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ASiva.1
Associate III
January 8, 2021
Question

STM32WB55 CubeMX Configuration

  • January 8, 2021
  • 5 replies
  • 2737 views

I am building a wireless application (BLE) with STM32WB55CG. For that, I am planning to use HSI and LSE (LSE as RF wake up clock and HSI as CPU1 and CPU2 clock). For that, I disabled HSE in the RCC part of CubeMX. After I did that, RF becomes inactive and unselectable. How can I solve this issue to make wireless application without using HSE? (I am using STM32Cube_FW version 1.8.0)

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5 replies

TDK
Super User
January 9, 2021

The RF front end requires a 32 MHz HSE as a clock source. Probably the HSI does not meet the high speed timing requirements for Bluetooth.

0693W000006I52qQAC.png 

If you hover over something in CubeMX that is disabled, it will usually tell you why. In this case, it does exactly that.

0693W000006I530QAC.png

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ASiva.1
ASiva.1Author
Associate III
January 9, 2021

Yes. I understand it. But, I have another doubt regarding this. When I set the HSE as external ceramic/crystal oscillator, RF gets activated, but in the clock configuration window in Cube MX I set system clocks such that, HSE is not used anywhere in the clock configuration (HSI as CPU clock and LSE as RTC wake up clock and the system works in the P-Nucleo-WB55 development board. How does this happen when I set HSE as enabled, but not used in Cube MX clock configuration?

ASiva.1
ASiva.1Author
Associate III
January 9, 2021

Yes. I understand it. But, I have another doubt regarding this. When I set the HSE as external ceramic/crystal oscillator, RF gets activated, but in the clock configuration window in Cube MX I set system clocks such that, HSE is not used anywhere in the clock configuration (HSI as CPU clock and LSE as RTC wake up clock and the system works in the P-Nucleo-WB55 development board. How does this happen when I set HSE as enabled, but not used in Cube MX clock configuration?

TDK
Super User
January 9, 2021

Is HSE activated?

Are CPU2 and HSE frequencies set to 32 MHz?

If not, show your clock configuration screen.

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ASiva.1
ASiva.1Author
Associate III
January 9, 2021

0693W000006I5rZQAS.png

TDK
Super User
January 9, 2021

Looks like you've satisfied the requirements. I don't see any issues here. It doesn't say CPU2 should be clocked from HSE. Although perhaps this is a bug, no idea.

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Khouloud ZEMMELI
ST Employee
January 11, 2021

Hello @ASiva.1​ 

Are you still facing an issue with CubeMX interface? If yes, please share your ioc file to check it.

Thanks, Khouloud

ASiva.1
ASiva.1Author
Associate III
January 11, 2021

Hello @Khouloud ZEMMELI​ ,

Please find the attached .ioc file