captouch_getCurrentState

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Anonymous
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I noticed this function in the v2.0.1 API reference guide:

Gets the current state of gpioPortPin.

Parameters
gpioPortPinThe port + pin to sense.
periodThe sampling period in number of 24MHz clock cycles.
Returns
The return value is the number of oscillations the capsense input oscillated in period.

Are there any examples of using this function or documentation on the hardware that it uses?  Which GPIO pins on the BCM20737/BCM20736S are compatible with this function? What is the oscillation frequency as a function of load capacitance? What (if anything) do I need to do to set up the pin for capacitive measurements?

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1 Solution
Anonymous
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Based on the comments in captouch_getCurrentState, I was able to figure out how to use the function.  A pullup resistor and capacitor on the pin is all that is necessary, and it does not appear to need any other setup (hardware or software).  The timing is based on the RC time constant.

Thanks for your help, JT!

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3 Replies
Anonymous
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Hello cdarling,

We are researching the oscillation frequency function and will get back to you.

Regarding the Captouch_getCurrentState

  1. You are correct, these are mentioned in both the BCM2073x devices.
  2. And we list these in hello_sensor and i2c_temperature_sensor apps.
  3. Let me check to see if we have had an internal example that implements CapTouch

Thanks

JT

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Anonymous
Not applicable

Based on the comments in captouch_getCurrentState, I was able to figure out how to use the function.  A pullup resistor and capacitor on the pin is all that is necessary, and it does not appear to need any other setup (hardware or software).  The timing is based on the RC time constant.

Thanks for your help, JT!

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Anonymous
Not applicable

Fantastic!

Thanks for sharing!

Let us know if you have further questions.

Have a great Holiday Weekend!

JT

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