MICROPROCESSOR LAB PROJECT

EC – 316

MADE BY:-

SAURABH VERMA 159/EC/13

SHREYANSH PATIYAL 167/EC/13

FACULTY ADVISOR:-

PROF. DHANANJAY V. GADRE

ACKNOWLEDGEMENT

We would sincerely like to thank Associate Prof. Dhananjay V. Gadre for

providing us with this opportunity as a part of EC-316 coursework and

for his endless support and motivation during the entire project

development. We would also like to express our gratitude to our family,

friends who have helped us throughout the project. A special thanks to

Vinod Sir and whole CEDT team, who helped us with the necessary

components and tools required for the project completion.

TABLE OF CONTENTS

Synopsis

Project Title: Courier Made Easy.

Project Description: An empty box of suitable size is taken fitted with ultrasonic sensors and the weight sensor which are interfaced with the microprocessor 8085 along with the LCD. The dimensions and the weight of the item placed inside the box will be measured by the ultrasonic sensors and the weight sensor respectively and will be displayed on the LCD.

INTRODUCTION

The 8085 microprocessor was introduced by Intel in 1976 as a successor

to the Intel 8080 microprocessor. The 8085 is upward compatible with

its predecessor, with only 2 minor instructions added to support its

interrupt and input-output features. The 8085 is a conventional Von-

Neumann design. Since its advent, the 8085 microprocessor has found

use in numerous applications such as early personal computers as well

as in several NASA space physics missions in the 1990s.

Few of its features are:

• The 8085 has 16 signal lines that are used as the address lines, which are divided into two segments: the higher order (A8 to A15) and lower order address lines (AD0 TO AD7).

2. 8 bit data bus

3. 6 general purpose 8 bit registers: B,C,D,E,H,L and Accumulator. the 8085 is an Accumulator based microprocessor.

4. Control signals, status signals and interrupts

The 8085 is available as a 40 pin DIP IC.

Figure 1: Pin Diagram of the 8085

BASIC BLOCK DIAGRAM

SCHEMATIC DIAGRAM

BOARD FILE

Basic Components

• Latch: The 74HC573 is an 8 bit D type transparent latch with three state outputs. It features a latch enable(LE) and an output enable(OE').

Functional Diagram of the

74HC573

The 74HC573 is made up of 8 D-type flip flops with a parallel input

parallel output connection, which allows output of 8 bit simultaneously

on the data bus lines. Each flip flop is enabled when the LE is high and

the OE' is low. It is generally used for interfacing output peripherals

( LEDs, seven segment display etc.) with the microprocessor.

Logic Gates: Logic gates are the fundamental components of most digital circuits. Basic logic gate ICs such as AND(7408), OR(7432) and NAND(7400) are usually employed in schematics for microprocessor based circuits to design the necessary addresses for the various input and output ports. This is further explained in the topic "Decoding Logic" under the section "Schematic Description of the Project".

Decoders: The decoder is a logic circuit that identifies each

combination of the signalspresent at its input. In general, if a decoder has 'n' input lines, then the number of output lines will be '2n' . Various types of decoder circuits are available for a user; for example, 74139 (a dual 2 to 4 line decoder) and 74138( a 3 to 8 line decoder).

A functional diagram of a 2-to-4 line decoder

Power Supply: This is the most important sub-circuit which

is required to run any schematic design's implementation

on a printed circuit board. Pin number 40 of the 8085,

namely 'Vcc', requires a steady supply of 5 volts. This can be

provided either by designing a regulated power supply

(linear or switched) for the circuit or by using a USB input

port, which can be connected to laptop.

Decoding Logic

The very fundamental concept involved in designing the schematic

of this project is assigning suitable addresses to the various input

and output ports, as well as appropriate memory address ranges

for both RAM and ROM. The decoding circuit is generated using

basic digital circuits such as latches, buffers and logic gates. The

chip enable pin for the buffers and the latches is enabled through a

combination of their desired address and the necessary control

signal.

Memory Interfacing

Memory interfacing refers to the interfacing of RAM and

EEPROM with the 8085 by allocating appropriate address ranges

to both. The RAM used is 58C256, which is a 32kB static ram and

is available in a 28 pin DIP package. Static rams are made up of

flip-flops and they store the bits as voltages. EEPROM used is

AT28c256, which is available as a 28 pin DIP package.

The lower order address bus of the 8085 microprocessor is multiplexed with the 8 bit data bus. The buses are de-multiplexed

using a 74HC573 Address Latch, which is enabled using the A15 address line from the microprocessor. When the latch is enabled, i.e. A15 =1, the RAM is selected and otherwise the ROM is selected. The remaining 15 address lines are used for both RAM and ROM, thus giving a size of 32kB for each.

The memory address map for the RAM and ROM are:

ROM: 0000H to 7FFFH

RAM: 8000H to FFFF

Read write logic

read and write logic for memory as well as input/output chips is

implemented using 3 to 8 decoder, three select lines for decoder are

WR*, RD* & IO/M* from 8085, IO/M* is used to select whether it is

memory or I/O and RD* & WR* are used to select whether it is read or

write command, by use of these three lines we can make all read and

write signal for memory and i/o chip.

OPERATION IO/M* RD* WR*

MEMORY READ (Y1) 0 0 1

MEMORY WRITE (Y2) 0 1 0

I/O READ (Y5) 1 0 1

I/O WRITE (Y6) 1 1 0

List of component Quantity DEVICE PACKAGE PARTS DESCRIPTION

2 10-XX B3F-10XX RESET, SWITCH

OMRON SWITCH

9 10-XX B3F-10XX S1, S2, S3, S4, S5, S6, S7, S8, S9

OMRON SWITCH

1 16X2LCD 16X2LCD LCD

1 58C256P DIL28-6 ROM-58C256 MEMORY

1 62256P DIL28-6 RAM-62256P MEMORY

1 8085 DIL40 8085 MICROPROCESSOR

2 82C55A DIL40 PORTS-82C55A, PORTS-82C55A1

PPI

13 C-EU025-024X044 C025-024X044 C1, C2, C3, C5, C7, C8, C9, C10, C12, C14, C15, C16, C17

CAPACITOR

1 C-EU050-024X044 C050-024X044 C6 CAPACITOR(EU)

2 C2,5-3 C2.5-3 C11, C18 CAPACITOR

2 CPOL-EUE5-8.5 E5-8,5 C4, C13 POLAR CAPACITOR

1 CRYSTALHC49US HC49US Q2 CRYSTAL

1 LED3MM LED3MM LED@SOD LED

29 R-EU_0204/7 0204/7 R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18

RESISTOR

1 74HCT00N DIL14 NAND NAND GATE

2 74HCT138N DIL16 DECODER 3 TO 8 DECODER

1 74HCT573N DIL20 ADDLATCH LATCH

1 LED5MM LED5MM LED1 LED

1 PRESET_LR PRESET_LR PRESET

1 ADC0801 DIL20 ADC

3 UDN2981A DIL18 IC1, IC2, IC3 DRIVER

1 USBSMD USB-MINIB USB USB PORT

GANTT CHART REVISITED AND COMPARISION WITH

ACTUAL RESULTS

Tools used:

Software tools:

EAGLE 7.3.0 – for schematic and board layout

8085 Simulator IDE by OshonSoft

EEPROM programmer software.

Proteus.

Hardware Tools:

Soldering Iron

Solder

Multimeter

+5V DC Power Supply

EEPROM Programmer.

Cutter, Tweezer, Hand File

BIBLIOGRAPHY

“Microprocessor Architecture, Programming, and Applications

with 8085” 5th edition

Author: Ramesh S. Gaonkar

Publisher: Penram International Publishing (India) Pvt. Ltd.

ISBN: 81-87972-09-2

CONCLUSION

It helped us develop a deep understanding of the 8085 microprocessor

and introduced us to various aspects of PCB development. We learned

how hardware and software are interlinked to make a meaningful

project. Apart from technical aspects, the project also helped us with

the concepts of time management and teamwork.