The document describes a traffic light control system using an 8085 microprocessor. It discusses the need for a traffic light system, describes the basic components including colors and signals. It then covers the hardware details of the 8085-based system and interface board, including ICs used. Algorithms and state diagrams are presented to show the logic for controlling lights and pedestrians.

1. Batch 5
MICRO PROCESSOR ASSIGN.
PRESENTATION. - 2

2. OUR TOPIC IS:
TRAFFIC LIGHT
CONTROL
SYSTEM

3. We mean:

4. NEED FOR THE SYSTEM :
Traffic lightsstoplights/ traffic lamps/
traffic signals/ signal lights/ robots/
semaphore
 signaling devices
 positioned at road intersections,
pedestrian crossings and other locations
 to control competing flows of traffic.
 Preventing accidents
 Improving safety
 Minimize travel time


5. ABOUT THE COLORS OF TRAFFIC LIGHT
CONTROL
Traffic lights alternate the right of way of road
users by displaying lights of a standard color
(red, yellow/amber, and green)
 By using a universal color code (and a
precise sequence to enable comprehension
by those who are color blind


6. SIGNAL FOR VEHICLE

7. SIGNAL FOR PEDESTRIAN

8. PROCESSOR USED:
8085
Microprocessor

9. WHY 8085?
 Sufficient
memory for the given scenario
 Basic units to be interfaced are supported by
8085
 Less complicated in the aspect of coding
 Supports the necessary instruction sets
 Simple and robust

10. BASIC BLOCK DIAGRAM
TIMER
5v Power
Supply
8085
Microprocessor
LED Display
OUTPUT
SIGNAL
INPUT
7 Segment
Display
DISPLAYS
WAITING

11. BLOCK DIAGRAM:

12. ALGORITHM

16. STATE DIAGRAM FOR TRAFFIC CONTROLER

17. PROPOSED SYSTEM:

18. HARWARE DETAILS:
2 PARTS
• 8085 Processor
based system
• Traffic Light
Controller
Interface board

19. IC’S USED:
8085 Micro processor
8255 PPI
8253 Timer
8279 Keyboard and Display Interface

20. 8255 PIN

21. INTERFACING WITH 8085:

22. I/O MAP:

23. 8255 FOR TRAFFIC LIGHT :

MVI A, 80H :
OUT 83H (CR) :
 START:
 MVI A, 09H
 OUT 80H (PA) :

MVI A, E4H
 OUT 81H (PB) :
Initialize 8255, port A and
port B
in output mode
Send data on PA to glow
R1 and R2

MVI A, 0CH
 OUT 82H (PB) :
Send data on PB to glow
G3 ,G4,G3R,G4R

Send data on PC to glow
G3 R ,G4L

24. 








MVI C, 28H :
Load multiplier count for
delay
CALL DELAY : Call delay subroutine
MVI A, 09H
OUT 80H (PA) :
R2
MVI A, 24H
OUT 81H (PB) :
G4
MVI A, 00H
OUT 82H (PB) :
,G4L &
MVI C, 28H :
Send data on PA to glow R1 and
Send data on PB to glow G3 and
Send data on PC to disable G3 L
Enable Pedestrian Crossing
Load multiplier count for
delay

25. 












MVI A, 12H
OUT (81H) PA :
OUT (81H) PB :
Y3 and
MVI C, 0AH :
CALL DELAY :
MVI A, E4H
OUT (80H) PA :
MVI A, 09H
OUT (81H) PB :
R3 and
MVI C, 28H :
MVI A, 03H
OUT 82H (PB) :
L ,G2L
CALL DELAY :
Send data on Port A to glow Y1 and
Y2
Send data on port B to glow
Y4
Load multiplier count for delay
Call delay subroutine
Send data on port A to glow G1 and
G2,G1R,G2R
Send data on port B to glow
R4
Load multiplier count for delay
Send data on PC to glow G1
Call delay subroutine

26. 











MVI A, E4H
OUT (80H) PA : Send data on port A to glow G1 and G2
MVI A, 09H
OUT (81H) PB :
Send data on port B to glow R3
and R4
MVI A, 00H
OUT 82H (PB) :
Send data on PC to disable G1 L
,G2L  Enable Pedestrian
Crossing
MVI C, 28H :
Load multiplier count (40i?) for delay
CALL DELAY : Call delay subroutine
MVI A, 12H
OUT PA :
Send data on port A to glow Y1
and Y2
OUT PB :
Send data on port B to glow Y3
and Y4
MVI C, 0AH : Load multiplier count (10i?) for delay

27. DELAY SUBROUTINE:

DELAY:

DCR C : Decrement counter

JNZ DELAY

RET : Return to main program

28. LOGIC FOR PEDESTRIANS CROSSING

29. 8279 DISPLAY INTERFACE

30. 7 SEGMENT DISPLAY FOR TRAFFIC
LIGHT- WORKING :
The processor initializes the look up table
pointer. The look up table contains the
format for the 7 segment display

31. SEGMENT CODES FOR COMMON CATHODE
DISPLAY

32. LOOK UP TABLE FOR DIGITS 1-8:

33. The microprocessor sends the data to the
latch
 From the latch, the data is sent to 8279
Display Interface
 It then stores the data in its 16 X 8 Internal
RAM


34. WRITING TO RAM:
There are 6 seven segment displays in 8085 kit
I 4 displays address
II 2 displays data
Here we make use of last two displays to interpret
the waiting time in each signal

35. 

Hence we require a decoder to select among the
two displays
Since there are 6 displays, we require a 3X8
decoder(74138)

The inputs to these pins will be s1,s2,s0 of 8279

Output of decoder  xx0 Left display xx1 
Right Display

Output to the seven segment displays will be from
A3-0 and B3-0

36. ANALOG TO DIGITAL CONVERTOR

This is required because 8085 will require only
+5V power supply

37. REFERENCES:

rbinnovations.com

gobookee.net

seminarprojects.com

eprlabs.blogspot.com

38. 
Batch members
DINESH .S
(11I309)
MARIA JERIN .J
(11I324)
SARATHY .K
(11I340)
SRINIVASAN .R
(11I347)
SUBASH .S
(11I348)
MURALI KRISHNAN .P (12I469)

39. FINAL PRODUCT: