BLUENRG-LP custom project issues

[LTrin.1]

Hello there

I have a custom board based on STEVAL-IDB011V2 EVM. Is the same schematic but I have a problem with this. Apparently it boots but not run...

When I flash "Hello World" example I have some issue that I can't check why.... The expected message does not is sent complete. So I have this output:

In this test, I reset the board sometimes. Some times it shows "Applicat", "Applicati", (Probably bootloader output?) Some times it shows truncated "Hello World".

I checked voltage levels by https://www.st.com/resource/en/application_note/an5503-bringing-up-the-bluenrglp-bluenrglps-devices-stmicroelectronics.pdf application note (bringing up the bluenrglp devices).

I tried the Power Supply test (flashing DTM Firmware - UART without update) and VDDA thats we expect 1.2V, I measured 0V. The Core voltage (VCAP) I measured 1.2V as expected.

I also tried flash other firmware examples without success.

Can someone help me?

[Laurent LOUAZON]

Hello,

Could you share your schematics and associated Bill of material?

Regards

Laurent

[LTrin.1]

Hello there

Please see you message inbox. I sent to you.

Regards,

Leonardo Trinta

[Laurent LOUAZON · Accepted solution]

Hi,

I just replied to your message.

I guess the problem was related to 22nH used for SMPS instead of 10uH (22nH is optional and can helps in sensitivity performances - "killing" the SMPS spurious).

Please confirm.

Regards

Laurent

[LTrin.1]

Hello there

Yes, was it that's what caused the issue. Sorry for inconvenience.

As suggestion, clarify it in EVM schematic.

Thank you

Regards,

Leonardo

[JMill.18]

Hi Laurent,

I just saw this post and I'm wondering if I have an issue with my schematic as well.

Based on schematic for STEVAL-IDB011V2, there is a 22nH inductor for L4 (attached to VLXSD) and based on the datasheet DS13282-rev-6, page 11, I have a similar thing, VLXSD->22nH->(VFBSD and (4.7uF || 0.1uF) caps to ground.)  

I do not have a 10nH inductor in series with the 22nH inductor as shown in the V1 schematic of UM2735 page 99).  Will this cause issues with SMPS ON operation?

Thank you