Rainbow Electronics AT91CAP9S250A - Manual (Page 113)

113
6264A–CAP–21-May-07
AT91CAP9S500A/AT91CAP9S250A
18. Watchdog Timer (WDT)
18.1 Description
The Watchdog Timer can be used to prevent system lock-up if the software becomes trapped in
a deadlock. It features a 12-bit down counter that allows a watchdog period of up to 16 seconds
(slow clock at 32.768 kHz). It can generate a general reset or a processor reset only. In addition,
it can be stopped while the processor is in debug mode or idle mode.
18.2 Block Diagram
Figure 18-1. Watchdog Timer Block Diagram
= 0
1 0
set
reset read WDT_SR
or
reset
wdt_fault
(to Reset Controller)
set
reset
WDFIEN
wdt_int
WDT_MR
SLCK 1/128
12-bit Down
Counter
Current
Value
WDD
WDT_MR
<= WDD
WDV
WDRSTT
WDT_MR
WDT_CR
reload
WDUNF
WDERR
reload
write WDT_MR
WDT_MR
WDRSTEN