Atmel Evaluation Kit AT91SAM9G25-EK AT91SAM9G25-EK Data Sheet

Product codes
AT91SAM9G25-EK
Page of 1102
119
SAM9G25 [DATASHEET]
11032C–ATARM–25-Jan-13
Figure 14-8. Watchdog Reset 
14.4.5 Reset State Priorities
The Reset State Manager manages the following priorities between the different reset sources, given in descending
order:
z
Backup Reset
z
Wake-up Reset
z
User Reset
z
Watchdog Reset
z
Software Reset
Particular cases are listed below:
z
When in User Reset: 
z
A watchdog event is impossible because the Watchdog Timer is being reset by the proc_nreset signal. 
z
A software reset is impossible, since the processor reset is being activated. 
z
When in Software Reset: 
z
A watchdog event has priority over the current state.
z
The NRST has no effect. 
z
When in Watchdog Reset: 
z
The processor reset is active and so a Software Reset cannot be programmed.
z
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