80486 Block Diagram

  • Microprocessor Tutorial

A greatly simplified block diagram of the 80186 architecture. Die of Intel 80186. The Intel 80186, also known as the iAPX 186, or just 186, is a microprocessor and microcontroller introduced in 1982. It was based on the Intel 8086 and, like it, had a 16-bit external data bus multiplexed with a 20-bit address bus.

  • 8085 Microprocessor

INTEL 80386 PROGRAMMER'S REFERENCE MANUAL 1986 Page 3 of 421 Training Center Locations To obtain a complete catalog of our workshops, call the nearest Training. BLOCK DIAGRAM OF COMPUTER: A computer can process data, pictures, sound and graphics. They can solve highly complicated problems quickly and accurately. VON NEUMANN ARCHITECTURE Most of today’s computers designs referred to as Von Neumann Architecture, are based on concepts developed by John Von Neumann. The Intel Microprocessors: 8086/8088, 8, 80286, 80386, 80486 Pentium, Architecture, Programming, and Interfacing, Eighth Edition Barry B. Brey Figure 13–3 The 8237A-5 programmable DMA controller. (a) Block diagram and (b) pin-out. (Courtesy of Intel Corporation.). Intel 80186 microprocessor, sometimes called i186, is an enhanced version of Intel 8086 16-bit processor. Being completely object code compatible with the 8086, the 80186 integrated many system components into one chip, added 7 new instructions, and added new operand types to three existing 8086 instructions.

  • 8086 Microprocessor
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8086 Microprocessor is an enhanced version of 8085Microprocessor that was designed by Intel in 1976. It is a 16-bit Microprocessor having 20 address lines and16 data lines that provides up to 1MB storage. It consists of powerful instruction set, which provides operations like multiplication and division easily.

80486 block diagram circuit

It supports two modes of operation, i.e. Maximum mode and Minimum mode. Maximum mode is suitable for system having multiple processors and Minimum mode is suitable for system having a single processor.

Features of 8086

The most prominent features of a 8086 microprocessor are as follows −

  • It has an instruction queue, which is capable of storing six instruction bytes from the memory resulting in faster processing.

  • It was the first 16-bit processor having 16-bit ALU, 16-bit registers, internal data bus, and 16-bit external data bus resulting in faster processing.

  • It is available in 3 versions based on the frequency of operation −

    • 8086 → 5MHz

    • 8086-2 → 8MHz

    • (c)8086-1 → 10 MHz

  • It uses two stages of pipelining, i.e. Fetch Stage and Execute Stage, which improves performance.

  • Fetch stage can prefetch up to 6 bytes of instructions and stores them in the queue.

  • Execute stage executes these instructions.

  • It has 256 vectored interrupts.

  • It consists of 29,000 transistors.

Comparison between 8085 & 8086 Microprocessor

  • Size − 8085 is 8-bit microprocessor, whereas 8086 is 16-bit microprocessor.

  • Address Bus − 8085 has 16-bit address bus while 8086 has 20-bit address bus.

  • Memory − 8085 can access up to 64Kb, whereas 8086 can access up to 1 Mb of memory.

  • Instruction − 8085 doesn’t have an instruction queue, whereas 8086 has an instruction queue.

  • Pipelining − 8085 doesn’t support a pipelined architecture while 8086 supports a pipelined architecture.

  • I/O − 8085 can address 2^8 = 256 I/O's, whereas 8086 can access 2^16 = 65,536 I/O's.

  • Cost − The cost of 8085 is low whereas that of 8086 is high.

Architecture of 8086

The following diagram depicts the architecture of a 8086 Microprocessor −

The microprocessor is the main important or the heart of the normal computer. Generally, we will use the microprocessors like Pentium, AMD, power PC, or any other brands and types of microprocessors. The microprocessor is also called as a central processing unit. The microprocessor is totally computation engine and it is fabricated on the single chip. The Intel has released the first microprocessor in the year 1971 and it contains the 4-bit microprocessor and having 2300 transistors, 640 bytes of memory addressing modes and with a clock speed of 108 kHz.

What is a Microprocessor?

80486 Block Diagram

Generally, the microprocessor is an integrated circuit and it incorporates core function of a computer’s central processing unit. The microprocessor is a programmable multipurpose silicon chip, register based, clock driven, it accepts input as a binary data and after the processing, it provides the output data as per the instructions stored in the memory.


Types of Microprocessors

Different types of microprocessors are explained below.

8085 Microprocessor

The 8085 microprocessor is designed by Intel in the year of 1977 with the help of NMOS technology. The 8085 microprocessor is pronounced as an eighty-eighty-five microprocessor and the configurations of this microprocessor are the 8-bit data bus, 16-bit address bus, it can address up to 64kb, 16-bit programmer counter & stack pointer, the six-bit registers are arranged in the pair of BC, DE, & HL. The 8085 microprocessor requires a 5-volt power supply.

8086 Microprocessor

This microprocessor is also designed by the Intel and the 8086 microprocessor has a 16-bit microprocessor with 20 address lines and 16 data lines with storage of 1MB. The 8086 microprocessor consists of a powerful instruction set, which gives the operations like multiplications, divisions easily.

