how to send LL_Control_PDU,like LL_VERSION_IND, LL_FEATRUE_REQ、and LL_Connect_UPDATA_REQ by nrf51822 and sdk12.03?

[luocan]

this packet is  capture  by wireshark .I use nrf51822 and  sdk12.3  connect    Balance car,but  the  packet not have LL_VERSION_IND, LL_FEATRUE_REQ、and LL_Connect_UPDATA_REQ these PDU(the second image),but  when I use the APP  to connect balance car,it has these PDU(the first image) ,so how I send these PDU  by  nrf51822 and SDK12.3?

[Edvin]

Hello,

The PDU packets are sent by the Softdevice. The same with the LL - messages.

 

To be specific:

Some LL messages are sent on connection (by the softdevice), but if you want to change some connection parameters from your application layer, these are also sent as LL commands (after these calls are sent to the softdevice via sd_"some command"() ).

The PDU messages are the BLE version of "I'm alive" messages. If too many of these are not received, then the connection will be considered lost, and the device will start advertising/scanning again.

 

So if you are in a connection, then these PDU messages are sent by the softdevice, so you don't have to do anything / can't do anything with them.

Except if you want to minimize the number of them, to save battery power, you can increase the connection interval.

 

Best regards,

Edvin

[luocan]

Hello,Edvin.

       my  NRF51822 device can  connect the Bluetooth  small car,but  when I capture package,I don't  see  the  LL_Control_PDU,so  I  can't  control  my   small  Bluetooth car,   but  when I use the mobile phone APP,I can capture these LL_Control_PDU package, so I guess  if I set these LL_Control_PDU, I  also control my car.as you say,these package  are send  by  softdevice,Is this version of softdevice without these LL messages?  if  it have,I should  how to send them  by  what  function.

[luocan]

开发板连接上蓝牙数据包1.pcapng苹果手机连接后数据包2.pcapng

[luocan]

the   first  package  is  my  nrf51822 device connect the Bluetooth car,the second package is IOS  connect decice

[luocan]

the   first  package  is  my  nrf51822 device connect the Bluetooth car,the second package is IOS  connect decice