How to configure HSE on Nucleo U5A5ZJ

[liquidloop]

Hi Team,

I am trying to use the HSE for Nucleo U5A5ZJ but I have some confusion. The document says ..

"HSE is the 16 MHz oscillator for the STM32 microcontroller. This clock is available depending on the target
STM32 series microcontroller used on the Nucleo-144 board."

So does this board have the external oscillator or not?

In the clock configuration diagram, it defaults the Input frequency to 8MHz. Why?

Even if i use this 8MHz HSE deploying the code to the board results in messages like "Target is not responding, retrying...".

Can you please give some guidance.

Thanks.
Sandeep

[TDK]

Does your board have a crystal in the X3 position, or is it empty?

[waclawek.jan]

At  

https://www.st.com/en/evaluation-tools/nucleo-u5a5zj-q.html#cad-resources 

is the schematics; identify which one is the oscillator; then at the same page in Bill of Materials, try to find that oscillator.

JW

[Tesla DeLorean]

For the Nucleo U5A5ZJ the HSE is most likely coming from the ST-LINK/V3 STM32F723 chip

The output speed on the MCO is configurable. Pretty sure that's never 16 MHz

https://community.st.com/t5/stm32-mcus/how-to-use-stlink-v3-mco-output-on-nucleo-boards-as-a-precise/ta-p/723361

https://www.st.com/resource/en/schematic_pack/mb1549-u5a5ziq-c04-schematic.pdf

X3 can be an NX2016SA 16 MHz if placed, and solder bridges made and capacitors added.

[liquidloop]

Thanks TDK. I do have a crystal here and it says 16 so likely 16MHz. However when we start a new project for STM32U5A5 and disable the USB_OTG, then the default value is 8 for input frequency.

I have updated that to 16 and configured prescaler to get 160MHz sysclk. It looks correct on the clock configuration.

But while flashing it goes "Target is not responding, retrying...". I also check that the FLASH_LATENCY_4 is set to 4. Hope I am not missing something.

[Amel NASRI · Accepted solution]

Hi @liquidloop ,

Based on the same user manual UM2861, to use the on-board oscillator crystal (X3) as the HSE source, configure the board as follows::

That said, the sentence from this user manual mentioned in your initial post is misleading. An internal ticket has been submitted to provide precise information about the HSE crystal (ticket #216017).

-Amel