BlueCoin RCC configuration issue / BlueCoin board (STEVAL-BCNCS01V1)

[ghibli]

Hi all,

I am trying to implement simple USB-FS communication on a BlueCoin board (STEVAL-BCNCS01V1). I am following the official STM tutorial on USB CDC and referencing the official SW package for BlueCoin.

So, for USB I need PLL source from HSE clock: BlueCoin schematic shows that there is a crystal oscillator @16Mhz (NDK NX2520SA) installed directly on the board, so I configured RCC HSE as Crystal/Ceramic Resonator; the problem is that the function HAL_RCC_OscConfig(&RCC_OscInitStruct) in SystemClock_Config retrieves HAL_TIMEOUT as a result. Timeout value is default at 100ms.

Clock configuration in STM32CubeMX is as suggested in the official USB tutorial:

My current debug configuration has BlueCoin connected via SWD to a NUCLEO-G0B1RE, as suggested in UM2240 (see page 14).

Could you please help me? Am I missing something? Thanks to anybody who can help!

[mƎALLEm]

Hello @ghibli and welcome to the ST community, 

I don't have idea about that BlueCoin board but referring to its schematic, it has indeed a crystal on it of 16MHz:

But from what you shared in the CubeMx screenshot, it seems you are configuring HSE in Bypass mode:

Only one pin is used in this case while you need OSC_IN and OSC_OUT for a crystal.

So you need to select Crystal/Ceramic Resonator in CubeMx for your case:

Bypass mode is used for example for crystal oscilators (XO) and not for crystals (XTAL).

PS: in your main.c you've attached, HSE is correctly configured! So that doesn't reflect the CubeMX configuration! which induces to some confisions here.. 

  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;

Hope that helps.

[ghibli]

Hi @mƎALLEm, thanks for your feedback and for the welcome!!

The confusion is due to the late hour at which I wrote the post... The screenshot is wrong, please forgive me for that.

Anyway, the correct configuration that you suggested is the one that I definitely tested in main.c file, but still it gets stuck in HAL_RCC_OscConfig for the same reason; the screenshot comes from a previous configuration that I tested (and which did not obviously work...).

Do you know whether I have to set some other configurations in order to have the external oscillator on the board working properly (maybe on ST-Link side)?

Thanks again for your support!

PS: the BlueCoin board is actually a product from ST, more information here. It's a pity that I could not find much documentation or samples about that because it's definitely a very interesting board for prototyping.

[mƎALLEm]

Hello,

1- You mentioned in a previous post NUCLEO-G0B1RE. So could you please confirm your are debugging on STEVAL-BCNCS01V1 that contains a STM32F446 and not NUCLEO-G0B1RE which contains a STM32G0B1 MCU?

2- Check you have that crystal on your board and that was not unsoldered:

3- Test if you can use HSI as source clock:

This is just for test.

[ghibli]

Hi @mƎALLEm, thanks for your feedback. I will try out your points and give a feedback as soon as possible.

[ghibli]

Hi @mƎALLEm, I tested your points. Here are my findings:

1) I confirm, debug is active on STM32F446

2) The oscillator is present on the board

3) If I switch to HSI, this is what I get (I guess USB-FS needs HSE):

Thanks again for your suppport.

[mƎALLEm]

Hello,

---

@ghibli wrote:

3) If I switch to HSI, this is what I get (I guess USB-FS needs HSE):

---

Because USB needs HSE with an external crystal to work properly in this product.

Forget about USB for now and deactivate it in CubeMx. Create a very simple project and select HSE with a 16MHz  with PLL as clock source. The test is to check whether there is an issue in your hardware.

[ghibli]

Hi @mƎALLEm, good suggestion. I set up a simple project which switches LEDs on and off using HSE and a timer and it works fine, so I assume the external oscillator is ok. I attach the project, maybe it can be useful to someone in the community. 

Getting back to the original USB project, I will compare the RCC_CR register to the simple project and check if something is wrong with the configuration.