Digital simulator commands

   1.  The following additional ":" commands are available with the
       Digital LOG simulator.  Except for STABILIZE they may be used
       in "log.cnf" files by preceding them with the word "16:", as
       in "16: stabdelay 2.5".

       DIGON      Turn digital simulation ON.  This is the normal case.

       DIGOFF     Turn digital simulation OFF.  This command is similar
                  the regular OFF command, except only the digital
                  simulator is affected.  If several simulators are
                  being run at once (say, digital and analog), the
                  other simulators will proceed unaffected.

                  Turn digital simulation ON or OFF.

       STABDELAY time
                  Set amount of time to wait for circuit stabilization
                  (see STABILIZE) to "time" seconds.  Default is 5.0.
                  With no argument, the command shows the current value.

       STABILIZE  Attempt to stabilize an oscillating circuit.  Because
                  all digital gates have identical, exact propagation
                  delays, oscillations can develop in feedback circuits
                  that would never arise in a real circuit, where the
                  propagation delays are not so exactly balanced.  The
                  STABILIZE command randomizes the propagation delays of
                  gates in order to kill such oscillations.  Of course,
                  a circuit that really is oscillating will continue
                  to do so.  The "stabilization" effect wears off after
                  about five seconds, usually plenty of time.

       DIGSTEP time-step
                  Set the amount of simulated time per digital timestep.
                  Since every digital time step is the same, this value
                  normally does matter unless you are using the digital
                  simulator along with another simulator which has a more
                  concrete idea of time (such as AnaLOG).  The default
                  value is "10ns", i.e., 1E-8 seconds.  The value may
                  be specified in engineering or real-number notation.
                  With no argument, the command shows the current value.

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