Circuit and method for extending microcontroller analog input capability

Abstract

A circuit and method extends the analog input capability of a microcontroller by including an autonomous sequence control circuit that supplies input signal setting data and implements delay functions independent of the microcontroller central processing unit (CPU). The sequence controller supplies input signal selection commands to an input multiplexer, and analog signal processing commands to one or more analog signal processing circuits. After a predetermined settling time, the sequence control circuit then initiates an analog-to-digital converter (ADC) to convert the select analog signal to digital data. The circuit and method extend the number of available external address bits and the maximum settling time of the ADC.

Description

TECHNICAL FIELD [0001] The present invention relates to microcontroller analog-to-digital (A / D) signal conversion and control and, more particularly, to a circuit and method for extending the analog input capability of microcontroller A / D converters (ADCs). BACKGROUND [0002] Microcontrollers are used in myriad devices and systems to implement one or more control and / or monitoring schemes. For example, many aircraft engines are controlled via an engine controller, such as a digital electronic engine controller (DEEC) or a full authority digital engine controller (FADEC), that may be implemented using a plurality of microcontrollers. The microcontrollers may receive various command signals, and a plurality of signals representative of various physical and / or operational parameters and, implementing one or more control laws via an on-board central processing unit (CPU), control the overall operation of the aircraft engine to achieve the desired performance. [0003] In many instances the...

AI Technical Summary

Benefits of technology

[0006] The present invention provides a circuit and method that extends the analog input capability of a microcontroller. In one embodiment, and by way of example only, a circuit includes a multiplexer, an analog signal processing circuit, queued analog-to-digital converter (QADC), and a sequence control circuit. The multiplexer is adapted to receive a plurality of analog signals and an input select signal, and is operable, in response to the input select signal, to output one of the received analog signals. The analog signal processing circuit is coupled to receive the analog signal output from the multiplexer and is further coupled to receive a process command signal representative of one or more analog signal processing parameters. The analog signal processing circuit is operable, in response to the process command signal, to process the analog signal using the one or more analog signal processing parameters and supply a processed analog signal. The QADC is coupled to receive the processed analog signal and a conversion trigger signal, and is operable, upon receipt of the conversion trigger signal, to convert the processed analog signal to digital data representative thereof. The sequence control circuit is operable to supply the input select signal, the process command signal, and the conversion trigger signal.

Problems solved by technology

However, these devices do suffer certain drawbacks.

In particular, the ADCs typically exhibit two performance limitations.

These limitations include the number of available external address bits, and the maximum settling time to which the ADC can be set.

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