Coded PHY Advertising on nRF Connect SDK

[Jared]

Hey All,

I ran into an issue on the nRF Connect SDK trying to get a nRF52840 advertising using CODED PHY. I figure it's not fully implemented yet are there any updates on timeline for that? I also posted a bug in the Zephyr repo.

Describe the bug
BLE advertising failed to start on a nRF52840 when enabling BT_LE_ADV_OPT_EXT_ADV.

[00:00:00.002,960] <inf> ble_m: BLE Stack Ready!
[00:00:00.002,960] <inf> ble_peripheral: Bluetooth initialized
[00:00:00.002,960] <err> ble_peripheral: Advertising failed to start (err -22)

To Reproduce

1. Choose any BLE example
2. Use a compatible board like nrf52840dk_nrf52840
3. Add CONFIG_BT_EXT_ADV=y to your prj.conf
4. When initializing struct bt_le_adv_param *adv_param = add these two flags BT_LE_ADV_OPT_CODED | BT_LE_ADV_OPT_EXT_ADV

Looks like this:

	struct bt_le_adv_param *adv_param =
		BT_LE_ADV_PARAM(BT_LE_ADV_OPT_CONNECTABLE |
				BT_LE_ADV_OPT_ONE_TIME | BT_LE_ADV_OPT_CODED |
				BT_LE_ADV_OPT_EXT_ADV,
				BT_GAP_ADV_FAST_INT_MIN_2,
				BT_GAP_ADV_FAST_INT_MAX_2,
				NULL);

For instance, if I used the throughput example in the SDK and try to set BT_LE_ADV_OPT_CODED | BT_LE_ADV_OPT_EXT_ADV as some of the parameters it always return -22. Looking further into it, it appears that CODED PHY advertising is (purposefully?) disabled in valid_adv_param.

Any insight is appreciated!


[Jared]

Update:

Adding these guys

# Link Layer
CONFIG_BT_LL_NRFXLIB_VS_INCLUDE=y
CONFIG_BT_LL_NRFXLIB_DEFAULT=y
CONFIG_BT_EXT_ADV=y
CONFIG_BT_CTLR_PHY_CODED=y

Seemed to have done the trick.

Now, I've set my device connectable using this block:

struct bt_le_ext_adv *adv;
struct bt_le_adv_param *adv_param =
BT_LE_ADV_PARAM(BT_LE_ADV_OPT_CONNECTABLE | BT_LE_ADV_OPT_ONE_TIME | BT_LE_ADV_OPT_CODED | BT_LE_ADV_OPT_EXT_ADV,
BT_GAP_ADV_FAST_INT_MIN_2,
BT_GAP_ADV_FAST_INT_MAX_2,
NULL);

But on the central device it always shows up as not connectable. I'm getting that info from the scan_filter_match callback.

static void scan_filter_match(struct bt_scan_device_info *device_info,
struct bt_scan_filter_match *filter_match,
bool connectable)
{
// int err;

LOG_INF("Filters matched. Connectable: %s",
connectable ? "yes" : "no");

If I try to auto-connect, the bt_conn_cb callback returns with an error of 2 which means a timeout. I'll fiddle with it more tomorrow..

[Susheel Nuguru]

I have not played with CODED PHY in Zephyr, but you seems to have a good progress on this. Jared, please keep us updated with this so that fellow developers gain from your experience.

[Jared]

Hi Susheel Nuguru

It appears that connectable advertising for CODED PHY is not implemented on Zephyr. I don't think there are any work arounds until this is implemented unfortunately. More updates in the Github issue.

[Jared]

Hi Susheel Nuguru

I didn't have much luck moving forward.

Some Nordic engineers on the Zephyr repo are convinced I should be able to use it with the Nordic LL. Any way to get more information?

Thanks!

[Jared]

I was instructed to try doing everything manually with the tests/bluetooth/shell example. My attempt looked like this:

bt init
bt adv-create conn-scan ext-adv coded
bt adv-select 0
bt adv-start

I had to use the adv- commands as they're specific for the new extended API. Unfortunately seems some type of kernel issue with the scheduler. Exactly sure what's going on there.

Advertiser[0] 0x20003944 set started
uart:~$ ASSERTION FAIL [!arch_is_in_isr()] @ ../../../../kernel/include/ksched.h:267

I only added a few Lins to the prj.conf:

CONFIG_BT_LL_NRFXLIB_VS_INCLUDE=y
CONFIG_BT_LL_NRFXLIB_DEFAULT=y
CONFIG_BT_MAX_CONN=2

Building with this:

west build -b nrf52840dk_nrf52840

[Susheel Nuguru]

Hi Jared,
The guys replying to you in the Zephyr forum are the guys I would have contacted internally too.  cuficarles and vinayak are the experts in this. Lets hope they have time reply in the zephyr forum.

[Jared]

Got it. Thank you

[Jared]

After a long while, I took another look at this. I got some nRF52840-PDK boards working with updated nRF5284s. I was then able to get a nRF9160+nRF52840 and a separate nRF52840 working over PHY CODED.

For some reason the connect_if_match parameter for scanning does not work for PHY CODED. I implemented my own connect in the filter match callback. Seems to be connecting well!