Connection Loss between nRF and Iphone

RE: Connection Loss between nRF and Iphone

MartinBL — Wed, 02 May 2018 11:52:11 GMT

That seems to be it. It looks like the crystal has a +-40 ppm accuracy, so you should try to use that in your code rather than 20. As David mentions, you can also try to use even higher PPMs or the internal RC source to rule out any issues with your external crystal.

RE: Connection Loss between nRF and Iphone

Mehdi — Tue, 01 May 2018 09:49:57 GMT

Hi David,

I think you talk about this table. Right ?

Best Regards

RE: Connection Loss between nRF and Iphone

David Edwin — Mon, 30 Apr 2018 15:57:56 GMT

Comments:

1. The timeout seems to be 720 ms, which should be ok as it gives more than 20 missed packets before the link drops due to supervision timeout. (at a connection interval of 30ms)

2. The accuracy used in the code is 20ppm but this needs to match the actual accuracy of the 32 KHz crystal as used by the manufacturer. The SDK code is intended to set the 32 KHz accuracy as it is on the board. If the number used in this case i.e. 20ppm is incorrect you will get link losses.

Actions on your end:

- Get the 32 KHz crystal accuracy from your manufacturer or from the datasheets of the module

- Change the crystal drift to a higher level perhaps 50ppm or more and verify if the stability increases

- You can also change the 32KHz source to the internal 32KHz RC source so you are not dependent on the module vendor's 32 KHz clock source. Verify if the stability increases.

RE: Connection Loss between nRF and Iphone

Mehdi — Mon, 30 Apr 2018 15:26:07 GMT

Hi David,

The occuracy i used is 20 PPM .

Please find attached the sniffer traces

Best Regards

devzone.nordicsemi.com/.../snifing-streaming.pcapng

RE: Connection Loss between nRF and Iphone

David Edwin — Mon, 30 Apr 2018 13:56:07 GMT

Can you attach the sniffer traces here here, you can also make the case private if desired.

I looked at the data sheet for the ISP130301 and I could not figure out the accuracy of the 32 KHz crystal used in the ISP130301. Please reach out to the manufacturer and get the accuracy of the 32 KHZ crystal.

Update the

ble_stack_init()

function in SDK 12.x to set the crystal accuracy as stated by the manufacturer of the nRF51 module as the default used may not be correct.

RE: Connection Loss between nRF and Iphone

Mehdi — Mon, 30 Apr 2018 13:36:02 GMT

Hi David,

Thank you for your quick reply.

the sniffer trace is bellow :

https://drive.google.com/file/d/1O8jS2S8YYREXJKIeDp3VmbPKmbHzRfdl/view?usp=sharing.

The markings on the top of my IC is : ISP130301 BL 1625C.
Clock source Crystal, i don't find clock occuracy on SDK_Config, so may be it's the default value.

Best Regards.

RE: Connection Loss between nRF and Iphone

David Edwin — Mon, 30 Apr 2018 13:00:19 GMT

Requested actions:

1. Can you post the sniffer traces

2. Can you state the 32 KHz clock source (Crystal or RC) and its accuracy (in ppm) on the nRF51 board

3. Can you state markings on top of your IC

4. I will look for the Sleep clock accuracy of the iPhone in the sniffer trace, which should be in the connect request. Please make sure that the connect request is present in the trace.