Maximum number of the peripheral node that can be bonded with the central node

[hardikp]

Hello,

In our application, the central device will connect to one peripheral node at a time, collect the data, and disconnect it. There may be more than 30 to 40 peripheral devices in the range of the central device. 

We are using nRF52840 as a central node and nRF52833 as a peripheral device.

We are using nRF5 SDK v17.0.0 and softdevice 140.

Can the central device connect to all 30-40 sensor node one by one? 

Is there any limitation on maximum number of bonds? 

[haakonsh]

The S140 supports up to 20 concurrent links. If you need to connect to more devices you will have to cycle through connections to get the data, or use advertisement extensions to get the data of them.

There is a limit on the number of bonds as each bond requires a certain amount of data stored in flash. It is not a fixed number. It depends on the number of flash pages you have dedicated to FDS, the size of each bond, and if anything else is storing data through the FDS.

The result will be that you receive a PM_EVT_STORAGE_FULL event. Then you can run garbage collection, or delete bonds.

[hardikp]

Thanks, Haakonsh.

It makes sense.

[haakonsh]

You can also use two Centrals serving 20 connections each. 
The channel hopping scheme of BLE makes the radios jump to one of the 37 data channels at random for every connection event, so it matters not that you run multiple BLE networks right on top of each other.