Connection interval for nrf52840

Hi ,

 For Battery operated devices, we are using NRF52840, and developing the firmware using Segger Embedded studio +  NRF SDK. s140nrf52720, nRF5SDK1702d674dde

For our application we are using the "Peripheral -  Nordic UART Service NUS" example to send the pressure data over the BLE.

To take it further we are going to add the

  • VT - Variable Transmission Time for sensor data ( adjustable interval from 1 sec to 1 minute)
  • DFU

With above context, while developing the firmware we are facing few issues,

For VT,  after reading the several Noridc forum, we come to know that it’s a Central who decide the connection parameters ( slave latency, connection interval MAX, and MIN, supervision timeout).

 Issue#1 : With below setting, we are able to connect with central after every 10 sec of interval , how can we increase it ? To have interval between connection equal to 60 sec. ?

 

In NUS example when we try to change the connection parameters then code didn’t work

Our plan is to use the connection interval always 1 sec and change the Slave latency to change interval between connection.

However , max connection supervision timeout we can set is 32Sec.

   

Issue#2:

 How can, peripheral firmware be able to accept the change in connection parameter ? is this sufficient to have in the firmware?

   Also, is there any simple way we can change the connection parameter from the Mobile APP and test it?

  

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  • Ah, okay. Then AFAIK that should work fine, but then it's most likely a mismatch in the connection parameter update is my guess, and that either the peripheral or central is opting for another slave latency/connection interval.

    It would be helpful to see either the logging information printing what the outcome of the connection parameter update is or the actual on-air sniffer log. You can get a sniffer log with Wireshark, a spare nRF52 series DK, and the nRF Sniffer firmware programmed onto it. I think a sniffer log would be the best next step to take here so we can see what's going on over the air exactly, and why the connection events only go up to ~10 seconds on your end.

    Best regards,

    Simon

  • Hi Simonr,

    I capture the sniffer log and share here for review.

    Thank you for suggestion. 

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