND to LCD COMMAND WRITE ADDRESS of LCD

STEP5: Repeat STEP4 and STEP5 until writing all COMMANDS

STEPS FOR WRITING DATA TO LCD

STEP6: Write each Character to LCD DATA WRITE ADRESS of LCD

STEP7: Repeat STEP7 and STEP8 until writing total data.

STEP8: End



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Flow Chart for LCD Module:



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/************************************************************//* PROJECT NAME: LCD */

/************************************************************/

/* Filename: LCD.c *//* Language: C *//* Compiler: Keil uV2 *//* Assembler: */

#include #define LCD P0#define RS P3_4#define EN P3_5

void lcdInit(void);void putComL(unsigned char);void putCharL(unsigned char);

void putStrL(unsigned char *,unsigned char);void delay(unsigned int d);

int main(void){

lcdInit();delay(1000);putStrL("LCD TEST",0x01);putStrL("OK",0xC0);

while(1);

}

void lcdInit(void){

putComL(0x38);putComL(0x0c);putComL(0x06);putComL(0x01);putComL(0x80);

}

void putComL(unsigned char cmd)

{RS=0;

}

Results: As per programmed application LCD is interface to the microcontrollerAT89s51 with neat schematic . Hence LCD application is verified on embedded 8051 kitby displaying data.



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Experiment No: 2

KEYPAD INTERFACING

Aim: To interface the keypad with the 8051 SDK microcontroller Development Kit andobserve the encryption and decryption of data.






5. Keil Software6. AC Power Supply

4 x 4 Keypad

A membrane keypad is provided as an add on module, the 4 Rows and 4 Column

signal lines are connected to Port1. The keypad can be unplugged from the board if required.

Schematic

Schematic of 4x4 Keypad:



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/**********************************************************************//*KEYPAD INTERFACING*/

/**********************************************************************/

;KEYCOUNT EQU 20H.0

ORG 00H

MOV P2, #0FFH ;P2 AS COLUMNSMOV R1, #40HMOV R2, #0

MOV TMOD, #20HMOV SCON, #50HMOV TH1, #0FDH

MOV DPTR, #CMDCONTINUE: CLR A

MOVC A, @A+DPTRJZ STARTPROCESSACALL COMMAND

INC DPTRSJMP CONTINUESTARTPROCESS: MOV DPTR, #STARTMSGACALL DISPLAY

MOV A, #0C0HACALL COMMAND

MOV DPTR, #STARTMSG1ACALL DISPLAYACALL DELAYACALL DELAY

MOV A, #01HACALL COMMAND

MOV DPTR, #MSGACALL DISPLAY


MOV DPTR, #MSG1ACALL DISPLAYACALL DELAYACALL DELAYACALL DELAY

MOV A, #01H



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ACALL COMMANDKEYPAD:

MOV P0, #0 ;P1 AS ROWSMOV A, P2ANL A, #00000111B; CHECKING FOR ALL KEYS OFF CONDITION

CJNE A, #00000111B, KEYPAD

BACK1: MOV A, P2ANL A, #00000111B ;CHECK IF ANY KEY IS PRESSED DUE TO NOISE

CJNE A, #00000111B, CHECKSJMP BACK1

CHECK: ACALL DELAY ;DELAY FOR 20MSECMOV A, P2

ANL A, #00000111BCJNE A, #00000111B, STARTSJMP BACK1

START: MOV P0, #11111110B ;GROUND ROW 0MOV A, P2ANL A, #00000111BCJNE A, #00000111B, ROW_0

MOV P0, #11111101B ;GROUND ROW 1MOV A, P2ANL A, #00000111BCJNE A, #00000111B, ROW_1



JMP BACK1

ROW_0: MOV DPTR, #ROW0JMP XX

ROW_1: MOV DPTR, #ROW1



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JMP XX



XX:RRC AJNC KEYFOUNDINC DPTR

JMP XX

KEYFOUND: CLR AMOVC A, @A+DPTR

; MOV R1, #40HMOV @R1, ACJNE A, #23H, CNTINUE

JMP LOOP

CNTINUE: ACALL DATA1;MOV @R1, AINC R1INC R2

JMP KEYPAD

LOOP: MOV R1,#40HMOV A, #0C0H

ACALL COMMANDMOV R0, #60H;MOV B, #2


MOV DPTR, #MSG2ACALL DISPLAYACALL DELAYACALL DELAYACALL DELAY

MOV A, #01HACALL COMMAND

MOV DPTR, #MSG2AACALL DISPLAY

MOV A, #0C0H



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ACALL COMMANDLOOP1: MOV A, @R1

ADD A, #3H

SUBB A, #9H

MOV @R0, AACALL TRANSMITACALL DATA1ACALL DELAYACALL DELAY

INC R1INC R0DJNZ R2, LOOP1

JMP $ ;STARTPROCESS2

/*STARTPROCESS2: MOV A, #01HACALL COMMANDACALL DELAYACALL DELAYACALL DELAYJMP STARTPROCESS */

;STARTPROCESS1: JMP STARTPROCESS

TRANSMIT: SETB TR1MOV SBUF, AJNB TI, $CLR TI

RET

RECEPTION: JNB RI, $CLR RIMOV A, SBUF

RET

DISPLAY: CLR AMOVC A, @A+DPTR

JZ XXXACALL DATA1

INC DPTRSJMP DISPLAYXXX: RET



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COMMAND: MOV P1, ACLR P3.5CLR P3.6SETB P3.7

ACALL DELAY CLR P3.7RET

DATA1: MOV P1, ASETB P3.5CLR P3.6SETB P3.7

ACALL DELAYCLR P3.7

RET

DELAY: MOV R6, #255HERE: MOV R7, #255

DJNZ R7, $DJNZ R6, HERE

RET

CMD: DB 38H, 0EH, 01H, 06H, 80H, 0

ROW0: DB '1','2','3'ROW1: DB '4','5','6'ROW2: DB '7','8','9'ROW3: DB '*','0','#'

STARTMSG: DB "------------------------------------------------------------------", 0STARTMSG1: DB " ENCRYPTION ", 0STARTMSG2: DB "------------------------------------------------------------------", 0

MSG: DB "ENCRYPTED DATA: ", 0MSG1: DB "ENTER THE PASSWORD: ", 0

STARTMSG3: DB "------------------------------------------------------------------", 0STARTMSG4: DB " DECRYPTION ", 0STARTMSG5: DB "------------------------------------------------------------------", 0MSG2: DB " DECRYPTED DATA: , 0END



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Output of the Program:

Results:

As per programmed application Data Encryption and Decryption, is that which is

possible with the help of microcontroller AT89s51, LCD with keypad, and PC. Hence

application is verified LCD on embedded 8051 kit as well as in PC Communication

terminal window.



