bt_adv_conn_data_set()

Description

Sets data to advertise with a pre-configured advertisement configuration for connectable advertising. Data is added to the advertising indication packet in the connectable advertising set. This does not override device name in GATT server settings, which is advertised in the scan response packet.

Syntax

bt_adv_conn_data_set(adv_data[], data_len);

Parameters

Variable	Input

Variable	Input
`adv_data[]`	An array of data to advertise. Must follow the BLE data format.
`data_len`	Length of the data to be advertised. Messages up to 31 bytes are supported.

Refer to the example below on how to construct the BLE payload.

Returns

Return value	Return explanation
SCRIPT_OPERATION_SUCCESS	Successfully added advertisement data.
SCRIPT_OPERATION_FAILED	Failed to add advertisement data.
SCRIPT_PARAM_INVALID	Given data length is bigger than data array.
SCRIPT_NO_ACCESS	This error signifies that Bluetooth communication was not initialized.

Constructing beacon data

A useful tool to help create Bluetooth LE advertisements: Bluetooth LE Advertisement Builder. The constructed payload can then be initialised as an array using the code example below.

To create custom advertised data, first select the data type you want to advertise. For example, to advertise specific "Service data" and "Manufacturer specific data" use data types 0x16 and 0xFF respectively, as indicated in the assigned numbers document:

Secondly, each data type has its own data:

For data type 0x16 (Service data), we'll advertise: 0x09, 0x6C.
For data type 0xFF (Manufacturer-specific data), we'll advertise: 0xAB, 0x41, 0x30.

After deciding on which data to advertise, the length of each data type entry needs to be calculated. Note that the data type byte is also added to the calculations.

For data type 0x16 (Service data), the data length is 3 (two data bytes and one data type byte).
For data type 0xFF (Manufacturer-specific data), the data length is 4 (three data bytes and one data type byte).

Finally, construct the BLE advertisement. Each data type follows this pattern: data length byte → AD type byte → data bytes. Multiple data types can be included in one message. The maximum total payload is 31 bytes.

Some BT scanners cannot discover beacons without the “discoverable” flag set. To enable this, add three bytes to the start of the advertisement payload: 0x02, 0x01, 0x06. This sets both the discoverable and BLE-only flags.

So the newly formed array (with BT flags) would look like this = {0x02, 0x01, 0x06, 0x03, 0x16, 0x09, 0x6C, 0x04, 0xFF, 0xAB, 0x41, 0x30}

Byte	Role	Notes

Byte	Role	Notes
0x02	Length	2 bytes follow (flags element)
0x01	AD type	Flags
0x06	Flags value	General discoverable + BLE-only
0x03	Length	3 bytes follow: `0x16`, `0x09`, `0x6C`
0x16	AD type	Service data type
0x09	Data
0x6C	Data
0x04	Length	4 bytes follow: `0xFF`, `0xAB`, `0x41`, `0x30`
0xFF	AD type	Manufacturer specific data
0xAB	Company ID (41AB)	In LE format
0x41	Company ID (41AB)	In LE format
0x30	Data

Function call example

#include <io>
#include <read>
#include <float>
#include <string>
#include <core>
#include <write>
#include <define>
#include <socket>
#include <bluetooth>

new demo_adv_array[] = [0x02, 0x01, 0x06, 0x03, 0x16, 0x09, 0x6C, 0x04, 0xFF, 0xAB, 0x41, 0x30];

main()
{
    bt_init();

    /* GATT server init code start */

    /* GATT server init code end */
    
    bt_adv_conn_data_set(demo_adv_array, sizeof(demo_adv_array));
    for(;;)
    {
        Delay(100);
    }
}