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Associate
October 30, 2024
Solved

Low voltage for logic high on Nucleo-G431KB

  • October 30, 2024
  • 3 replies
  • 1182 views

Hello STM community,

I have a problem with my Nucleo-G431KB. I am trying to communicate to a sensor device over SPI. The problem I have is that when I use PA5 as SPI1_SCK, the logic high is only 1.4 V instead of the 3.3 V on other pins. When I configure PA5 as normal GPIO output I also get a 1.4 V output. When I use another pin as SPI1_SCK it works as expected. 

I have this problem when the Nucleo is connected to the sensor, but also when there is no load except for the oscilloscope.

At first I thought that it might be a production error, but I have the problem on both of my boards.

Is it normal that this pin has a lower voltage? If so, can I change it somehow?

 

Best answer by AScha.3

Hi,

from circuit :

AScha3_0-1730284556961.png

seems PA5 connected to PB7 (dont ask me why ! ) ; so open SB7 to get PA5 working as expected.

3 replies

Andrew Neil
Super User
October 30, 2024

Have you checked the board's User Manual and/or Schematics to see if there's anything else on that pin?

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
AScha.3
AScha.3Best answer
Super User
October 30, 2024

Hi,

from circuit :

AScha3_0-1730284556961.png

seems PA5 connected to PB7 (dont ask me why ! ) ; so open SB7 to get PA5 working as expected.

"If you feel a post has answered your question, please click ""Accept as Solution""."
Andrew Neil
Super User
October 30, 2024

@AScha.3 wrote:

don't ask me why ! 


Something about "I2C SDA support on ARDUINO Nano A4"

AndrewNeil_0-1730284950532.png

 

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
Associate
October 30, 2024

Thanks!

I put PB7 and PA15 (connected to PA6 for MISO) to the reset state, and now the SPI works.

If I want to use PB7 and PA15 for something else I should open SB2 and SB3, if I see things correctly.