watchdog - monitor multiple inputs for a "heartbeat"
loadrt watchdog num_inputs=N
You must specify the number of inputs, from 1 to 32. Each input
has a separate timeout value.
- process
- Check all input pins for transitions, clear the ok-out pin if any
input has no transition within its timeout period. This function does not
use floating point, and should be added to a fast thread.
- set-timeouts
- Check for timeout changes, and convert the float timeout inputs to int
values that can be used in process. This function also monitors
enable-in for false to true transitions, and re-enables monitoring
when such a transition is detected. This function does use floating point,
and it is appropriate to add it to the servo thread.
- watchdog.input-n
bit in
- Input number n. The inputs are numbered from 0 to
num_inputs-1.
- watchdog.enable-in
bit in (default: FALSE)
- If TRUE, forces out-ok to be false. Additionally, if a timeout occurs on
any input, this pin must be set FALSE and TRUE again to re-start the
monitoring of input pins.
- watchdog.ok-out
bit out (default: FALSE)
- OK output. This pin is true only if enable-in is TRUE and no timeout has
been detected. This output can be connected to the enable input of a
charge_pump or stepgen (in v mode), to provide a heartbeat
signal to external monitoring hardware.
- watchdog.timeout-n float in
- Timeout value for input number n. The inputs are numbered from 0 to
num_inputs-1. The timeout is in seconds, and may not be below zero.
Note that a timeout of 0.0 will likely prevent ok-out from ever
becoming true. Also note that excessively long timeouts are relatively
useless for monitoring purposes.