gazell maximum channel table size not honoured?

RE: gazell maximum channel table size not honoured?

ovrebekk — Wed, 22 Nov 2017 11:14:55 GMT

According to the developer the issue is most likely that your retransmit counter is too low.
The device will give up before getting to the channel that is shared with the host, and the next time you try again the same thing will happen.

Could you try to increase the TX attempt counter to a larger number on the device, and see if it improves the performance?

For instance, a TX attempt number of 250 should be sufficient.

Best regards

RE: gazell maximum channel table size not honoured?

ovrebekk — Tue, 21 Nov 2017 13:49:06 GMT

Hi again

A quick update: The developer has also been able to reproduce the issue. He needs some more time to look into it, but I should hear back from him in a day or two.

Best regards

RE: gazell maximum channel table size not honoured?

ovrebekk — Thu, 16 Nov 2017 07:11:34 GMT

Sorry for the late reply, I have been out in travel lately.

I just tested this myself, and I do see some irregularities when using channel tables larger than 8 channels. I will check this with the developer and see if there are some issues in the implementation.

Best regards

RE: gazell maximum channel table size not honoured?

Andrew Kohlsmith — Tue, 24 Oct 2017 13:32:35 GMT

Perhaps I haven't explained my problem sufficiently.

I understand how to set the timeslot period and timeslots per channel so that the host and device.

I have no problem with the host/device initialization when I use a channel table using 1-7 channels. If I try to use a channel table with 8 or more elements then I am unable to communicate. No errors are reported by nrf_gzll_set_channel_table(), it just does not work.

In the SDK, NRF_GZLL_CONST_MAX_CHANNEL_TABLE_SIZE is set to 16. Does this not mean I should be able to use a channel table with 16 channels?

RE: gazell maximum channel table size not honoured?

ovrebekk — Mon, 23 Oct 2017 19:05:48 GMT

Hi Andrew

The critical aspect is that the total channel cycle time has to be the same in the device and the host. In other words if you multiply the number of channels with the timeslot time and the periods per channel factor it should be the same on both sides.

In other words, if you want to have a different number of channels configured on each side you have to change the timeslot period accordingly. Also, if you have a different timeslot in each side one of them would have to be a multiple of the other.

Best regards
Torbjørn