[evla-sw-discuss] Re: A MIB Requirement

[Wayne Koski]

I think we should be very causious in this.  We have a situation here
of power-on conditions which can be complex.  So here is my take on it.

1.  The MIB and Device at power-on will have a reset applied to them.

    Note that the above resets could be produced by the same reset
    device or different devices.  We have not imposed a coordinated
    reset requirement.  Thus the problem is different reset periods for
    the MIB and Device.

2.  For the Device, its reset must place it into a SAFE mode of
    operation.  It shouldn't harm itself or other Devices it may be
    connected too.

    This immediately protects the hardware, and the MIB can actually
    not be connected or the MIB can be in a failed state.  In other
    words the Device should enter a SAFE mode of operation, with or
    without the presence of the MIB. I think this is what Kevin was
    trying in part to get across.

3.  After the MIB resets, it can then load parameters, etc. in order
    to place the Device into an INTIALIZED mode of operation.

    Obviously the INITIALIZED mode show also not cause damage to the
    Device or any Devices connected to it.

4.  A contentious possibility:  Once a particular module has been
    INITIALIZED or in an OPERATIONAL mode, the MIB might signal a
    downstream Device that it is safe to apply signals from the
    upstream device. A method to use intermodule communications as
    an additional layer of protection.

Example:  The 1st LO Synthesizer is set to a value and the output
          power is determined to be in range.  The Synthesizer could
          then signal the RF/LO/IF switch that the level could now
          be applied to the Front-end, etc.

Just remember, I view the above as an additional layer of protection.
Expensive items should be protected via hardware as much as possible.

-wayne-