Circuitry for autonomously measuring analog signals and related systems, methods, and devices

1. An apparatus, comprising:

a signal analyzing circuitry to:

be enabled responsive to an assertion of a first enable signal;

compare an amplified analog input signal to one or more threshold values responsive to an assertion of a second enable signal, the assertion of the second enable signal following the assertion of the first enable signal; and

generate an alert signal responsive to a determination that the amplified analog input signal falls outside of a range of values defined by the one or more threshold values; and

a central processing unit (CPU) to provide timer values associated with timing of assertions of the first enable signal and the second enable signal, wherein the signal analyzing circuitry to perform, using the one or more threshold values and the timer values, periodic analog measurements with threshold checks independently from intervention or supervision from the CPU.

2. The apparatus of claim 1 , comprising:

a timing circuitry to assert the first enable signal at a first time and the second enable signal at a second time, the second time following the first time.

3. The apparatus of claim 2 , wherein the timing circuitry to assert the first enable signal and the second enable signal periodically.

4. The apparatus of claim 2 , wherein the timing circuitry includes a first timing circuit to generate the first enable signal and a second timing circuit to generate the second enable signal.

5. The apparatus of claim 4 , wherein the first timing circuit to assert the first enable signal responsive to expiration of a countdown from a first timer value of the timer values.

6. The apparatus of claim 1 , wherein the signal analyzing circuitry includes an analog to digital converter.

7. The apparatus of claim 1 , wherein the signal analyzing circuitry includes an analog comparator.

8. The apparatus of claim 7 , wherein the signal analyzing circuitry includes a digital to analog converter to generate one or more reference signals respectively associated with the one or more threshold values, the analog comparator to compare the amplified analog input signal to the one or more reference signals.

9. The apparatus of claim 1 , comprising:

an operational amplifier circuit to enable responsive to the assertion of the first enable signal, the operational amplifier circuit to, if enabled, generate an amplified analog input signal responsive to an analog input signal.

10. The apparatus of claim 9 , wherein the operational amplifier circuit comprises a low-pass filter to filter the analog input signal.

11. The apparatus of claim 9 , wherein the operational amplifier circuit and the signal analyzing circuitry are disabled for a majority of a time during the periodic analog measurements.

12. The apparatus of claim 9 , wherein the signal analyzing circuitry to disable the operational amplifier circuit and the signal analyzing circuitry after comparing the amplified analog input signal to the one or more threshold values.

13. The apparatus of claim 1 , wherein the alert signal comprises an interrupt signal to interrupt operation of the CPU to take remedial action.

14. The apparatus of claim 1 , wherein the alert signal is provided to a peripheral device.

15. The apparatus of claim 1 , wherein the analog input signal is generated by a smoke sensor of a smoke detector.

16. A method, comprising:

activating a signal analyzing circuitry responsive to an assertion of a first enable signal;

determining, by the signal analyzing circuitry, whether an amplified analog input signal is outside of a predetermined range of values defined by one or more threshold values responsive to an assertion of a second enable signal;

generating, by the signal analyzing circuitry, an alert signal responsive to a determination that the amplified analog input signal is outside of the predetermined range of values;

providing, via a Central Processing Unit (CPU), timer values associated with timing of assertions of the first enable signal and the second enable signal; and

performing, using the one or more threshold values and the timer values, periodic analog measurements with threshold checks independently from intervention or supervision from the CPU.

17. The method of claim 16 , comprising:

disabling the signal analyzing circuitry responsive to the determination that the amplified analog input signal is inside of the predetermined range of values.

18. The method of claim 17 , comprising initializing, with the CPU, the one or more threshold values and timing of assertions of the first enable signal and the second enable signal, wherein the determining, generating, performing, and asserting operations are performed independently from the CPU after the initializing.

19. The method of claim 16 , comprising:

receiving an analog input signal at an input of an operational amplifier circuit; and

activating the operational amplifier circuit responsive to the assertion of the first enable signal to generate an amplified analog input signal at an output of the operational amplifier circuit.

20. The method of claim 19 , wherein receiving the analog input signal at the input of the operational amplifier circuit comprises receiving the analog input signal from a smoke sensor.

21. The method of claim 19 , wherein activating the signal analyzing circuitry comprises activating one of an analog to digital converter and an analog comparator.

22. The method of claim 19 , comprising asserting the second enable signal, wherein asserting the second enable signal comprises activating a timing circuit to provide the second enable signal.

23. The method of claim 17 , comprising asserting the first enable signal, wherein asserting the first enable signal and asserting the second enable signal comprises periodically asserting the first enable signal and the second enable signal.