Datasheet

Bit 3 – WDE: Watchdog System Reset Enable

WDE is overridden by WDRF in MCUSR. This means that WDE is always set when WDRF is set. To

clear WDE, WDRF must be cleared first. This feature ensures multiple resets during conditions causing

failure, and a safe startup after the failure.

Bits 2:0 – WDP[2:0]: Watchdog Timer Prescaler 2, 1, and 0

The WDP[3:0] bits determine the Watchdog Timer prescaling when the Watchdog Timer is running. The

different prescaling values and their corresponding timeout periods are shown in the following table.

Table 11-2. Watchdog Timer Prescale Select

WDP[3] WDP[2] WDP[1] WDP[0] Number of WDT Oscillator (Cycles) Oscillator

0 0 0 0 2K (2048) 16ms

0 0 0 1 4K (4096) 32ms

0 0 1 0 8K (8192) 64ms

0 0 1 1 16K (16384) 0.125s

0 1 0 0 32K (32768) 0.25s

0 1 0 1 64K (65536) 0.5s

0 1 1 0 128K (131072) 1.0s

0 1 1 1 256K (262144) 2.0s

1 0 0 0 512K (524288) 4.0s

1 0 0 1 1024K (1048576) 8.0s

1 0 1 0 Reserved

1 0 1 1

1 1 0 0

1 1 0 1

1 1 1 0

1 1 1 1

Atmel ATmega16M1/32M1/64M1 [DATASHEET]

Atmel-8209F-ATmega16M1/32M1/64M1_Datasheet_Complete-10/2016