nRF52832 BLE UUID value incorrect

RE: nRF52832 BLE UUID value incorrect

Håkon Alseth — Tue, 04 Jun 2024 08:31:29 GMT

Hi,

[quote user="Metaresearch"]Let me try a different approach, where is the MAC address / UUID stored in the nRF5_sdk_17_1/examples//ble_perpiheral/ ble_app_hrs project?[/quote]

As mentioned:

[quote user="hkn"]It is to be expected that the MAC address differs from one device to another. By default, the mac address used is loaded from the FICR DEVICEADDR register, which is uniquely generated for each device.[/quote]

More detailed info here:

RE: How to get 6 byte mac address at nrf51822

This is written for 51-series devices, but is valid for all nRF5-series devices.

If there's another 6 byte string/address/ID that you're changing, please share a screenshot/log or something to let me know what you're actually trying to change.

[quote user="Metaresearch"]Unfortunately changing the load cap to 22pF made no difference, the UUID remains the same as before.[/quote]

The MAC address will only change if the firmware changes it.

Is the "CL" value 12 pF for your xtal? You must do a calculation based on the formula that I previously posted to ensure that the 32M is loaded properly.

[quote user="Metaresearch"]

The Johanson 2450AT42A100E chip antenna does not require a matching network.

[/quote]

I highly recommend that you add a pi-network (shunt-series-shunt) and use a 0 ohm for the series-component as a place-holder.

You currently have no way to tune your antenna design, and antennas will always need tuning towards your specific design.

If you check other antennas from Johanson, you will see that they recommend antenna tuner components.

[quote user="Metaresearch"]

The L3 and C18 components are 0402 in this layout. I cannot find your reference layout, please send me the URL.

By changing the UUID in my Android app I am able to communicate perfectly with the nRF52832.

[/quote]

Capacitors shall be NP0. Inductors should have a resonance freq > 3 GHz (for instance murata LQP-series).

Please also take note of the orientation and grounding of the capacitor on the ANT pin:

This is crucial, as also noted in the PS:

Kind regards,

Håkon

RE: nRF52832 BLE UUID value incorrect

Metaresearch — Mon, 03 Jun 2024 17:09:01 GMT

Let me try a different approach, where is the MAC address / UUID stored in the nRF5_sdk_17_1/examples//ble_perpiheral/ ble_app_hrs project?

RE: nRF52832 BLE UUID value incorrect

Metaresearch — Mon, 03 Jun 2024 16:18:27 GMT

Unfortunately changing the load cap to 22pF made no difference, the UUID remains the same as before.

RE: nRF52832 BLE UUID value incorrect

Metaresearch — Mon, 03 Jun 2024 15:35:02 GMT

Thank you for your comments.

An alternative PCB layout (attached) UUID is EB:9E:40:D1:D2:F1 is closer but still not correct.

The Johanson 2450AT42A100E chip antenna does not require a matching network.

devzone.nordicsemi.com/.../2450AT42A100.pdf

The 32MHz crystal is YXC X322532MOB4SI I will try a 20pF load. Unfortunately I am not able to measure the exact frequency.

devzone.nordicsemi.com/.../32MHz-xtal.pdf

The L3 and C18 components are 0402 in this layout. I cannot find your reference layout, please send me the URL.

By changing the UUID in my Android app I am able to communicate perfectly with the nRF52832.

RE: nRF52832 BLE UUID value incorrect

Håkon Alseth — Mon, 03 Jun 2024 09:54:15 GMT

Hi,

[quote user=""]My nRF52832 code runs correctly on a PCA10040 development board (UUID = E9:4A:AF:04:D2:16). My custom hardware advertises correctly but the UUID is incorrect (C9:7C:A5:8B:19:EB). [/quote]

It is to be expected that the MAC address differs from one device to another. By default, the mac address used is loaded from the FICR DEVICEADDR register, which is uniquely generated for each device.

[quote user=""]The 32MHz xtal is +/-10ppm @ 12pF load[/quote]

Does your XTAL have a "Cl" parameter of 12 pF?

If yes, then the loading caps should be ~20 pF.

C = 2*CL - Cpin

Cpin = 4pF

C=2*12-4=20 pF.

Your layout seems to differ from the reference design:

* Please note how the reference layout aligns the first inductor on the ANT pin: https://docs.nordicsemi.com/bundle/ps_nrf52832/page/ref_circuitry.html#d941e1505

* Your chip antenna lacks antenna-tuner components. Usually 3 components, either a pi-network or a T-network.

* The components L3 and C18 seems to be 0603 - we recommend that you use 0402 component size.

Kind regards,

Håkon