The 8086 microprocessor has two modes of operations, which are maximum mode and minimum mode of operations. The maximum mode of operation is used for the system having multiple processors. The minimum mode of operation is used for the system having the single processor. The features of this microprocessor are explained below.

8086 Microprocessor

Features of 8086 Microprocessor

The most important features of the microprocessor are following

1. To improve the performance of this microprocessor there are two stages of pipelining, which are fetching & execute stage.

2. The fetch stage can transfer the data in 6 bytes of instructions and stored in a line

3. The execute stage will execute the instructions

4. The 8086 microprocessor consists of 2900 transistors and it has 256 vectored interrupts

5. It is the first 16-bit processor with 16 bit ALU & register, internal data bus and 16-bit external data bus.

Comparison Table Between 8085 & 8086 Microprocessors

8085 Microprocessor8086 Microprocessor
  • It is an 8-bit microprocessor
  • It has 16-bit address bus
  • In this, the memory can access up to 64kb
  • The 8085 processor does not consist of pipeline architecture
  • In this processor, the I/O address is 28 = 256 I/O’s
  • The cost of this processor is low
  • This is a 16-bit microprocessor
  • 8086 has 20-bit address bus
  • Where in the process the memory is up to 1 MB
  • While in the 8086 processors consist of pipeline architecture
  • In the 8086 processors, the I/O address is about 216 = 65536 I/O’s
  • The cost of this processor is high

Classifications of Microprocessors

The microprocessor can be classified into three different types, which are

  • RISC processor
  • CISC processor
  • Special processor

RISC Processor

The RISC stands for Reduced Instruction Set Computer and it is designed to reduce the execution time by using the simplifying the instruction set of computer. In the microprocessor, each instruction set requires only one clock cycle to implement result at a uniform execution time. Therefore, it reduces the efficiency for more lines of code, hence it required an extra RAM to store the instructions. The compiler is used to convert the high-level language instruction set in a machine language.

There are some processors in the RISC which are

  • Power PC: 601, 604, 615, 620
  • DEC Alpha: 210642, 211066, 21068, 21164
  • MIPS: TS (R10000) RISC Processor
  • PA-RISC: HP 7100LC

Architecture of RISC Processor

The following block diagram shows the architecture of the RISC processor and this type of processor is used for the highly optimised set of instructions and the applications of the RISC processor is for the portable devices like Apple iPod due to its power efficiency. The characteristics of this processor are explained below.

Block Diagram Creator

Characteristics of RISC Processor

Some of the major and important characteristics of RISC processor are below

  • In the RISC processor, there are simple instructions.
  • It consists the number of registers and less number of transistors.
  • To access the memory location the LOAD & STORE instructions are used.
  • This processor has one cycle execution time.

CISC Processor

This processor is designed to minimise the number of instructions per program and it will ignore the number of cycles per instructions. The compiler is used to translate a high-level language to assembly level language because the length of the code is relatively short and an extra RAM is used to store the instructions. Some different CISC processors are following.

  • IBM 370/168
  • VAX 11/780
  • Intel 80486

Architecture of CISC

80486 block diagram labeled

The following block diagram shows the architecture of CISC microprocessor. It is designed to decrease the cost of memory because more storage is required in large programs resulting in higher memory cost. To overcome this number of instructions per program can be reduced by using the embedding the operations in a single instruction.


This Processor consists of different addressing modes

  • It has a large number of instructions
  • To execute once instruction it requires several cycles
  • The instruction coding logic is complex.
  • For multiple addressing modes once instruction is required

Special Processors

The special processors are designed for some special processors and some of them are explained below.


The coprocessor designed especially for microprocessors. It can handle it practical function for many times faster than the normal microprocessors.

The example of the coprocessor is the math coprocessor and some of them are 8087 is used with 8086, 80287 is used with 80286, 80387 is used with 80386.

Input/Output Processor

This processor will have its own local memory. It is used to control I/O devices with the involvement of the CPU. The examples of the input/output processor are DMA control, keyboard & mouse control, graphic display control, and SCSI port control.


This processor is also having its own local memory and also having links to connect one transputer to another transputer for inter-processor communication.

The Transputer is used for single processor system or it can be connected to external links reduce the construction cost and increases the performance. Some examples of this processor are floating point of processors like T800. T805, T9000.

Digital Signal Processors

80486 Microprocessor Architecture Block Diagram

The components required for this processor are a programmed memory, data memory, input/output, and compute engine. This processor is designed to process the analogue signal to digital form. This process is done by some regular intervals and converts the voltage into digital form.

80486 Block Diagram Circuit

The applications of this processor are sound & music production, video signal processing, and 2D & 3D graphics acceleration. The example of this processor is TMS320C40.

This article gives the information on different types of microprocessors and their uses. I hope by reading this article you have gained some basic information different types of microprocessors. If you have any queries about this article or about the implementation of Microcontroller projects, please feel free to comment in the below section. Here is the question for you, what are the functions of the different microprocessors?