ATxmega64A4U Atmel Corporation, ATxmega64A4U Datasheet - Page 119

• Manufacturer Part Number: ATxmega64A4U
• Manufacturer: Atmel Corporation

Specifications of ATxmega64A4U

• Flash (kbytes): 64 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 34
• Ext Interrupts: 34
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Twi (i2c): 2
• Uart: 5
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 12
• Adc Speed (ksps): 2000
• Analog Comparators: 2
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 4
• Eeprom (bytes): 2048
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.6 to 3.6
• Operating Voltage (vcc): 1.6 to 3.6
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 5
• Output Compare Channels: 16
• Input Capture Channels: 16
• Pwm Channels: 16
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

10. Battery Backup System
10.1
10.2
8331A–AVR–07/11
Features
Overview
•
•
•
Many applications require a real-time clock that keeps running continuously, even in the event of
a main power loss or failure. The battery backup system includes functions for this through auto-
matic power switching between main power and a battery backup power supply. No external
components are required.
On devices with a battery backup system, a backup battery can be connected to the dedicated
V
time counter (RTC), a 32.768kHz crystal oscillator with failure detection monitor, and two backup
registers. The battery backup system does not provide power to other parts of the volatile mem-
ory in the device, such as SRAM and I/O registers outside the system.
The device uses its BOD to detect main power loss and switch to power from the V
main power is restored, the battery back system will automatically switch back to being powered
from the main power again. The backup battery is drained only when main power is not present,
and this ensures maximum battery life.
On devices with the battery backup system, the RTC will keep running in all sleep modes.
BAT
Integrated battery backup system ensuring continuos, real-time clock during main power failure
Battery backup power supply from dedicated V
Automatic power switching between main power and battery backup power:
– One 32-bit real-time counter
– One ultra low power 32.768kHz crystal oscillator with failure detection monitor
– Two battery backup registers
– Switching from main power to battery backup power at main power loss
– Switching from battery backup power to main power at main power return
power pin. If the main power is lost, the backup battery will continue and power the real-
Figure 10-1 on page 120
BAT
pin to power:
Atmel AVR XMEGA AU
shows an overview of the system.
BAT
pin. After
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