problem about nRF52832's bluetuth

RE: problem about nRF52832's bluetuth

visionwang — Thu, 15 Mar 2018 10:09:28 GMT

Q1: only one device has this issue;

Q2: yes,all devices have the same offset;

Q3: yes,i do, but the issue doesn't disappear, not only replacing the crystal, but also replacing other components , such as Cl,nRF52832,antenna,and so on

Q4: no, how can i get SDK v14? what is the purpose?

how do i test receiver sensitivity of blue tooth

RE: problem about nRF52832's bluetuth

Håkon Alseth — Thu, 15 Mar 2018 09:59:21 GMT

Your crystal loading seems to be correct.

Q1: How many devices are showing this issue?

Q2: Does all devices have the same offset?

Q3: Have you tried replacing the crystal to see if this issue is then fixed?

Q4: Are you testing with a unmodulated carrier (for instance by using radio_test in SDK v14) ?

Best regards,

Håkon

RE: problem about nRF52832's bluetuth

visionwang — Thu, 15 Mar 2018 04:08:21 GMT

crystal's part number is FA-128 32.0000MF10Z-AJ3 ,Cl is 8pF

RE: problem about nRF52832's bluetuth

Håkon Alseth — Wed, 14 Mar 2018 13:33:36 GMT

Hi,

A frequency offset of 199 kHz is 82.8 ppm offset, which is quite a lot.

It sounds like the capacitors does not match the "CL" of your crystal (the CL is per your requirement, Digikey has 32M FA128 crystals with CL of 8, 10, 12, and 18 pF).

The formula is:

C = 2*CL - Cpin - Cpcb

Where Cpin = 4 pF, and Cpcb is normally 0 - 2 pF, depending on the PCB track length.

Your capacitors of 12 pF indicates then a "CL" of 8 pF on your crystal part. Can you please double check what the "CL" of your crystal is?

Best regards,

Håkon