21.5.1 Control A

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

Bit 76543210 
 WINDOW[3:0]PERIOD[3:0] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset xxxxxxxx 

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.
ValueNameDescription
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.
ValueNameDescription
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