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Experiment No: 3

SQUARE WAVE DEVICE DRIVER DEVELOPMENT

Aim: Linux is a clone of UNIX.AS in all version of UNIX, hardware devices are

presented to normal programs as special files. Therefore, devices implement file

semantics within ihe kernel.Because of this, it is worth taking a short look at how files in

general are treated in linux before attempting to understand how device drivers are

written.

Files

The generic filesystems header file, , defines several structuresfor accessing files, super_block holds basic information about each filesystemm,and

super_oeratoins is a structure of pointers to fuynctions which are associated with a

filesystems superblock.Through that structure are reached inode_operations, the last

defing functions that can be used to access files.In normal filesystems, there is one set of

file operations on device special files.insted, those devices define their own file

operations and register their own file_operations structure with the VFS.

The VFSThe VFS is the common abbreviaton for the Virtual Filesystem Switch.

Generic filesystem operations are handled by generic filesystem code, and only when

filesystem dependent or device dependent operations need to be done is the code for that

specific filesystem or device actually called. The function needed is looked up in the

proper instance of one of the *_operations structures and called.The VFS code is kept in

the fs/ subdirectory of the Linux kernel source, and the code to the individual filesystems

is kept in subdirectories of the fs/ subdirectory.

OperationsWhat I mean by operations may not be very clear at this point.An operation

is something that needs to be done as a result of a system call or buffer cache activity, or

beacauseof hardware irregularities.Nearly all operatons are caused directly or indirectly



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by system calls, and so you can think of the VFS as code that translates raw system calls

into filesystem operations.

Special files and file systems

All versions of Unix have device special files. The concept has even beenpicked up by such primitive operating systems as Microsofts DOS. However, the VFS is

so flexible that not only can special files be created, special filesstems can to.Linux has a

filesystems called the proc filesystem ,or profs, which is essentially a special

filesystems. The file in this filesystem are not stored on disk;they are instead generated

on-the fly from kernel data structures.they are,you could say,virtual devices designed to

report on the state of the kernel.

/************************************************************//* PROJECT NAME: SQUARE WAVE */

/************************************************************/

#include#include#include#include#include

#define PORT 0x378

#define NSEC_PER_SEC 1000000000 /*using clock_nanosleep of librt*/extern int clock_nanosleep(clockid_t_clock_id, int_flags,_const structtimespec*_req,struct timespec*_rem);static inline void tsnorm(stuct timespec *ts){While(ts->tv_nsec>= NSEC_PER_SEC){ts->tv_nsec -=NSEC_PER_SEC;ts->tv_sec++;}} /*increment counter and write to parallelport*/

void out()Static unsigned char state=0;Outb(state++,PORT);}int main(int argc,char** argv){struct timespec t;struct sched_param param; /*defaultinterval=50000ns=50us;*cycle duration=100us*/



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int interval=50000; /*set permissions of parallelport*/ioperm(PORT,1,1);if(argc>=2&&atoi(argv[1])>0){printf(using realtime,priority:%d/n,atoi(argv[1]));

param.sched_priority =atoi(arvg[1]); /*enable realtime fifo scheduling*/if(sched_setscheduler(0.SCED_FIFO,&param)==-1){perror(sched_setscheduler failed);exit(-1);}}if(argc>=3)interval=atoi(avgv[2]);clock_gettime(0,&t);t.tv_sec++;

while(1){clock_nanosleep(0,TIMER_ABSTIME,&t,NULL);out();t.tv_nsec+=interval;tsnorm(&t);}Return 0;}

Compilation:

gcc_0 square square_wave.c-lrt-wall

Execution:

./square

./square 8 20000

Explanation:

By default, this driver program will generate the square wave on the system

parallel port with a timer interval of 50us.At this point of time, the default system

resources are used. If we give the priority less than the default, this driver uses more no.

of system resources so all other processes get less priority.

The parallel pin color notations and respective PRI of generating square waveare,

2ndpin - Blue (2*x)3rd pin - White (4*x)4th pin - Yellow (8*x)5th pin - Orange (16*x)



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6th pin Black (32*x)10th pin Navy Blue (64*x)25th pin Green(GND)

RESULTHence the Square wave Device Driver, the default system resources are used.

If we give the priority less than the default, this driver uses more no. of system resources

so all other processes get less priority.



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Experiment No: 4

LED INTERFACE TO 8051

Aim: To read inputs from switches and produce different dancing patterns for LEDs by

interfacing the 8051-SDK kit with the computer.






5. Keil Software

6. AC Power Supply

Theory:

It is a semiconductor diode having radiative recombination. It requires a definite

amount of energy to generate an electron-hole pair. The same energy is released when an

electron recombines with a hole. This released energy may result in the emission of

photon. Here the amount of energy released when the electro reverts from the conduction

band to the valence band appears in the form of radiation. Alternatively the released

energy may result in a series of photons causing lattice vibration. Finally the released

energy may be transferred to another electron. The recombination radiation may lie in the

infra-red and visible light spectrum. In forward biased region the radiation is peaked

around the band gap energy and the phenomenon is called injection luminescence. In a

junction biased in the avalanche break down region, there results a spectrum of photons

carrying much higher energies. Almost White light then gets emitted from micro-plasma

breakdown region in silicon junction. Diodes having radiative recombination are termed

as Light Emitting Diodes, abbreviated as LEDs.



