Electrical device command system, single wire bus and smart octal controller arrangement therefor

摘要

A multiplex system for addressing, commanding and monitoring the status of a plurality of electrical devices disposed throughout a motor vehicle. A dual-duty cycle type voltage waveform generated by a microcomputer provides address signals for enabling four individual controllers connected to a bi-directional single wire bus coupled at one end to a driver and receiver circuit of the microcomputer. After the individual controller is addressed, another portion of the waveform provides information for operating one of the eight electrical devices connected thereto in response to a polarity control data bit portion of the same voltage signal to turn the connected element either ON or OFF. Circuits within the addressed controller provides current signal indicative of the ON or OFF status of the electrical device.