Could nRF52805 be a BLE master and BLE slave at the same time?

[StevenW807]

Hi, I'm using BC805M module (nRF52805 SoC). I understand that the nRF52805 doesn't support BLE mesh. I would like to ask about the availability of using BLE (S112/S113) for my project. 

BC805M #1: reads sensor 1 data via I2C, and send the data to the BC805M #2 via BLE

BC805M #2: reads sensor 2 data via I2C, receives the BC805M #1 data via BLE, and send both sensors data to the user's phone via BLE

User's phone: receive both sensor's data from the BC805M #2 via BLE

1) Is this feasible? Basically, I would like to ask: could BC805M be a BLE (S112/S113) master and BLE slave at the same time? (it's OK to have a little delay)

2) If it's infeasible, could I use ANT to communicate between two BC805M, and use BLE to send data to the user's phone? (i.e. BC805M is an ANT slave and BLE master at the same time)

3) Is it true that 1 BLE salve can only receive the data from 1 BLE master? 

Thank you very much! 

[Kenneth]

Hi,

Not sure if I have a simple answer for you here, it will depend on the amount of flash and ram you need also. You can find an overview here on the amount of flash and ram available for different variants of the nRF52-series:

https://infocenter.nordicsemi.com/topic/struct_nrf52/struct/nrf52.html

If you click on each of the S1xx softdevices here you can find how many peripheral and central links it can support:

https://infocenter.nordicsemi.com/topic/struct_nrf52/struct/nrf52_softdevices.html

For instance the S112 and S113 only support peripheral role, so it can't be a central role. However if you choose a softdevice release (e.g. S132) that support both peripheral and central role, then I don't see any reason why your proposed description won't work:

"reads sensor 2 data via I2C, receives the BC805M #1 data via BLE, and send both sensors data to the user's phone via BLE"

Once you know which softdevice to use, then you must use a nRF52-variant that can use that softdevice, this is found under each nRF52-variant, e.g. for the nRF52832 you can find:

https://infocenter.nordicsemi.com/topic/comp_matrix_nrf52832/COMP/nrf52832/ble_qdid_qual_matrix.html

Based on the above I don't think BC805M can be used to relay data as you want to, you will need for instance nRF52832.

Best regards,
Kenneth

[StevenW807]

Thanks for your clear and detailed answer, Kenneth. 

All I need is to receive 2 BLE data from two BC805M and display the data on my phone App.

1) Could I use two BC805M (nRF52805 only supports S112, S113) as 2 independent BLE peripheral / broadcaster roles, and send the 2 data to my phone app (central / master device) concurrently, please? i.e. 1 master, 2 slaves

2) According to the S112 website, it says "Up to 4 connections as a Peripheral can be run concurrently with a Broadcaster". Does it mean the S112 device is a peripheral device, it can be connected by 4 central devices at the same time? Meanwhile, it can be a broadcaster at the same time? 

Thanks! 

[Kenneth]

1) Sure yes.

2) That is correct.