HVAC controller having keypad input and method of operation thereof

Patent metadata

Field	Value
Publication number	US-9933179-B2
Application number	US-201514692335-A
Country	US
Kind code	B2
Filing date	Apr 21, 2015
Priority date	May 19, 2014
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

A heating, ventilation and air conditioning (HVAC) controller, a method of receiving signals from a keypad and an HVAC system incorporating the controller or the method. In one embodiment, the HVAC controller includes: (1) a keypad having at least first and second banks, (2) a reference signal source configured to generate a time-varying untransformed reference signal and provide the untransformed reference signal to the first bank, (3) transformation circuitry configured to transform the untransformed reference signal into a transformed reference signal and provide the transformed reference signal to the second bank and (4) a processor having interrupt pins coupled to corresponding keys of both the first and second banks and a further interrupt pin coupled to receive one of the untransformed and transformed reference signal.

First claim

What is claimed is:

1. An HVAC controller, comprising:
a keypad having at least first and second banks;
a reference signal source configured to generate a time-varying untransformed reference signal and provide said untransformed reference signal to said first bank;
transformation circuitry configured to transform said untransformed reference signal into a transformed reference signal and provide said transformed reference signal to said second bank;
a processor having interrupt pins coupled to corresponding keys of both said first and second banks and a further interrupt pin coupled to an output of the transformation circuitry to receive one of said untransformed and transformed reference signal;
wherein said processor is further configured to:
respond to an interrupt by determining whether a signal on at least one interrupt pin of said interrupt pins differs from a signal on said further interrupt pin;
responsive to a determination that said signal on said at least one interrupt pin of said interrupt pins differs from said signal on said further interrupt pin, identify that a key in said second bank asserted said interrupt; and
responsive to a determination that said signal on said at least one interrupt pin of said interrupt pins does not differ from said signal on said further interrupt pin, identify that a key in said first bank asserted said interrupt.

2. The HVAC controller as recited in claim 1 wherein said transformation circuitry is configured to phase-shift said untransformed reference signal to yield said transformed reference signal.

3. The HVAC controller as recited in claim 1 wherein transformation circuitry is configured to invert said untransformed reference signal to yield said transformed reference signal.

4. The HVAC controller as recited in claim 1 wherein said untransformed reference signal is periodic.

5. The HVAC controller as recited in claim 1 wherein said untransformed reference signal varies between zero volts and a digital logic voltage.

6. The HVAC controller as recited in claim 1 wherein said untransformed reference signal is a square wave.

7. A method of receiving signals from a keypad, comprising:
providing, by a transformation circuit, one of an untransformed and a transformed time-varying reference signal to an input pin of a processor, wherein the input pin of the processor is coupled to an output of the transformation circuit;
providing said untransformed reference signal to an interrupt pin of said processor when a key in a first bank is pressed;
providing said transformed reference signal to said interrupt pin when a key in a second bank is pressed;
determining whether a signal on said interrupt pin differs from a signal on said input pin;
responsive to a determination that said signal on said interrupt pin differs from said signal on said input pin, identify that a key in said second bank asserted said interrupt; and
responsive to a determination that said signal on said interrupt pin does not differ from said signal on said input pin, identify that a key in said first bank asserted said interrupt.

8. The method as recited in claim 7 further comprising phase-shifting said untransformed reference signal to yield said transformed reference signal.

9. The method as recited in claim 7 further comprising inverting said untransformed reference signal to yield said transformed reference signal.

10. The method as recited in claim 7 wherein said untransformed reference signal is periodic.

11. The method as recited in claim 7 wherein said untransformed reference signal varies between zero volts and a digital logic voltage.

12. The method as recited in claim 7 wherein said untransformed reference signal varies is a square wave.

13. An HVAC system, comprising:
a compressor;
a furnace associated with said compressor;
a blower associated with said compressor and furnace;
and controller associated with said compressor, said furnace and said blower, said controller having:
a keypad having at least first and second banks, a reference signal source configured to generate a time-varying untransformed reference signal and provide said untransformed reference signal to said first bank, transformation circuitry configured to transform said untransformed reference signal into a transformed reference signal and provide said transformed reference signal to said second bank, and a processor having interrupt pins coupled to corresponding keys of both said first and second banks and a further interrupt pin coupled to an output of the transformation circuitry to receive one of said untransformed and transformed reference signal;

wherein said processor is further configured to:
respond to an interrupt by determining whether a signal on at least one interrupt pin of said interrupt pins differs from a signal on said further interrupt pin;
responsive to a determination that said signal on said at least one interrupt pin of said interrupt pins differs from said signal on said further interrupt pin, identify that a key in said second bank asserted said interrupt; and
responsive to a determination that said signal on said at least one interrupt pin of said interrupt pins does not differ from said signal on said further interrupt pin, identify that a key in said first bank asserted said interrupt.

14. The system as recited in claim 6 wherein said transformation circuitry is configured to phase-shift said untransformed reference signal to yield said transformed reference signal.

15. The system as recited in claim 6 wherein transformation circuitry is configured to invert said untransformed reference signal to yield said transformed reference signal.

16. The system as recited in claim 6 wherein said untransformed reference signal is periodic and a square wave.

17. The system as recited in claim 6 wherein said untransformed reference signal varies between zero volts and a digital logic voltage.

Assignees

• Lennox Ind Inc

Inventors

• Hadzidedic Darko
• Murugesan Sakthi Narayan Kumar

Classifications

• G05B15/02

  electric · CPC title

• F24F11/46

  Improving electric energy efficiency or saving · CPC title

• F24F11/30 Primary

  for purposes related to the operation of the system, e.g. for safety or monitoring · CPC title

• H03M11/00

  Coding in connection with keyboards or like devices, i.e. coding of the position of operated keys (keyboard switch arrangements, structural association of coders and keyboards H01H13/70, H03K17/94) · CPC title

• F24F11/006 Primary

  Mechanical Engineering · mapped topic