Atmel Evaluation Kit AT91SAM9X25-EK AT91SAM9X25-EK Data Sheet

112

SAM9X25 [DATASHEET]

11054E–ATARM–10-Mar-2014

The Reset State Manager manages the following priorities between the different reset sources, given in descending 
order:



Backup Reset



Wake-up Reset



User Reset



Watchdog Reset



Software Reset

Particular cases are listed below:



When in User Reset: 



A watchdog event is impossible because the Watchdog Timer is being reset by the proc_nreset signal. 



A software reset is impossible, since the processor reset is being activated. 



When in Software Reset: 



A watchdog event has priority over the current state.



The NRST has no effect. 



When in Watchdog Reset: 



The processor reset is active and so a Software Reset cannot be programmed.



A User Reset cannot be entered. 

Only if 

WDRPROC = 0

SLCK

periph_nreset

proc_nreset

wd_fault

NRST

(nrst_out)

EXTERNAL RESET LENGTH

8 cycles (ERSTL=2)

MCK

Processor Startup 

= 3 cycles

Any

Freq.

RSTTYP

Any

XXX

0x2 = Watchdog Reset