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Difference between 8080 and 8085 Microprocessor

Last Updated : 21 Apr, 2023
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Introduction :

The 8080 and 8085 microprocessors are two closely related microprocessors developed by Intel in the 1970s and 1980s. The 8080 was the first 8-bit microprocessor developed by Intel, while the 8085 was an improved version of the 8080 with some additional features and enhancements.

The 8080 microprocessor was released in 1974 and was the first microprocessor to be used in a commercially successful personal computer, the Altair 8800. It had an 8-bit data bus, a 16-bit address bus, and a clock speed of up to 2 MHz. The 8080 had 76 instructions and was capable of executing up to 500,000 instructions per second.

The 8085 microprocessor was released in 1976 and was a newer version of the 8080 with some additional features and enhancements. It had the same 8-bit data bus and 16-bit address bus as the 8080, but it could run at a faster clock speed of up to 3 MHz. The 8085 had 246 instructions and was capable of executing up to 1 million instructions per second.

Both the 8080 and 8085 microprocessors were widely used in a variety of applications, including personal computers, industrial control systems, and scientific instruments. They were also used in many early arcade video games, such as Space Invaders and Pac-Man. Despite being replaced by newer microprocessors in the 1980s and 1990s, the 8080 and 8085 remain important historical milestones in the development of microprocessors and personal computing.

In this section, we will see some differences between Intel 8080 MPU, and Intel 8085 MPU. The Intel 8080 microprocessor was the predecessor of the 8085. Both was designed and manufactured by Intel, Both was an 8-bit Microprocessor. Intel 8080 Microprocessor was released on April 1974 and Intel 8085 Microprocessor was introduced in 1976. 8085 is very close to the 8080 microprocessor, but some slight changes and modifications are present. Difference between 8080 and 8085 Microprocessor :

Sr.No. 8080 microprocessor 8085 microprocessor
1 There is 8 dedicated pins are there as Data bus (D0 to D7). There is multiplexed 8 bit data pins are present for data bus (AD0 to AD7).
2 There is 16 address pins are present (A0 to A15). There is 8 pins Higher order Address bus (A8 to A15) and 8 multiplexed address bus (AD0 to AD7), and the Address Latch Enable (ALE) pins are present.
3 The power supply voltage is +5, -5 and +12 volts. The power supply is only +5 volts.
4 Single Interrupt pins are there (INT). With INT, there are four more interrupt pins (TRAP, RST7.5, RST6.5, RST5.5).
5 Serial Communication facility is not present. The Serial Communication facility is present with SID, SOD Pins and RIM, SIM instructions.
6 Additional chips for Clock and system controlling is needed. No additional chips are needed for clock and system controlling tasks.
7 It consists of 5 flags (Sign Flag, Zero Flag, Auxiliary Carry Flag, Parity Flag, Carry Flag). It also consists of 5 flags (Sign Flag, Zero Flag, Auxiliary Carry Flag, Parity Flag, Carry Flag).
8 Processor speed is upto 3.1 MHz. Processor speed is upto 6 MHz.
9 8080 requires 8224 clock oscillator as well as 8228 system controller to operates. 8085 is functional with only latches and gates.
10 8080 supports upto 256 Input/Output(I/P) ports. 8085 also supports upto 256 Input/Output(I/P) ports.
Feature

8080

8085

Data bus width 

8 bits 

8 bits

Address bus width 

16 bits 

16 bits

Clock speed 

Up to 2 MHz 

Up to 3 MHz

Number of instructions 

76 

246

Instruction set  No direct I/O instructions, no CALL/RETURN instructions, no single-step interrupt  Has direct I/O instructions, has CALL/RETURN instructions, has single-step interrupt
 
Interrupts  Non-maskable interrupt (NMI), maskable interrupts (INT and TRAP)  Same as 8080, plus a new RST 6.5 interrupt
 
Pin compatibility  Not pin-compatible with other microprocessors  Pin-compatible with the 8080 microprocessor
 
Power consumption  Higher power consumption  Lower power consumption
 
Instruction execution time  Slower execution time  Faster execution time
 

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