BLE advertisement on 1 particular Channel

[Manjunath S]

I am building an application nrf52840 SDK v17.0.2  soft device is S140 with Segger embedded studio.

Application is to send advertisement data in one single channel (say channel 39) with property type BLE_GAP_ADV_TYPE_NONCONNECTABLE_NONSCANNABLE_UNDIRECTED.

Below is the line used to configure/mask channels

m_adv_params.channel_mask[4] = 0x60;    //For masking 37 and 38.

If I set the time interval to 100ms, I get the advertising packets in the below order according to nrf connect mobile app

I get 40 packets for 1st 4 seconds then there's a gap of 8 seconds and again 40 packets with 100ms and a gap of 8sec. this sequence continues

what is the reason for this?  how do i get the data continuously?

[Simonr]

Hi

This seems to be because your mobile device scans on all the BLE advertising channels (37, 38, and 39) for 4 seconds each. As it only has one antenna it will have to jump between the frequencies, so if your peripheral only advertises on one of these, then the gaps make sense.

Best regards,

Simon

[Manjunath S]

So the device will actually be sending on only 1 channel?

I will confirm this by using multiple mobile phones.