ATMEGA644P-20AQ Atmel, ATMEGA644P-20AQ Datasheet - Page 311

• Manufacturer Part Number: ATMEGA644P-20AQ
• Description: MCU AVR 64K FLASH 20MHZ 44-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644P-20AQ

• 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
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 24-11. Serial Programming Instruction example
8011O–AVR–07/10
Byte 1
Load Program Memory Page (High/Low Byte)/
Load EEPROM Memory Page (page access)
Bit 15 B
Byte 2
Adr MSB
Adr dr M
A
r MS S B
Notes:
If the LSB in RDY/BSY data byte out is ‘1’, a programming operation is still pending. Wait until
this bit returns ‘0’ before the next instruction is carried out.
Within the same page, the low data byte must be loaded prior to the high data byte.
After data is loaded to the page buffer, program the EEPROM page, see
311.
1. Not all instructions are applicable for all parts.
2. a = address.
3. Bits are programmed ‘0’, unprogrammed ‘1’.
4. To ensure future compatibility, unused Fuses and Lock bits should be unprogrammed (‘1’) .
5. Refer to the correspondig section for Fuse and Lock bits, Calibration and Signature bytes and
6. Instructions accessing program memory use a word address. This address may be random
7. See htt://www.atmel.com/avr for Application Notes regarding programming and programmers.
Byte 3
Adr LSB
Page size.
within the page range.
Page Offset
0
Serial Programming Instruction
Byte 4
Program Memory/
EEPROM Memory
Page Buffer
Page N-1
Page 0
Page 1
Page 2
Byte 1
Page Number
Bit 15 B
ATmega164P/324P/644P
Write Program Memory Page/
Write EEPROM Memory Page
Byte 2
Adr MSB
Byte 3
Adr LSB
A A dr dr LS
LSB
SB
Figure 24-11 on page
0
Byte 4
311