ATMEGA644-20PU Atmel, ATMEGA644-20PU Datasheet - Page 179
![IC AVR MCU FLASH 64K 40DIP](/photos/6/70/67049/453-40-dip_sml.jpg)
ATMEGA644-20PU
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
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATMEGA644-20PU
Manufacturer:
Atmel
Quantity:
1 930
- Current page: 179 of 376
- Download datasheet (8Mb)
17.8.3
2593N–AVR–07/10
Asynchronous Operational Range
Figure 17-7. Stop Bit Sampling and Next Start Bit Sampling
The same majority voting is done to the stop bit as done for the other bits in the frame. If the stop
bit is registered to have a logic 0 value, the Frame Error (FEn) Flag will be set.
A new high to low transition indicating the start bit of a new frame can come right after the last of
the bits used for majority voting. For Normal Speed mode, the first low level sample can be at
point marked (A) in
(B). (C) marks a stop bit of full length. The early start bit detection influences the operational
range of the Receiver.
The operational range of the Receiver is dependent on the mismatch between the received bit
rate and the internally generated baud rate. If the Transmitter is sending frames at too fast or too
slow bit rates, or the internally generated baud rate of the Receiver does not have a similar (see
Table
bit.
The following equations can be used to calculate the ratio of the incoming data rate and internal
receiver baud rate.
D
S
S
S
R
Table 17-2
that Normal Speed mode has higher toleration of baud rate variations.
F
M
slow
17-2) base frequency, the Receiver will not be able to synchronize the frames to the start
(U2X = 0)
(U2X = 1)
Sample
Sample
RxD
R
slow
and
Sum of character size and parity size (D = 5 to 10 bit)
Samples per bit. S = 16 for Normal Speed mode and S = 8 for Double Speed
mode.
First sample number used for majority voting. S
for Double Speed mode.
Middle sample number used for majority voting. S
S
is the ratio of the slowest incoming data rate that can be accepted in relation to the
receiver baud rate. R
accepted in relation to the receiver baud rate.
=
M
Table 17-3
= 5 for Double Speed mode.
------------------------------------------ -
S 1
–
Figure
(
D
+
1
1
+
D S ⋅
1
2
17-7. For Double Speed mode the first low level must be delayed to
list the maximum receiver baud rate error that can be tolerated. Note
)S
+
3
2
S
F
4
fast
5
3
is the ratio of the fastest incoming data rate that can be
6
7
4
8
STOP 1
9
5
10
R
fast
(A)
0/1
6
=
0/1
F
-----------------------------------
(
= 8 for normal speed and S
D
M
(B)
0/1
0/1
(
+
= 9 for normal speed and
D
1
+
)S
2
)S
+
ATmega644
S
M
(C)
F
179
= 4
Related parts for ATMEGA644-20PU
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
![ATmega644](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
Atmel Corporation
Datasheet:
![ATMEGA644-20MU](/photos/12/13/121316/313-44-qfn_tmb.jpg)
Part Number:
Description:
IC AVR MCU FLASH 64K 44-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA644-20AU](/photos/6/70/67042/313-44-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU FLASH 64K 44TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA644-20AUR](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
MCU AVR 64K FLASH 20MHZ 44TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA644-20MUR](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
MCU AVR 64K FLASH 20MHZ 44QFN
Manufacturer:
Atmel
Datasheet:
![atmega644v](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Atmega644 8-bit Avr Microcontroller With 64k Bytes In-system Programmable Flash
Manufacturer:
ATMEL Corporation
Datasheet:
![ATmega64](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
Atmel Corporation
Datasheet:
![ATMEGA64-16 AU](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
ATMEL Corporation
Datasheet:
![ATMEGA64-16 AC](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
ATMEL Corporation
Datasheet:
![ATMEGA64-16AU](/photos/12/13/121332/313-64-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 64K 16MHZ 5V 64TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA64-16MU](/photos/12/13/121326/313-64-qfn_tmb.jpg)
Part Number:
Description:
IC AVR MCU 64K 16MHZ 5V 64-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA64-16AC](/photos/12/13/121332/313-64-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 64K 16MHZ COM 64-TQFP
Manufacturer:
Atmel
Datasheet: