ATmega1280 Atmel Corporation, ATmega1280 Datasheet - Page 62

• Manufacturer Part Number: ATmega1280
• Manufacturer: Atmel Corporation

Specifications of ATmega1280

• Flash (kbytes): 128 Kbytes
• Pin Count: 100
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 86
• Ext Interrupts: 32
• Usb Speed: No
• Usb Interface: No
• Spi: 5
• Twi (i2c): 1
• Uart: 4
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 16
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 8
• Eeprom (bytes): 4096
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 6
• Output Compare Channels: 16
• Input Capture Channels: 4
• Pwm Channels: 15
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

12.2.4
12.3
12.3.1
2549N–AVR–05/11
Internal Voltage Reference
Watchdog Reset
Voltage Reference Enable Signals and Start-up Time
Figure 12-5. Brown-out Reset During Operation
When the Watchdog times out, it will generate a short reset pulse of one CK cycle duration. On
the falling edge of this pulse, the delay timer starts counting the Time-out period t
“Watchdog Timer” on page 55.
Figure 12-6. Watchdog Reset During Operation
ATmega640/1280/1281/2560/2561 features an internal bandgap reference. This reference is
used for Brown-out Detection, and it can be used as an input to the Analog Comparator or the
ADC.
The voltage reference has a start-up time that may influence the way it should be used. The
start-up time is given in
reference is not always turned on. The reference is on during the following situations:
1. When the BOD is enabled (by programming the BODLEVEL [2:0] Fuse).
2. When the bandgap reference is connected to the Analog Comparator (by setting the
3. When the ADC is enabled.
Thus, when the BOD is not enabled, after setting the ACBG bit or enabling the ADC, the user
must always allow the reference to start up before the output from the Analog Comparator or
ACBG bit in ACSR).
CC
INTERNAL
TIME-OUT
RESET
RESET
V
CC
“System and Reset Characteristics” on page
for details on operation of the Watchdog Timer.
ATmega640/1280/1281/2560/2561
CK
V
BOT-
V
t
TOUT
BOT+
372. To save power, the
TOUT
.
See
62