Multilink + NUS data reception problem

RE: Multilink + NUS data reception problem

JeanG. — Tue, 03 Dec 2019 22:35:55 GMT

Thanks! I tried to reduce the connection interval to the minimum (7.5 ms) and NRF_SDH_BLE_GAP_EVENT_LENGTH to 1.25 ms but it's still not fast enough.

I'm going to see if I can find something else, but I think that I'm at the limit here...

RE: Multilink + NUS data reception problem

Håkon — Mon, 02 Dec 2019 17:46:53 GMT

Hi,

Good, it works OK when transmitting more seldom.

I am not sure how you do things in your code.
However, a few things worth mentioning after discussing with my colleagues.

The minimum connection interval in BLE is 7.5 ms, per link.

It is possible to to decide how must time is set aside for each link on each connection interval
NRF_SDH_BLE_GAP_EVENT_LENGTH - The time set aside for this connection on every connection interval in 1.25 ms units.

It is possible to use the Enhanced Shockburst protocol in applications where shorted connection intervals are needed.

RE: Multilink + NUS data reception problem

JeanG. — Fri, 29 Nov 2019 22:10:31 GMT

Hi,

Thanks for your answer! If I try to send data every 100ms, it works, I only receive one data set from each peripheral at a time. But I need to send the data faster.

I'm printing the data with the Dongle using the app_usbd_cdc_acm_write() function when the BLE_NUS_C_EVT_NUS_TX_EVT is called.

"Otherwise you can print your data only when you have at least one data set from each peripheral device, e.g. using only the latest data."
Do you have an idea on how I can implement that in my program?

"It could look like you are printing all of the data you have available for a giving peripheral device"
Yes, maybe that's what is happening!

Thanks,

Jean

RE: Multilink + NUS data reception problem

Håkon — Thu, 28 Nov 2019 14:54:53 GMT

Hi,

I am not sure what you use case is, hence I am not sure if my proposals are valid or suited for you.

Can you try to send your data not this often, e.g. every 100ms and see if this solves your issue?
Otherwise you can print your data only when you have at least one data set from each peripheral device, e.g. using only the latest data.

Another item, printing every packet you receive will en up in a massive amount printing when you are receiving 3 packets each ms.

I am wondering about how are you printing.
It could look like you are printing all of the data you have available for a giving peripheral device, before checking if there are available data for another device instead of only printing when you receive a new data set.

BR,
Håkon