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In gallium arsenide diode, recombination is predominantly a radiation

recombination and the probability of this radiative recombination far exceeds that in

either germanium or silicon. Hence GaAs LED has much higher efficiency in terms of

photons emitted per carrier. The internal efficiency of GaAs LED may be very close to

100% but because of high index of refraction, only a small fraction of the internal

radiation can usually come out of the device surface. In spite of this low efficiency of

actually radiated light, these LEDs are efficiently used as light emitters in visual display

units and in optically coupled circuits. The efficiency of light generation increases with

the increase of injected current and with decrease in temperature. The light so generated

is concentrated near the junction since most of the charge carriers are obtained within one

diffusion length of the diode junction.

The following are the merits of LEDs over conventional incandescent

and other types of lamps

1. Low working voltages and currents

2. Less power consumption

3. Very fast action

4. Emission of monochromatic light

5. Small size and weight

6. No effect of mechanical vibrations

7. Extremely long life

Typical LED uses a forward voltage of about 2V and current of 5 to 10mA.GaAs

LED produces infra-red light while red, green and orange lights are produced by gallium

arsenide phosphide (GaAs) and gallium phosphide(Gap) .

Eight leds connected on Port-2 through a latch. All the 8-leds are active high.



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Schematic of LEDS:

Diagram: LEDS

Eight-Tactile (SPST) switches

Eight Tactile switches are connected to port-1. Each key generates an interrupt on INT0 (port3.2) with the help of diodes.

Schematic of Eight Tactile (SPST) switches:



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Diagram: Eight Tactile (SPST) switches

/**********************************************************************//*PROGRAM TO READ INPUTS FROM SWITCHES AND PRODUCE

DIFFERENT DANCING PATTERNS ON LEDS*/

/**********************************************************************/

SW1 EQU P0.0SW2 EQU P0.1SW3 EQU P0.2SW4 EQU P0.3SW5 EQU P0.4SW6 EQU P0.5SW7 EQU P0.6SW8 EQU P0.7ORG 00H /*START OF THE PROGRAM*/

/*INITIALIZATION OF PORTS*/

MOV P0,#0FFHMOV P1,#0FFHMOV P2,#0FFHMOV P3,#0FFHCHECK: MOV P1, #0FFH

MOV P2, #0FFHMOV P3, #0FFH

BACK: JNB SW1, PTRN1 /*CHECKING OF

EIGHT SWITCHES CONTINUOUSLY*/

JNB SW2, PTRN2JNB SW3, PTRN3JNB SW4, PTRN4JNB SW5, PTRN5AJNB SW6, PTRN6AJNB SW7, PTRN7AJNB SW8, PTRN8A

JMP BACK /*STAY IN THE LOOP UNTIL ANY ONE OF THE SWITCHES*/

/* IS PRESSED*/

PTRN1: JNB SW1, PTRN1 /*PATTERN 1*/PTRN_1: MOV P1, #11111111BMOV P2, #11111111BMOV P3, #11111111B



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ACALL DELAY1MOV P1, #0MOV P2, #0MOV P3, #0ACALL DELAY1

JMP PTRN_1 /*SWITCH IS PRESSED TO COME OUT OF THIS LOOP*/PTRN5A: JMP PTRN5PTRN6A: JMP PTRN6

/*PATTERN 2*/

PTRN2: JNB SW2, PTRN2PTRN_2: MOV P1, #11110000BACALL DELAY1MOV P1, #00001111BACALL DELAY1MOV P2, #11110000B

ACALL DELAY1MOV P2, #00001111BACALL DELAY1MOV P3, #11110000BACALL DELAY1MOV P3, #00001111BACALL DELAY1JMP PTRN_2PTRN8A: JMP PTRN8

/*PATTERN 3*/PTRN3: JNB SW3, PTRN3PTRN_3: MOV P1, #10101010BACALL DELAY1MOV P1, #01010101BACALL DELAY1MOV P2, #10101010BACALL DELAY1MOV P2, #01010101BACALL DELAY1MOV P3, #10101010BACALL DELAY1MOV P3, #01010101BACALL DELAY1JMP PTRN_3PTRN7A: JMP PTRN7

/*PATTERN 4*/

PTRN4: JNB SW4, PTRN4PTRN_4: ACALL DELAY1



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MOV P1, #11001100BMOV P2, #11001100BMOV P3, #11001100BACALL DELAY1MOV P1, #00110011B

MOV P2, #00110011BMOV P3, #00110011BACALL DELAY1

/* MOV P3, #11011101BMOV P2, #10101010BACALL DELAY1

/* MOV P1, APTRN_4: RR AMOV P2, A

ACALL DELAY1RL AMOV P3, AACALL DELAY1

/* MOV P2, #11111100BACALL DELAY1MOV P3, #00111111BACALL DELAY1

/* MOV P1, #00110011BACALL DELAY1MOV P2, #00110011BACALL DELAY1MOV P3, #00110011BACALL DELAY1 */

JMP PTRN_4PTRN5: JNB SW5, PTRN5

/*PATTERN 5*/

PTRN_5: MOV P1, #0FFHACALL DELAY1MOV P2, #0FFHACALL DELAY1MOV P3, #0FFHACALL DELAY1MOV P1, #7EHACALL DELAY1MOV P2, #7EH



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ACALL DELAY1MOV P3, #7EHACALL DELAY1MOV P1, #3CHACALL DELAY1

MOV P2, #3CHACALL DELAY1MOV P3, #3CHACALL DELAY1MOV P1, #18HACALL DELAY1MOV P2, #18HACALL DELAY1MOV P3, #18HACALL DELAY1MOV P1, #0H

ACALL DELAY1MOV P2, #0HACALL DELAY1MOV P3, #0HACALL DELAY1MOV P1, #0HACALL DELAY1MOV P2, #0HACALL DELAY1MOV P3, #0HACALL DELAY1MOV P1, #18HACALL DELAY1MOV P2, #18HACALL DELAY1MOV P3, #18HACALL DELAY1MOV P1, #3CHACALL DELAY1MOV P2, #3CHACALL DELAY1MOV P3, #3CHACALL DELAY1MOV P1, #7EHACALL DELAY1MOV P2, #7EHACALL DELAY1MOV P3, #7EHACALL DELAY1MOV P1, #0FFH



