ATxmega128A4U Atmel Corporation, ATxmega128A4U Datasheet - Page 120

• Manufacturer Part Number: ATxmega128A4U
• Manufacturer: Atmel Corporation

Specifications of ATxmega128A4U

• Flash (kbytes): 128 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: 7
• 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): 8
• 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

10.3
10.3.1
10.3.2
8331A–AVR–07/11
Battery Backup System
Power Supervisor
Power Switch
The battery backup system consists of a V
lator with failure monitor, a 32-bit real-time counter (RTC), and two backup registers.
Figure 10-1. Battery backup system and its power domain implementation.
The power supervisor monitors the voltage on the V
The power-on detection (BBPOD) function detects when power is applied to the V
when the backup battery is inserted. When this happens the battery backup power-on detection
flag (BBPODF) is set and the power switch is disconnected to prevent the backup battery from
being drained before the device is configured.
The brown-out detection (BBBOD) function monitors the V
powered from the V
backup bod flag (BBBODF) is set. The BBBOD samples the V
rate, and is designed for detecting slow voltage changes. The BBBOD is turned off when the
device runs from the main power.
The power detection (BBPWR) function controls the V
present on the V
battery is not present or has been drained. BBPODF, BBBODF, and the BBPWR flag are later
referred to as the power supervision flags.
The power switch switches between main power and the V
happens automatically, and is controlled from the main BOD in the device.
TOSC1
TOSC2
VBAT
supervisor
BAT
power
V
BAT
Oscillator
Registers
monitor
Backup
Failure
Crystal
pin, the battery backup power flag will be set. This indicates that the backup
BAT
RTC
pin. If the V
Power
switch
BAT
voltage drops below a threshold voltage, the battery
BAT
power supervisor, a power switch, a crystal oscil-
Programming
Watchdog w/
Atmel AVR XMEGA AU
Internal
BAT
Ooscillator
Interface
RAM
OCD &
BAT
pin. It performs three main functions:
Peripherals
voltage after a reset. If no voltage is
BAT
BAT
&
BAT
voltage level when the system is
CPU
EEPROM
& Fuses
FLASH,
pin to power the system. This
supervision
Oscillator &
voltage level at around a 1Hz
controller
power
sleep
Main
BAT
XTAL1
XTAL2
VDD
pin, i.e.,
GPIO
120