ATmega48/88/168
2. Overview
The ATmega48/88/168 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced
RISC architecture. By executing powerful instructions in a single clock cycle, the
ATmega48/88/168 achieves throughputs approaching 1 MIPS per MHz allowing the system
designer to optimize power consumption versus processing speed.
2.1
Block Diagram
Figure 2-1. Block Diagram
Watchdog
Timer
Power
Supervision
POR / BOD &
RESET
debugWIRE
Watchdog
Oscillator
PROGRAM
LOGIC
Oscillator
Circuits /
Clock
Flash
SRAM
Generation
CPU
EEPROM
AVCC
AREF
GND
2
8bit T/C 0
8bit T/C 2
16bit T/C 1
A/D Conv.
Analog
Comp.
Internal
Bandgap
6
USART 0
PORT D (8)
PD[0..7]
SPI
PORT B (8)
PB[0..7]
TWI
PORT C (7)
PC[0..6]
RESET
XTAL[1..2]
ADC[6..7]
The 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
5
2545M–AVR–09/07
ATMEL [ ATMEL ]
