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SMula
Associate II
September 23, 2019
Question

Does STM32F042K6T6(LQF-32) microcontroller require boot pin to be grounded through resistor?

  • September 23, 2019
  • 4 replies
  • 1301 views

Hi,

I am working on STM32F042K6T6(LQF-32) ARM microcontroller with STM32CubeMX and Keil software, according to the datasheet boot0 pin is available in pin-31 but when I open the same controller in STM32CubeMX I am neither finding any such pin nor its function like BOOT0

So should I include 10k ohm resistor at pin-31 and ground it irrespective of its availability?

Can anyone help me out here?

Regards

Shivakumar

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4 replies

Tesla DeLorean
Guru
September 23, 2019

Yes, you should have a pull down to ensure consistent start up performance. ​

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SMula
SMulaAuthor
Associate II
September 23, 2019

Thank you Clive!

Even though there is no BOOT0 function available in the pin-31(PB8) as attached in the image here, I should directly connect a pull down right?

Otherwise(if I do not use pull down) is there any chances of reading garbage data from stored flash data everytime when I restart the controller?

Regards

Shivakumar

Ozone
Principal
September 23, 2019

> Otherwise(if I do not use pull down) is there any chances of reading garbage data from stored flash data everytime when I restart the controller?

A floating BOOT pin will make your board startup into system mode (ROM bootloader) or other modes seemingly at random.

> Even though there is no BOOT0 function available in the pin-31(PB8) as attached in the image here, I should directly connect a pull down right?

BOOT0 is not "selectable functionality" - it is the pin's functionality at startup (POR), before you application. Check the datasheet.