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ACALL DELAY1MOV P2, #0FFHACALL DELAY1MOV P3, #0FFHACALL DELAY1

JMP PTRN_5

PTRN6: JNB SW6, PTRN6 /*PATTERN 6*/MOV A, #10000000BMOV P1, AACALL DELAY1;MOV P2, A;ACALL DELAY1;MOV P3, A;ACALL DELAY1

PTRN_6: RR AMOV P1, AACALL DELAY1RR AMOV P2, AACALL DELAY1RR AMOV P3, AACALL DELAY1

JMP PTRN_6PTRN7: JNB SW7, PTRN7 /*PATTERN 7*/MOV A, #11111110BMOV P1, AACALL DELAY1MOV P2, AACALL DELAY1MOV P3, AACALL DELAY1PTRN_7: RL AMOV P1, AACALL DELAY1RR AMOV P2, AACALL DELAY1RL AMOV P3, AACALL DELAY1JMP PTRN_7



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PTRN8: JNB SW8, PTRN8 /*PATTERN 8*/PTRN_8: MOV P1, #0H

ACALL DELAY1MOV P1, #0FFHACALL DELAY1MOV P2, #0HACALL DELAY1MOV P2, #0FFHACALL DELAY1MOV P3, #0HACALL DELAY1MOV P3, #0FFHACALL DELAY1

JMP PTRN_8

PTRN8A: JMP PTRN8

DELAY1: MOV R6, #150 /*DELAY TO VISUALISE THEPATTERNS*/

HERE: MOV R7, #150 /*MORE CLEARLY*/

BACKK: JNB SW1, PTRN_1A /*CHECKING OF EIGHTSWITCHES

CONTINUOUSLY*/JNB SW2, PTRN_2AJNB SW3, PTRN_3AJNB SW4, PTRN_4AJNB SW5, PTRN_5AJNB SW6, PTRN_6AJNB SW7, PTRN_7AJNB SW8, PTRN8_ADJNZ R7, BACKKDJNZ R6, HERERETPTRN8_A: JMP PTRN8PTRN_7A: JMP PTRN7PTRN_6A: JMP PTRN6PTRN_5A: JMP PTRN5PTRN_4A: JMP PTRN4PTRN_3A: JMP PTRN3PTRN_2A: JMP PTRN2PTRN_1A: JMP PTRN1



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END /*END OF THE PROGRAM*//**********************************************************************/

/* Program for 8 Switches and 8 LEDs using C Language*/

/**********************************************************************/

#include sfr LEDS = 0X80;void delay(int );void PATTERN1(void);void PATTERN2(void);void PATTERN3(void);void PATTERN4(void);void PATTERN5(void);void PATTERN6(void);void PATTERN7(void);void PATTERN8(void);

sbit sw1=P1^0;sbit sw2=P1^1;sbit sw3=P1^2;sbit sw4=P1^3;sbit sw5=P1^4;sbit sw6=P1^5;sbit sw7=P1^6;sbit sw8=P1^7;void main(){

P1=0xff;P2=0xff;

while(1){

//while(P1==0xff);

if(sw1==0)PATTERN1();





if(sw6==0)



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PATTERN6();if(sw7==0)

PATTERN7();if(sw8==0)

PATTERN8();

} }

void PATTERN1(void){

while(sw1==0); /*debounce check */

while(sw1==1) /* repeat this loop till switch1 is pressed */{

LEDS=0;delay(100);

LEDS=0XFF;delay(100);}

while(sw1==0); /*debounce check */}


while(sw2==0); /*debounce check */

while(sw2==1){

LEDS=0X55;delay(100);LEDS=0XAA;delay(100);

}while(sw2==0);

}void PATTERN3(void){

while(sw3==0);

while(sw3==1){

LEDS=0XF0;delay(100);LEDS=0X0F;delay(100);



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}

while(sw3==0);}

void PATTERN4(void){while(4==0);while(sw4==1)

{LEDS=0X33;delay(100);LEDS=0XCC;delay(100);

}while(sw4==0);

}void PATTERN5(void){

while(sw5==0);while(sw5==1)

{LEDS=0X81;delay(100);LEDS=0X42;delay(100);LEDS=0X24;delay(100);LEDS=0X18;delay(100);LEDS=0X24;delay(100);LEDS=0X42;delay(100);LEDS=0X81;delay(100);

}while(sw5==0);

}


while(sw6==0);LEDS=0XFC;while(sw6==1)



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Results: As per programmed application leds and switches are interface to themicrocontroller AT89s51 with neat schematic . Hence dancing of LEDs application is

verified on embedded 8051 kit.



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Experiment No: 5

SERIAL DATA TRANSMISSION USING 8051

Aim: To perform an experiment demonstrating the serial communication i.e.,

transmission and reception, between the PC and the 8051 SDK microcontroller

development kit.






5. Keil Software

6. AC Power Supply

General Description:

There are 2 ways to transfer the data in computer one is serial and another is the

parallel communication. In parallel communication data is transferred using 2 or more lines.

Parallel communication is used to transfer data to the devices which are a few feet away and

it is fast. In Serial communication the data is sent one bit at a time. Data can be transferred to

longer distances with minimum number of wires efficiently. It is economical and error free

compared to parallel communication. To establish serial communication we need a

RS232 Serial connector, MAX232 (to match voltage levels of 2 devices) and a serial cable.

Schematic of Serial Communication:



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Hardware Explanation:

RS-232C:

RS-232 (ANSI/EIA-232 Standard) is a standard serial protocol used to establish a

communication between the two same or different processors. RS232 is developed to

support different voltage levels of devices in the range of

+3V to +25V for logic 0

-3V to -25V for logic 1

RS-232 hardware can be used for serial communication up to a distance of 12 feet.

RS232 or DB-9 pin connector:

Pin Functions:

Data: TX on pin 3, RX on pin 2

Handshake: RTS on pin 7, CTS on pin 8, DSR on pin 6,

CD on pin 1, DTR on pin 4

Common: Common pin 5(ground)

Other: RI on pin 9

The method used by RS-232 for communication allows for a simple connection of

three lines: TX, RX, and Ground. The three essential signals for 2 way RS-232

communication are:

TXD: carries data from DTE to the DCE.

