ATMEGA644A-PU Atmel, ATMEGA644A-PU Datasheet - Page 307

• Manufacturer Part Number: ATMEGA644A-PU
• Description: IC MCU AVR 64K FLASH 40PDIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644A-PU

• 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): 1.8 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: ATmega
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: JTAG, TWI, SPI, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

26.7.12
26.7.13
26.7.14
8272A–AVR–01/10
Reading the Fuse and Lock Bits
Reading the Signature Bytes
Reading the Calibration Byte
The algorithm for reading the Fuse and Lock bits is as follows (refer to
on page 302
1. A: Load Command “0000 0100”.
2. Set OE to “0”, and BS2, BS1 to “00”. The status of the Fuse Low bits can now be read at
3. Set OE to “0”, and BS2, BS1 to “11”. The status of the Fuse High bits can now be read at
4. Set OE to “0”, and BS2, BS1 to “10”. The status of the Extended Fuse bits can now be
5. Set OE to “0”, and BS2, BS1 to “01”. The status of the Lock bits can now be read at DATA
6. Set OE to “1”.
Figure 26-6. Mapping Between BS1, BS2 and the Fuse and Lock Bits During Read
The algorithm for reading the Signature bytes is as follows (refer to
page 302
1. A: Load Command “0000 1000”.
2. B: Load Address Low Byte (0x00 - 0x02).
3. Set OE to “0”, and BS to “0”. The selected Signature byte can now be read at DATA.
4. Set OE to “1”.
The algorithm for reading the Calibration byte is as follows (refer to
page 302
1. A: Load Command “0000 1000”.
2. B: Load Address Low Byte, 0x00.
3. Set OE to “0”, and BS1 to “1”. The Calibration byte can now be read at DATA.
4. Set OE to “1”.
164A/164PA/324A/324PA/644A/644PA/1284/1284P
DATA (“0” means programmed).
DATA (“0” means programmed).
read at DATA (“0” means programmed).
(“0” means programmed).
for details on Command and Address loading):
for details on Command and Address loading):
for details on Command loading):
Extended Fuse Byte
Fuse Low Byte
Fuse High Byte
Lock Bits
BS2
BS2
0
1
0
1
BS1
0
1
”Programming the Flash” on
”Programming the Flash” on
”Programming the Flash”
DATA
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