Is S2 or S8 supported in SD140 v6.0.0?

[Davide]

I'm evaluating BT5 feature using the PCA10056 preview dev kit and SDK v15.

When working with LE Coded PHYs, is the S2 or S8 version? In the SoftDevice release notes only S2 is mentioned, but measuring the on air time for packet (and looking in some discussion in this form) it is more likely that it is using S8.

Could somebody clarify this?

[Einar Thorsrud]

Hi,

The S140 version 6.0.0 SoftDevice does not have an API for selecting coding, and all transmitted packets have S=8 encoding. However, the SoftDevice support reception of both S=2 and S=8 encoded packets.

[Davide]

Hi Einar,

thank you for the answer. Then, from what you say, it is not possible to set S8 for the transmission.

To me this looks strange because using the att_mtu_throughput example and setting PHY=Coded, data_length=27, connection interval 50ms, I clearly see the TX phase to be approximately 2.5ms.

By calculating the TX duration for such a packet I obtain 2.512ms for S8 and 910us for S2, then from the observation it seems that the att_mtu_throughput example is using S8. How can this be if the softdevice doesn't have the API to set S8? What Am I missing?

[Einar Thorsrud]

Hi,

You are right. I swapped S=2 and S=8, so it is the other way around. I will update the original answer so that it is correct (the S140 version 6.0.0 can only transmit with S=8 encoding.)

[Davide]

Perfect, thank you for your time.

Davide.