The MEGA8A Atmel Microcontroller IC designed as an effectively low-power, high-performance CMOS 8-bit microcontroller. The Microchip AVR® enhanced RISC architecture was used to create this microcontroller. The Atmel AVR core has 32 general-purpose working registers and a large instruction set. All 32 registers are directly coupled to the Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in one clock cycle with a single command. As a result, the resultant design is more code efficient than traditional CISC microcontrollers, with throughputs up to 10 times quicker.
In this Atmel microcontroller, by combining a flexible 8-bit CPU with in-system programmable Flash on a monolithic chip. Thus Atmel ATMEGA128A becomes effectively powerful microcontroller. In order that it delivers a highly flexible and affordable solution to various embedded control applications. Moreover, the Atmel MEGA8515 features 8 Kbytes of In-System Programmable Flash with Read-While-Write capabilities, 512 bytes of EEPROM, 1 Kbyte of SRAM, 23 general purpose I/O lines, 32 general purpose working registers, three flexible Timer/Counters with compare modes. It also consists of internal and external interrupts, a serial programmable USART, a byte oriented Twowire 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 CPU is turned off in Idle Mode, leaving the RAM, timers/counters, serial port, and interrupt system to continue working. The Power-down mode, on the other hand, saves the RAM data but freezes the oscillator. All other chip functions are disabled until the next external interrupt or hardware reset. It is appropriate for battery-operated applications because of these two properties. The asynchronous timer continues to operate in Power-save mode. As a result, the user may keep a timer running while the rest of the device sleeps.