Atmega8a vs Atmega328P[Video+FAQ]

ATmega8A Overview

The Microchip AVR® ATmega8A is a low-power CMOS 8-bit microcontroller based on the AVR RISC architecture. By executing powerful instructions in a single clock cycle, the ATmega8A achieves throughputs approaching 1 MIPS per MHz, allowing the system designer to optimize power consumption versus processing speed.

 ATmega328P Overview

Microchip's ATMEGA328P is a high-performance, low-power controller. The ATMEGA328P is an 8-bit microprocessor built on the AVR RISC architecture. It is the most widely used AVR controller, as it is found in ARDUINO boards.

The ATMEGA328P and ATmega8A are two 28-pin chips, and they have the same pinout as illustrated in the pin diagram above. Many of the chip's pins have many functions. In the table below, we will describe the functions of each pin.

Atmega8a Features

• High-performance, Low-power  Atmel AVR  8-bit Microcontroller 

• Advanced RISC Architecture 

   - 131 powerful instructions – most single clock cycle execution 

   - 32 × 8 General Purpose Working Registers + Peripheral Control Registers 

   - Fully Static Operation 

   - Up to 16MIPS Throughput at 16MHz 

   - On-chip 2-cycle Multiplier

• High Endurance Non-volatile Memory segments 

   - 8KBytes of In-System Self-programmable Flash program memory 

   - 512Bytes EEPROM  

   - 1KByte Internal SRAM 

   - Write/erase cycles: 10,000 flash/100,000 EEPROM 

   - Data retention: 20 years at 85°C/100 years at 25°C(1) 

   - Optional Boot Code Section with Independent Lock Bits 

• In-System Programming by On-chip Boot Program 

• True Read-While-Write Operation 

   -  Programming Lock for Software Security 

• Peripheral Features 

   – Two 8-bit Timer/Counters with Separate Prescaler and compare mode 

   – One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture Mode 

   – Real-Time Counter with Separate Oscillator 

   – Three PWM Channels 

   – 8-channel ADC in TQFP and VQFN package  

Eight Channels 10-bit Accuracy 

   – 6-channel ADC in the PDIP package 

• Six Channels 10-bit Accuracy 

   –  Master/Slave SPI  Serial Interface 

   – Programmable Watchdog Timer with On-chip Oscillator 

   – On-chip Analog Comparator 

   – Byte-Oriented 2-wire Serial Interface 

• Special Microcontroller Features 

  – Power-on Reset and Programmable Brown-out Detection 

  – Internal Calibrated RC Oscillator 

  – External and Internal Interrupt Sources 

  – Six Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, Standby, and  Extended Standby 'I/O and              Packages 

    ̶ - 23 Programmable  I/O  Lines 

    ̶  -28-lead PDIP, 32-lead TQFP, and 32-pad VQFN 

• Operating voltage 

   – 2.7 - 5.5V 

   – 0 - 16MHz 

• Power Consumption at 4MHz, 3V, 25°C 

   - Active: 3.6mA 

   - Idle Mode: 1.0mA 

   - Power-down Mode: 0.5µA 

Atmega328P Features

• High Performance, Low Power AVR®  8-Bit  Microcontroller Family

• Advanced RISC Architecture  

   -131 Powerful Instructions – Most Single Clock Cycle Execution

   -32 x 8 General Purpose Working Registers

   -Fully Static Operation

   -Up to 20 MIPS Throughput at 20MHz

   -On-chip 2-cycle Multiplier

• High Endurance Non-volatile Memory Segments

    -4/8/16/32KBytes of In-System Self-Programmable Flash program memory

    -256/512/512/1KBytes EEPROM

    -512/1K/1K/2KBytes Internal SRAM

    -Write/Erase Cycles: 10,000 Flash/100,000 EEPROM

    -Data retention: 20 years at 85°C/100 years at 25°C(1)

    -Optional Boot Code Section with Independent Lock Bits

• In-System Programming by On-chip Boot Program

• True Read-While-Write Operation

•  Programming Lock for Software Security

• QTouch® library support

     -Capacitive touch buttons, sliders, and wheels

     -QTouch and QMatrix™ acquisition

     -Up to 64 sense channels

• Peripheral Features

     -Two 8-bit  Timer /Counters with Separate Prescaler and Compare Mode

     -One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture Mode

     -Real-Time  Counter with Separate Oscillator

     -Six PWM Channels

     -8-channel 10-bit  ADC  in  TQFP  and  QFN /MLF package

• Temperature Measurement

     -6-channel 10-bit ADC in  PDIP Package

• Temperature Measurement

     -Programmable Serial USART

     -Master/Slave SPI Serial Interface

     -Byte-oriented 2-wire Serial Interface (Philips I2C compatible)

     -Programmable Watchdog Timer with Separate On-chip Oscillator

     -On-chip Analog Comparator

     -Interrupt and Wake-up on Pin Change

• Special Microcontroller Features

     -Power-on Reset  and Programmable Brown-out Detection

     -Internal Calibrated Oscillator

     -External and Internal Interrupt Sources

     -Six Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, Standby, and Extended Standby

• I/O  and Packages

     -23 Programmable I/O Lines

     -28-pin PDIP, 32-lead TQFP, 28-pad QFN/MLF, and 32-pad QFN/MLF

• Operating Voltage:

     -1.8 - 5.5V

•  Temperature Range:

     --40°C to 85°C

• Speed Grade:

       ̶ 0 - 4MHz@1.8 - 5.5V, 0 - 10MHz@2.7 - 5.5.V, 0 - 20MHz @ 4.5 - 5.5V

• Power Consumption at 1MHz, 1.8V, 25°C

      ̶  Active Mode: 0.2mA

      ̶ Power-down Mode: 0.1µA

• Power-save Mode: 0.75µA (Including 32kHz RTC)

Atmega8a and Atmega328P can be used in the same applications due to their similar parameters. And some examples are listed below:

• Weather systems

• Wireless communication applications

• Security-based applications

• Medical & health-related projects & systems

• Automobile related applications

• Industrial machinery controlling systems

• Solar-powered machinery and applications

• IoT based applications

• Power supply and charger based applications

ATMEGA328P can be replaced by ATMEGA8

ATMEGA8 can be replaced by ATMEGA328P

Atmega8P Block Diagram

Atmega328P Block Diagram

Atmega8a Datasheet

Atmega328p Datasheet

     To gain long-term performance or to use the Atmega328P and Atmega8a for years in your electronic device or project, keep in mind that chips or ICs are quite delicate and must be handled with care. The supplied voltage should not be more than 5.5V. Before connecting to the IC, always check the voltage source output. When testing on the breadboard or soldering in a circuit, it is strongly advised to verify all of the pins for the short circuits before powering on the IC. It is preferable to use an IC socket for the IC, but check the IC socket pins for a short circuit before placing the IC in it.