The CHASSIS expansion is used to simulate some functions usally found in the Chassis domain of a car:
- Steering Wheel
- Parking Brake
Although not traditionally part of the Chassis domain, the lighting switch is also present on the Chassis domain, out of convenience.
The Steering wheel is simulated by a rotating potentiometer. A TVS diode is used for ESD protection, and a capacitor also protects the ECU input from chattering.
Schematic of the Steering wheel circuitry
The parking brake is simulated by a pulled-up sliding switch. A TVS diode is used for ESD protection.
Schematic of the Parking Brake circuitry
The lighting switch is simulated by a rotating switch from the NR01 series of NKK switches. A TVS diode is used for ESD protection. The rotation of the switch selects a point from a voltage divider , which is measured by an ADC on the ECU.
Schematic of the Lighting switch circuitry
Pinout of the CHASSIS expansion's connector