User guide

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3.3.4 <description> : Characteristic User Description element
The XML element is used to define a user description of the characteristic. This can be used to <description>
name a characteristic in a user friendly way. This information is exposed in the GATT database can be used to
populate user interfaces with user friendly strings.
Below some constant string examples:
Characteristic Description Example
<characteristic uuid="2a37">
<properties notify="true" />
<value length="2" />
<description>Heart Rate Measurement</description>
</characteristic>
Properties element can be used to allow remote modification of an attribute, for example to allow remote
reading but with bonding required for writing:
Characteristic Description Example
<characteristic uuid="2a37">
<properties notify="true" />
<value length="2" />
<description>
<properties read="true" write="true" authenticated_write="true" />
<value variable_length="true" length="20" />
</description>
</characteristic>
If a description is writable then the GATT Parser automatically adds the extended properties attribute
with bit set to be compliant. writable_auxiliaries Bluetooth
3.3.5 <aggregate> : Characteristic Aggregated Format Definition element
The XML element enables the creation of an aggregated characteristic format descriptor by <aggregate>
automatically converting ID's to attribute handles.
Attribute ID's should refer to characteristic presentation format descriptors.
Below an example how to add a characteristic aggregate:
Characteristic Aggregate Format Example
<characteristic uuid="da8a80c0-829d-498f-b70b-e85c95e0f839">
<properties notify="true" read="true"/>
<value length="10" />
<aggregate>
<attribute id="format1" />
<attribute id="format2" />
</aggregate>
</characteristic>
3.3.6 <descriptor> : Characteristic Descriptor Definition element
The XML element can be used to define a generic characteristic descriptor. <descriptor>