How to Test BLE on Custom STM32WB Board

[ICMosquera]

Dear Everyone,

I created a custom STM32WB55 board taking hardware consideration from the RF hardware guide. Instead of a discrete matching network that was used on the Nucleo, we used IPD (integrated passive device), which was pretty much the equivalent. Based on pg.32 of AN5165. The schematic and the actual PCB design are shown below. The custom MCU of the custom board was ok, I could load firmware, debug and code just fine, but when I tried the BLE, I could not even detect the device on the BLE toolbox. I tried the Beacon sample firmware still nothing can be seen.

Can someone help me with this issue, or has somebody encountered the same problem?

I’ve exhausted the net, scouring for a possible solution, but it is hard. That is why I’m asking for somebody’s expertise regarding this.

[Remi QUINTIN]

Just some more clarifications:

• What binary did you load on your board for the stack?
• Did you try one of the applications proposed in the CubeWB FW package like BLE_p2pserver?
• When you say "device is not detected", do you mean no BLE emission despites advertising?
• BLE Toolbox? Those on mobile phone? Which one?

[ICMosquera]

HI @Remi QUINTIN​ ,

Thanks for the response.

1. I tried to load the Full BLE Binary File
2. Yes, I tried the BLE_p2pServer.
3. Clarification on this, I tried the YT tutorial on how to send from Phone to Nucleo. I have a nucleo and it's working. But when I do this to my board it's not advertising. here's the vid. https://youtu.be/CKYWy7LKL68
4. Yes, it's ST's BLE ToolBox on Android.

Any troubleshooting tips would really help me, I'm willing to share here the design file.

[FWiew.1]

Hi,

I faced a similar problem with a custom board that I designed using the stm32wb35. Following the tutorial "BLE Security with STM32WB - 04 Simple BLE application generated from CubeMX" on YouTube and flashing the full stack version 1.15.0 with the cube programmer I got something out of my board.

But since the reflow in my toaster oven seems to not have correctly soldered on the MLPF-WB-01E3, I needed to remove it. This means no antenna was connected and I have to get really close with my phone to see the BLE advertising. I hope this helps you.

PS: It seems that the manual changes to the code as proposed in the video are no longer necessary. For me it even works without them.

With best regards

Felix

[ICMosquera]

I see, thank you for your input sir @FWiew.1​, However, in my case, the board that I had with me is straight from PCBway, so I'm assuming that they made it right on the assembly. But since I had a spare board, ill try to remove the matching filter. Anyways thank you very much. Seems I'm not the only person encountering this issue.

[ICMosquera]

Update,

Hi @FWiew.1​, I removed the MLPF-WB-01E3, hoping that this is the cause of the problem. And tried the YT tutorial you suggested. But it still didn't work on my End even though I'm as close as possible on my board.

Perhaps there are some parameters that need to tune. :(. @Remi QUINTIN​ any help will be much appreciated.

We plan to mass produce these board and use it on our weather system here in our country so any tips that will make this work will really help. I'm starting to have second thoughts about using other BLE modules. But still, I'm hoping that this is a matter of software issues.

[Javier1]

• Are you able to SWD debug your custom board?
• Is your HSE XTALproviding the right freq
• IS that a roge gnd trace going undernmeath your PCB antenna?

[Remi QUINTIN]

Indeed, one key point mentioned by Javier: Is the HSE crystal delivering the correct frequency = 32 MHz with max 50 ppm?

What crystal do you use? Did you trim it on your custom board?

[ICMosquera]

Hi @Javier Muñoz​ 

1. Yes, I was able to SWD debug my board, it works like magic.
2. HSE and LSE are perfectly working to for I was able to run RTC code snippets (RTC are clocked with LSE)
3. That is not a GND trace, it's some silk screen at the back. The antenna trace is free of other signals even below layers.

@Remi QUINTIN​ Yep, Crystal is working fine :)

BIG UPDATE!,

I was able to solve the issue, a big thanks to Andry Brown's page (Bluetooth Low Energy and the STM32WB55 MCU | Andys Workshop (andybrown.me.uk)) where I landed.

The problem with me is that I had not uploaded a FUS binary file, Just the BLE stack. After I uploaded the FUS and the full stack BLE binary files, I get a signal now on my board.

I hope this will also answer some people's problems.

Happy Designing!

Ian

[Remi QUINTIN]

When you write "uploaded a FUS binary file", you mean "updated the FUS to the latest version"... I assume.