RXD: carries data from DCE to the DTE

MAX232:

Max232 is used to convert the TTL voltage levels of microcontroller (logic0-0v,

logic15v) into voltage levels of RS232 standards (logic0 - +3 to +25v, logic1 - 3 to

25v).

MAX232 is a DC-to-DC converter, which takes TTL levels as input and produces RS232

levels, which are required for DTE to DTE communication. RS-232 communication is



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asynchronous. That is a clock signal is not sent with the data. Each word is synchronized

using its start bit, and an internal clock on each side, keeps tabs on the timing.

The RS232 levels are generated internally using switching latches and capacitors of 10ufeach.

Max232 pin configuration:

Serial Communication Block Diagram:

Serial communication can be established with the help of 2 wires one for transmit and the

one for receiving data.



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Hardware connections:

SFRs Used for Serial Communication:

The special function registers used in serial communication are,

(i) SCON

(ii) TMOD Register

(iii) TCON Register

(iv) Timer(T1) Registers

SCON (Serial Control register):

Load the SCON register with 0x50 to select serial communication in mode 1

(8 bit with variable baud rate).

Serial Mode Selection:

SM2: This bit is used in multi processor communication, hence place SM2=0

REN: (Receive Enable): To receive data in serial communication REN bit must be 1



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Enabling of this bit will not effect the transmission

TB8 & RB8: Transmit 8th bit and receive 8th bit these are used for 9 bit data transferMode when 8-bit data is transmitting place TB8 =0 & RB8 = 0

TI & RI: The Transmit and Receive Interrupt bits these are system control bits activate

When a byte of data is transmitted or received. TI =0 & RI =0

TMOD (Timer Mode Register):

Load the TMOD register with 0x20 to select the TIMER1 in auto reload mode whichgenerates corresponding Baud Rate.

TMOD is dedicated solely to the two timers (T0 & T1).

The timer mode SFR is used to configure the mode of operationof each of the two

timers. Using this SFR your program may configure each timer to be a 16-bit timer, or

13 bit timer, 8-bit auto reload timer, or two separate timers. Additionally you may

configure the timers to only count when an external pin is activated or to count

events that are indicated on an external pin.

It can consider as two duplicate 4-bit registers, each of which controls the action of

one of the timers.

To set TMOD for serial communication the bits in this register are

Gate bit =0

TIMER Mode operation:

TCON (Timer Control Register):



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The timer control SFR is used to configure and modify the way in which the 8051s

two timers operate. This SFR controls whether each of the two timers is running or

stopped and contains a flag to indicate that each timer has overflowed. Additionally,

some non-timer related bits are located in TCON SFR.

These bits are used to configure the way in which the external interrupt flags are

activated, which are set when an external interrupt occurs.

D7 D6 D5 D4 D3 D2 D1 D0

TF1: Timer 1 over flow flag. Set by hardware when Timer/Counter 1 overflows

TR1: Timer 1 run control bit. Set (or) clear by software to turn Timer/Counter 1 ON and

OFF.

TF0: Timer 0 over flow flag. Set by hardware when Timer/Counter 0 overflows

TR0: Timer 0 run control bit. Set (or) clear by software to turn Timer/Counter 0 ON and

OFF.

IE1: External interrupt 1. Edge flag set by hardware

IT1: Interrupt 1 type control bit. Set (or) cleared by software

IE0: External interrupt 0. Edge flag set by hardware.

IT0: Interrupt 0 type control bit. Set (or) cleared by software

Set the TR1 bit in TCON register to run the TIMER 1 which helps in generation of Baud

rate for serial communication i.e. TR1=1.

BAUD RATE CALCULATION

Internal timer stages are as follows



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Divided by X block can be replaced with T1 timer so that by changing the value oftimer we can obtain the required baud rate.

Let XClk = 11.0592 MHz

Baud Rate = (XClk / 12 / 16 / 2 / X)

For attaining 9600 baud Rate

X can be calculated as

= (11.0592 x 106 ) / (12 * 16 * 2 * 9600)

= 3

So set the 2s Complement of 3 (FD) in Timer 1 so that we can achieve 9600 baud rates.

Note: Assuming 8-bit Auto reload mode and 8-bit variable baud rate modes.

Algorithm:

Serial Transmition Algorithm:

STEP1: Set the baud rate using SCON and TMOD.

STEP2: Copy the data into SBUF.

STEP3: Checks if TI is HIGH, if no go to 3.

STEP4: Clear TI.

STEP5: End.

Serial Reception Algorithm:

STEP1: Set the baud rate using SCON and TMOD.

STEP2: Checks if RI is HIGH, if no go to 2.

STEP3: Clear RI.

STEP4: Copy SBUF into Memory

STEP5: En



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Flow Chart:



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/**********************************************************************//*SERIAL RECEPTION*/

/*FROM PC TO MICROCONTROLLER*//**********************************************************************/

RS11 EQU P2.0 ;ASSIGN NAMES TO THE PORT PINS AS MENTIONEDRW11 EQU P2.1EN EQU P2.2

ORG 00HMOV DPTR, #CMD ;INITIALIZATION OF LCD COMMANDS

BACK1: CLR AMOVC A, @A+DPTR

JZ NEXTACALL COMMANDINC DPTR

SJMP BACK1

NEXT: MOV TMOD, #20H;TO SELECT TIMER 1 IN MODE 2 (AUTO RELOAD)

