The document provides an overview of microprocessors and the Intel 8085 microprocessor. It discusses the evolution of microprocessors from early 4-bit designs to modern 32-bit and 64-bit designs. It then describes the key components and architecture of the Intel 8085, an early 8-bit microprocessor, including its 40-pin interface, address bus, data bus, registers, arithmetic logic unit, and interrupt controls. Finally, it provides a functional block diagram of the 8085, highlighting its main components like the ALU, registers, instruction decoder, and interrupt controls.

1. INTRODUCTIONINTRODUCTION
TOTO
MICROPROCESSMICROPROCESS
OROR ANDAND
ORGANIZATIONORGANIZATION
OFOF 8085.8085.

2. Microprocessor is a multipurpose, programable logical
device that reads binary instructions from a storage
device called memory. It accepts binary data as input
and process data according to those instructions and
provide result as output.
What Is Microprocessor ?What Is Microprocessor ?

3. After invention of transistors, integreted circuits (ICS)
appeared on the scene at the end of 1950. IC consist of
several transistors,diods and resistors on single chip. In
1960 Small Scale Integration (SSI) technology evolved.
As semiconductor technology advanced ,more than 100
gates were fabricated on single chip this was Medium
Scale Integrity (MSI). After that 1000 gates were
fabricated on single chip this was Large Scale Integrity
(LSI) . After that Very Large Scale (VLSI) . And because
of LSI it become possible to built many computing
functions on single chip and now it is known as
MICROPROCESSOR .
Evolution Of Microprocessor :-Evolution Of Microprocessor :-

4. Generations Of Microprocessor :-
First GenerationFirst Generation :- The first microprocessor introduced in
market , that was Intel 4004. It was 4-bit microprocessor
introduced in 1971. This was used in calculator . And also
Toshiba’s T 3472 4-bit microprocessor was also introduced in
this genration.
Second GenerationSecond Generation :- In 1976 Intel’s 8-bit microprocessor 8085
was introduced. This was completely developed microprocessor
at that time with CPU, ROM, RAM , clock , I/O ports all is
single package. Also Motorola introduced MC 6801 8-bit
microprocessor.

5. Third GenerationThird Generation :-The other major direction of microprocessor:-The other major direction of microprocessor
evolution has been towards one which performs all functions ofevolution has been towards one which performs all functions of
a microcomputer . Intel introduced its high performance 16-bita microcomputer . Intel introduced its high performance 16-bit
microprocessor in 1978 that was microprocessor 8086 now it ismicroprocessor in 1978 that was microprocessor 8086 now it is
called as APX 86 . Another examples are Intel 8088, Zylogcalled as APX 86 . Another examples are Intel 8088, Zylog
z8000, M 6800 etc. these all are 16 bit microprocessor.z8000, M 6800 etc. these all are 16 bit microprocessor.
Fourth GenerationFourth Generation :- Recently in 1981 Intel introduced 32-bit:- Recently in 1981 Intel introduced 32-bit
microprocessor 80386 which can access physical memory up to 4microprocessor 80386 which can access physical memory up to 4
gega bytes . Also M68020, HP32, iAPX432 32-bitgega bytes . Also M68020, HP32, iAPX432 32-bit
microprocessors were introduced.microprocessors were introduced.
Fifth GenerationFifth Generation :- Now we are in fifth generation Pentium I , II,:- Now we are in fifth generation Pentium I , II,
III , IV are recently introduced microprocessors by Intel. AndIII , IV are recently introduced microprocessors by Intel. And
now a days Intel Dual Core ,Intel XEON, core i3 , core i5, corenow a days Intel Dual Core ,Intel XEON, core i3 , core i5, core
i7 are most advanced microprocessors.i7 are most advanced microprocessors.

6. Block Diagram For Generic Microprocessor :-Block Diagram For Generic Microprocessor :-
Before studying 8085 microprocessor,Before studying 8085 microprocessor,
let us understand the block diagram oflet us understand the block diagram of
generic microprocessor i.e. generalgeneric microprocessor i.e. general
microprocessor. The block diagrammicroprocessor. The block diagram
consist of :consist of :
1.1. Arithmetic Logic Unit (Arithmetic Logic Unit (ALUALU).).
2.2. Several registersSeveral registers : Instruction registers,: Instruction registers,
accumulator, status registeraccumulator, status register
,temporary registers , stack pointers,,temporary registers , stack pointers,
data address registers.data address registers.
3.3. Program counter.Program counter.
4.4. Instruction decoder.Instruction decoder.
5.5. Timing and control section.Timing and control section.
6.6. Bus buffers and latches.Bus buffers and latches.
7.7. Internal buses and control lines.Internal buses and control lines.
8.8. Several control I/P & O/P .Several control I/P & O/P .
9.9. Interrupt control.Interrupt control.

