Simultaneous BLE Peripheral for mobile phone, BLE Central for 1M PHY and Coded PHY beacons, 1M PHY beacons distance measurement

[Egor Dolgalev]

Hello,

I'm trying to evaluate a FW development for several features of BLE used simultaneously. I need a BLE Peripheral for mobile phone connection (advertise only once during device provisioning), BLE Central for 1M PHY and Coded PHY beacons to scan for them and (which is very important) be able to measure the distance to the 1M PHY beacons using Nordic Distance Toolbox (NDT). I would like to know the limitations of this approach (to design the system accordingly). Is it viable? What could be a good starting point (any examples, tutorials, etc.)

[Kenneth]

Hello,

To get started with developing I recommend our dev academy:
https://academy.nordicsemi.com/

As to your requirement, the functionality can be performed if they are multiplexed in time. There is only one radio, and the radio can only perform one operation at a time, it will be needed to divide in time. It's possible to scan, then advertise, then in a connection, then scan again etc. The BLE softdevice controller can handle multiple operations, but it will be divided over time. So there will be trade-off you will need to consider as you develop your project. For new development you may consider checking out the nRF54L15 instead, which have a new feature in BLE called channel sounding, that for instance can be used for distance measurements:
https://docs.nordicsemi.com/bundle/ncs-latest/page/nrfxlib/softdevice_controller/doc/channel_sounding.html 

Kenneth

[Egor Dolgalev]

Kenneth, 

I used example project central_hr_coded and modify it. Enable CODED PHY scan, enable peripheral role and introduced custom characteristic, enable advertisement. For some reason I get my FW crashed (assert) on my dev board nrf52840dk in about 30 to 60 seconds after start. I increased all task stacks but the issue is still presented. I enabled Thread analyzer and stacks look good before the assert. There are many beacons around and they advertise. I don't do anything after FW starts just look to the console output. 

Thread analyze:
 BT CTLR ECDH        : STACK: unused 752 usage 208 / 960 (21 %); CPU: 0 %
 BT RX WQ            : STACK: unused 3728 usage 368 / 4096 (8 %); CPU: 0 %
                     : Total CPU cycles used: 1369
 thread_analyzer     : STACK: unused 3640 usage 456 / 4096 (11 %); CPU: 3 %
                     : Total CPU cycles used: 15262
 mcumgr smp          : STACK: unused 1856 usage 192 / 2048 (9 %); CPU: 0 %
                     : Total CPU cycles used: 0
 usbd_workq          : STACK: unused 832 usage 192 / 1024 (18 %); CPU: 0 %
                     : Total CPU cycles used: 0
 BT LW WQ            : STACK: unused 7576 usage 616 / 8192 (7 %); CPU: 0 %
                     : Total CPU cycles used: 71
 sysworkq            : STACK: unused 7736 usage 520 / 8256 (6 %); CPU: 0 %
                     : Total CPU cycles used: 68
 MPSL Work           : STACK: unused 7796 usage 460 / 8256 (5 %); CPU: 0 %
                     : Total CPU cycles used: 3050
 usbworkq            : STACK: unused 832 usage 192 / 1024 (18 %); CPU: 0 %
                     : Total CPU cycles used: 0
 shell_dummy         : STACK: unused 1712 usage 336 / 2048 (16 %); CPU: 0 %
                     : Total CPU cycles used: 4
 idle                : STACK: unused 4032 usage 64 / 4096 (1 %); CPU: 95 %
                     : Total CPU cycles used: 485977
 main                : STACK: unused 3472 usage 624 / 4096 (15 %); CPU: 0 %
                     : Total CPU cycles used: 949
 ISR0                : STACK: unused 7268 usage 988 / 8256 (11 %)
ASSERTION FAIL [0] @ WEST_TOPDIR/nrf/subsys/bluetooth/controller/hci_driver.c:311
        SoftDevice Controller ASSERT: 50, 501

I tried to look to the this assert but don't understand what is the reason. Do you have any tips or suggestions what coul be the reason? I use SDK 2.9.0

I attached my project sources.

5751.central_hr_coded.zip