ATMEGA644-20PU Atmel, ATMEGA644-20PU Datasheet - Page 369

• Manufacturer Part Number: ATMEGA644-20PU
• Description: IC AVR MCU FLASH 64K 40DIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644-20PU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Processor Series: ATMEGA64x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: 2-Wire/SPI/USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT, ATAVRRZ541, ATAVRRAVEN, ATAVRRZRAVEN, ATAVRRZUSBSTICK, ATAVRRZ201
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• Controller Family/series: AVR MEGA
• No. Of I/o's: 32
• Eeprom Memory Size: 2KB
• Ram Memory Size: 4KB
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Rohs Compliant: Yes
• Package: 40PDIP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 20 MHz
• For Use With: ATSTK600-TQFP44 - STK600 SOCKET/ADAPTER 44-TQFPATSTK600-DIP40 - STK600 SOCKET/ADAPTER 40-PDIP770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAGATAVRISP2 - PROGRAMMER AVR IN SYSTEM
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table of Contents
2593N–AVR–07/10
1
2
3
4
5
6
7
Features ..................................................................................................... 1
Pin Configurations ................................................................................... 2
Overview ................................................................................................... 3
Resources ................................................................................................. 7
About Code Examples ............................................................................. 8
AVR CPU Core .......................................................................................... 9
AVR Memories ........................................................................................ 18
System Clock and Clock Options ......................................................... 28
1.1Disclaimer ..................................................................................................................3
2.1Block Diagram ...........................................................................................................3
2.2Pin Descriptions ........................................................................................................4
5.1Introduction ................................................................................................................9
5.2Architectural Overview ..............................................................................................9
5.3ALU – Arithmetic Logic Unit ....................................................................................10
5.4Status Register ........................................................................................................11
5.5General Purpose Register File ................................................................................12
5.6Stack Pointer ...........................................................................................................13
5.7Instruction Execution Timing ...................................................................................14
5.8Reset and Interrupt Handling ..................................................................................14
6.1In-System Reprogrammable Flash Program Memory .............................................18
6.2SRAM Data Memory ...............................................................................................19
6.3EEPROM Data Memory ..........................................................................................20
6.4I/O Memory ..............................................................................................................26
7.1Clock Systems and their Distribution .......................................................................28
7.2Clock Sources .........................................................................................................29
7.3Low Power Crystal Oscillator ...................................................................................31
7.4Full Swing Crystal Oscillator ....................................................................................32
7.5Low Frequency Crystal Oscillator ............................................................................33
7.6Calibrated Internal RC Oscillator .............................................................................34
7.7128 kHz Internal Oscillator ......................................................................................35
7.8External Clock .........................................................................................................36
7.9Clock Output Buffer .................................................................................................37
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