I am using the stm32wb boards to learn OpenThread and develop a low power application to read some sensor data. My plan is to use a CoAP message to send the payload, and have been studying the THREAD_SED_Coap_Multicast example in an attempt to learn. When looking at the power consumption of the board, I have been unable to determine the cause of some short spikes in current when in low power. In all the figures shown, I have disabled the SED polling, and the CoAP messages are sent every 30 seconds. I would expect the current to drop to roughly 2.5 uA (as it does) in between messages and stay there, but instead after a transmission, there are exactly 5 small spikes in current, which from their shape I am assuming are radio activity? These are spaced 1 second apart. Then as the sleep cycle goes on, there will be other slightly larger spikes.
Here is the consumption over about 80 seconds
The tall spikes are the CoAP messages be transmitted
This is the shape of the 5 evenly spaced spikes following every transmitted message
And here is the shape of the other spikes which occur intermittently
It would be very helpful if I was able to get some insight into what may be causing this - as all I changed from the example is a longer time between coap messages (this occurs the same if I include polling). Running a similar SED for zigbee does not include any activity between transmissions, as shown below
Thank you very much
