ATxmega32A4 Atmel Corporation, ATxmega32A4 Datasheet - Page 24

• Manufacturer Part Number: ATxmega32A4
• Manufacturer: Atmel Corporation

Specifications of ATxmega32A4

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 34
• Ext Interrupts: 34
• Usb Speed: No
• Usb Interface: No
• 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): 4
• Eeprom (bytes): 1024
• 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

12.3.5
12.3.6
13. WDT - Watchdog Timer
13.1
13.2
8069Q–AVR–12/10
Features
Overview
PDI reset
Software reset
The MCU can be reset through the Program and Debug Interface (PDI).
The MCU can be reset by the CPU writing to a special I/O register through a timed sequence.
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The XMEGA A4 has a Watchdog Timer (WDT). The WDT will run continuously when turned on
and if the Watchdog Timer is not reset within a software configurable time-out period, the micro-
controller will be reset. The Watchdog Reset (WDR) instruction must be run by software to reset
the WDT, and prevent microcontroller reset.
The WDT has a Window mode. In this mode the WDR instruction must be run within a specified
period called a window. Application software can set the minimum and maximum limits for this
window. If the WDR instruction is not executed inside the window limits, the microcontroller will
be reset.
A protection mechanism using a timed write sequence is implemented in order to prevent
unwanted enabling, disabling or change of WDT settings.
For maximum safety, the WDT also has an Always-on mode. This mode is enabled by program-
ming a fuse. In Always-on mode, application software can not disable the WDT.
11 selectable timeout periods, from 8 ms to 8s.
Two operation modes
Runs from the 1 kHz output of the 32 kHz Ultra Low Power oscillator
Configuration lock to prevent unwanted changes
– Standard mode
– Window mode
XMEGA A4
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