Description of Operation
17-4
ADSP-BF537 Blackfin Processor Hardware Reference
To start the watchdog timer:
1. Set the count value for the watchdog timer by writing the count
value into the watchdog count register (
WDOG_CNT
). Since the
watchdog timer is not enabled yet, the write to the
WDOG_CNT
regis-
ters automatically pre-loads the
WDOG_STAT
register as well.
2. In the watchdog control register (
WDOG_CTL
), select the event to be
generated upon timeout.
3. Enable the watchdog timer in
WDOG_CTL
. The watchdog timer then
begins counting down, decrementing the value in the
WDOG_STAT
register.
If software does not serve the watchdog in time,
WDOG_STAT
continues dec-
rementing until it reaches 0. Then, the programmed event is generated.
The counter stops decrementing and remains at zero. Additionally, the
WDRO
latch bit in the
WDOG_CTL
register is set and can be interrogated by
software in case event generation is not enabled.
When the watchdog is programmed to generate a reset, it resets the pro-
cessor core and peripherals. If the
NOBOOT
bit in the
SYSCR
register was set
by the time the watchdog reset the part, the chip is not rebooted. This is
recommended behavior in slave boot configurations. The reset handler
may evaluate the
RESET_WDOG
bit in the software reset register
SWRST
to
detect a reset caused by the watchdog. For details, see
To prevent the watchdog from expiring, software serves the watchdog by
performing dummy writes to the
WDOG_STAT
register address in time. The
values written are ignored, but the write commands cause the
WDOG_STAT
register to be reloaded from the
WDOG_CNT
register.
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...