Difference between 8051 and AVR

Prerequisite – Micro-controller (µC) and Microprocessor (µP) A micro-controller is a single Integrated Circuit 

Introduction :

(IC) which is comparable to a little stand alone computer and it is designed to perform the specific tasks of embedded systems. 8051 and AVR comes under the family of micro-controller. 8051 micro-controller and AVR micro-controller differs from each other in terms of different architecture and different sets of instruction, speed, cast, Memory, Power Consumption, Bus Width etc. Now let’s understand in detail how they differs from each other.

1. 8051 micro-controller : It is 8 bit family of micro-controller. It is an entry level micro-controller used for most basic applications all across the world and it consumes low power and available with low budget. It was developed by the Intel in the year 1981. This micro-controller is used in various devices and the major areas includes automobiles, medical devices and energy management.

2. AVR micro-controller : AVR micro-controller was developed by Atmel corporation in the year 1996. It is based RISC Instruction set Architecture (ISA) and also called as Advanced Virtual RISC. AT90S8515 was the initial micro-controller belongs to AVR family. AVR micro-controller is most popular category of controller and it is cheap. It is used in many robotic applications. 
Difference between 8051 and AVR :

S.No.	8051	AVR
01.	8051 micro-controller has 8 bit bus width.	AVR micro-controller has 8 bit but some are 32 bit bus width.
02.	Micro-controllers are from Intel company.	Micro-controllers are from Atmel comapny.
03.	8051 micro-controller is based on von neuman architecture.	AVR micro-controller is based on Modified Harvard architecture.
04.	8051 micro-controller uses CISC Instruction Set Architecture.	AVR micro-controller uses RISC Instruction Set Architecture.
05.	It uses SPI, I2C, UART, USART communication protocol.	It uses UART, USART, LIN, CAN, Ethernet, SPI, I2S communication protocols.
06.	It consumes average power.	It consumes low power.
07.	Its family includes 8051 variants.	Its family includes Atmega, Tiny, Xmega, special purpose AVR.
08.	It has vast community support.	It has very good communication support.
09.	It uses ROM, SRAM, FLASH memory.	It uses Flash, SRAM, EEPROM memory.
10.	Its speed is 12 clock per instruction cycle.	Its speed is 1 clock per instruction cycle.
11.	Popular micro-controllers are AT89C51, P89v51, etc.	Popular micro-controllers are Atmega8, 16, 32, Arduino Community.

Feature	8051	AVR
Architecture	8-bit	8-bit or 32-bit
CPU Speed	Typically up to 33 MHz	Typically up to 20 MHz
Power Consumption	Higher	Lower
Instruction Set	Limited	More complex and diverse
On-chip memory	Limited	More and larger on-chip memory
On-chip peripherals	Limited	More and diverse on-chip peripherals
Interrupt handling	Simple and limited	More complex and efficient
Development tools	Widely available and mature	Growing ecosystem
Cost	Lower	Lower (compared to some ARM and MSP430)