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STM32WB55 continuously switching between USB and DFU mode

sajul88
Associate

‎2024-09-09 03:04 PM

We are using STM32WB55VGQ in one of our products. 

This product is a thermostat which reads temperature humidity along with 6 other sensor values and was installed in customer site. This unit was working fine for last few months untill last week when it started showing a white screen. on trying to pull debug logs through USB, we identified that the usb was switching continuously between normal USB mode and DFU mode. On power cycling the device, it went back to normal operation.

We were not able to reproduce the issue after this, the site is one of our beta stes and we are concerned about such behavior.

There is a 20K pull down provided on the Boot 0 pin.

 

What could be the possible chances for such a behavior?

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FBL
ST Employee

‎2024-09-18 03:49 AM

Hi @sajul88 

Are you sure VDDUSBIO is connected to 3.3V? Would you share USB schematic sheet?

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sajul88
Associate

‎2024-09-18 02:01 PM

Hi I checked the VDD USB, that one is tied to 3.3V as per recommendations.

sajul88_0-1726693262241.png

 

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FBL
ST Employee

‎2024-09-27 09:16 AM

Hi @sajul88 

Can you share USB traffic for normal operations? are there any STALLs ? 

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