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Full step -clock

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Full step –anti clock

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ULN 2003SEVEN DARLINGTONS PER PACKAGEOUTPUT CURRENT 500mA PER DRIVER( 600mA

PEAK) OUTPUT VOLTAGE 50VINTEGRATED SUPPRESSION DIODES FOR

INDUCTIVE LOADSOUTPUTS CAN BE PARALLELED FORHIGHER

CURRENT TTL/CMOS/PMOS/DTL COMPATIBLE INPUTS INPUTS PINNED OPPOSITE OUTPUTS TO

SIMPLIFY LAYOUT6LAKSHMI.B.E.

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ULN 2803

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How to Driving the Relay:Digitals system and microcontroller pins are

couldn’t produce sufficient current to drive the relay.

While relay’s coil’s need 10mA current to be energized. But the microcontroller pin provide a maximum 1-2mA current

For these reason, we place a driver (or) power transistor in between the micro controller and relay

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DRIVE CIRCUIT:

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INTERFACING WITH OPTOCOUPLER

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Opto isolator is otherwise called as opto coupler. It isolates two parts of a system.

In an example for driving a motor, the motor can produces back emf.

Back emf is a high voltage spike produced by a sudden change of current.

In ordinary circuits, the unwanted spike voltage is reduced by using decoupling capacitors.

In any systems, that have inductors (coil windings), such as motors, decoupling capacitor or a diode will not reduce the spike voltages. In such cases, opto isolators can be used.

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An opto isolator has an LED transmitter and a photo sensor receiver, both are separated from each other by a small gap.

When current flows through the LED, it transmits a light signal to the receiver.

The receiver produces the signal with the same phase but a different current and amplitude.

The opto isolator comes in a small IC Package with four or more pins. There are also packages that contain more than one opto isolator. When placing an opto isolator between two circuits, we must use two separate voltage sources, one for each side

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IL 74SINGLE CHANNEL

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ILD 74 ILQ74

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7 segment displays

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CONFIGURATION

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COMMON ANODENEGATIVE LOGIC

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PIN DIAGRAM

+5V SUPPLY 26LAKSHMI.B.E.

CODES

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CONNECTION DIAGRAM

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SINGLE DIGIT0 DISPLAY PROGRAMORG 0H

START:MOV P1,#11000000BACALL DELAYSJMP START DELAY:MOV R1,#255DELAY1:MOV R2,#255DELAY2:DJNZ R2,DELAY2DJNZ R1,DELAY1

RETEND 

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Program Using Rotate Instruction

ORG 0HMOV A,#11111110B

START: RL AMOV P1,AACALL DELAYSJMP START DELAY:MOV R1,#255DELAY1:MOV R2,#255DELAY2:DJNZ R2,DELAY2DJNZ R1,DELAY1RETEND

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RELATED INSTRUCTIONS AND REGISTERREGISTER NAME:DPTRThe Data Pointer (DPTR) is the 8051’s only

user-accessible 16-bit (2-byte) register. The Accumulator, "R" registers, and "B" register are all 1-byte values.

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INSTRUCTIONDB DEFINE BYTE DIRECTIVES

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PROGRAM USING LOOK UP TABLEORG 0H

MOV R0,#10

MOV DPTR,#SEG

START :CLR A

MOVC A,@A+DPTR

MOV P3,A

ACALL DELAY

INC DPTR

DJNZ R2,START

DELAY:……………

RET

ORG 400H

SEG:DB 0c0h,0f9h,0a4h,0b0h,99h,

92h,82h,0f8h, 80h,90h

END

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INTERFACING 7SEG WITH DECODER

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7-SEGMENT WITH DECODER USING LOOKUP TABLE

org 0hagain:mov a,#0hmov r0,#0hbranch:mov a,r0mov dptr,#400hmovc a,@a+dptrmov p2,ainc r0acall delaycjne r0,#10h, branch ljmp again 

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delay:mov r1,#255delay1:mov r2,#255delay2:djnz r3,delay2djnz r2,delay1ret org 400hdecodercode:db0,1,2,3,4,5,6,7,8,9end

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MULTIPLEXING

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7-SEGMENT MUTLIPLEXING AND SWITCH (Binary Inputs 0-255)ORG 0HMOV P1,#0FFHLOOP:MOV A,P1MOV B,#100DIV ABORL A,#010000000BMOV R0,AMOV A,BMOV B,#10DIV ABORL A,#00100000BMOV R1,AMOV A,B

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ORL A,#00010000B

MOV P3,A

ACALL DELAY

MOV P3,R1

ACALL DELAY

MOV P3,R0

ACALL DELAY

SJMP LOOP

 DELAY:MOV R4,#2

REPEAT:MOV R3,#230

REPEAT1:DJNZ R5, REPEAT1

DJNZ R4, REPEAT

RET

END

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The End

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