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MSP430FR2633: CAP Sensitivity Issue (Keypad CAPIOs) in New Design using MSP430FR2633

sanath rai
Genius 3875 points
Part Number: MSP430FR2633


Hello Everyone,

I am working on MSP430FR2633.

We developed an Application for Capacitive touch and Tested on Capactive Touch Development Board(Capacitive-FR2633) for Keypads and Slider ,which worked properly.

So we designed our new board for our application with 5 buttons and  Slider(which is compressed in length but same resolution) with back lights for the keypad buttons.

Now we are testing the newly designed board. we are facing some of the following issues.

1)The Keypad designed for the New board is not working(CAP I/OS are same as the one used in the development board) which are rooted properly we have checked the design only difference in this board we are using 5 buttons .

2) Slider is working but the sensitivity is very low but good thing at least its sensing.

What might be the issue and what may increase the sensitivity .any parameters in software need to be tuned?

Regards,

Sanath Rai

  • 0
    TI__Guru 56685 points
    Hello Sanath,

    Can you double check your Design Center connections to make sure the code you write to the device matches with your physical connections? If you provide your design center project, I can review as well. Also, how are you doing the LED backlights? Are you following the recommendations within the CapTIvate Technology Guide? Are you using Self or Mutual Capacitance button configurations?

    For sensitivity issues, there are two places to look into. One being HW design, the other is SW tuning of the sensors. Please look into your conversion count and conversion gain settings within the Design Center to adjust sensitivity. Please keep in mind, the SW tuning can only do so much with the hardware it runs on. The first step in ensuring good sensitivity is by laying out hardware that promotes good sensitivity. Also, what kind of overlay and mechanical stack-up are you employing?.

    Please see the CapTIvate Technology Guide for more information about sensitivity from a Hardware and Software perspective. I will also list out some sub headings below to guide you.

    CapTIvate Technology Guide: www.ti.com/CapTIvateTechGuide

    Sub Headings:
    SW Sensitivity information:
    FAQ -> Design Kit -> How can I increase the sensitivity of the proximity sensor in the out-of-box experience demo?
    FAQ -> CapTIvate Technology -> Why does sensitivity decrease as I increase the Conversion Gain?
    Glossary -> Conversion Count

    HW Layout Considerations:
    Design Guide -> Best Practices (Mechanicals, LEDs, Layout Considerations, Ground Planes)
    Design Guide -> Buttons
    Design Guide -> Sliders and Wheels
  • 0 in reply to Jace H
    Genius 3875 points

    Hello Jace,

    Thank you very much for the suggestions and insight on the problem.

    We have found out the issue.It was on the hardware side.Now the Keypad buttons and Slider are working smoothly.

    Regards,

    Sanath Rai

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