STM32WLE5 clock section tab in the Cube-Mx

[viola]

Hi ,

Regarding working with the STM32WLE5 with SUBGHZ block in the CUBE-MX.

in the clock section tab in the CUBE-MX I dont see any mention of the RF-PLL clock. 

if i understood correctly - in order to work with the LORA SUB-GHZ BLOCK i need to supply a 32 Mhz HSE clock . 

I dont see in the clock section tab in the CUBE-MX any mention of this "must -have" 32 mhz HSE clock . 

it seems any clock source is possible and any frequency is possible .

Does the clock section tab in the CUBE-MX dont represent the CLOCK tree in  the STM32WLE5 ?

I see this issue even when I open example code for sughz block within the CUBE-MX.

Thank you,

Viola

[STTwo-32 · Accepted solution]

Hello @viola 

There are 2 'main' clocks for 2 independent system:

1. Radio always sourced from HSE TCXO.
2. The sys clock for the system and Cortex and IPs. This is by default on MSI. Can also be sourced from the HSE (e.g. TCXO), HSI.

I've request to add a warning or a restriction on using the Radio module without HSE enabled (internal ticket number 196877).

The RF-PLL is used as the frequency synthesizer for the generation of the local oscillator
frequency (flo) for both transmit and receive chains. The RF-PLL uses auto calibration and
uses the 32 MHz HSE32 reference. So, it is not a Clock that should be set on the clock tree of the MX, it works will HSE is available, and it can be set by Set_RfFrequency() command that take the Channel RF frequency as input (868MHz...).

Best Regards.

STTwo-32

[Elliot12488]

Kudos to you - I hope this gets into Cube, as I just ran into this ambiguity myself.  Surprising that the clock tree from the datasheet and Cube look so different, with Cube completely omitting the RF line showing the source.

Thankfully I still popped an HSE pad on the design, so I can, hopefully, at least get some dev going on the prototype.