Rainbow Electronics ATmega8L - Manual (Page 3)

3
ATmega8
2486AS–08/01
Overview
The ATmega8 is a low-power CMOS 8-bit microcontroller based on the AVR RISC
architecture. By executing powerful instructions in a single clock cycle, the ATmega8
achieves throughputs approaching 1 MIPS per MHz, allowing the system designer to
optimize power consumption versus processing speed.
Block Diagram Figure 1. Block Diagram
INTERNAL
OSCILLATOR
OSCILLATOR
WATCHDOG
TIMER
MCU CTRL.
& TIMING
OSCILLATOR
TIMERS/
COUNTERS
INTERRUPT
UNIT
STACK
POINTER
EEPROM
SRAM
STATUS
REGISTER
USART
PROGRAM
COUNTER
PROGRAM
FLASH
INSTRUCTION
REGISTER
INSTRUCTION
DECODER
PROGRAMMING
LOGIC
SPI
ADC
INTERFACE
COMP.
INTERFACE
PORTC DRIVERS/BUFFERS
PORTC DIGITAL INTERFACE
GENERAL
PURPOSE
REGISTERS
X
Y
Z
ALU
+
-
PORTB DRIVERS/BUFFERS
PORTB DIGITAL INTERFACE
PORTD DIGITAL INTERFACE
PORTD DRIVERS/BUFFERS
XTAL1
XTAL2
CONTROL
LINES
VCC
GND
MUX &
ADC
AGND
AREF
PC0 - PC6 PB0 - PB7
PD0 - PD7
AVR CPU
TWI
RESET