ATMEGA644-20AU Atmel, ATMEGA644-20AU Datasheet - Page 31
ATMEGA644-20AU
Manufacturer Part Number
ATMEGA644-20AU
Description
IC AVR MCU FLASH 64K 44TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Specifications of ATMEGA644-20AU
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
44-TQFP, 44-VQFP
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
SMD/SMT
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
Cpu Family
ATmega
Device Core
AVR
Device Core Size
8b
Frequency (max)
20MHz
Total Internal Ram Size
4KB
# I/os (max)
32
Number Of Timers - General Purpose
3
Operating Supply Voltage (typ)
3.3/5V
Operating Supply Voltage (max)
5.5V
Operating Supply Voltage (min)
2.7V
Instruction Set Architecture
RISC
Operating Temp Range
-40C to 85C
Operating Temperature Classification
Industrial
Mounting
Surface Mount
Pin Count
44
Package Type
TQFP
Package
44TQFP
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/JTAG770-1005 - ISP 4PORT FOR ATMEL AVR MCU JTAG770-1004 - ISP 4PORT FOR ATMEL AVR MCU SPIATAVRISP2 - PROGRAMMER AVR IN SYSTEM
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATMEGA644-20AU
Manufacturer:
OKI
Quantity:
101
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7.4
2593N–AVR–07/10
Full Swing Crystal Oscillator
Table 7-4.
Notes:
This Crystal Oscillator is a full swing oscillator, with rail-to-rail swing on the XTAL2 output. This is
useful for driving other clock inputs and in noisy environments. The current consumption is
higher than the
Oscillator will only operate for Vcc = 2.7 to 5.5 volts.
Some initial guidelines for choosing capacitors for use with crystals are given in
crystal should be connected as described in
The operating mode is selected by the fuses CKSEL3..1 as shown in
Table 7-5.
Notes:
Table 7-6.
Oscillator Source /
Power Conditions
Crystal Oscillator, BOD
enabled
Crystal Oscillator, fast
rising power
Crystal Oscillator, slowly
rising power
Frequency Range
Oscillator Source /
Power Conditions
Ceramic resonator, fast
rising power
Ceramic resonator, slowly
rising power
Ceramic resonator, BOD
enabled
Ceramic resonator, fast
rising power
1. These options should only be used when not operating close to the maximum frequency of the
2. These options are intended for use with ceramic resonators and will ensure frequency stability
1. The frequency ranges are preliminary values. Actual values are TBD.
2. If 8 MHz frequency exceeds the specification of the device (depends on V
device, and only if frequency stability at start-up is not important for the application. These
options are not suitable for crystals.
at start-up. They can also be used with crystals when not operating close to the maximum fre-
quency of the device, and if frequency stability at start-up is not important for the application.
Fuse can be programmed in order to divide the internal frequency by 8. It must be ensured
that the resulting divided clock meets the frequency specification of the device.
0.4 - 20
Start-up Times for the Low Power Crystal Oscillator Clock Selection (Continued)
Full Swing Crystal Oscillator operating modes
Start-up Times for the Full Swing Crystal Oscillator Clock Selection
”Low Power Crystal Oscillator” on page
(1)
(MHz)
Start-up Time from
Start-up Time from
Power-down and
Power-down and
Power-save
Power-save
16K CK
16K CK
16K CK
258 CK
258 CK
1K CK
1K CK
CKSEL3..1
011
”Clock Source Connections” on page
Additional Delay
Additional Delay
14CK + 4.1 ms
14CK + 4.1 ms
14CK + 65 ms
Recommended Range for Capacitors C1
14CK + 4.1 ms
14CK + 65 ms
(V
(V
from Reset
from Reset
CC
CC
14CK
30. Note that the Full Swing Crystal
14CK
(2)
= 5.0V)
= 5.0V)
(2)
(1)
(1)
(2)
and C2 (pF)
Table
12 - 22
ATmega644
CKSEL0
CKSEL0
7-5.
CC
0
0
0
0
1
1
1
), the CKDIV8
Table
29.
SUT1..0
SUT1..0
7-6. The
00
01
10
11
01
10
11
31
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