LoRa synchronization point to point

[vsilv.1]

Hello!

I use two stm32wl55jc1 boards for a point-to-point connection via LoRa, simple, without a gateway. Everything goes well until I introduced the possibility to change the communication parameters (press a button and enter on UART). After the input, the "master" must transmit the parameters to the "slave" and it must give an "ACK". And to move to new parameters.

From this moment, the order is received well, and one board is in reception and one is transmitting, but they are not found. On the oscilloscope it can be seen that the transmission periods fall on the reception ones.

It is interesting that after I reset the "slave" immediately sees the "master", takes the data, sends "ACK" and the two switch to the new settings.

Please help.

[Tesla DeLorean]

Trying to unpack this.

What's the failure here?

It doesn't send an ACK or it misses it?

​One end doesn't change speed?

Any retry/recovery logic here?

[vsilv.1]

1. The problem is: one emits and the other receives, but nothing happens.
2. The slave does not send "ACK" because it does not receive the parameters from the master
3. If the packets are transmitted, both change the settings, without problems.

Without making changes to the initial parameters, the system works, data is exchanged.

[Tesla DeLorean]

Then you'll probably need to work on debugging the speed change transmission, protocol and robustness.​