ATMEGA645A-AU Atmel, ATMEGA645A-AU Datasheet - Page 285

• Manufacturer Part Number: ATMEGA645A-AU
• Description: IC MCU AVR 64K FLASH 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA645A-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• 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: 64-TQFP
• Processor Series: ATmega
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: SPI, USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 54
• Number Of Timers: 3
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8285B–AVR–03/11
ATmega165A/165PA/325A/325PA/3250A/3250PA/6
Table 26-4.
Note:
Table 26-5.
Note:
The status of the Fuse bits is not affected by Chip Erase. Note that the Fuse bits are locked if
Lock bit1 (LB1) is programmed. Program the Fuse bits before programming the Lock bits.
Fuse High Byte
OCDEN
JTAGEN
SPIEN
WDTON
EESAVE
BOOTSZ1
BOOTSZ0
BOOTRST
Fuse Low Byte
CKDIV8
CKOUT
SUT1
SUT0
CKSEL3
CKSEL2
CKSEL1
CKSEL0
(1)
1. The SPIEN Fuse is not accessible in serial programming mode.
2. The default value of BOOTSZ1...0 results in maximum Boot Size. See
3. See
4. Never ship a product with the OCDEN Fuse programmed regardless of the setting of Lock bits
5. If the JTAG interface is left unconnected, the JTAGEN fuse should if possible be disabled. This
1. The default value of SUT1:0 results in maximum start-up time for the default clock source. See
2. The default setting of CKSEL3:0 results in internal RC Oscillator @ 8MHz. See
3. The CKOUT Fuse allow the system clock to be output on PORTE7. See
4. See
(3)
(4)
(4)
(3)
(5)
for details.
and JTAGEN Fuse. A programmed OCDEN Fuse enables some parts of the clock system to
be running in all sleep modes. This may increase the power consumption.
to avoid static current at the TDO pin in the JTAG interface.
Table 27-13 on page 326
page 34
on page 36
Fuse High Byte
Fuse Low Byte
”WDTCR – Watchdog Timer Control Register” on page 53
”System Clock Prescaler” on page 36
for details.
Bit No
Bit No
7
6
5
4
3
2
1
0
7
6
5
4
1
for details.
3
2
0
Description
Enable OCD
Enable JTAG
Enable Serial Program and Data
Downloading
Watchdog Timer always on
EEPROM memory is preserved
through the Chip Erase
Select Boot Size (see
for details)
Select Boot Size (see
for details)
Select Reset Vector
Description
Divide clock by 8
Clock output
Select start-up time
Select start-up time
Select Clock source
Select Clock source
Select Clock source
Select Clock source
for details.
Table 25-6
Table 25-6
for details.
Default Value
0 (programmed)
1 (unprogrammed)
1 (unprogrammed)
0 (programmed)
0 (programmed)
0 (programmed)
1 (unprogrammed)
0 (programmed)
Default Value
1 (unprogrammed, OCD disabled)
0 (programmed, JTAG enabled)
0 (programmed, SPI prog.
enabled)
1 (unprogrammed)
1 (unprogrammed, EEPROM not
preserved)
0 (programmed)
0 (programmed)
1 (unprogrammed)
for details.
Table 25-6 on page 278
”Clock Output Buffer”
(1)
(2)
(2)
(2)
(2)
(2)
(1)
(2)
Table 8-10 on
285