Raw count differs from basline

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Anonymous
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Hi,

   

 

   

I'm using the CY8C21534 in a capsense project. If I read correct in the documetation, if no finger on the button, raw count value and baseline value should be the same. In my project with 5 buttons, I set the ref value for 2 buttons to value 4 and for the other 3 buttons ref value is 5.

   

If I monitor raw count and baseline, I see that for the 3 with ref value 5, raw count matches baseline value. But for the 2 buttons with ref value 4, the raw count differs from the baseline value. ( baseline = 10172 while raw count measures 7992 ).

   

Anyone an idea what is wrong? My project is enclosed.

   

 

   

Thanks.

   

 

   

Danny

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3 Replies
Anonymous
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Hi Danny,

   

 

   

Could you please add CSD_ScanSensor(bCtr) before CSD_InitializeSensorBaseline(bCtr); to act as a dummy scan? Since Vref setting is changed, CMOD needs settling time.

   

I will do a test on your project. Also please let me know whether you are testing this on Development kit or your custom board?

   

 

   

Thanks

   

Sujay

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Anonymous
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Hi Sujay,

   

I'm using this project on my custom board. I will test your solution soon and let you if it is solved.

   

 

   

Best regards,

   

Danny

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Anonymous
Not applicable

Hi Sujay,

   

I tested your suggestion, but it doesn't solve the problem. The raw count is still about 2200 units lower then the baseline value for buttons 1 and 2.

   

For the other buttons, the raw count matches the baseline value.

   

Any other suggestions?

   

 

   

Danny

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