ATmega8 Microcontroller
It is an 8 bit CMOS technology based microcontroller belongs to the AVR family of microcontroller developed in 1996. It is built on RISC (Reduced Instruction Set Computer) architecture. Their main advantage is it doesn?t contain any accumulator register and the result of any operation can be stored inside any register, defined by an instruction.
ATmega8 Architecture:
Consider the block diagram representation of internal architecture configuration of ATmega8 microcontroller is:
Memory:
ATmega8 microcontroller consists of 1KB of SRAM, 8KB of flash memory and 512 bytes of EEPROM.
The 8KB flash memory is divided into two parts:-
- The upper part used as application flash section
- The lower part used as boot flash section
In ATmega8 microcontroller all the registers are connected directly with Arithmetic Logic Unit (ALU). The EEPROM memory is used for storing the user defined data.
Input/output ports:
ATmega8 microcontroller consists of 3 I/O ports, named as B, C and D with a combination of 23 I/O lines. Port D consists of 8 I/O lines, Port C consists of 7 I/O lines, and Port B consists of 8 I/O lines.
Registers corresponding to the Input/output port X (B, C or D) are:
- DDRX: Data Direction Register of Port X
- PORTX: Data register of Port X
- PINX: Input register of Port X