2. Overview
The ATmega64A 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 ATmega64A achieves throughputs approaching 1 MIPS
per MHz, allowing the system designer to optimize power consumption versus processing speed.
2.1
Block Diagram
Block Diagram
PF0 - PF7
PA0 - PA7
PC0 - PC7
Figure 2-1.
VCC
GND
PORTF DRIVERS
AVCC
DATA REGISTER
PORTF
DATA DIR.
REG. PORTF
DATA REGISTER
PORTA
DATA DIR.
REG. PORTA
DATA REGISTER
PORTC
DATA DIR.
REG. PORTC
8-BIT DATA BUS
PORTA DRIVERS
PORTC DRIVERS
XTAL1
AREF
ADC
INTERNAL
OSCILLATOR
XTAL2
OSCILLATOR
JTAG TAP
PROGRAM
COUNTER
STACK
POINTER
WATCHDOG
TIMER
CALIB. OSC
OSCILLATOR
ON-CHIP DEBUG
PROGRAM
FLASH
SRAM
MCU CONTROL
REGISTER
TIMING AND
CONTROL
RESET
BOUNDARY-
SCAN
INSTRUCTION
REGISTER
GENERAL
PURPOSE
REGISTERS
X
Y
Z
TIMER/
COUNTERS
PEN
PROGRAMMING
LOGIC
INSTRUCTION
DECODER
INTERRUPT
UNIT
CONTROL
LINES
ALU
EEPROM
STATUS
REGISTER
USART0
SPI
USART1
2-WIRE SERIAL
INTERFACE
ANALOG
COMPARATOR
DATA REGISTER
PORTE
DATA DIR.
REG. PORTE
DATA REGISTER
PORTB
DATA DIR.
REG. PORTB
DATA REGISTER
PORTD
DATA DIR.
REG. PORTD
DATA REG. DATA DIR.
PORTG REG. PORTG
+
-
PORTE DRIVERS
PORTB DRIVERS
PORTD DRIVERS
PORTG DRIVERS
PE0 - PE7
PB0 - PB7
PD0 - PD7
PG0 - PG4
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 architecture is more code efficient while achieving
throughputs up to ten times faster than conventional CISC microcontrollers.
The ATmega64A provides the following features: 64 Kbytes In-System Programmable Flash with Read-While-
Write capabilities, 2 Kbytes EEPROM, 4 Kbytes SRAM, 53 general purpose I/O lines, 32 general purpose working
registers, Real Time Counter (RTC), four flexible Timer/Counters with compare modes and PWM, two USARTs, a
byte oriented Two-wire Serial Interface, an 8-channel, 10-bit ADC with optional differential input stage with pro-
grammable gain, programmable Watchdog Timer with internal Oscillator, an SPI serial port, IEEE std. 1149.1
ATmega64A [DATASHEET]
8160DS–AVR–02/2013
3
ATMEL [ ATMEL CORPORATION ]
