ATXMEGA256A3-MU Atmel, ATXMEGA256A3-MU Datasheet - Page 24

• Manufacturer Part Number: ATXMEGA256A3-MU
• Description: 8-bit Microcontrollers - MCU 8/16 bit 1.6V-3.6V 256KB + 8KB
• Manufacturer: Atmel

Specifications of ATXMEGA256A3-MU

• Product Category: 8-bit Microcontrollers - MCU
• Rohs: yes
• Core: AVR
• Data Bus Width: 8 bit/16 bit
• Maximum Clock Frequency: 32 MHz
• Program Memory Size: 256 KB
• Data Ram Size: 16 KB
• On-chip Adc: Yes
• Package / Case: QFN EP
• Mounting Style: SMD/SMT
• A/d Bit Size: 12 bit
• A/d Channels Available: 8
• Data Rom Size: 4 KB
• Interface Type: I2C, SPI, USART
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 50
• Number Of Timers: 7
• Processor Series: ATXMega
• Program Memory Type: Flash
• Factory Pack Quantity: 260
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 1.6 V

12.3.6
13. WDT - Watchdog Timer
13.1
13.2
8068T–AVR–12/10
Features
Overview
Software reset
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 A3 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 A3
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