Download How to Driving the Relay

LAKSHMI.B.E.
1
Full step -clock
LAKSHMI.B.E.
2
Full step –anti clock
LAKSHMI.B.E.
3
LAKSHMI.B.E.
4
LAKSHMI.B.E.
5
ULN 2003
 SEVEN DARLINGTONS PER PACKAGE
 OUTPUT CURRENT 500mA PER DRIVER( 600mA PEAK)
 OUTPUT VOLTAGE 50V
 INTEGRATED SUPPRESSION DIODES FOR INDUCTIVE
LOADS
 OUTPUTS CAN BE PARALLELED FORHIGHER
CURRENT
 TTL/CMOS/PMOS/DTL COMPATIBLE INPUTS
 INPUTS PINNED OPPOSITE OUTPUTS TO SIMPLIFY
LAYOUT
LAKSHMI.B.E.
6
LAKSHMI.B.E.
7
LAKSHMI.B.E.
8
LAKSHMI.B.E.
9
ULN 2803
LAKSHMI.B.E.
10
LAKSHMI.B.E.
11
LAKSHMI.B.E.
12
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
LAKSHMI.B.E.
13
DRIVE CIRCUIT:
LAKSHMI.B.E.
14
LAKSHMI.B.E.
15
INTERFACING WITH OPTOCOUPLER
LAKSHMI.B.E.
16
 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.
LAKSHMI.B.E.
17
 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
LAKSHMI.B.E.
18
IL 74SINGLE CHANNEL
LAKSHMI.B.E.
19
ILD 74
ILQ74
LAKSHMI.B.E.
20
LAKSHMI.B.E.
21
LAKSHMI.B.E.
22
7 segment displays
LAKSHMI.B.E.
23
CONFIGURATION
LAKSHMI.B.E.
24
COMMON ANODENEGATIVE
LOGIC
LAKSHMI.B.E.
25
PIN DIAGRAM
+5V SUPPLY
LAKSHMI.B.E.
26
CODES
LAKSHMI.B.E.
27
CONNECTION DIAGRAM
LAKSHMI.B.E.
28
SINGLE DIGIT0 DISPLAY
PROGRAM
ORG 0H
START:MOV P1,#11000000B
ACALL DELAY
SJMP START
DELAY:MOV R1,#255
DELAY1:MOV R2,#255
DELAY2:DJNZ R2,DELAY2
DJNZ R1,DELAY1
RET
END
LAKSHMI.B.E.
29
Program Using Rotate Instruction
ORG 0H
MOV A,#11111110B
START: RL A
MOV P1,A
ACALL DELAY
SJMP START
DELAY:MOV R1,#255
DELAY1:MOV R2,#255
DELAY2:DJNZ R2,DELAY2
DJNZ R1,DELAY1
RET
END
LAKSHMI.B.E.
30
RELATED INSTRUCTIONS AND
REGISTER
 REGISTER NAME:
 DPTR
 The 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.
LAKSHMI.B.E.
31
INSTRUCTION
 DB DEFINE BYTE DIRECTIVES
LAKSHMI.B.E.
32
PROGRAM USING LOOK UP TABLE
ORG 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
LAKSHMI.B.E.
33
INTERFACING 7SEG WITH DECODER
LAKSHMI.B.E.
34













7-SEGMENT WITH DECODER USING LOOKUP TABLE
org 0h
again:mov a,#0h
mov r0,#0h
branch:mov a,r0
mov dptr,#400h
movc a,@a+dptr
mov p2,a
inc r0
acall delay
cjne r0,#10h, branch
ljmp again
LAKSHMI.B.E.
35
 delay:mov r1,#255
 delay1:mov r2,#255
 delay2:djnz r3,delay2
 djnz r2,delay1
 ret

 org 400h
 decodercode:db 0,1,2,3,4,5,6,7,8,9
 end
LAKSHMI.B.E.
36
MULTIPLEXING
LAKSHMI.B.E.
37
7-SEGMENT MUTLIPLEXING AND
SWITCH (Binary Inputs 0-255)
ORG 0H
MOV P1,#0FFH
LOOP:MOV A,P1
MOV B,#100
DIV AB
ORL A,#010000000B
MOV R0,A
MOV A,B
MOV B,#10
DIV AB
ORL A,#00100000B
MOV R1,A
MOV A,B
LAKSHMI.B.E.
38
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
LAKSHMI.B.E.
39
LAKSHMI.B.E.
40
The End
LAKSHMI.B.E.
41