All the stuff in the steering column
There’s a lot of logic hard-coded into the switches. Logic that has to be decoded to determine the actual position of the switch.
Summary of I/O
|Ignition Switch (D)||30↑ logic common high||15↑ and 50|
|Indicator Stalk (E2 E3 E4 E19)
with Emergency Flash (K6)
|30↑ supplies power to K6
56 and P tied as logic input
|49a (sinks flashing).
49↑, 56a, 56b, PL and PR
|Cruise Control||4 as logic input (high)||1, 2 and 3|
|Wash/Wipe and Horn (E22 H)||53a logic common (high).
71↑ to battery
|31↑, 53b, 53, J, H and T|
|MFA Function and Memory Select (E86 E109)||1 logic input (high)||2, 3 and 4|
Inputs marked ↑ must remain high, even when the node goes to sleep to conserve the battery. Outputs marked ↑ will cause the node to wake up from sleep mode, in addition to other events.
The slave node will go to sleep when told to do so by the LINbus master.
The slave node controller will be able to manage with just one (1) switched output as a logic input for switch sensing and one (1) output for driving the flashing emergency indicator lamp in the steering column. A total of 20 logic inputs are required to resolve all possible switch positions.
Anti-theft immobilization can be implemented by blocking the starting of the engine by not setting the state of terminal 50 to on in the device status, preventing a start of the engine by key; and by setting the immobilizer block status bit. The latter can be used to flash an idiot light in the dashboard, showng that starting was blocked by the immobilizer.