MOV SCON, #50H; TO SELECT SERIAL COMMUNICATION IN MODE 1; AND RECEIVER ENABLE

MOV TH1, #0FDH ; TO SET THE BAUD RATE TO 9600

BACK: SETB TR1 ; TO START THE TIMER

JNB RI,$;WAIT FOR THE CHARACTER TO BE LOADED INTO SBUF

CLR RI; CLEAR RI FOR THE NEXT RECEPTION

MOV A, SBUF ; TO MOVE THE RECEIVED CHARACTER INTO A

ACALL DATA1 ; CALL SUBROUTINE FOR DISPLAY ON THE LCD

JMP BACK

COMMAND: MOV P1, ACLR RS11



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CLR RW11SETB EN

ACALL DELAYCLR EN

RET

DATA1: MOV P1, ASETB RS11CLR RW11SETB EN

ACALL DELAYCLR EN

RET

DELAY: MOV R6, #255

HERE: MOV R7, #255DJNZ R7, $DJNZ R6, HERERET

CMD: DB 38H, 0EH, 01H, 06H, 80H, 0END



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/**********************************************************************//*SERIAL TRANSMISSION*/

/*FROM MICROCONTROLLER TO PC*//**********************************************************************/

ORG 00H MOV TMOD, #20H;TO SELECT TIMER 1 IN MODE 2(AUTO RELOAD)

MOV SCON, #50H; TO SELECT SERIAL COMMUNICATION IN MODE 1; AND RECEIVER ENABLE

MOV TH1, #0FDH ; TO SET THE BAUD RATE TO 9600MOV DPTR, #MSG

BACK: CLR A

MOVC A,@A+DPTR ; TO LOAD THE MESSAGE INTO; ACCUMULATOR CHARACTER BYCHARACTER

JZ NEXTACALL TRANSMIT ;CALL SUBROUTINE FOR TRANSMISSION

INC DPTRSJMP BACK

NEXT: SJMP NEXT ;TERMINATION OF THE PROGRAM/*TRANSFERRING DATA SERIALLY*/TRANSMIT: SETB TR1 ; TO START THE TIMER

MOV SBUF, A ; LOAD DATA INTO SBUFJNB TI, $ ;WAIT FOR THE TRANSMISSION TO BE

;COMPLETEDCLR TI ;CLEAR TI FOR NEXT TRANSMISSION

RETMSG:

DB 13, 10,"Welcome to Nishitha College Of Engineering & Technology,Hyderabad, 13,10,13,10, "You are working with WINKIT Brand World Class, State-of-Art EmbeddedSystems Lab Trainer Board", 13, 10, 0END

Results: As per programmed application serial communication, LCD and PC interface to

the microcontroller AT89s51 with the help of RS-232 cable. Hence Serial



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communication application is verified on embedded 8051 kit and PC with the help of keil

uvision and Encript, with communication terminal in the PC.

Output of the Program:

Screen 1 : Transmitter Window

Screen 2 : Receiver Window



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RESULTS: Demonstrating the serial communication i.e., transmission and reception,

between the PC and the 8051 SDK microcontroller has been verified.

Experiment No: 6

ANALOG-TO-DIGITAL CONVERTER

Aim: To interface an analog-to-digital converter (ADC) with the 8051-SDK

Microcontroller Development Kit and send the analog data such as the temperature to the

PC.






5. Keil Software

6. AC Power Supply

ANALOG TO DIGITAL CONVERTER, DIGITAL TO ANALOG CONVERTER

(PCF8591P)

It is an I2C device which consists of 4 Channel 8-bit Analog to Digital Converterand 1 channel 8 bit Digital to Analog Converter, which is connected to I2C bus.

General Description:

The PCF8591 is a single-chip, single-supply low power 8-bit CMOS data acquisition

device with four analog inputs, one analog output and a serial I2C-bus interface. Three

address pins A0, A1 and A2 are used for programming the hardware address, allowing the

use of up to eight devices connected to the I2C-bus without additional hardware. Address,

control and data to and from the device are transferred serially via the two-line bidirectional

I2C-bus. The functions of the device include analog input multiplexing, on-chip track and

hold function, 8-bit analog-to-digital conversion and an 8-bit digital-to-analog conversion.

The maximum conversion rate is given by the maximum speed of the I2C.



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Schematic of ADC/DAC:



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Features:

Single power supply

Operating supply voltage 2.5 V to 6 V

Low standby current

Serial input/output via I2C-bus

Address by 3 hardware address pins

Sampling rate given by I2C-bus speed

4 analog inputs programmable as single-ended or differential inputs

Auto-incremented channel selection

Analog voltage range from VSS to VDD

On-chip track and hold circuit

8-bit successive approximation A/D conversion

Multiplying DAC with one analog output.

Applications:

Closed loop control systems

Low power converter for remote data acquisition Battery operated equipment

Acquisition of analog values in automotive, audio and TV applications.



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/*********************************************************************//* program to send the adc data(temperature) to pc */

**********************************************************************/#include #includesbit RD1 = P2^5;sbit WR1 = P2^6;sbit INTR1 =P2^7;sfr adcdata = 0x90;//void display(unsigned char );

void delay(int );void main(){ unsigned char value;

SCON=0X50;TMOD=0X20;TH1=0XFD;TR1=1;printf("temeperature:");adcdata=0xff;INTR1=1;RD1=1;

while(1){ WR1=0;

delay(5);

WR1=1;while(INTR1==1);RD1=0;value=adcdata;printf("%d",value);//display(value);RD1=1;

}}/*void display(unsigned char ){ unsigned char x,d1,d2,d3;

x=value/10;d1=value%10;d2=x%10;d3=x/10;*/

void delay(int n){ int x,y;

for(x=0;x


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for(y=0;y


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Experiment No: 7

REAL TIME CLOCK

Aim: To interface a real time clock (RTC) with the 8051-SDK MicrocontrollerDevelopment Kit.






