How do I (simply) do a non-connectable advert on nRF52 using SDK 15?

[Michael McClary at CloudLeaf]

I am porting a peripheral project from nRF51822 on SDK 11 to nRF52832 on SDK 15.  Currently I'm using15.0, with S132 6.0.0.  I used the template project for an initial pattern for working with SDK 15.

One thing it needs to do is (if I have the term right): "Peripheral Advertiser", i.e.

• When unconnected it advertises normally, as a connectable peripheral.
• While connected it advertises as unconnectable (so other centrals can still SEE it), but otherwise identically.
• When the connection is ended, it reverts to the connectable advertisement.

I am having difficulty finding any simple explanation for how to do this.

• Nearly everything I found was for earlier SDKs - but advertising changed massively between 14 and 15.
  • Under 15 it seems to have switched to advertising structures managed by the soft device in the latter's storage,
  • addressed by a handle/index rather than a pointer
  • not to be modified on-the-fly, but replaced by a new one (and the old one unavailable for reuse until the soft device has finished some post processing on it)
  • The automatic turn-on of advertising on connection drop (on_disconnected()) sets the type to BLE_ADV_MODE_DIRECTED_HIGH_DUTY, rather than, say,
• The closest I did find on SDK 15 was https://devzone.nordicsemi.com/f/nordic-q-a/32824/dynamically-updating-advertising-data-in-sdk-15/126346#126346,
  • That seems to be an in-process debug of a rotating-triple-buffer scheme that is also supporting on-the-fly modification of the contents of the advertisement in other ways.
  • It also seems to involve replacing components/ble/ble_advertising/* with a roll-your-own substitute.

Can someone give me (or give me a pointer to) a simple (or as simple as practical under SDK 15) scheme for just doing the basic keep-advertising-while-connected, switch-between-connectable-and-unconnectable function.

============

(I WILL be needing on-the-fly adjustment of the manufacturing field in another month or so, so info on that would also be nice.  But I need the above right away.)

Thanks.

[Vidar Berg]

Please review and test the example I uploaded in my previous comment.  Just remove the code below from update_advertising_data() if you want the data to be updated while connected. 

    /* In this demo we update advertising while we're disconnected*/
    if (m_conn_handle != BLE_CONN_HANDLE_INVALID)
    { 
        return;
    }

[awneil]

I had separately tried to do it without adjusting priorities:

https://devzone.nordicsemi.com/f/nordic-q-a/47391/sdk-15-3-0-restart-non-connectable-advertising-after-timeout

But that has its own issues!

Will have a look at your latest ...

[awneil]

Vidar Berg said:

Please review and test the example I uploaded in my previous comment

I connected & disconnected, then left it connected for a while.

When I came back, this had happened:

<info> app: 8816 Template example with non-connectable advertising while connected.
<info> app: Fast advertising.
<info> app: Connected.
<info> app: Disconnected.
<info> app: Fast advertising.
<info> app: Connected.
<error> app: ERROR 8198 [Unknown error code] at main.c:478
PC at: 0x0002F33B
<error> app: End of error report

Line 478 is the APP_ERROR_CHECK at the end of sleep_mode_enter():

    // Go to system-off mode (this function will not return; wakeup will cause a reset).
    err_code = sd_power_system_off();
    APP_ERROR_CHECK(err_code);

The code is unmodified, apart from the name displayed in the startup log.

EDIT

And again - this time while advertising:

:
:
:
<info> app: Fast advertising.
<info> app: Connected.
<info> app: Disconnected.
<info> app: Fast advertising.
<error> app: ERROR 8198 [Unknown error code] at main.c:478
PC at: 0x0002F33B
<error> app: End of error report

Is this just an artefact of having the RTT logger attached?

[awneil]

Vidar Berg said:

Just remove the code below from update_advertising_data() if you want the data to be updated while connected

Actually, that code means that the Advertising Data is never updated after the first connection!

This is due to a bug in the original Template code - which never clears m_conn_handle after a connection!

We need to add it on the BLE_GAP_EVT_DISCONNECTED event:

/**@brief Function for handling BLE events.
 *
 * @param[in]   p_ble_evt   Bluetooth stack event.
 * @param[in]   p_context   Unused.
 */
static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
    ret_code_t err_code = NRF_SUCCESS;

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_DISCONNECTED:
            NRF_LOG_INFO("Disconnected.");

            m_conn_handle = BLE_CONN_HANDLE_INVALID;   //  <<<<<  HERE !

            // LED indication will be changed when advertising starts.

[Vidar Berg]

I was not aware of this bug, thanks for pointing it out. Anyway, the main purpose of this demo was to show how you can use the "update" API. 

awneil said:

Is this just an artefact of having the RTT logger attached?

I forgot to disable timeout for the non-connectable advertisement, that's why sleep_mode_enter() got called.

sd_power_system_off() will return with an error when the chip is in debug interface mode, see emulated system OFF mode: https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/power.html?cp=3_1_0_17_1_0#unique_1199040052