Sony AR-B1570 ユーザーズマニュアル

AR-B1570 User’s Guide 

27 

 

The watchdog timer is a circuit that maybe be used from your program software to detect crash or hang up. The 

       Watchdog timer is automatically disabled after reset. Once you enabled the watchdog timer, your program should 

trigger the watchdog timer every time before it times out. After you trigger the watchdog timer, the timer will be set 
to zero and start to count again. If your program fails to trigger the watchdog timer before times out, it will generate 
a reset pulse to reset the system or trigger the IRQ 9 signal in order to tell your system that the watchdog time is 
out. 

        Please refer to the following table in order to properly program Watchdog function 
 
 

D7  

   D6 

   D5   D4   D3   D2   D1   D0    

1   Enable   Reset 

0   Disable   IRQ 9 

               Time period 

 
       Users could test watchdog function under ‘Debug’ program as follows: 
         

C:>debug 

! 

O  214  C8H 

Generally, watchdog function would 
reset system after 8 seconds 

! 

O  214  0H 

                      Disable watchdog function 

 

                          

C:>debug 

! 

O  214  88H 

Generally, watchdog function would 
generate IRQ 9 after 8 seconds 

! 

O  214  0H 

                      Disable watchdog function 

 

       After you enable the watchdog timer, your program must write the same factor as triggering to the watchdog timer 

at least once during every time-out period. You can change the time-out period by writing another timer factor to 
the watchdog register at any time, and you must trigger the watchdog during every new time-out period in next 
trigger. 

 

C:>debug 

! 

O 214 CFH 

Generally, watchdog function would 
reset system after 15 seconds 
 

! 

O 214 40H 

                      Disable watchdog function 

       Trigger success.