ATxmega256A3 Atmel Corporation, ATxmega256A3 Datasheet - Page 111

• Manufacturer Part Number: ATxmega256A3
• Manufacturer: Atmel Corporation

Specifications of ATxmega256A3

• Flash (kbytes): 256 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 50
• Ext Interrupts: 50
• Usb Speed: No
• Usb Interface: No
• Spi: 10
• Twi (i2c): 2
• Uart: 7
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 16
• Adc Resolution (bits): 12
• Adc Speed (ksps): 2000
• Analog Comparators: 4
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 16
• Eeprom (bytes): 4096
• 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: 7
• Output Compare Channels: 22
• Input Capture Channels: 22
• Pwm Channels: 22
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

10. Battery Backup System
10.1
10.2
Features
Overview
•
•
•
The Battery Backup System includes functionality that enables automatic power switching
between main power and a battery backup power.
of the system.
The Battery Backup Module supports connection of a backup battery to the dedicated V
power pin. This will ensure power to the 32-bit Real Time Counter, a 32.768 kHz crystal oscilla-
tor with failure detection monitor and two battery backup registers when the main power source
is unavailable.
Upon main power loss the device will detect this and automatically switch the Battery Backup
Module to be powered from the V
POR and BOR are released, the Battery Backup Module will automatically switch back to be
powered from main power again. The main BOD is used to detect the Vcc voltage levels, and
this must be enabled for the power switching to work.
The 32-bit Real Time Counter (RTC) must be clocked from the 1 Hz or 1.024 kHz output of a
32.768 kHz crystal oscillator connected between the TOSC1 and TOSC2 pins when running
from V
the XMEGA A Manual.
Battery Backup voltage supply from dedicated V
Automatic switching from main power to battery backup power at:
Automatic switching from battery backup power to main power:
– One Ultra Low-power 32-bit Real Time Counter
– One 32.768 kHz crystal oscillator with failure detection monitor
– Two Battery Backup Registers
– Brown-Out Detection (BOD)
– Device reset after Brown-Out Reset (BOR) is released
– Device reset after Power-On Reset (POR) and BOR is released
BAT
. For more details on the 32-bit RTC refer to the “32-bit Real Time Counter” section in
BAT
pin. After main power has been restored and both main
BAT
Figure 10-1 on page 112
power pin for:
shows an overview
BAT