Problem with advertising on custom board

RE: Problem with advertising on custom board

FormerMember — Mon, 12 Mar 2018 08:05:40 GMT

When doing a design with the nRF51, it can be useful to have a look at the tutorial "General PCB design guidelines for nRF51 series".

RE: Problem with advertising on custom board

AmbystomaLabs — Sun, 11 Mar 2018 16:33:46 GMT

Assuming this is a 2 layer design, based on your layout files it looks like you failed to include the ground via pattern and bottom ground plane under the nRF.

The via pattern is critical to the operation of the nRF. This combined with the other mistakes I noted before, means I see no reason to continue trying to debug your board. You should redesign and respin the board.

I recommend you have someone familiar with RF and mixed signal design review your updated schematic and layout before you commit to having the board made.

Refer to 11.1.1 PCB Layout Example of the nRF51422 product spec for the ground via/ ground plane pattern.

RE: Problem with advertising on custom board

AmbystomaLabs — Thu, 08 Mar 2018 21:29:50 GMT

You will have to post the drill layer too. I can't see the vias under the nRF.

RE: Problem with advertising on custom board

ilkobg — Thu, 08 Mar 2018 16:42:21 GMT

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RE: Problem with advertising on custom board

AmbystomaLabs — Tue, 06 Mar 2018 15:18:39 GMT

You had said that it transmitted for 26 seconds or so and stopped. The Softdevice will never start unless HF EXT starts. So it would not have been possible to transmit for even 26 seconds.

It is common for people to accidentally rotate the crystal 90 degrees so that it doesn't work. But again, you said it worked for a while.

If you want, post your layout and I can look for obvious mistakes in the layout.

RE: Problem with advertising on custom board

ilkobg — Tue, 06 Mar 2018 13:22:23 GMT

I tried to manually turn on the external 16mhz crystal with all possible ways, but it's not starting even without softdevice.

So probably the internal 16mhz RC oscillator is used and device is not working correctly because internal 16mhz RC is not accurate enough.

Am I missing something from the design part?

Used crystal is NX3225SA-16.000M-STD-CSR-1, 8 pF, 15 ppm.

RE: Problem with advertising on custom board

ilkobg — Fri, 02 Mar 2018 20:08:24 GMT

Thank you for the discovering this issue. I'll review the design again carefully.

One thing I forgot to mention is that I'm powering the board from nrf51-DK for now and the TPS and MCP are not used.

RE: Problem with advertising on custom board

AmbystomaLabs — Fri, 02 Mar 2018 20:07:30 GMT

Last word then I am done, if you run LiPo you should set the charge monitor for 4.1v not 4.2. All the newer ones support this. Reason is the life of the LiPo is significantly better if you cycle at 4.1 vs. 4.2 and only minor change in mAh capacity.

RE: Problem with advertising on custom board

AmbystomaLabs — Fri, 02 Mar 2018 20:04:01 GMT

Also, not sure what is going on with your battery management philosophy.

Seems like you have a charge controller for 4.2V Li-Ion, LiPo. Then the TPS is a boost converter not buck converter as it should be.

Something very wrong there. Maybe you were thinking of running it from single cell nimh?

Since it seems like you have a little re-working to do on your design, you should look over the TI website. They have some really nice single chip charge management and buck converter combo solutions.

RE: Problem with advertising on custom board

AmbystomaLabs — Fri, 02 Mar 2018 19:45:01 GMT

First thing I saw on your schematic is the serious lack of capacitance. While the nRF doesn't require a lot locally, it does require a solid source.

The TPS is spec'd to have 10uF on its input and its output.

As a result, I would suspect the TPS is not stable and you are getting a lot of ripple and switcher noise on the supply.