5. Keil Software

6. AC Power Supply

: /*********************************************************************//* program for RTC */

**********************************************************************/

#include

#include

#include

#include

void send(unsigned char dat) // uart baud rate set to 9600

{

TMOD = 0X20;

TH1 = 0XFD;

SCON = 0X50;TR1 = 1;

SBUF = dat;

while(TI == 0){}

TI = 0;

TR1 = 0;



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}

void print(char *str)

{

while(*str != '\0')

{

send(*str);

str++;

}

}

void ToASCII(unsigned int t)

{

if(t


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__bit __at(0x94) SCLK;

__bit __at(0x95) SDA;

bit ACK;

#define HIGH 01;

#define LOW 00;

unsigned int read_time[0x03];

void set_rtc_time();

void get_rtc_time();

int get_hour();

int get_minute();

int get_second();

unsigned int hour,minute,second;

void set_hour() // load the RTC hour register (0x04)

{

I2C_START();

I2C_WRITE(0XA0);

I2C_WRITE(0x04);

I2C_WRITE(0x02);

I2C_STOP();

}void set_minute() // load the RTC minute register

(0x03)

{

I2C_START();

I2C_WRITE(0XA0);

I2C_WRITE(0x03);

I2C_WRITE(0x15);

I2C_STOP();}

void set_second() // load the RTC second register (0x02)

{

I2C_START();

I2C_WRITE(0XA0);



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I2C_WRITE(0x02);

I2C_WRITE(0x56);

I2C_STOP();

}

int get_second() // read RTC second register (0x02)

{

unsigned char s;

I2C_START();

I2C_WRITE(0XA0);

I2C_WRITE(0x02);

I2C_STOP();

I2C_START();

I2C_WRITE(0XA1);

s = I2C_READ();

I2C_STOP();

return(s);

}

int get_minute() // read the RTC minute register (0x03)

{

unsigned char m;I2C_START();

I2C_WRITE(0XA0);

I2C_WRITE(0x03);

I2C_STOP();

I2C_START();

I2C_WRITE(0XA1);

m = I2C_READ();

I2C_STOP();

return(m);

}

int get_hour() // read the RTC hour register (0x04)

{

unsigned char h;



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I2C_START();

I2C_WRITE(0XA0); //RTC write command

I2C_WRITE(0x04); //RTC Control Register address

I2C_STOP();

I2C_START();

I2C_WRITE(0XA1); //RTC read command

h = I2C_READ();

I2C_STOP();

return(h);

}

void main()

{

set_hour();

set_hour();

set_minute();

set_second();

while(1)

{

second = get_second();

minute = get_minute();hour = get_hour();

minute = get_minute();


hour = get_hour();

print("\n\r Real Time Clock = ");

ToASCII(hour/16);

ToASCII(hour%16);

send(0x20);

ToASCII(minute/16);

ToASCII(minute%16);






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send(0x20);

ToASCII(second/16);

ToASCII(second%16);

}

}

void I2C_START() //starting i2c by creating a clock pulse by settingand clearing the port pins

{

SCLK =LOW;

SDA =LOW;

Delay_Time();

Delay_Time();

SCLK=HIGH;

Delay_Time();

Delay_Time();

SDA=HIGH;

Delay_Time();

Delay_Time();

SDA=LOW;

Delay_Time();

Delay_Time();

SCLK=LOW;

}

void I2C_WRITE(unsigned char j) //write data/command to RTC registers

{

dat=j;for(i=0;i


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Delay_Time();

SCLK=LOW;

}

Delay_Time();

Delay_Time();

SDA = LOW;

Delay_Time();

Delay_Time();

SCLK = HIGH;

Delay_Time();

Delay_Time();

SCLK = LOW;

Delay_Time();

Delay_Time();

SDA = HIGH;

return(j);

}

void Delay_Time()

{ unsigned long int i;for(i=0;i


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Experiment No: 8

DIGITAL-TO-ANALOG CONVERTER

Aim: To interface an digital-to-analog converter (DAC) with the 8051-SDK

Microcontroller Development Kit using I2C protocol.


1. 12V DC, 1.5A Adaptor2. 8051 SDK Microcontroller Development Kit



5. Keil Software

6. AC Power Supply

/*********************************************************************//* program for DAC */

**********************************************************************/

#include

#define HIGH 01;

#define LOW 00;

__xdata __at 0xffc5 unsigned char swt;

__idata unsigned char dat;

__idata unsigned char i;

__bit __at(0x94) SCLK;

__bit __at(0x95) SDA;

bit ACK;

void I2C_Start(void);

void I2C_Stop(void);

void I2C_Write(unsigned char j);



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unsigned char I2C_Read(void);

void Delay_Time();

void I2C_Start(void) //Start I2C by creating clock by setting and clearing the portpins

{

SCLK=LOW;

SDA=LOW;

Delay_Time();

SCLK = HIGH;

Delay_Time();

SDA=HIGH;

Delay_Time();

SDA = LOW;

Delay_Time();

SCLK = LOW;

}

void I2C_Stop(void) //Stop I2C operation by clearing the SCLK Pin

{

SCLK = LOW;

Delay_Time();

SDA = HIGH;

}

void I2C_Write(unsigned char j) // shifting data bit by bit to MSB andmoving through i2c

{

dat=j;

for(i=0;i


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SCLK = LOW;

}

SDA=HIGH;

Delay_Time();

SCLK = HIGH;

Delay_Time();

ACK = SDA;

Delay_Time();

SCLK = LOW;

}

unsigned char I2C_Read(void) //reading from i2c device bit by bit

{

unsigned char i,j;

j = 0;

i = SDA;

for(i=0;i


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void main()

{

unsigned int i=0x00;

I2C_Start();

I2C_Write(0x9E); //send device address

I2C_Write(0x40); //send device's control register address

I2C_Start();

I2C_Write(0x9E); // send command for read

while(1)

{

if((swt & 0x1f)== 0x1E)

{

i=i+0x0a;

if(i>0xff)

i=0x00;

I2C_Write(i);

Delay_Time();

}

}

}void Delay_Time()

{

unsigned int i;

for(i=0;i


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Experiment No: 9

STEPPER MOTOR

Aim: To interface a stepper motor with the 8051-SDK Microcontroller Development

Kit.






5. Keil Software

6. AC Power Supply

: /*********************************************************************//* program for stepper motor */

**********************************************************************/

#include

void serial_intr (void) interrupt 4;void delay_ms(unsigned int j){unsigned int k;while(j-->0){

for(k=0;k


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delay_ms(5);

P1 = 0x66;delay_ms(5);

P1 = 0xaa;delay_ms(5);

P1 = 0x99;delay_ms(5);

}}

RESULT :

As per programmed application stepper motor is interface to the microcontroller

AT89s51.



