BLE kw40 to kw30 migration

[glad4enkonm]

kw40; kw30 frdm-kw40z porting; ble controller

Dear NXP Community,

we designing a device on KW30z. First prototype was made on the FRDM-KW40Z.
We checked BLE - it workes fine.

But after we manufactured prototype on KW30z we can not launch our firmware with BLE.
We used "Software Porting From MKW40Z to MKW30Z and MKW20Z Wireless MCUs" guide,
although issue is not solved. We can programm KW30z on this bord, can detect it throug a cellphone, but can not connect. The same happens with wireless uart example. We ported this example ussing mentioned above guide and checked on our board (KW30z).

In attachments you can find the guide we used, our prototype schematic and two versions of wireless uart example.
One requeres SDK, another is portable.

Looking forward to getting any advice regarding this issue.

Thanks, Nikolai

[gerardo_rodriguez]

Hello Nikolai, sorry for the late response.

By your description of the issue, it appears to me that this could be related to poor RF performance. Did you check out the Hardware Design Considerations for MKW40Z/30Z/20Z BLE and IEEE 802.15.4 Devices document? We recommend copying the critical layout area from one of our reference design boards as this can have a huge impact on the RF performance.

You mention that the smartphone can detect the KW30. Does the received signal strength (RSSI) is comparable to the one from the FRDM-KW40Z or is it weaker?

Regards,

[glad4enkonm]

Hello Gerardo,

both boards show the same signal level -48dB.
We think firmware is the problem, but can not locate it.

Will you be able to take a look at the layout if we send it?

Thanks for your reply,
Nikolai

[gerardo_rodriguez]

Hello Nikolai,

Unfortunately, I cannot do a deep review of your layout but I can have quick look to see if I notice something wrong with it. I think our BLE beacon reference design can also be useful for you, since it uses the KW30 MCU. You can download and view the design files of this reference design.

I noticed in your schematic that you are using 8pF load capacitors for the 32MHz crystal, while our reference designs use 11pF load capacitors. This can affect the frequency of the BLE radio and could be the reason that the KW30Z can’t receive packets correctly.

I suggest checking out the following documents for more information on how to change the XTAL trim value in KW30Z:

Importance of trimming the XTAL on wireless systems 

Changing the default XTAL trim 

Adjusting XTAL trim to modify central frequency in the KW40 

These documents use the SMAC connectivity test and you won’t be able to run this demo because KW30Z only supports BLE and not 802.15.4, but you can use any Bluetooth demo and analyze the frequency offset in the advertising channels.

Additionally, you could use a USB-KW41Z as a sniffer to further analyze the BLE communication.

Let me know your findings.

Regards,

[glad4enkonm]

Hello Gerardo,

thanks for your reply.

Wich layout format would be better for you?

Nikolai

[gerardo_rodriguez]

Hello Nikolai,

You can share the Gerber files if you like.

Regards,

[glad4enkonm]

Hello Gerardo,

Did you have a chance to look at gerber files?

Thanks,

Nikolai

[glad4enkonm]

Hello Gerardo,

Gerber files on google drive:

ST-mkw30z.GBL - Google Drive 

ST-mkw30z.GTL - Google Drive 

Thanks, 

Nikolai