What is maximum number of BLE connections that can be made with the nRF51422?

[Thomas]

What is maximum number of BLE connections that can be made with the nRF51422? I see that the the nRF51822 will support 8 in a star network using the 120 soft device.

Thanks in advance, -Thomas

[Ulrich Myhre]

I'm not sure what you are asking about. The S120 is a softdevice and can run on both of the chips you list. The S120 is only Bluetooth LE however, and there is no ANT+ in that softdevice. Please clarify what you mean.

[Thomas]

The sample application like the one found at

devzone.nordicsemi.com/.../a00085.html

references the use of BLE multi-link of up to 8 nodes on the nRF51822. Will this code work on the nRF51422? I only need 6 nodes to be honest. My topology is a star network so one central node and 5 slave nodes. I have purchased two dev kits for the nRF51422 to decide whether BLE or ANT is a better fit. If I can connect 6 nodes then BLE would be a better fit. I know that I can do this with ANT but long term BLE is a better solution for this project.

Thank you for your time, -Thomas

[Ulrich Myhre]

Yes, all code that works on nRF51822 should work on nRF51422 if I'm not mistaken. nRF51422 just has the ability to run ANT+ enabled softdevices in addition. You can use the S120 to connect to 8 BLE peripheral devices, but it cannot function in the peripheral role (i.e. for advertising). The S130 alpha can do both roles concurrently, but is limited to 3 central and 1 peripheral link. None of these SoftDevices can do ANT+ for the time being.

For your project, it should be enough to use the S120 as a master and some peripheral devices as slaves (S110, or S130 in peripheral role). For your number of links, there should be minimal overlap of connections even at short connection intervals. If 3 slaves links had been enough, you could use 4 devices and either have a tree topology where the master unit collects, parses and sends data to another central.