132
8331B–AVR–03/12
Atmel AVR XMEGA AU
The initial values of these bits are set by the watchdog window timeout period (WDWP) fuses,
and are loaded at power-on. In normal mode these bits are not in use.
In order to change these bits, the WCEN bit must be written to one at the same time. These bits
are protected by the configuration change protection mechanism. For a detailed description,
refer to
”Configuration Change Protection” on page 13
Note:
Reserved settings will not give any timeout for the window.
• Bit 1 – WEN: Window Mode Enable
This bit enables the window mode. In order to change this bit, the WCEN bit in
Window Mode Control register” on page 131
must be written to one at the same time. This bit is
protected by the configuration change protection mechanism. For a detailed description, refer to
”Configuration Change Protection” on page 13
.
• Bit 0 – WCEN: Window Mode Change Enable
This bit enables the ability to change the configuration of the
”WINCTRL – Window Mode Control
. When writing a new value to this register, this bit must be written to one at
the same time for the changes to take effect. This bit is protected by the configuration change
protection mechanism, but not protected by the WDT lock fuse.
Table 11-2.
Watchdog closed window periods
WPER[3:0]
Group Configuration
Typical Closed Window Periods
0000
8CLK
8ms
0001
16CLK
16ms
0010
32CLK
32ms
0011
64CLK
64ms
0100
128CLK
0.128s
0101
256CLK
0.256s
0110
512CLK
0.512s
0111
1KCLK
1.0s
1000
2KCLK
2.0s
1001
4KCLK
4.0s
1010
8KCLK
8.0s
1011
Reserved
1100
Reserved
1101
Reserved
1110
Reserved
1111
Reserved