Connection interval with slave latency multiple wake ups

[cliffelion]

Hello

nRF54L15 - Zephyr project.

Connection interval = 50ms.
Slave Latency = 16

Connection interval with slave latency is 850ms.
Power chart shows three pulses on every other connection
Cant find any other activity in the code that would cause this - is there a BLE reason for this?

Thank You

[Hung Bui]

Hi Cliff, 

What's the interval of the three pulses ? Please give the interval between the pulse internally and the interval between the 3 pulses group. (Not the period between the 1 pulse and the 3 pulse group)

They look to me like advertising packets. Have you checked if the chip actually doing any advertising during connection ? 

[cliffelion]

Hi Hung

The interval between the three pulses is 50ms. (the connection interval) - we stop advertising once connected and advertising interval is 1s so I don't think that's it. 

Can you confirm if this is unexpected, or is it possibly a reason for BLE to have three consecutive connection intervals every other slave latency period?

Thanks

Cliff

[Hung Bui]

Hi Cliff, 
Could you send us the scope file so we can have a closer look ? 
Also could you try to capture a sniffer trace ? 

It's possible to have 3 pulse , but it's not normal to always have 3 pulse on each connection interval. I would need to see the scope (and/or the sniffer trace) to be able to tell. You usually have one pulse when you have one RX&TX transaction, there can be multiple RX&TX transaction on one connection event when there is still data to transmit (MD bit = 1).