SNPD node input D1 is either set to GND or connected to the output of the master. The output of the first node, D2, is connected to the input, D1 of the second node, and so on resulting in a daisy chain. Each configuration pin Dx (x=1-2) has additional circuitry to aid in the position detection. Switchable resistive pull-up to Vbat Pull-down to GND Comparator referenced to Vbat/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 (D2) 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 D1 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 D2 2 Subsequent auto-addressing LIN messages 2.1 The first non addressed SNPD node is selected. It is identified by having the input D1 low (D2 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 D2 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 Bus shunt method (BSM) Each slave node has two LIN pins bus_in bus_out Each slave node needs some additional circuitry compared to the standard LIN circuitry to aid in the position detection. The standard pull-up must be switchable Switchable 2 mA current source from Vbat Shunt resistor Differential amplifier Analog to digital converter BSM auto-addressing procedure At the start of the procedure, none of the SNPD devices have a NAD assigned. The autoaddressing routine is performed during the sync field. The sync field is broken into three phases: 1 Offset current measurement 1.1 All outputs pull-ups and current sources are switched off 1.2 The bus current is measured, Ioffset 2 Pull-up mode 2.1 Pull-ups are turned on and current sources remain off 2.2 The bus current is measured, IPU 2.3 Nodes with ΔI = IPU-Ioffset < 1 mA are "selected" 3 Current source mode 3.1 Selected nodes switch current source on and others switch pull-ups off 3.2 Bus current is measured, ICS 3.3 Node with ΔI = ICS-Ioffset < 1 mA is detected as the last node 3.4 Current