Restarting the network core

[Nick Stoughton]

We have a project on a 5340 based system, that only occasionally needs to have Bluetooth running. We have a relatively small battery in the device, and want to save every microamp possible. We can shut down the net core with

nrf_reset_network_force_off(NRF_RESET_S, true);

and indeed, power consumption drops. The problem is how to re-enable `hci_rpmsg` when we need to use BLE. Simply turning the netcore back on leads to a crash. Is there a recommended method to re-initialize the IPC subsystem after re-enabling the netcore?

Thanks!

Nick

[Amanda Hsieh]

Hi, 

The issue could be caused by [161] RESET: Core is not fully reset after Force-OFF. You can check the workaround or my colleague's code in this post. 

Regards,
Amanda H.

[Nick Stoughton]

Thanks...unfortunately we have CONFIG_RESET_ON_FATAL_ERROR set to 'y' everywhere except the main app. 

I think this is more a matter of "how do I re-initialize hci_rpmsg after a netcore reset" ... the crash I see is an assertion fail while waiting for the sync done semaphore (running NCS 2.5.0, this is a line 338 of hci_core.c). I need a way of (a) cleanly shutting down the net core, and (b) once it is down, handling a restart and re-enabling the entire IPC mechanism.

[Nick Stoughton]

Oh, and I tried the anomaly-161 work-around with no effect.

[Amanda Hsieh]

Check out this post. 

[Nick Stoughton]

bt_disable() fails with EOPNOTSUPP because, in the 5340 drivers/bluetooth/hci/rpmsg.c driver (we are using NCS 2.5.0) there is no close function.

However, I see that v3.5.99-ncs1 has implemented this, so I will try moving to that. Thanks.