Atmel AVR XMEGA D Series, Manual, Page: 98 / 331

98
8210C–AVR–09/11
Atmel AVR XMEGA D
• Bit 1 – ENABLE: Enable
This bit enables the WDT. Clearing this bit disables the watchdog timer.
In order to change this bit, the CEN bit in ”CTRL – Control register” on page 97 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 11 .
• Bit 0 – CEN: Change Enable
This bit enables the ability to change the configuration of the ”CTRL – Control register” on page
97 . 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 mecha-
nism. For a detailed description, refer to
”Configuration Change Protection” on page 11 .
9.7.2 WINCTRL – Window Mode Control register
• Bit 7:6 – Reserved
These bits are unused and reserved for future use. For compatibility with future devices, always
write these bits to zero when this register is written.
• Bit 5:2 – WPER[3:0]: Window Mode Timeout Period
These bits determine the closed window period as a number of 1kHz ULP oscillator cycles in
window mode operation. The typical different closed window periods are found in
Table 9-2 . 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.
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
Table 9-1. Watchdog timeout periods (Continued).
PER[3:0] Group Configuration Typical Timeout Periods
Bit 7 6 5 4 3 2 1 0
+0x01 – – WPER[3:0] WEN WCEN WINCTRL
Read/Write
(unlocked)
R R R/W R/W R/W R/W R/W R/W
Read/Write
(locked)
R R R R R R R/W R/W
Initial Value
(x = fuse)
0 0 X X X X X 0