Installation guide

Block Parameters
Working Values Before Applying
Preset
Working Values After Applying Pre-
setB
Off @ Min Not Checked Not Checked
Mute Checked Not Checked
In essence, when working with presets, simply remember that the working values of a system block always
reflect the values found in the most recently applied preset that contains that block. If no preset has affected
a specific block, that block continues to reflect its original (or default) values.
Are there different ways of controlling presets? If so, what are the different control types? Which
approach should I use?
There are three preset control types—Toggle, Selector, and Command. Regardless of its control type, each pre-
set accomplishes the same thing—it overwrites the system's current working values with its stored values. So
why are there different control types? The primary reason is to provide flexibility in how you and your end
users can control the preset. The control type you choose determines some of the preset's characteristics,
which in turn affects control of the preset.
For a better understanding of the three preset control types, review the sections below:
Asserting Versus Activating/Deactivating a Preset
One of the first things to understand and one of the first things to decide when creating HAL System
presets is whether you want to assert Command presets or activate and deactivate Toggle and/or Selec-
tor presets. The difference between these two approaches is really quite simple. Whereas you can turn
Toggle and Selector presets on (activate) and off (deactivate), you can only turn Command presets on
(assert).
NOTE FOR DRAG NET USERS: Asserting a Command preset is the same as recalling a Dragnet pre-
set.
Whether you assert a Command preset or activate a Toggle/Selector preset, the system does the same
thing. It places that preset at the top of the Active Presets list
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—which means its parameter values over-
write the current working values for the corresponding system parameters. When you deactivate a Tog-
gle/Selector preset, the system removes it from the Active Presets list. You cannot, however, remove or
un-assert a Command preset. The Command preset remains at the top of the list until you assert another
Command preset or activate a Toggle or Selector preset, which is then placed above it in the list. But
even though the original Command preset drops in the priority list, it is still active. The working values
changed by the Command preset remain the same until another preset changes them.
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A dynamic list of active presets maintained by the system that changes as presets are asserted, activated, and deac-
tivated. The presets are listed in priority order. When a preset is asserted or activated, it goes to the top of the list
and its parameter values overlay the current working values for the corresponding system parameters. When a pre-
set is deactivated it is removed from the list.
HAL SYSTEM DESIGN GUIDE
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