STM32WBA52 LSE as GPIO Issue

[rajdeep_01]

Hi,

Requirement: Use LSE pins: PC14/PC15 as GPIO Output.
MCU: STM32WBA52CGU6
Issue: Output voltage not sustain at 3.3V but getting 3.152V (GPIO connected circuit consumes 300uA only).

- For clean firmware, generated firmware based on IOC, configured only these two pins as output, push-pull, High state.
- Attached related IOC-file, debug-SFR-states-screenshot and generated-project files.

I thinks that this is STM MCU level limitation and STM-Team must provide errata for same with workaround-status.

Please guide me in case anyone have known workaround.

Thanks

[Peter BENSCH]

Please check the current flowing from the GPIO and the voltage at VCC again. The output characteristics in the data sheet, table 70, result in some 50...65mohms internal Rdson, so that with your 0.3mA about 3.285V of the (hopefully) 3.3V should be measurable.

Regards
/Peter

[Andrew Neil]

What board is this on?

Please see the Posting Tips:

https://community.st.com/t5/community-guidelines/how-to-write-your-question-to-maximize-your-chances-to-find-a/ta-p/575228

Does the datasheet specify any restrictions on these pins when used as GPIO ?

Do other GPIOs reach 3.3V ?

[rajdeep_01]

1. Part Number: STM32WBA52CGU6: (Checked in both Nucleo-WBA52CG & Custom-Board.)
2. Environment: SDK: V1.4.1, CMSIS: V5.9.0, STM32WBAxx CMSIS: V1.4.0, STM32CubeIDE V1.15.1 (GCC12).

@Peter BENSCH 

- Thanks for quick reply,
- Double checked that upon make GPIO left unconnected, then properly getting 3.3V but upon with minor resistance connected with only 300uA consumption, voltage down to 3.152V.
- Can you please share datasheet, because I have go through Datasheet, Reference-Manual & Errata but not able to find relevant information.
- Note that this case happens with only LSE GPIOs not with other GPIOs.

@Andrew Neil 
- Thanks for guide, I will try to cover all relevant information.
- No restriction mentioned on these LSE Pins for make work as GPIO, even informed that we can use those pins as GPIO.

Thanks.