Datasheet

WDP2 WDP1 WDP0 Number of WDT Oscillator

Cycles

Typical

Time-out at

= 3.0V

Typical

Time-out at

= 5.0V

1 0 0 256K (262,144) 0.27s 0.26s

1 0 1 512K (524,288) 0.55s 0.52s

1 1 0 1,024K (1,048,576) 1.1s 1.0s

1 1 1 2,048K (2,097,152) 2.2s 2.1s

The following code example shows one assembly and one C function for turning off the WDT. The

example assumes that interrupts are controlled (for example by disabling interrupts globally) so that no

interrupts will occur during execution of these functions.

Assembly Code Example

WDT_off:

; Reset WDT

wdr

in r16, WDTCR

ldi r16, (1<<WDCE)|(1<<WDE)

; Write logical one to WDCE and WDE

ori r16, (1<<WDCE)|(1<<WDE)

out WDTCR, r16

; Turn off WDT

ldi r16, (0<<WDE)

out WDTCR, r16

ret

C Code Example

void WDT_off(void)

{

/* Reset WDT*/

_WDRC();

/* Write logical one to WDCE and WDE */

WDTCR |= (1<<WDCE) | (1<<WDE);

/* Turn off WDT */

WDTCR = 0x00;

}

Atmel ATmega64A [DATASHEET]

Atmel-8160E-ATmega64A_Datasheet_Complete-09/2015