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Experiment No: 10

SEVEN SEGMENT DISPLAY

Aim: To interface seven segment display with the 8051-SDK Microcontroller

Development Kit






5. Keil Software

6. AC Power Supply

Description:

Each of the segments of the display is connected to a pin on the 8051 (the

schematic shows how to do this). In order to light up a segment on the the pin must be set

to 0V. To turn a segment off the corresponding pin must be set to 5V. This is simply done

by setting the pins on the 8051 to '1' or '0'.

LED displays are

Power-hungry (10ma per LED)

Pin-hungry (8 pins per 7-seg display)

But they are cheaper than LCD display

7-SEG Display are available in two types -1. Common anode & 2. common cathode ,

but command anode display are most suitable for interfacing with 8051 since 8051 port

pins can sink current better than sourcing it.



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CREATING DIGIT PATTERN

For displaying Digit say 7 we need to light segments -a ,b, c. Since we are using

Common anode display , to do so we have to to provide Logic -0 (0 v) at anode of these

segments.

so need to clear pins- P1.0 ,P1.1,P1.2. that is 1 1 1 1 1 0 0 0 -->F8h .

Digit Seg. h Seg. g Seg. f Seg. e Seg. d Seg. c Seg. b Seg. a HEX

0 1 1 0 0 0 0 0 0 C0

1 0 0 0 0 0 1 1 0 06

2 1 0 1 0 0 1 0 0 A4

3 1 0 1 1 0 0 0 0 B0

4 1 0 0 1 1 0 0 1 99



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Connection

You can also do this for some characters like A ,E .. but not for D or B because it

will be same as that of 0 & 8 . So this is one of limitation of 7-seg display.Since we can Enable only one 7-seg display at a time ,we need to scan these display at

fast rate .The scanning frequency should be high enough to be flicker-free. At least 30HZ

.Therefore time one digit is ON is 1/30 seconds

INTERFACING

Note that I am using Common Anode display. so the common Anode pin is tied to

5v .The cathode pins are connected to port 1 through 330 Ohm resistance (current

limiting).


Segment number 8051 pin number

a P1.0

b P1.1

c P1.2

d P1.3

e P1.4

f P1.5

g p1.6

h(dp) P1.7


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float measure_temp(void);

unsigned char pulse,temp_id[9];

unsigned char a,b,c;

bit t_flag=0;

unsigned char cnt;

int n;

float m;

void main (void)

{

unsigned char k,l,u,r,g,h,j;

float f;

init();

clr();

while(1)

{

j=0xf0;

f=measure_temp();

k=f;

l=k/10;u=k%10;

j=j+u;

m=f-k;

m=m*100;

r=m;

g=r/10;

h=r%10;

write(1,15);

write(2,15);

write(3,15);

write(4,15);

write(5,l);

write(6,j);



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write(7,g);

write(8,h);

delay_ms(1000);

}

}

float measure_temp(void)

{

float f;

pulse=reset();

if(pulse==0)

write_byte(0xcc); //skip rom

write_byte(0x44); //convert temp

delay_ms(750);

pulse=reset();

if(pulse==0)

write_byte(0xcc); //skip rom

read_ds1822();

f=measure_ds1822();

return f;}

float measure_ds1822(void)

{

unsigned char temp_msb,temp_lsb,temp,mask=0x01,decimal=0;

int sign=1,cnt=16;

float f=0.0;

temp_lsb=temp_id[0];

temp_msb=temp_id[1];

if(temp_msb>=0x80)

{

sign=-1;

temp_lsb=(~temp_lsb)+1;



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temp_msb=~temp_msb;

}

decimal=(temp_lsb4;

temp=temp_msb4;

do

{

if(decimal&mask)

f=f+((float)1/cnt);

cnt=cnt/2;

mask=mask*2;

}while(mask


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/*-------------------------------------------------------------------------------------------*/

unsigned char reset()

{

unsigned char presence;

WIRE=0;

delay_micro(29);

WIRE=1;

delay_micro(3);

presence=WIRE;

delay_micro(25);

return presence;

}

void write_byte(unsigned char c)

{

int mask1;

for(mask1=1;mask1


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c=c|mask1;

}

return c;

}

void write_bit1()

{

WIRE=0;

_nop_();_nop_();

_nop_();_nop_();

_nop_();_nop_(); //6us

WIRE=1;

delay_micro(3); //60us

}

void write_bit0()

{

WIRE=0;


WIRE=1;_nop_();_nop_();

_nop_();_nop_();

_nop_();_nop_();

_nop_();_nop_();

_nop_();_nop_(); //10us

}

unsigned char read_bit()

{

unsigned char b;

WIRE=0;

_nop_();_nop_();

_nop_();_nop_();



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_nop_();_nop_(); //6us

WIRE=1;

_nop_();_nop_();

_nop_();_nop_();

_nop_();_nop_();

_nop_();_nop_();_nop_(); //9us

b=WIRE;


return b;

}

/*-------------------------------------------------------------------------------------------*/

//generates delay in milli seconds

void delay_ms(unsigned int i)

{

unsigned int j;

while(i-->0)

{

for(j=0;j


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void init(void)

{

write(0x09,0xff);//decode mode reg set to nodecode operation

write(0x0a,0x0f);//intensity reg set to maximum intensity

write(0x0b,0x07);//scan limit reg set to 4 seven segments

write(0x0c,0x01);//shutdown reg set tonormal mode

write(0x0f,0x00);//display test reg is ste to 0 i.e. normal operation

clr();

}

void write(unsigned char address, unsigned char dataa)

{

unsigned char i,mask=0x80;

LOAD=0;

for(i=0;i>1;

}

mask=0x80;

for(i=0;i


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CLK=0;

if(dataa & mask)

DI=1;

else

DI=0;

CLK=1;

mask=mask>>1;

}

LOAD=1;

}

void clr(void)

{

write(dig1,0x00);

write(dig2,0x00);

write(dig3,0x00);

write(dig4,0x00);

write(dig5,0x00);

write(dig6,0x00);

write(dig7,0x00);

write(dig8,0x00);}

RESULTS: Interface seven segment display with the 8051-SDK Microcontroller

Date post:	04-Apr-2018
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Shiva ES Experiments

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