ATMEGA644A-PU Atmel, ATMEGA644A-PU Datasheet - Page 305

• 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

26.7.6
26.7.7
26.7.8
8272A–AVR–01/10
Reading the Flash
Reading the EEPROM
Programming the Fuse Low Bits
Figure 26-4. Programming the EEPROM Waveforms
The algorithm for reading the Flash memory is as follows (refer to
page 302
1. A: Load Command “0000 0010”.
2. H: Load Address Extended Byte (0x00- 0xFF).
3. G: Load Address High Byte (0x00 - 0xFF).
4. B: Load Address Low Byte (0x00 - 0xFF).
5. Set OE to “0”, and BS1 to “0”. The Flash word low byte can now be read at DATA.
6. Set BS to “1”. The Flash word high byte can now be read at DATA.
7. Set OE to “1”.
The algorithm for reading the EEPROM memory is as follows (refer to
on page 302
1. A: Load Command “0000 0011”.
2. G: Load Address High Byte (0x00 - 0xFF).
3. B: Load Address Low Byte (0x00 - 0xFF).
4. Set OE to “0”, and BS1 to “0”. The EEPROM Data byte can now be read at DATA.
5. Set OE to “1”.
The algorithm for programming the Fuse Low bits is as follows (refer to
on page 302
1. A: Load Command “0100 0000”.
2. C: Load Data Low Byte. Bit n = “0” programs and bit n = “1” erases the Fuse bit.
3. Give WR a negative pulse and wait for RDY/BSY to go high.
164A/164PA/324A/324PA/644A/644PA/1284/1284P
RESET +12V
RDY/BSY
PAGEL
XTAL1
DATA
XA1
XA0
BS1
BS2
WR
OE
for details on Command and Address loading):
for details on Command and Address loading):
for details on Command and Data loading):
0x11
A
ADDR. HIGH
G
ADDR. LOW
B
DATA
C
XX
E
ADDR. LOW
B
DATA
C
K
XX
E
”Programming the Flash” on
”Programming the Flash”
”Programming the Flash”
L
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