Clock configuration in STM32CubeMX for STM32L4R5ZI: Why are CPU clocks <= 14 MHz marked as incorrect configuration?

[Björn Haase]

Posted on April 10, 2018 at 15:17

In the clock tree configuration for the STM32L4R5ZI the CubeMX tool only allows for frequencies >14 MHz for the HCLK subsystem. For lower clock frequencies the HCLK window is marked in red (illegal configuration).

In the Microcontroller datasheet, however I find data (e.g. regarding power consumption) also for frequencies as low as 100 kHz.

Moreover I observe a bug in the current Eclipse plugin for the CubeMX tool that does not allow for properly specifying the input frequencies of the oscillators. This bug, seems to have been fixed in the plain windows tool. However, the file formats for the .ioc file for the windows and eclipse version seem to be incompatible.

Any idea on how to fix this?

The project has been generated from the default template for the Nucleo144-L4R5ZI board.

[waclawek.jan]

Posted on April 10, 2018 at 23:37

You told CubeMX you want to use USB, didn't you?

JW

[Björn Haase]

Posted on April 11, 2018 at 08:44

Dear Jan,

>You told CubeMX you want to use USB, didn't you?

Not intentionally. But you are right. Actually, this seems to be activated by default when generating the project from scratch for the NUCLEO-L4R5ZI board. I just checked it. After switching the USB peripheral off, everything worked as expected and as I know it from the other chipsets.

Thank’s for your fast reply,

Björn.

BTW: I assume that you are aware of the strange bug regarding the external clock source’s frequency settings in the current CubeMX eclipse plugin? I see this bug in the eclipse plugin that I did download yesterday but not in the W32 executable (which IIRC has a one version higher ID .25 instead as .24?).

Mit freundlichen Grüßen I Best Regards

Dr. Björn Haase

[waclawek.jan]

Posted on April 11, 2018 at 10:18

I assume that you are aware[...]

Me? No. I wouldn't touch Cube and its siblings with a stick.

You may want to open a new thread, otherwise this won't get any attention.

JW