ATMEGA325A-AUR Atmel, ATMEGA325A-AUR Datasheet - Page 10

• Manufacturer Part Number: ATMEGA325A-AUR
• Description: IC MCU AVR 32K FLASH 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA325A-AUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6. AVR CPU Core
6.1
6.2
10
Introduction
Architectural Overview
ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/645
This section discusses the AVR core architecture in general. The main function of the CPU core
is to ensure correct program execution. The CPU must therefore be able to access memories,
perform calculations, control peripherals, and handle interrupts.
Figure 6-1.
In order to maximize performance and parallelism, the AVR uses a Harvard architecture – with
separate memories and buses for program and data. Instructions in the program memory are
executed with a single level pipelining. While one instruction is being executed, the next instruc-
tion is pre-fetched from the program memory. This concept enables instructions to be executed
in every clock cycle. The program memory is In-System Reprogrammable Flash memory.
The fast-access Register File contains 32 x 8-bit general purpose working registers with a single
clock cycle access time. This allows single-cycle Arithmetic Logic Unit (ALU) operation. In a typ-
Control Lines
Instruction
Instruction
Program
Memory
Block Diagram of the AVR Architecture
Decoder
Register
Flash
Program
Counter
and Control
EEPROM
Registrers
I/O Lines
Purpose
General
SRAM
Data Bus 8-bit
Status
32 x 8
Data
ALU
Comparator
I/O Module1
I/O Module 2
I/O Module n
Watchdog
Interrupt
Timer
Analog
Unit
Unit
SPI
8285B–AVR–03/11