5
8271D–AVR–05/11
ATmega48A/PA/88A/PA/168A/PA/328/P
2.
Overview
The ATmega48A/PA/88A/PA/168A/PA/328/P 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 ATmega48A/PA/88A/PA/168A/PA/328/P 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 1
8bit T/C 0
A/D Conv.
Internal
Bandgap
Analog
Comp.
SPI
TWI
SRAM
Flash
EEPROM
Watchdog
Oscillator
Watchdog
Timer
Oscillator
Circuits /
Clock
Generation
Power
Supervision
POR / BOD &
RESET
VCC
GND
PROGRAM
LOGIC
debugWIRE
2
GND
AREF
AVCC
D
ATA
B
U
S
ADC[6..7]
PC[0..6]
PB[0..7]
PD[0..7]
6
RESET
XTAL[1..2]
CPU