1.) Interval/Timouts only taken from _fast_? 2.) SoftDevice s113 limited to 4dbm TX power on nRF52840?

[JoWi]

Hi Forum,

1.) The APP_ADV_... parameters in ble_advertising (SDK 16.0) are taken only from _fast_  , is this intended?

    init.config.ble_adv_slow_enabled = true;
    init.config.ble_adv_slow_interval = APP_ADV_INTERVAL; // Ignored in ble_advertising_init(?)
    init.config.ble_adv_slow_timeout = APP_ADV_DURATION; // Ignored in ble_advertising_init(?)
    /* Error in ble_advertising.c: interval/timeout only from _fast_ ? */
    init.config.ble_adv_fast_enabled = false; // (false by default)
    init.config.ble_adv_fast_interval = APP_ADV_INTERVAL;
    init.config.ble_adv_fast_timeout = APP_ADV_DURATION;

    init.evt_handler = NULL; // on_adv_evt; (removed)

    err_code = ble_advertising_init(&m_advertising, &init);

2.) s113 allows only TX_POWER of 4dbm, although the nRF52840 has 8dbm?

Best regards,
Jo

(BTW.: the nRF52840 is really an incredible good product!!! If only the documentation was a little bit better..)

[Simonr]

Hi

The reason the S113 SoftDevice doesn't support +8dBm TX power is that this SoftDevice supports other devices as well ( the nRF52811 for example), which does not have the HW to support +8dBm TX power. If you need the +8dBm TX power functionality, I suggest using SoftDevice S140 instead.

Best regards,

Simon

[Shahar]

Simonr as the SoftDevice can access register INFO.PART (Address offset 0x100 on the FICR registers) and check for the value of 0x52840 to allow the ability to set the TX power to +8db...

what is the limitation of adding this if/then case to the S113 SoftDevice?

Regarding the S140 suggestion, S140 (AFAIK) does perform this check, as it can run on chips which do not have +8db (like the nRF52811 you mentioned)

[Simonr]

Hi Shahar

Sorry about the delayed reply, but we're in the middle of the summer vacation period here in Norway, and I just got back into the office today. The S113 SoftDevice was designed for the nRF52811 which has a rather limited amount of Flash memory space. Therefore minimizing the Flash memory required by the SoftDevice was prioritized rather than adding support (and this check) for a TX power that the nRF52811 doesn't support. 

Best regards,

Simon

[Shahar]

I got an updated answer via the RSM where 8db TX is scheduled to be added to S113 and S112 (coming in August 2020).

So this seems more like an error or oversight and less than an actual Flash limitation.

This is based on the fact that 8db capability is purely based on hardware capability - and adding one more value to the switch case of values can't take that much flash space...