PCA10040 change notes

[WoutEcto]

Hello,

We are using some nRF52 DKs (PCA10040) for running tests in production and we noticed there was a small but significant difference in the RSSI value reported by the nRF52 DK (which acts as central) between two tests with the same setup. When investigating, we noticed that the versions of the nRF52 DKs are different, the nRF52 DK which reports higher RSSI values is of version 1.1.1and the other nRF52 DK which reports lower RSSI values is of version 2.0.0.

We tried to make sure to make both test setups as similar as possible, and I realize that RSSI is a metric that's influenced by a lot of things, but I was wondering if there are some sort of change notes available that list out the changes between nRF52 DK versions? 

[dejans]

Hi,

Which SDK do you use?
Could you provide more information about both test setup configurations? 
Where and how do you measure RSSI values?

Best regards,
Dejan

[WoutEcto]

Hi Dejan, 

Thank you for responding. The main question is if there are change notes available for the PCA10040 hardware revisions. All the rest is context to why we are interested in that information at this moment, although it's in general useful information I believe.

To answer your questions, we are using SDK 16.0.0 with Softdevice S132 version 7.0.1, for both versions of PCA10040.

We have our device (peripheral) placed in a shielded box together with the nRF52 DK (central) at a controlled distance. The device is turned on, a connection is established and a set of operations are performed while the connection is live. This whole operation takes 5 seconds after which our device is turned off. During these 5 seconds, an RSSI sample is read out every second from the central device which gets its RSSI sample from sd_ble_gap_rssi_get(). Those 5 RSSI samples are then averaged out to get to a final (average) RSSI value which is recorded in a file. It is this recorded (average) RSSI value that seems to be consistently different between the test setups. We're still investigating some other options, but one obvious difference is the two versions of PCA10040 used as central.

Best regards,

Wout

[dejans]

Hi Wout,

What are the RSSI values that you obtained in your 2 different setups?

Best regards,
Dejan

[WoutEcto]

Hi Dejan,

Again, that's not really relevant to my question about whether there are change notes available for PCA10040 or not. I don't really see how listing RSSI values that are highly dependent on a lot of factors will help to achieve that goal.

But just for completeness: the RSSI values reported by the PCA10040 on version 1.1.1 are in the range of -27 - -29dBm whereas value for the same DUTs measured with the PCA10040 on version 2.0.0 is on average 7.5dBm lower.

Best regards,

Wout

[dejans]

Hi,

You could take a look at nRF52-DK hardware files changelog, revision 1 errata, revision 2 errata and SoC revisions and variants.

Best regards,
Dejan