ATMEGA48V_11 ATMEL [ATMEL Corporation], ATMEGA48V_11 Datasheet - Page 50

• Manufacturer Part Number: ATMEGA48V_11
• Description: 8-bit Atmel Microcontroller with 4/8/16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

2545T–AVR–05/11
The watchdog always on (WDTON) fuse, if programmed, will force the watchdog timer to system
reset mode. With the fuse programmed the system reset mode bit (WDE) and Interrupt mode bit
(WDIE) are locked to 1 and 0 respectively. To further ensure program security, alterations to the
Watchdog setup must follow timed sequences. The sequence for clearing WDE and changing
time-out configuration is as follows:
1. In the same operation, write a logic one to the watchdog change enable bit (WDCE) and
2. Within the next four clock cycles, write the WDE and watchdog prescaler bits (WDP) as
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 (for example by disabling
interrupts globally) so that no interrupts will occur during the execution of these functions.
WDE. A logic one must be written to WDE regardless of the previous value of the WDE
bit.
desired, but with the WDCE bit cleared. This must be done in one operation.
ATmega48/88/168
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