Direct Advertisement, how to setup central?

[FI]

Hello,

I have a peripheral based on the nrf52 that connects to my Android phone already in direct advertisement mode.

I am trying to get a NRF52 central working with this direct advertisement. Normal advertisement modes works.

What is the key steps that is needed to have the central setup correctly?

Thanks in advance!

FI

[FormerMember]

When using direct advertising, there is no specific setup for the central, except that you have to make sure that the central is scanning with appropriate scan interval/scan window.

In order to achieve a fast connection establishment a possible, the central should have close to continuous scanning and have a fairly short scan interval. Bluetooth core specification v.4.2, vol. 3, part C, appendix A recommends the following parameters for a fast connection initiation:

• Scan interval: 30 ms to 60 ms
• Scan window: 30 ms
• Minimum time for doing the scanning (scan period): 30.72 s.

[FI]

Here is what was checked:

1. Central device address and its type via UART at central at first connection is

• type: 1
• address: 56 67 B3 36 5B D7

2. Using a sniffer, indirect advertisement Initiator Address is the same 56 67 B3 36 5B D7

3. Address type is checked on the peripheral side via UART as type 1.

Here is the packet data from TI sniffer

+----------------------------------------------------+----------------- - - - | Packet sniffer frame header | +----+-------------+-------------------------+-------+ |info| Packet nbr. | Time stamp | Length| Packet data +----+-------------+-------------------------+-------+----------------- - - - | 01 | 60 02 00 00 | 51 05 A8 33 02 00 00 00 | 18 00 | 17 D6 BE 89 8E C1 0C 2C 69 2E 02 3C DF 56 67 B3 36 5B D7 E7 D1 1F 40 A5 +----+-------------+-------------------------+-------+----------------- - - -

The central sees the Direct Advertisement from this particular peripheral, and a trap catches the peer advertisement in the BLE_GAP_EVT_ADV_REPORT handler:

peer type: 1
2C 69 2E 2 3C DF

Still the central is not connecting when the peripheral goes into Direct ADV. What are the necessary steps for nrf52 central to connect to this guy? Thanks.