Hvac controller having multiplexed input signal detection and method of operation thereof

A method of detecting multiplexed input signals, comprising:

• converting received AC input signals into corresponding square wave signals of a digital logic voltage;
• selecting one of the square wave signals;
• and
• evaluating multiple samples of the selected one of the square wave signals to derive a binary state.

A heating, ventilation, and air conditioning (HVAC) system, comprising:

• a compressor;
• a furnace;
• a blower;
• and
• a controller associated with the compressor, the furnace and the blower, the controller having:
• a signal conditioner configured to convert alternating current (AC) input signals into corresponding square wave signals of a digital logic voltage;
• a multiplexer configured to select one of the square wave signals;
• a sample analyzer configured to evaluate multiple samples of the selected one of the square wave signals to derive a binary state;
• wherein the sample analyzer is configured to employ a clock signal to sample the selected one of the square wave signals;
• wherein the sample analyzer is configured to determine a total number of assertions of the selected one of the square wave signals occurring during a window of time;
• and
• responsive to a determination that the total number of assertions of the selected one of the square wave signals reaches a threshold number of assertions during the window of time, the derived binary state is assumed to be one.