ata6616 ATMEL Corporation, ata6616 Datasheet - Page 79

• Manufacturer Part Number: ata6616
• Description: Microcontroller With Lin Transceiver, 5v Regulator And Watchdog
• Manufacturer: ATMEL Corporation

9132A–AUTO–10/08
DRAFT
The following code example shows one assembly and one C function for turning off the Watch-
dog Timer. The example assumes that interrupts are controlled (e.g. by disabling interrupts
globally) so that no interrupts will occur during the execution of these functions.
Assembly Code Example
C Code Example
Notes:
WDT_off:
void WDT_off(void)
{
}
; Turn off global interrupt
cli
; Reset Watchdog Timer
wdr
; Clear WDRF in MCUSR
in
andi
out
; Write logical one to WDCE and WDE
; Keep old prescaler setting to prevent unintentional time-out
lds r16, WDTCR
ori
sts WDTCR, r16
; Turn off WDT
ldi
sts WDTCR, r16
; Turn on global interrupt
sei
ret
__disable_interrupt();
__watchdog_reset();
/* Clear WDRF in MCUSR */
MCUSR &= ~(1<<WDRF);
/* Write logical one to WDCE and WDE */
/* Keep old prescaler setting to prevent unintentional time-out */
WDTCR |= (1<<WDCE) | (1<<WDE);
/* Turn off WDT */
WDTCR = 0x00;
__enable_interrupt();
1. See
2. If the Watchdog is accidentally enabled, for example by a runaway pointer or brown-out con-
dition, the device will be reset and the Watchdog Timer will stay enabled. If the code is not
set up to handle the Watchdog, this might lead to an eternal loop of time-out resets. To
avoid this situation, the application software should always clear the Watchdog System
Reset Flag (WDRF) and the WDE control bit in the initialization routine, even if the Watch-
dog is not in use
r16, MCUSR
r16, (0xff & (0<<WDRF))
MCUSR, r16
r16, (1<<WDCE) | (1<<WDE)
r16, (0<<WDE)
Section 4.2.6 “About Code Examples” on page 31
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ATA6616/ATA6617 [Preliminary]
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