This article describes the difference between 8085 and 8086 microprocessor. 8085 and 8086 are two types of microprocessors manufactured by Intel.
A microprocessor behaves like the brain of an automated electronic device. It refers to an integrated circuit that works as a central processing unit (CPU) of a computer. A microprocessor contains the logic and arithmetic circuits to perform functions according to the CPU commands. It is made of semiconductor materials such as silicon. Transistors are present on its integrated chip for performing different logic functions.
There are two types of microprocessors namely, 8085 microprocessor and 8086 microprocessor. These two microprocessors were initially introduced by Intel Corporation in the 20th century. In this article, you will get to know the key differences between these two microprocessors. Let’s start with the introduction to 8085 and 8086 microprocessors.
What is an 8085 Microprocessor?
8085 microprocessor was introduced by Intel Corporation using NMOS technology. It is an 8-bit microprocessor used for various applications including small computers to industrial control systems. The 8-bit microprocessor is capable to process 8 bits in a single scale. The address bus for this 8 bits microprocessor, is 16 bits. Its maximum memory is 64 kB or 216 bytes.
This is the maximum accessible memory capacity for the 8085 microprocessor. Moreover, the voltage supply for this microprocessor is +5 V. The 8085 microprocessor is operated on a 3.2 MHz frequency. It utilizes the CLK segment for frequency oscillations. The size of the Arithmetic Logic Unit (ALU) can decide the name of this device. As the ALU size for the 8085 microprocessor is 8 bits, so we call this microprocessor as 8 bits microprocessor.
The 8085 microprocessor can perform mathematic functions such as addition, subtraction, or even comparators. It also performs functions for logic gates such as AND, OR, XOR, compliments, or shift registers. 80 instructions and 246 operational codes are present in the 8085 microprocessor.
Output results from ALU for the 8085 microprocessor are stored in the accumulator as this microprocessor is an accumulator-based microprocessor. There are 3 stages to perform a function for a specific instruction. These three stages are fetching, decoding, and execution.
What is an 8086 Microprocessor?
Intel Corporation introduced the 8086 microprocessor after the successful journey of 8085 but with advancement in the 8086 microprocessor. It contains more advanced functions as compared to the previous 8085 microprocessor. Contrary to the 8085 microprocessor, the 8086 microprocessor is 16 bits data bus. This indicates that the 8086 microprocessor can process 16 bits in one cycle.
The address bus for the 8086 microprocessor is 20 bits. It indicates that it can read/access 220 address locations with its 220 powerful address bits. It has the maximum accessible memory capacity which is 1 MB or 220 bytes. It can perform only fixed arithmetic point operations but it is incapable of floating points. This is a disadvantage as compared to the 8085 microprocessor.
This microprocessor is called 16-bit due to the size of its ALU. The size of the 8086 microprocessor ALU is 16 bits. It can perform arithmetic operations such as multiplication and division of numbers. This is a plus point of the 8086 microprocessor as compared to the 8085 microprocessor.
The 8086 microprocessor is available in the range of 5 MHz to 10 MHz clock operations. This microprocessor is based on general-purpose registers as these registers are used to store the data for different instructions and provide the output of ALU.
Difference between 8085 and 8086 Microprocessor
The major differences between 8085 and 8086 microprocessors are listed in the following table:
8085 Vs 8086 Microprocessor
| Factor | 8085 Microprocessor | 8086 Microprocessor |
| Data Bit Architecture | 8085 microprocessor has 8 bits for its data bus. | 8086 microprocessor has 16 bits for its data bus. |
| Address Bus Architecture | The size of the 8085 microprocessor address bus is 16 bits. | The size of the 8086 microprocessor address bus is 20 bits. |
| Microprocessor Type | It is an accumulator type and accumulates instructions and gives output for ALU. | 8086 microprocessor is general purpose register based. |
| Maximum Memory | The maximum memory for the 8085 microprocessor is 64 kB. | The maximum memory for the 8086 microprocessor is 1 MB. |
| No. of Operations | 8085 microprocessor can perform up to 28 or 256 operations. | 8086 microprocessor can perform up to 216 or 65536 operations. |
| Port Address | The port address for the 8085 microprocessor is 8 bits. | The port address for the 8086 microprocessor is 16 bits. |
| Arithmetic Logic Unit (ALU) | ALU size for 8085 microprocessor is 8 bits. | ALU size for the 8086 microprocessor is 16 bits. |
| Clock Speed | Typically it is 3.2 MHz for an 8085 microprocessor. | The clock speed range lies between 5 to 10 MHz for the 8086 microprocessor. |
| Operations | 8085 microprocessors can perform addition, subtraction, comparators, logic gates, and compliment. 8085 microprocessor is not capable to perform multiplication or division. | 8086 microprocessor can perform all functions of the 8085 microprocessor with the addition of multiplication and division. |
| Price | 8085 microprocessor is cheaper than 8086 microprocessor. | 8086 microprocessor is more expensive than the 8085 microprocessor. |
| Pin Count | 8085 microprocessor is available in 40 pins. | 8086 microprocessor is available in 40 and 68 pins. |
| Power Consumption | It consumes less power. | It consumes more power than the 8085 microprocessor. |
| Pipelining Structure | 8085 microprocessor cannot support pipelining structure. | 8086 microprocessor can support pipelining structure. |
| Mode of Operation | 8085 microprocessor can only perform in single processor mode. | 8086 microprocessor can perform in single and multi-processor mode. |
| Queue Instruction | 8085 microprocessor cannot support queue instruction. | 8086 microprocessor can support queue instruction. It has a queue instruction of 6 bytes stored in the FIFO(First in First Out) register. |
| Flags | 8085 microprocessor support 5 flags. These are carry, auxiliary carry, parity, zero, and sign flag. | 8086 microprocessor support 9 flags. These are carry, auxiliary carry, parity, zero, sign flag, trap, interrupt, direction, and overflow flag. |
| Segmentation | 8085 microprocessor does not support memory segmentation. | 8086 microprocessors can support memory segmentation. Memory segmentation means we can divide the primary memory into segments. |
Conclusion
We can conclude that the 8086 microprocessor has more benefits due to advanced technology than the 8085 version. Both microprocessors are capable of different functions but both have specific limitations too. Cost wise the 8086 microprocessor is more expensive but it offers more functions and provides more accessible memory as compared to the 8085 microprocessor.