Multi-position switch for single digital I/O pin

A digital circuit for measuring a plurality of positions of a multi-position switch using a single digital input pin, comprising:

• a multi-position switch having at least three positions;
• a clock signal input to at least one position node of said multi-position switch, said clock signal being significantly other than a 50% duty cycle clock signal;
• and
• a digital input device having said single digital input pin in communication with a common node of said multi-position switch.

A digital circuit for measuring a plurality of positions of a multi-position switch using a single digital input pin, comprising:

• a multi-position switch having at least three positions;
• a clock signal input to at least one position node of said multi-position switch;
• a digital input device having said single digital input pin in communication with a common node of said multi-position switch;
• a second multi-position switch in series with said multi-position switch having at least three positions;
• and
• an inverter in communication with one position of said second multi-position switch, said inverter inverting a signal from said common node of said multi-position switch before input to said one position of said second multi-position switch.

A digital circuit for measuring a plurality of positions of a multi-position switch using a single digital input pin, comprising:

• a multi-position switch;
• a series resistor chain connected at one end to a power source, said series resistor chain forming a plurality of nodes each connected to a corresponding input position of said multi-position switch;
• a digital input device having said single digital input pin;
• and
• an RC network between a common node of said multi-position switch and said single digital input pin.

A method of determining a position of each of a plurality of multi-position switches, comprising:

• combining a first multi-position switch in series with a second multi-position switch;
• inputting an output of said second multi-position switch into a single digital input pin;
• and
• determining a position of said first multi-position switch and a position of said second multi-position switch by repeatedly sampling said single digital input pin.

A method of determining a position of a multi-position switch having at least three positions using a single digital input pin, comprising:

• inputting a clock signal to at least one input position of said multi-position switch;.
• inputting a signal other than said clock signal to another input position of said multi-position switch;
• and
• repeatedly sampling said single digital input pin to determine a presence of said clock signal.

Apparatus for determining a position of each of a plurality of multi-position switches, comprising:

• means for combining a first multi-position switch in series with a second multi-position switch;
• means for inputting an output of said second multi-position switch into a single digital input pin;
• and
• means for determining a position of said first multi-position switch and a position of said second multi-position switch by repeatedly sampling said single digital input pin.

Apparatus for determining a position of a multi-position switch having at least three positions using a single digital input pin, comprising:

• means for inputting a clock signal to at least one input position of said multi-position switch;
• means for inputting a signal other than said clock signal to another input position of said multi-position switch;
• and
• means for repeatedly sampling said single digital input pin to determine a presence of said clock signal.