UART communication between Raspberry Pi 4 and stm32f411re

[suhfi]

Hi, i want the communication between stm32f411re board and raspberry pi 4. i tried to do with uart2 through USB cable it is working fine. but sometimes it is not able to communicate properly. there is a delay while communicating sometimes. will i2c or spi communication works with USB cable to communicate. which is better and i want the one efficient to work as i want both ways communication.

[Andrew Neil]

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@suhfi wrote:

 sometimes it is not able to communicate properly. there is a delay while communicating sometimes

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There no inherent reason why that should happen with a UART connection.

You need to find out what's causing this delay - it must be something elsewhere in your system.

Changing to some other transport won't fix that.

Have you tried using the Raspberry Pi's hardware UART ?

PS:

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@suhfi wrote:

 uart2 through USB cable 

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Please give more details of that.

I assume you mean a USB-to-UART cable/adaptor somewhere?

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

[SofLit]

Hello,

Related to this thread: https://community.st.com/t5/stm32-mcus-products/communication-between-nucleo-f411re-and-raspberry-pi-using-st/td-p/721443

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@suhfi wrote:

but sometimes it is not able to communicate properly. there is a delay while communicating sometimes. 

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Need to clarify this statement. From which side? STM32 delays the transmit or Raspberry-Pi?

[Andrew Neil]

We've been through this before:

https://community.st.com/t5/stm32-mcus-products/communication-between-nucleo-f411re-and-raspberry-pi-using-st/m-p/721443

So what's changed now?

[suhfi]

No, i didn't do the communication by connecting the gpio pins, but from the usb cable. there is a delay for sure. i didn't mention any delay with that, then why am i facing delay with the comunication.

[Andrew Neil]

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@suhfi wrote:

 i didn't do the communication by connecting the gpio pins, but from the usb cable. 

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Again, you need to give more details.

How, exactly, are you making this USB connection?

Show a schematic.

Post photographs.

What, exactly, is the "stm32f411re board" you are using?

Is it still the same as this:

https://community.st.com/t5/stm32-mcus-products/communication-between-nucleo-f411re-and-raspberry-pi-using-st/m-p/721443

[Andrew Neil]

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@suhfi wrote:

i didn't mention any delay with that, 

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With what, exactly?

[SofLit]

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@suhfi wrote:

No, i didn't do the communication by connecting the gpio pins, but from the usb cable. there is a delay for sure. i didn't mention any delay with that, then why am i facing delay with the comunication.

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Need also to post your code

+ Show how you did connect the Nucleo board with the Raspberry board.. Share photo(s).

[suhfi]

Thank you for the replies, i did solve the problem.

[Andrew Neil]

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@SofLit wrote:

Need to clarify this  statement. From which side? STM32 delays the transmit or Raspberry-Pi?

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Indeed.

@suhfi Also, how much of a delay is it?

How do you observe this delay?