Microcontroller with sequencer driven analog-to-digital converter
AssigneeMicrochip Technology Incorporated
InventorsZeke Lundstrum, Keith Curtis, Burke Davison, Sean Steedman, Yann LeFaou
Life of this patent
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Abstract
An automated sequencer for a microcontroller is provided which makes a CVD conversion process a hardware function. The sequencer controls the charging/discharging of the sensor and ADC sample-and-hold capacitances, as well as the voltage division process. It also initiates the ADC conversion, with an optional second conversion for greater resolution, or a differential conversion.
Claims22
A microcontroller comprising:
- a central processing unit (CPU);
- at least one analog input port coupled with a first external pin of the microcontroller which is operable to be coupled with an external sensor capacitor,
- an analog to digital converter (ADC) for measuring a capacitance of the external sensor capacitor;
- a pre-charge unit operable to independently pre-charge the external sensor capacitor and an internal sample & hold capacitor of the ADC to either one of a first and second voltage;
- a sequencer operable to be programmed by said CPU and operable to determine a timing sequence for pre-charging said external and internal capacitors, parallel switch said internal and external capacitors to share a charge and control the ADC to measure the shared charged.
A microcontroller comprising:
- a central processing unit (CPU);
- at least one analog input port coupled with a first external pin of the microcontroller which is operable to be coupled with an external sensor capacitor,
- a capacitive touch sensor unit including an analog to digital converter for measuring a capacitance of the external sensor capacitor, the capacitor touch sensor unit configured to independently pre-charge the external sensor capacitor and an internal sample & hold capacitor of the ADC to a selected pre-charge voltage and being programmable by said CPU to determine a timing sequence for pre-charging said external and internal capacitors, parallel switch said internal and external capacitors to share a charge and control the ADC to measure the shared charged.
A method of operating microcontroller comprising a central processing unit (CPU), at least one analog input port coupled with a first external pin of the microcontroller, an analog to digital converter (ADC), a pre-charge unit, and a sequencer operable to be programmed by said CPU and operable to determine a timing sequence for pre-charging said external and internal capacitors, parallel switch said internal and external capacitors to share a charge and control the ADC to measure the shared charged;
- wherein for performing an automated touch sensing, said sequencer is programmable by said central processing unit:
- to control the pre-charge unit to pre-charge a sample and hold capacitor to a first voltage and to pre-charge an external sensor capacitor coupled with said first external pin to a second voltage during a programmably defined first period;
- to couple said sample and hold capacitor with said external sensor capacitor during a subsequent programmably defined second period,
- to subsequently de-couple said sample and hold capacitor from said external sensor capacitor and couple said sample and hold capacitor with said ADC for conversion of a first voltage stored on said sample and hold capacitor.
Dependencies are inferred from the claim text.