Packets per connection interval in Central mode


Apologies if this is already answered, I couldn’t find it through documentation or on the forums.

When the Duo is operating in Central mode, what is the maximum number of 20 byte packets that can be transmitted per connection interval? Assume the peripheral can handle the max allowed by BLE.

Also, what is the minimum connection interval allowed in milliseconds?



This feature varies from different chip-set. @mringwal, do you have any discovery on BCM43438?

According to the Bluetooth core specification 4.0, the minimum connection interval is 7.5 ms.



Thanks. Yes, I am wondering the max packets per connection interval for the BCM chipset.

As for the min connection interval, that is the BLE standard minimum, but does the BCM support 7.5mSec? Many vendors don’t, and I am curious to the specifications of the Duo.


hi. which chipsets don’t support 7.5 ms? It’s in the Bluetooth Spec. iOS e.g. does not allow for this interval, but that’s Apple’s decision to not allow it, probably in order to save energy, not a technical.

I would be surprised if the the BCM43438 does not support 7.5 ms.
I don’t know how many packets can be sent. I would suggest to give it a try by sending as fast as possible.