Monday, December 17, 2012




The Atmel®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.

The Atmel®AVR® AVR core combines a rich instruction set with 32 general purpose working registers. All the 32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in one single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers.

The ATmega8A provides the following features: 8K bytes of In-System Programmable Flash with Read-While-Write capabilities, 512 bytes of EEPROM, 1K byte of SRAM, 23 general purpose I/O lines, 32 general purpose working registers, three flexible Timer/Counters with compare modes, internal and external interrupts, a serial programmable USART, a byte oriented Two-wire Serial Interface, a 6-channel ADC (eight channels in TQFP and QFN/MLF packages) with 10-bit accuracy, a programmable Watchdog Timer with Internal Oscillator, an SPI serial port, and five software selectable power saving modes. The Idle mode stops the CPU while allowing the SRAM, Timer/Counters, SPI port, and interrupt system to continue functioning. The Power-down mode saves the register contents but freezes the Oscillator, disabling all other chip functions until the next Interrupt or Hardware Reset. In Power-save mode, the asynchronous timer continues to run, allowing the user to maintain a timer base while the rest of the device is sleeping. The ADC Noise Reduction mode stops the CPU and all I/O modules except asynchronous timer and ADC, to minimize switching noise during ADC conversions. In Standby mode, the crystal/resonator Oscillator is running while the rest of the device is sleeping. This allows very fast start-up combined with low-power consumption.

Features :

  •  High-performance, Low-power Atmel®AVR® 8-bit Microcontroller
  • Advanced RISC Architecture
    – 130 Powerful Instructions – Most Single-clock Cycle Execution
    – 32 x 8 General Purpose Working 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, one Compare Mode
    – One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture
    – Real Time Counter with Separate Oscillator
    – Three PWM Channels
    – 8-channel ADC in TQFP and QFN/MLF package
        • Eight Channels 10-bit Accuracy
    – 6-channel ADC in PDIP package
        • Six Channels 10-bit Accuracy
    – Byte-oriented Two-wire Serial Interface
    – Programmable Serial USART
    – Master/Slave SPI Serial Interface
    – Programmable Watchdog Timer with Separate On-chip Oscillator
    – On-chip Analog Comparator
  • Special Microcontroller Features
    – Power-on Reset and Programmable Brown-out Detection
    – Internal Calibrated RC Oscillator
    – External and Internal Interrupt Sources
    – Five Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, and Standby
  • I/O and Packages
    – 23 Programmable I/O Lines
    – 28-lead PDIP, 32-lead TQFP, and 32-pad QFN/MLF
  • Operating Voltages
    – 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

Pinout Diagram

Download Datasheet ATMEGA8

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