Editing Local Interconnect Network (section)

=== Extra wire daisy chain (XWDC) ===
Each slave node has to provide two extra pins, one input, D<sub>1</sub>, and one output, D<sub>2</sub>.
* The first SNPD node input D1 is either set to GND or connected to the output of the master.
** The output of the first node, D<sub>2</sub>, is connected to the input, D<sub>1</sub> of the second node, and so on resulting in a daisy chain.

Each configuration pin D<sub>x</sub> (x=1-2) has additional circuitry to aid in the position detection.
# Switchable resistive pull-up to V<sub>bat</sub>
# Pull-down to GND
# Comparator referenced to V<sub>bat</sub>/2

==== XWDC auto-addressing procedure ====
At the start of the procedure no SNPD devices have a NAD assigned

1 First auto-addressing LIN message
:1.1 All outputs (D<sub>2</sub>) are set to a high level, all pull-downs are turned off
:1.2 The first SNPD node is selected. It is identified by having the input D<sub>1</sub> low (hardwired).
:1.3 The selected node takes the address from the LIN configuration message
:1.4 The detected node turns on the pull-down at the output D<sub>2</sub>
2 Subsequent auto-addressing LIN messages
:2.1 The first non addressed SNPD node is selected. It is identified by having the input D<sub>1</sub> low (D<sub>2</sub> of previous node).
:2.2 The selected node takes the address from the LIN configuration message
:2.3 The detected node turns on the pull-down at the output D<sub>2</sub>
:2.4 Steps 2.1-2.4 are repeated until all slave nodes are assigned an address
3 All pull-ups and pull-downs are turned off completing the addressing procedure