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Occasional jumps during TSC reading

xx58
Associate

I am working on touch detection with STM32L412cbt6 MCU. I am reading from two channels via G1 of TSC and it is working fine. However, when I look at the other group (i.e. G2), there are fluctuations in both channels from time to time but these values ​​are very large (like 0-1500). I could not observe any situation that could cause this noise on the board. I checked the sampling capacitors with an oscilloscope and I could not see any difference with the working group. The sampling capacitor value was used as 47nF in both groups. This design was made by considering the design guidelines given by ST in my previous PCB design. While doing this work, I also tried it with ST's TSC library but these jumps occurred again. We cannot understand what is causing the problem at the moment.

1 REPLY 1
Stassen.C
ST Employee

Hello xx58,

Did you check that you are not in the errata sheet scenerio? https://www.st.com/resource/en/errata_sheet/es0456-stm32l412xx422xb-device-errata-stmicroelectronics.pdf

Regards,
Stassen

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