Bluetooth split stack issues with nRF91 and nRF52 in NCS

[Lukáš]

Hi,

I am trying to build a simple example that will run nRF91 as BLE host and nRF52 as BLE controller in the latest stable NCS 1.4 and nRF9160DK 0.8.2. However, I have encountered two issues.

My sample for nRF91 won't communicate with HCI UART driver flashed to nRF52840 on nRF9160DK.

This is what I get from the log.

00> *** Booting Zephyr OS build v2.4.0-ncs1-5-g1664f186a309  ***
00> 
00> [00:00:00.000,274] <inf> main: Bluetooth trying to init
00> [00:00:00.002,868] <inf> fs_nvs: 2 Sectors of 4096 bytes
00> [00:00:00.003,143] <inf> fs_nvs: alloc wra: 0, ff0
00> [00:00:00.003,387] <inf> fs_nvs: data wra: 0, 0
00> [00:00:00.610,656] <wrn> bt_hci_core: OpCode 0x0000 completed instead of expected 0x0c03
00> [00:00:00.611,053] <wrn> bt_hci_core: opcode 0x0c03 status 0xc0
00> [00:00:00.611,358] <err> main: Bluetooth init failed (err -5)

Steps to reproduce:

1. Build HCI UART from ncs/zephyr/samples/bluetooth/hci_uart and flash it to nRF52840 on nRF9160DK
2. Build my sample code from https://github.com/lukasbrchl/nrf91_bluetooth_host and flash it to nRF9160 on nRF9160DK
3. Restart DK and observe the error

The weird thing is that when I use the prebuilt hci_uart.hex file from this thread. Then it works without any problem. Even when I try to build and flash the LTE BLE Gateway sample, then it also initializes Bluetooth without problems.

Bluetooth MAC address is not kept static after reset in the split stack

Steps to reproduce:

1. Flash the prebuilt hci_uart.hex file from this thread to nRF52840 on nRF9160DK
2. Build my sample code from https://github.com/lukasbrchl/nrf91_bluetooth_host and flash it to nRF9160 on nRF9160DK
3. Observe in nRF Connect on a mobile phone that MAC address changes on each restart.

It was already discussed in this thread. Since I cannot get working the hci_uart sample (first issue) I cannot experiment in adding additional settings/configs. 

Please let me know your thoughts.

[Simon]

I tried to investigate this a little, and think I made some progress. The value of id_addr->a was consistent and always the same after each reset. However, the value of addr changed every time, and this value was equal to the one I saw in the nRF Connect Mobile phone app. I'm not sure why this is. Maybe because the variable is stored inside a local scope or something? I did not get time to get any further today, but will continue tomorrow. Maybe you are able to figure this out?

Best regards,

Simon

[Lukáš]

Simon, great to hear from you. Unfortunately, I must say that my knowledge ends up here. I have no idea how to debug this further as I see no error in the code.

[Simon]

I'm sorry for the delay on this, I'll just tell you that I'm still looking into this and eager to get to the bottom of it.

[Lukáš]

Thanks for the message and your time debugging this issue.. To be honest with you, I already gave up. It's too complex for me. 

[Simon]

I asked internally about this and got tipsed about setting CONFIG_PRIVACY=n and to use bt_set_id_addr(). However I was not able to make this work. Before investigating further I would like to clarify something: Are you interested in setting the MAC address yourself using bt_set_id_addr(), or would you like it to get set automatically by Zephyr (using the values in NRF_FICR->DEVICEADDR[])?

Best regards,

Simon