Advertising services

[swathi p]

Hi,

I have to use current time service and one other customized service in my project.I am able to advertise only one service i.e customized one.can you please let me know the cause that might stop current time service from advertising?Below is the code attached

Thanks & Regards,

Swathi P

[Joakim Jakobsen]

Hi.

Are you sure that you have space to put both services int he avertising packet? Note that you only have 31 bytes available in the advertising packet.

You might want to place one of the services in the Scan response packet. The ble_app_uart example shows how this can be done.

Br,
Joakim

[swathi p]

Hi,

Thanks for your reply.As you suggested I have included one service in advertising packet and the other service in scan response packet.I am able to advertise two vendor UUID's.

Now,I am unable to advertise more than two vendor UUID's.I want to advertise one or two Standard BLE Services along with five manufacturer specific services.

I am getting an ERROR 12  [NRF_ERROR_DATA_SIZE] from ble_advertising_init().

After going through similar posts on devzone,got some suggestions to add  uuids_more_available or p_tx_power_level in advertising_init?what those variables exactly mean?

Can you please let me know the way I can make it possible?

Thanks & Regards,

Swathi P

[Joakim Jakobsen]

Hi.

As I mentioned there are only 31 bytes available in your advertising packet. With the required headers and flags, you are left with 29 bytes of data. 

The 128-bit UUID will use 16 of those bytes so there isn't possible to advertise two in the same advertising packet. Even with the scan response packet, you only have room for two in total.
One option could be to look at extended advertising. If you really need to advertise all the UUID's,  EA allows you to advertise up to 255 bytes.

Br,
Joakim

[swathi p]

Hi,

Thank you for suggestion.I will try implementing using extended adverisement.Can you please let me know any example where this extension advertisement is used?

Thanks & Regards,

Swathi P

[Joakim Jakobsen]

You can take a look at the ble_app_rscs example. This has EA enabled by default.

Br,
Joakim

[swathi p]

Hi,

I have tried implementing extended advertising by adding the below statements into the code:

  ble_advertising_init_t init;

init.config.ble_adv_primary_phy = BLE_GAP_PHY_1MBPS;
init.config.ble_adv_secondary_phy = BLE_GAP_PHY_2MBPS;
init.config.ble_adv_extended_enabled = true;

But after adding those statements i.e after enabling EA I am unable to Scan on nRF Connect.?And I have seen the same with ble_app_rscs example.Please let me know the way I can be able to scan on nRF Connect.

Thanks & Regards,

Swathi P.

[swathi p]

Hi,

After posting reply that I was unable to scan services in nRF Connect,after enabling EA.I have went through several posts related on same issue but I coudn't find any appropriate answer.I read few posts saying that it is due to bluetooth version in the android may not be supporting EA.I am using OPPO A71 to test.Is it true?

If yes,then please let me know the way in which I will be able to advertise and scan more than two vendor UUIDs.

Thanks & Regards,

Swathi P

[Joakim Jakobsen]

Yes, that is most likely due to the Phone not supporting AE.

If you are unable to use AE, there is no way to advertise more than two vendor UUIDs simultaniously. Then you have to advertise a vendor UUID, stop advertising, update your advertising packet with another UUID and start advertising again.

Br,
Joakim

[swathi p]

Hi,

I have six services in my project to send in advertising packet.As you said If not through EA, I can do it by advertising a vendor UUID, stop advertising, update your advertising packet with another UUID and start advertising again.But the thing is I have a need to make all the services available to the user at a time.It should be user choice to choose the service.

If I have only way to do this by stop and start advertising:

To justify my need Can I advertise each service for every 20ms(Bluetooth Specification specifies that the advertising interval should be between 20 ms to 10.24 sec),as there are six services for every 120-140ms I will be able to advertise all the services one after the other.will it be the correct way to do?If yes,will there be issues with power consumptions?If no,suggest me the way in which I can make it possible?

NOTE:Before starting this stop and start advertising in a loop I need to have device in conneced state.As we are starting advertising for every 20ms for each service.Will it be like we need to connect to the device for every 2ms?

Among all six let me explain about three services that I need in my project:

Two are vendor specific and one is standard service.

1)RTC Service  2)Notification Service  3)Battery Service.

I will set some value to the CC register using RTC Service.Then when counter ticks matches given CC value,We need to get notification on to the mobile.This getting notifications on to the mobile when an event generated is done by Notification Service.

Battery service is I want to make use of standard BLE service,for every 60sec/any given particular interval it should check the battery status.whenever battery is below certain percentage it should send notification to the mobile.Again here this sending notification to the mobile is done by using Notification Service.

This is how services are dependent in my project.I hope you understood my concept.Please guide me with appropriate way to implement.

Thanks & Regards,

Swathi P