what's ARV?
what's ARV?
1. Introduction to AVR MCU
1.1. The Birth of AVR
AVR single-chip microcomputer is an enhanced RISC simplistic instruction set high-speed single-chip microcomputer with built-in Flash developed by ATMEL in 1997. It can be widely used in various fields such as computer peripheral equipment, industrial real-time control, instrumentation, communication equipment, and household appliances.
1.2. Features of AVR
Using RISC Reduced Instruction Set
RISC (Reduced Instruction Set Computer) is relative to CISC (Complex Instruction Set Computer). RISC is not simply to reduce instructions, but to improve the computing speed of the computer by making the structure of the computer simpler and more reasonable. At present, most of the common microcontrollers on the market use the RISC instruction set, including AVR and ARM. and many more. RISC gives priority to simple instructions with the highest frequency of use, avoids complex instructions, and fixes the instruction width to reduce the types of instruction formats and addressing modes, thereby shortening the instruction cycle and increasing the operating speed. Because AVR adopts this structure of RISC, the AVR series microcontrollers have a high-speed processing capability of 1MIPS/MHz (million instructions per second/MHz). It can be applied to scenarios that require higher computing power.
Embedded high-quality Flash program memory
High-quality Flash is easy to erase and write, supports ISP and IAP, and is convenient for product debugging, development, production, and updating. The built-in long-life EEPROM can save key data for a long time to avoid loss when power off. The large-capacity RAM in the chip can not only meet the needs of general occasions, but also more effectively support the use of high-level language to develop system programs, and can expand the external RAM like MCS-51 single-chip microcomputer.
All I/O pins have configurable pull-up resistors
In this way, it can be individually set as input/output, can be set (initial) high-impedance input, and has strong drive capability (power drive devices can be omitted), making the I/O port resources flexible, powerful, and fully functional. use.
On-chip multiple independent clock dividers
Can be used for URAT, I2C, SPI respectively. Among them, the 8/16-bit timer has up to 10-bit prescaler, and the frequency division coefficient can be set by software to provide various levels of timing time.
Enhanced high-speed USART
It has the functions of hardware generation check code, hardware detection and verification, two-level receiving buffer, automatic adjustment and positioning of baud rate, shielding data frame, etc., which improves the reliability of communication, facilitates program writing, and makes it easier to form a distributed network and realize For the complex application of multi-computer communication system, the serial port function greatly exceeds the serial port of MCS-51 single-chip microcomputer, and because the AVR single-chip microcomputer is fast and the interrupt service time is short, it can realize high baud rate communication.
Stable System Reliability
AVR MCU has automatic power-on reset circuit, independent watchdog circuit, low voltage detection circuit BOD, multiple reset sources (automatic power-on reset, external reset, watchdog reset, BOD reset), configurable startup delay Run the program at any time, which enhances the reliability of the embedded system.
2. Introduction to AVR microcontroller series
The series of AVR single-chip microcomputers are complete, which can be applied to the requirements of various occasions. There are 3 grades in total, which are:
Low-grade Tiny series: mainly Tiny11/12/13/15/26/28 etc.;
Mid-range AT90S series: mainly AT90S1200/2313/8515/8535, etc.; (being eliminated or transformed into Mega)
High-grade ATmega: mainly ATmega8/16/32/64/128 (storage capacity is 8/16/32/64/128KB) and ATmega8515/8535, etc.
AVR device pins range from 8 pins to 64 pins, and there are various packages for users to choose according to actual conditions.
3. Advantages of AVR MCU
Harvard structure, with 1MIPS/MHz high-speed processing capability;
Super-functional reduced instruction set (RISC), with 32 general-purpose working registers, overcomes the bottleneck phenomenon caused by the single ACC processing of 8051 MCU;
Fast access to register groups and single-cycle instruction system greatly optimize the size and execution efficiency of the target code. Some models have very large FLASH, which is especially suitable for development using high-level languages;
When used as an output, it is the same as PIC’s HI/LOW, and can output 40mA. When used as an input, it can be set as a three-state high-impedance input or an input with a pull-up resistor, and has the ability to sink current from 10mA to 20mA;
The chip integrates RC oscillators with multiple frequencies, power-on automatic reset, watchdog, start-up delay and other functions, the peripheral circuit is simpler, and the system is more stable and reliable;
Most AVRs have rich on-chip resources: with E2PROM, PWM, RTC, SPI, UART, TWI, ISP, AD, Analog Comparator, WDT, etc.;
In addition to the ISP function, most AVRs also have the IAP function, which is convenient for upgrading or destroying applications.
4. Application of AVR MCU
Based on the excellent performance and the above characteristics of the AVR single-chip microcomputer, it can be seen that the AVR single-chip microcomputer can be applied to most embedded application scenarios at present. The plug-in single-chip microcomputer allows students to design and weld a minimum system of a single-chip microcomputer by themselves, and learn software and hardware technologies.