ATMEGA644-20PU Atmel, ATMEGA644-20PU Datasheet - Page 290
![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
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25.7
25.7.1
25.7.2
25.7.3
25.7.4
290
Parallel Programming
ATmega644
Enter Programming Mode
Considerations for Efficient Programming
Chip Erase
Programming the Flash
The following algorithm puts the device in parallel programming mode:
1. Apply 4.5V - 5.5V between V
2. Set RESET to “0” and toggle XTAL1 at least six times.
3. Set the Prog_enable pins listed in
4. Apply 11.5V - 12.5V to RESET. Any activity on Prog_enable pins within 100 ns after
5. Wait at least 50 µs before sending a new command.
The loaded command and address are retained in the device during programming. For efficient
programming, the following should be considered.
• The command needs only be loaded once when writing or reading multiple memory locations.
• Skip writing the data value 0xFF, that is the contents of the entire EEPROM (unless the
• Address high byte needs only be loaded before programming or reading a new 256 word
The Chip Erase will erase the Flash and EEPROM
not reset until the program memory has been completely erased. The Fuse bits are not
changed. A Chip Erase must be performed before the Flash and/or EEPROM are
reprogrammed.
Note:
Load Command “Chip Erase”
1. Set XA1, XA0 to “10”. This enables command loading.
2. Set BS1 to “0”.
3. Set DATA to “1000 0000”. This is the command for Chip Erase.
4. Give XTAL1 a positive pulse. This loads the command.
5. Give WR a negative pulse. This starts the Chip Erase. RDY/BSY goes low.
6. Wait until RDY/BSY goes high before loading a new command.
The Flash is organized in pages, see
the program data is latched into a page buffer. This allows one page of program data to be pro-
grammed simultaneously. The following procedure describes how to program the entire Flash
memory:
A. Load Command “Write Flash”
1. Set XA1, XA0 to “10”. This enables command loading.
2. Set BS1 to “0”.
EESAVE Fuse is programmed) and Flash after a Chip Erase.
window in Flash or 256 byte EEPROM. This consideration also applies to Signature bytes
reading.
100 ns.
+12V has been applied to RESET, will cause the device to fail entering programming
mode.
1. The EEPRPOM memory is preserved during Chip Erase if the EESAVE Fuse is programmed.
CC
and GND.
Table 25-11 on page 289
Table 25-7 on page
(1)
memories plus Lock bits. The Lock bits are
287. When programming the Flash,
to “0000” and wait at least
2593N–AVR–07/10
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