7. 1.1. Address BusAddress Bus :- It is a group of 16 lines and it is unidirectional:- It is a group of 16 lines and it is unidirectional
i.e. bits are flows in one direction –from MPU to peripherali.e. bits are flows in one direction –from MPU to peripheral
device.device.
2.2. Data BusData Bus :- It is group of 8 lines used for data flow . It is:- It is group of 8 lines used for data flow . It is
bidirectional , It flows in both directions between MPU &bidirectional , It flows in both directions between MPU &
peripheral & memory . Actually it is used to transferring data.peripheral & memory . Actually it is used to transferring data.
3.3. Data Address RegisterData Address Register :- It is a two 8 bit register that can be:- It is a two 8 bit register that can be
used separately or as combined pair. They are labeled as H & L.used separately or as combined pair. They are labeled as H & L.
4.4. AccumulatorAccumulator :- It is the 8-bit register generally used to store the:- It is the 8-bit register generally used to store the
8-bit data in ALU & in logical operations . The result is stored is8-bit data in ALU & in logical operations . The result is stored is
accumulator.accumulator.
5.5. Program counterProgram counter :- It is the 16-bit register it stores the address:- It is the 16-bit register it stores the address
of next instruction to be executed.of next instruction to be executed.
6.6. Bus Buffer & LatchesBus Buffer & Latches :- A latch is the flip-flop. It is used to:- A latch is the flip-flop. It is used to
store one bit of information.store one bit of information.

8. 8085 Microprocessor :-8085 Microprocessor :-
Intel’s 8085 is a 8-bit general purposeIntel’s 8085 is a 8-bit general purpose
microprocessor. This microprocessor ismicroprocessor. This microprocessor is
capable of addressing 64k of memory.capable of addressing 64k of memory.
This device has 40 pins, requires +5This device has 40 pins, requires +5
single phase clock. It is the enhancedsingle phase clock. It is the enhanced
version of 8080. It is upward compatibleversion of 8080. It is upward compatible
with 8080.with 8080.
The 8085 Pin Diagram & Function:-The 8085 Pin Diagram & Function:- 80858085
is a 40 pin dual-in-line package (DIP).is a 40 pin dual-in-line package (DIP).
All pins are divided into six groups :All pins are divided into six groups :
1.1. Address bus.Address bus.
2.2. Multiplexed address/Data bus.Multiplexed address/Data bus.
3.3. Control & status signalsControl & status signals
4.4. Power supply & frequency signals.Power supply & frequency signals.
5.5. Externally initiated signals.Externally initiated signals.
6.6. Serial I/O portsSerial I/O ports

9. 1.1. Address BusAddress Bus :- 8085 has:- 8085 has
signal 8 lines A15 –A8 thatsignal 8 lines A15 –A8 that
are unidirectional.are unidirectional.
2.2. MultiplexedMultiplexed
address/Data Busaddress/Data Bus:- The:- The
signal lines AD7-AD0 aresignal lines AD7-AD0 are
bidirectional .They are userbidirectional .They are user
as lower order address busas lower order address bus
as well as the data busas well as the data bus
3.3. Power SupplyPower Supply :- It needs:- It needs
the +5V power supply.the +5V power supply.
4.4. Serial I/O PortsSerial I/O Ports :- It has:- It has
two pins to implementtwo pins to implement
serial transmission , Serialserial transmission , Serial
input data (SID) & serialinput data (SID) & serial
output data (SOD).output data (SOD).

10. Functional Block Diagram Of 8085 :-Functional Block Diagram Of 8085 :-
Let us look at the blockLet us look at the block
diagram of 8085.diagram of 8085.
It includes ALU , timingIt includes ALU , timing
& control unit,& control unit,
instruction register &instruction register &
decoder , registerdecoder , register
array, interruptsarray, interrupts
control & serial I/Ocontrol & serial I/O
control.control.

11. Arithmetic Logical Unit (ALU)Arithmetic Logical Unit (ALU) :- ALU:- ALU
performs arithmetic ,logic and rotateperforms arithmetic ,logic and rotate
operations . The result is typicallyoperations . The result is typically
stored in accumulators . Accumulator ,stored in accumulators . Accumulator ,
temporary register and flag register istemporary register and flag register is
closely associated with ALU. Theclosely associated with ALU. The
temporary registers are used to hold thetemporary registers are used to hold the
data during arithmetic operations . Anddata during arithmetic operations . And
the result is typically stored inthe result is typically stored in
accumulator.accumulator.