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'll look into this today/tomorrow and try to reproduce the problem.

Best regards,

Simon

[Lukáš]

Hi Simon,

ok, looking forward to your thoughts. Yesterday, I was again inspecting it for a few more hours but haven't been able to find the issue.

Lukas

[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

[Lukáš]

I guess for most users, it is preferred to get it automatically by Zephyr from the registers you specified. For us, it is also the easiest option.

[Simon]

Okay, I will ask about this internally.

[Simon]

Coud you try using the option BT_LE_ADV_OPT_USE_IDENTITY?

[Lukáš]

Hello Simon,

BT_LE_ADV_OPT_USE_IDENTITY does nothing. You can try it yourself by replacing line 77 by

struct bt_le_adv_param *adv_param =	BT_LE_ADV_PARAM(BT_LE_ADV_OPT_CONNECTABLE | BT_LE_ADV_OPT_USE_NAME | BT_LE_ADV_OPT_USE_IDENTITY,
			BT_GAP_ADV_FAST_INT_MIN_2, BT_GAP_ADV_FAST_INT_MAX_2, NULL);

err = bt_le_adv_start(adv_param, ad, ARRAY_SIZE(ad), NULL, 0);

As I said in the beginning, I don't understand the stack. However, I think it's "too late" to set something in the advertisement options. From my point of view, there must be something messed up in the stack when settngs_load() is called. Could someone from your team inspect it, please?

[Lukáš]

Simon, I know its a Christmas time now. But could you at least report this as a bug so it gets fixed by some of your developers? I am pretty sure this should work out of the box for split controller + host. I mean it should behave the same as it is running on a single chip with host & controller which is not the case right now.

[Simon]

Sorry for the delay on this. I've been gone lately due to vacation. I have filed a report on this internally. I will keep you updated on the progress. However, I'll be gone until the 4th of January and I won't be able to provide an answer until then.

Best regards,

Simon

[Lukáš]

Hi Simon, any update on this?

[Simon]

I'll put off some time Tuesday/Wednesday and see if I can get to the bottom of this.

Best regards,

Simon

[Simon]

I was able to make this work* by setting these at the nrf9160 host side (ncs\v1.4.0\nrf\samples\bluetooth\nrf91_bluetooth_host\prj.conf):

CONFIG_BT_HCI_VS=y
CONFIG_BT_HCI_VS_EXT=y

Can you check if you're able to make it work as well?

Set SW5 to nRF52 and run nrfjprog --memrd 0x100000A4 --n 8 and check that the output is the same as the advertising address.

---

*For outside readers: Automatically advertise with the address stored in the register DEVICEADDR on the nRF9160 DK, where the nRF9160 operates as the host and the nRF52840 operates as the controller

Best regards,

Simon