NAME

       watchdog - monitor multiple inputs for a "heartbeat"

SYNOPSIS

       loadrt watchdog num_inputs=N

       You  must  specify  the number of inputs, from 1 to 32.  Each input has a separate timeout
       value.

FUNCTIONS

       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.

PINS

       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.

PARAMETERS

       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.

LICENSE

       GPL