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MSP430FR2522: Best solution for 3x5 buttons and proximity

Part Number: MSP430FR2522
Other Parts Discussed in Thread: BOOSTXL-CAPKEYPAD, , MSP430FR2672

We're designing a keypad with 3x5 capacitive touch buttons, where we want wake-on-proximity functionality. I have the BOOSTXL-CAPKEYPAD for testing, and it seems to work good, except that it has 3 buttons less than what we want.

I have set up 3x5 buttons in the Captivate Control Center and added the proximity sensor. When clicking "auto assign" I got the following error: "sensor proximitySensor, Electrode TX00 is unconnected".  

I connect TX00 to one of the pins and it seems to be happy.

Is this an okay assignment, or do I have to use another MSP430 with more captivate IOs to get this working?

What I really want is to get the best proximity sensing distance possible? Please see the screen shot below for our very premature Keypad PCB.
-Would it be possible to use one of the TX channels and increase it with a track surrounding the board. And sample all RX channels at the same time to achive a sensor as large as possible?
-Or is it possible to use the RX channel(s) as both a self-capacitance sensor for proximity and later as mutual capacitive sensor when the device is awake?

Please let me know if you can guide me in the right direction having a 3x5 keypad with proximity using the , or if it is necessary to switch to one of the larger MSP430's?

  • Hi 

    Here is my comments:

    1. If you care more about the cost, you can use the MSP430FR2522. You can use all button as proximity sensor. But the performance is not better with the a dedicate channel to do this.

    2. If you care more about the performance, I will recommend to use MSP430FR2672

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