BlueNRG-LP maximum advertisement delay.

[jbie]

Hello,

When I try to set advertisement delay more than 10000ms, the function aci_gap_set_advertising_configuration return an error 0x82 (BLE_STATUS_INVALID_PARAMS).

According to the function declaration, it must be ok:

/*
....
* @param Primary_Advertising_Interval_Min Minimum advertising interval for
 *        undirected and low duty cycle directed advertising. Time = N * 0.625
 *        msec.
 *        Values:
 *        - 0x00000020 (20.000 ms)  ... 0x00FFFFFF (10485759.375 ms) 
 * @param Primary_Advertising_Interval_Max Maximum advertising interval for
 *        undirected and low duty cycle directed advertising. Time = N * 0.625
 *        msec.
 *        Values:
 *        - 0x00000020 (20.000 ms)  ... 0x00FFFFFF (10485759.375 ms)
...
*/

Here is my function:

BLE_ConfigureDeviceAdvertising(uint32_t adv_interval)
{
ret = aci_gap_set_advertising_configuration(0, GAP_MODE_GENERAL_DISCOVERABLE,
												  ADV_PROP_CONNECTABLE|ADV_PROP_SCANNABLE|ADV_PROP_LEGACY,
												  (adv_interval*1000)/625,(adv_interval*1000)/625,
												  ADV_CH_ALL,
												  PUBLIC_ADDR,NULL,
												  ADV_NO_WHITE_LIST_USE,
												  0, /* 0 dBm */
												  LE_1M_PHY, /* Primary advertising PHY */
												  0, /* 0 skips */
												  LE_1M_PHY, /* Secondary advertising PHY. Not used with legacy advertising. */
												  0, /* SID */
												  0 /* No scan request notifications */);
...
}

Do you have some idea?

Thank you

[Sebastien DENOUAL]

Hi @jbie​ ,

This is expected behavior considering 10sec is the maximum advertising interval allowed by Bluetooth spec.

Regards,

Sebastien.

[jbie]

Edit: Response not correct

I understand.

But is there any way to bypass this limitation ? I want to make a very low power device.

The BLE link will not be with a smartphone but another proprietary device.

Regards,

Jean

[Sebastien DENOUAL]

Hi @jbie​ ,

As BlueNRG-LP is a certified Stack => by default you can not extend advertising interval outside BLE spec (between 20msec and 10sec)

Using timer (or VTimer), you may stop/start advertising. That could be valid alternative.

Regards,

Sebastien.

[jbie]

Hello Sebastien,

There is an interpretation error from ST. The Core spec 5.2 says 10485 seconds and not 10 seconds.

 

Regards,

Jean

[Sebastien DENOUAL · Accepted solution]

Hi @jbie​ ,

Agree maximum is not exactly 10sec (this is a common language we used).

Maximum allowed according to BT core spec is 10.24sec for the legacy advertising you are using.

See : BT core spec 5.2 - §7.8.5 : LE Set Advertising Parameters command

 

The 10,485 value you are mentioning refer to the "extended advertising".

Coming back to your point, this maximum of 10.24sec is indeed supported by BlueNRG-LP stack in accordance with BT core spec.

You can test ADV_interval = 16384 (10.24sec = 16384*0.625)

You can check our "Beacon example" from SDK for more details.

Regards,

Sebastien.

[jbie]

Hello Sebastien,

Thank you for the precision.

Regards,

Jean

[jbie]

Hello @Sebastien DENOUAL ,

I have another question related to this topic.

Do you have a maximum duration of advertisement ?

I want to do a very low power device, so I have an advertisement every 10 seconds for an infinity amount of time.

After around 2.5 hours (900 advertisements), the Bluetooth stops advertising. Do you have any idea ?

Regards,

Jean