Microprocessor 8085 Block Diagram and Architecture


Hey, in this article we are going to see the microprocessor 8085 block diagram and architecture. Here, you will get the concept of the internal components and circuit of the microprocessor. A microprocessor is a digital data processing device that performs different types of arithmetic and logical operations. The arithmetic operations performed by a microprocessor are - sum, subtraction, division, multiplication, and more. The logical operations performed by a microprocessor are OR, AND, greater than, less than, and more.

The microprocessor 8085 is the first successful processor used in practical applications. It is designed by Intel in 1977. This microprocessor is manufactured using NMOS Technology. The 8085 microprocessor is used in different devices and projects such as calculators, video game players, embedded systems, automation systems, digital controllers, smartwatches, etc. 8085 is an 8-bit general purpose microprocessor. The 8085 microprocessor operates at a +5V DC power supply with a 3.2 MHz single-phase clock. 

Here, you can see the block diagram of 8085 microprocessor.

Microprocessor 8085 Block Diagram, Microprocessor 8085 Architecture


The microprocessor 8085 has the following internal parts and components,


1. ALU or Arithmetic and Logic Unit

It is the main part of the microprocessor. As its name suggests, it is a digital circuit that performs arithmetic or mathematic operations such as addition, substruction, multiplication, division, and logical operations such as OR, AND, NOT, increment, decrement. It works with 8-bit data only. During the program executions, it takes data from the accumulator and temporary register.


2. Accumulator

The accumulator is an 8-bit register with supplies the data directly to the ALU during program executions to perform the arithmetic and logical operations. In fact, it helps to store load and store new data. It is connected between the internal bus and ALU.


3. General Purpose Registers

The microprocessor 8085 has six general-purpose registers named as B, C, D, E, H, and L. Each of them can store 8-bit data. Also, 16-bit data can be stored using pairs such as B-C or D-E, or H-L.


4. Flag Register

It s also an 8-bit register, it only store either 0 or 1 depending upon which value is stored in the accumulator after the program execution.


5. Temporary Register

 The temporary register is an 8 bit register that is used to store data temporarily during the program executions. When the ALU starts executing a program the data comes from the general-purpose register and is stored in the temporary register. It helps to provide the supporting data to the ALU.


6. Instruction Register and Decoder

To start a program execution when the instruction is fetched from the main memory, it is stored in the instruction register. And the instruction decoder helps to decode the instruction to understand what work operation is to be performed by the ALU.


7. Program Counter

The program counter is a 16-bit register that stores the memory address of the instruction that will be executed in the next. The program counter will be increment by one whenever the instruction is executed.


8. Stack Pointer

The Stack pointer is also a 16-bit register that works like a stack and it always makes increments or decrements by 2 during the push and pop operation. It stores the content of the register which will be used in the next execution.


9. Timing and Control Unit

It is the combination of analog and digital circuits that provides all the clock or pulse signals to all the components of the microprocessor to perform tasks or to do program executions. It not only provides signals to the internal components but also provides the timing and control signal to the external component and circuit connected to the microprocessor such as READY, RD, WR, HOLD, HLDA, etc.


10. Interrupt Control

The interrupt control system in the microprocessor controls the interrupts during program execution. When an interrupt occurs by an external or internal input, the ALU stops the current program execution and processes the task given by the interrupt. Once the task is completed given by the interrupt, again it starts its own work.


11. Serial Input/Output Control

It is a system for controlling the serial communication between the microprocessor and external devices through serial input and serial output ports such as SID and SOD.


12. Data Bus and Address Bus

The 8085 microprocessor has an 8-bit data bus and a 16-bit address bus. The data bus is used to carry and transfer the data is to be stored. It is a bidirectional bus. On the other hand, the address bus carries the location address of the memory where the data is to be stored. It is a unidirectional bus.


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Microprocessor 8085 Block Diagram and Architecture Microprocessor 8085 Block Diagram and Architecture Reviewed by Author on 11/09/2021 Rating: 5
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