What is the relationship between AVR and Arduino? Analysis of the advantages of AVR microcontroller and Arduino

       Many times we can see that AVR and Arduino can appear almost at the same time, so what is the difference between them? This article mainly focuses on the differences and advantages between AVR and Arduino.

　　AVR Introduction

　　AVR microcontroller is an enhanced RISC (Reduced InstrucTIon Set Computer) high-speed 8-bit microcontroller with built-in Flash developed by ATMEL in 1997. AVR microcontrollers can be widely used in various fields such as computer peripherals, industrial real-time control, instrumentation, communication equipment, and household appliances. In 1997, Mr. A and Mr. V from Atmel's Norwegian Design Center jointly developed a RISC high-speed 8-bit microcontroller with reduced instruction set, referred to as AVR, using Atmel's new Flash technology.

　　Features of avr microcontroller:

　　1. Fast speed. AVR microcontrollers execute powerful instructions in a single clock cycle, and can achieve a processing capacity of 100 MIPS per MHz. They are the 8-bit microcontrollers with the highest MIPS/mW capability. AVR microcontrollers use large fast access register files and fast single-cycle instructions. Its fast access RISC register file consists of 32 general-purpose working registers. AVR uses 32 general-purpose registers to replace the accumulator, avoiding the traditional data transfer between the accumulator and the memory. It can execute one instruction in one clock cycle to access two independent registers. The code efficiency is ten times faster than that of conventional CISC microcontrollers. AVR microcontrollers execute one instruction in one clock cycle, that is, the next instruction is taken out when the previous instruction is executed, and then the instruction is executed in one cycle (similar to DSP). It is the first true RISC microcontroller among 8-bit microcontrollers.

　　2. High performance-price ratio. AVR microcontrollers include devices with fewer pins (8 pins) and devices with larger storage capacity and more pins, giving users ample choice. AVR microcontrollers use Harvard structure, and the program memory and data memory are separate. You can directly access 8M bytes of program memory and 8M of data memory. AVR microcontrollers have rich on-chip resources. Including: 1K-128K bytes of downloadable Flash memory, 64-4K bytes of EEPROM, 128-4K bytes of RAM, 5-32 general I/O lines, 32 general working registers, analog comparators, timers/counters, programmable asynchronous serial ports, internal and external interrupts, programmable watchdog timers with internal crystal oscillators, SPI serial ports designed for downloading programs, 10-bit AD converters, and two selectable power-saving modes: idle mode and power-down mode. AVR microcontrollers have a high degree of confidentiality. The program memory FLASH has multiple password protection lock (LOCK) functions, and it is impossible to decrypt.

　　3. In-System Programming (ISP In-System Programming) Function The AVR MCU has downloadable FLASH memory inside, which can be reprogrammed in the system (ISP In-System Programming) through the SPI serial interface or a general programmer, bringing great convenience to the development of new products and the upgrading and maintenance of old products.

　　4. Wide operating voltage range (2.7-6V) and strong anti-interference ability. In short, the AVR microcontroller combines the enhanced performance RISC 8-bit CPU with the downloadable FLASH in one chip, making it an embedded and efficient microcontroller suitable for many requirements, with high flexibility and low cost.

　　Advantages of avr microcontroller:

　　1: AVR runs fastest under the same system clock;

　　2: The capacity of Flsah, EEPROM and SRAM inside the chip is large;

　　3: All models of Flash and EEPROM can be burned repeatedly, and all support online programming (ISP);

　　4: Multiple frequency internal RC oscillators, power-on automatic reset, watchdog, start-up delay and other functions, zero peripheral circuit can also work; 5: Each IO port can output high and low levels in a push-to-switch drive mode, with strong driving ability;

　　6: Rich internal resources, generally integrated AD, DA analog-to-digital devices; PWM; SPI, USART, TWI, I2C communication ports; rich interrupt sources, etc.