Specifications

8. SNAP Node Configuration Parameters
You make your SNAP nodes do completely new things by loading SNAPpy scripts into them. You can
often adjust the way they do the things that are already built-in
by adjusting one or more Configuration
Parameters.
These Configuration Parameters are stored in a section of Non-Volatile (NV) memory within the
SNAP node. For this reason Configuration Parameters are also referred to as NV Parameters.
SNAPpy scripts can access these NV Parameters by using the loadNvParam(id) function. SNAPpy
scripts can change these parameters by using the saveNvParam() function (and then rebooting so that
the changes will take effect).
When using the loadNvParam() and saveNvParam() functions, you must specify which NV Parameter
by numeric ID.
You can also easily view and edit these parameters using Portal. Refer to the Portal Reference
Manual. When you view and edit these parameters from Portal, you do not need to know the NV
Parameter ID. Portal takes care of that for you.
Some of the NV Parameters control the functionality of your nodes at a very fundamental level.
Making careless changes to these parameters can cause you to lose access to your nodes, either over
the air, over a serial connection, or both. If you find you are unable to make any connection to a node,
you will be able to return the node to your control through the Factory Default NV Params... option in
Portal. (It may first be necessary to use the Erase SNAPpy Image... option in Portal, if the image
loaded into the node is setting NV Parameters.)
Here are all of the System (Reserved) NV Parameters (sorted by numeric ID), and what they do.
NOTE – You can also define your own NV Parameters (in the range 128-254) which your script can
access and modify, just like the system ones.
Remember – you must reboot a node after changing any system NV Parameter for the change to
actually take effect.
ID 0 – Reserved for Synapse Use
0 means “erased” inside the actual NV storage.
ID 1 – Reserved for Synapse Use
used to support a NV page-swapping scheme internally.
ID 2 – MAC Address
The eight byte address of the SNAP Node. This parameter is not modified when you reset parameters
to factory defaults.
Page 92 of 202 SNAP Reference Manual Document Number 600-0007K