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If the watchdog function is enabled, the time-out period is immediately reset so that
the new value can take effect. An error (EINVAL) is displayed if the timeout period
is less than 1 second or longer than 180 minutes.
Note – The LOMIOCDOGTIME is not intended for general-purpose use. Setting the
watchdog time-out to too low a value might cause the system to receive a hardware
reset if the watchdog and reset functions are enabled. If the timeout is set too low,
the user application must be run with a higher priority (for example, as a real-time
thread) and must be rearmed more often to avoid an unintentional expiration.
Enabling or Disabling the Watchdog
The LOMIOCDOGCTL IOCTL enables or disables the watchdog, and it enables or
disables the reset capability. See
"Finding and Defining Data Structures" on page 80
for the correct values for the watchdog timer.
The argument is a pointer to the lom_dogctl_t structure. This structure is
described in greater detail in
"Finding and Defining Data Structures" on page
80.
Use the reset_enable member to enable or disable the system reset function. Use
the dog_enable member to enable or disable the watchdog function. An error
(EINVAL) is displayed if the watchdog is disabled but reset is enabled.
Note – If LOMIOCDOGTIME has not been issued to set up the timeout period prior
to this IOCTL, the watchdog is not enabled in the hardware.
Rearming the Watchdog
The LOMIOCDOGPAT IOCTL rearms, or pats, the watchdog so that the watchdog
starts ticking from the beginning; that is, to the value specified by
LOMIOCDOGTIME. This IOCTL requires no arguments. If the watchdog is enabled,
this IOCTL must be used at regular intervals that are less than the watchdog
timeout, or the watchdog expires.
Appendix A
Watchdog Timer Application Mode
79
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