Interrogating circuitry ascertaining switch positions in motor vehicle - connects switch terminals to fixed potential and to microcomputer via resistors

摘要

A microcomputer (1) connects one terminal of each switch to a fixed potential and the other to a microcomputer input and to a resistor. The resistors (10,11,18,19) can be connected to a potential different from the fixed potential via switches (12,20) controlled by the microcomputer. The microcomputer holds the switches in the conducting state at least for the duration of the interrogation of the inputs. ADVANTAGE - High noise separation and low leakage resistor effects despite low power losses.