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AHape.1
Associate
December 19, 2023
Solved

NUCLEO-F756ZG SPI1 issue

  • December 19, 2023
  • 3 replies
  • 2406 views

Dear ST,

I try to use SPI1 in full-duplex slave mode with hardware NSS and interrupts.

Interrupts work fine, the only problem is that data is all 0

After connecting the logic analyzer I noticed that the CS and SCK signals are ok but the MOSI and MISO are low.

 

I generate the SPI data using MCP2210 breakout board, it works fine if I connect only the logic analyzer to the MCP2210 all signals are fine. when adding the nucleo in the circuit MISO and MOSI are pulled low!!! 

I use CubeMX for configuration

pins are:

PA5 - SPI1_SCK

PA6 - SPI1_MISO

PA7 - SPI1_MOSI

PA4 - SPI1_NSS

Has anyone ever seen anything similar.. where to look for the issue ?

Thank you

Best answer by TDK

PA7 is used by the ethernet. If you want to use it as SPI, you'll need to remove JP6.

TDK_0-1703020099306.png

 

Use the schematic to determine what pins are actually available. Consider defining them as GPIO output and toggling and monitoring with a logic analyzer or multimeter to ensure the pin is making it to the header you're connected to.

https://www.st.com/en/evaluation-tools/nucleo-f756zg.html#cad-resources

 

3 replies

TDK
TDKBest answer
December 19, 2023

PA7 is used by the ethernet. If you want to use it as SPI, you'll need to remove JP6.

TDK_0-1703020099306.png

 

Use the schematic to determine what pins are actually available. Consider defining them as GPIO output and toggling and monitoring with a logic analyzer or multimeter to ensure the pin is making it to the header you're connected to.

https://www.st.com/en/evaluation-tools/nucleo-f756zg.html#cad-resources

 

"If you feel a post has answered your question, please click ""Accept as Solution""."
AHape.1
AHape.1Author
Associate
December 19, 2023

Thank you TDK,

 

In the link you send me, in the MB1137 PDF - "nucleo-144 for everything" the text on the schematic around the arduino connector is misleading x(

 

I changed the pins allocations and now it works fine!

 

where do I find the schematic for nucleo-f756ZG ???

bad sch.jpg

TDK
December 19, 2023

> In the link you send me, in the MB1137 PDF - "nucleo-144 for everything" the text on the schematic around the arduino connector is misleading x(

What is misleading about it? I see you have posted a screenshot with a red rectangle, but I see no issue with what's in the rectangle.

> where do I find the schematic for nucleo-f756ZG ???

I posted the link in my last response.

"If you feel a post has answered your question, please click ""Accept as Solution""."
AHape.1
AHape.1Author
Associate
December 20, 2023

Hi All,

First,  thank you for all the help.

I try to get used to ST tools... It will take me a while to get used to them.

Another small question: where do i find a document that contains a table of all alternative functions for the pins , for f756 ??

I had to go pin by pin with the mouse in cubeMX ... it wasn't fun

Thank you very much

Andy

AHape.1
AHape.1Author
Associate
December 20, 2023

Bless you TDK,

I completely forgot that ST has separe Datasheet from Reference Manual