Data Sheet

5
8161D–AVR–10/09
ATmega48PA/88PA/168PA/328P
2. Overview
The ATmega48PA/88PA/168PA/328P 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
ATmega48PA/88PA/168PA/328P 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
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
PORT C (7)PORT B (8)PORT D (8)
USART 0
8bit T/C 2
16bit T/C 18bit T/C 0 A/D Conv.
Internal
Bandgap
Analog
Comp.
SPI TWI
SRAMFlash
EEPROM
Watchdog
Oscillator
Watchdog
Timer
Oscillator
Circuits /
Clock
Generation
Power
Supervision
POR / BOD &
RESET
VCC
GND
PROGRAM
LOGIC
debugWIRE
2
GND
AREF
AVCC
DATA BU S
ADC[6..7]PC[0..6]PB[0..7]PD[0..7]
6
RESET
XTAL[1..2]
CPU