ATMEGA644A-AU Atmel, ATMEGA644A-AU Datasheet - Page 296

• Manufacturer Part Number: ATMEGA644A-AU
• Description: IC MCU AVR 64K FLASH 44TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644A-AU

• 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: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

26.2
8272A–AVR–01/10
Fuse Bits
Table 26-2.
Notes:
The ATmega164A/164PA/324A/324PA/644A/644PA/1284/1284P has four Fuse bytes.
26-3
the Fuse bytes. Note that the fuses are read as logical zero, “0”, if they are programmed.
Table 26-3.
Note:
164A/164PA/324A/324PA/644A/644PA/1284/1284P
–
–
–
–
–
BODLEVEL2
BODLEVEL1
BODLEVEL0
BLB1 Mode
Fuse Low Byte
-
Table 26-5
1
2
3
4
1. Program the Fuse bits and Boot Lock bits before programming the LB1 and LB2.
2. “1” means unprogrammed, “0” means programmed
1. See
Memory Lock Bits
(1)
(1)
(1)
Lock Bit Protection Modes
Extended Fuse Byte
”System and Reset Characteristics” on page 335
BLB12
describe briefly the functionality of all the fuses and how they are mapped into
1
1
0
0
7
6
5
4
3
2
1
0
Bit No
BLB11
1
0
0
1
Description
–
–
–
–
–
Brown-out Detector trigger level
Brown-out Detector trigger level
Brown-out Detector trigger level
Protection Type
No restrictions for SPM or (E)LPM accessing the Boot Loader
section.
SPM is not allowed to write to the Boot Loader section.
SPM is not allowed to write to the Boot Loader section, and
(E)LPM executing from the Application section is not allowed to
read from the Boot Loader section. If Interrupt Vectors are
placed in the Application section, interrupts are disabled while
executing from the Boot Loader section.
(E)LPM executing from the Application section is not allowed to
read from the Boot Loader section. If Interrupt Vectors are
placed in the Application section, interrupts are disabled while
executing from the Boot Loader section.
(1)(2)
(Continued)
for BODLEVEL Fuse decoding.
Default Value
1
1
1
1
1
1 (unprogrammed)
1 (unprogrammed)
1 (unprogrammed)
Table
296