Concurrent link on 52833

RE: Concurrent link on 52833

Einar Thorsrud — Tue, 05 May 2020 14:12:33 GMT

Hi,

[quote user="cpi"]* We want to attach as many BT peripheral devices to one BT central device as possible. There is a support of up to 20 connections using the combination of the S140 wit the nRF52833 or nRF52840. What are the limiting factors? Is it RAM/FLASH/CPU Performance or a radio limitation?[/quote]

All of the factors you mentioned can be limiting, it depends on the configuration.

Also, note that it is much easier to get better performance when the nRF is acting as a central and has many connections with peripheral devices, then if the nRF is acting as a peripheral with many connections with central. In the first case, the nRF can schedule the various connections to not overlap. In the latter case, the nRF has no control and there are likely to be many more conflicts.

[quote user="cpi"]* The nRF52833 and nRF52840 are differently equipped with RAM and FLASH. Is one of those SoCs better suitable for up to 20 connections? Please also bear in mind that we want to run the SoC only in a modem mode.[/quote]

If the limiting factor is flash and/or RAM, then the nRF52840 is a better choice. But this depends on your specific use case. If radio time/scheduling is the limiting factor, then it does not matter.

[quote user="cpi"]* What kind of solution would you suggest, if the 25 parallel BLE connections are a must-have? Maybe going for two ICs?[/quote]

The highest supported number of connections on any nRF device is 20 (for recent SoftDevice versions). You will need to use two nRF devices to support a higher number of connections. Note that this will introduce new problems, though. Since these two devices will be independent, there will likely be some overlap in the radio times. This becomes more of an issue the more traffic there is. If they are very close by, then most/all collisions will lead to packet losses and retransmissions, and this could greatly reduce the performance you get.

RE: Concurrent link on 52833

cpi — Tue, 05 May 2020 09:14:39 GMT

Hi,

I really would like to reply to this blog entry because I think it really fits fine. I need some detailed information regarding a new development project.

* We want to attach as many BT peripheral devices to one BT central device as possible. There is a support of up to 20 connections using the combination of the S140 wit the nRF52833 or nRF52840. What are the limiting factors? Is it RAM/FLASH/CPU Performance or a radio limitation?

* The nRF52833 and nRF52840 are differently equipped with RAM and FLASH. Is one of those SoCs better suitable for up to 20 connections? Please also bear in mind that we want to run the SoC only in a modem mode.

* What kind of solution would you suggest, if the 25 parallel BLE connections are a must-have? Maybe going for two ICs?

Thank you very much for any feedback!!!

RE: Concurrent link on 52833

Einar Thorsrud — Mon, 03 Feb 2020 08:23:39 GMT

Hi,

The nRF52833 is supported with S140 or S113 (see SDKs and SoftDevices compatibility matrix). The S113 can only act as a peripheral (or broadcaster), so for a Central device, you would use S140. This supports up to 20 connections (in any combination of roles), but it may be limited by the available RAM, depending on configuration, etc.

RE: Concurrent link on 52833

ran — Sun, 02 Feb 2020 10:27:48 GMT

This with NRF52833 in a "master" role.