21.5.1 Control A

Name:	CTRLA
Offset:	0x00
Reset:	From FUSE.WDTCFG
Property:	Configuration Change Protection


Bit	7	6	5	4	3	2	1	0
	WINDOW[3:0]				PERIOD[3:0]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	x	x	x	x	x	x	x	x

Bits 7:4 – WINDOW[3:0] Window

Writing a non-zero value to these bits enables the Window mode and selects the duration of the closed period accordingly.

The bits are optionally lock-protected:

If the LOCK bit in WDT.STATUS is ‘1’, all bits are change-protected (Access = R)
If the LOCK bit in WDT.STATUS is ‘0’, all bits can be changed (Access = R/W)

Note: Refer to the Electrical Characteristics section for specific information regarding the 32.768 kHz Ultra-Low Power Oscillator (OSC32K) accuracy.

Value	Name	Description
0x0	OFF	-
0x1	8CLK	7.8125 ms
0x2	16CLK	15.625 ms
0x3	32CLK	31.25 ms
0x4	64CLK	62.5 ms
0x5	128CLK	0.125s
0x6	256CLK	0.250s
0x7	512CLK	0.500s
0x8	1KCLK	1.0s
0x9	2KCLK	2.0s
0xA	4KCLK	4.0s
0xB	8KCLK	8.0s
Other	-	Reserved

Bits 3:0 – PERIOD[3:0] Period

Writing a non-zero value to this bit enables the WDT and selects the time-out period in the Normal mode accordingly. In the Window mode, these bits select the duration of the open window.

The bits are optionally lock-protected:

If the LOCK bit in WDT.STATUS is ‘1’, all bits are change-protected (Access = R)
If the LOCK bit in WDT.STATUS is ‘0’, all bits can be changed (Access = R/W)

Note: Refer to the Electrical Characteristics section for specific information regarding the 32.768 kHz Ultra-Low Power Oscillator (OSC32K) accuracy.

Value	Name	Description
0x0	OFF	-
0x1	8CLK	7.8125 ms
0x2	16CLK	15.625 ms
0x3	32CLK	31.25 ms
0x4	64CLK	62.5 ms
0x5	128CLK	0.125s
0x6	256CLK	0.250s
0x7	512CLK	0.500s
0x8	1KCLK	1.0s
0x9	2KCLK	2.0s
0xA	4KCLK	4.0s
0xB	8KCLK	8.0s
Other	-	Reserved