Local Interconnect Network - Slave Node Position Detection (SNPD) Ie Autoaddressing - Bus Shunt Method (BSM) - BSM Auto-addressing Procedure

BSM Auto-addressing Procedure

At the start of the procedure no 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 I_offset

2 Pull-up Mode

2.1 Pull-ups are turned on and current sources remain off

2.2 The bus current is measured I_PU

2.3 Nodes with ΔI = I_PU-I_offset < 1mA 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 I_CS

3.3 Node with ΔI = I_CS-I_offset < 1mA is detected as the last node

3.4 Current sources are switched off and pull-ups are switched on

3.5 The last node will accept the address contained in the LIN configuration message

This technique is covered by the following patents:
EP 1490772 B1
US 7091876