Implement proper AGC reset for SX126x, LR11x0 & SX1276

[weebl2000]

Might be good to have this in RadioLib, based on these PRs:

• fix agc reset on SX126x, SX1276 & LR11x0 chips meshcore-dev/MeshCore#1743
• Implement 'agc' reset for SX126x & LR11x0 chip families meshtastic/firmware#9705

For SX126x & LR11x0: reset analog registers, for SX1276: sleeping should be sufficient. I based this off the SX1262 datasheet & user manuals.

relates to #521

[jgromes]

Thank you, this will be a very useful contribution!

I know the issue has been reported on SX126x - are there some reports this is also happening on LR11xx too, sicne this PR also contains reset method for those radios? And if so, is there a test that could be run on LR2021 to figure if it is happening there as well?

[weebl2000]

Thank you, this will be a very useful contribution!

I know the issue has been reported on SX126x - are there some reports this is also happening on LR11xx too, sicne this PR also contains reset method for those radios? And if so, is there a test that could be run on LR2021 to figure if it is happening there as well?

No reports on LR11x0 that his happens there too. I feel like the LR11x0 is a little more sophisticated with the AGC than the SX126x.

But I dove into the docs and LR1110 is largely done in the same way as the SX1262, so I added it for anyone that would like to try it. It could definitely help when an LR1110 is exposed to big interference say at like a cell site.

UPDATE: LR2021 is largely the same, implemented there too.

[jgromes]

Thanks, I think should be safe to merge - however, before doing that, I will try to run some tests to see if this issue actually manifests on the other radios from Semtech, because we only have it confirmed on the SX126x series so far. So if it doesn't actually manifest there it doesn't make that much sense to be including the AGC reset methods for the other radios IMO. And if it does manifest, then we will know for a fact whether AGC reset resolves it or not.

[weebl2000]

Thanks, I think should be safe to merge - however, before doing that, I will try to run some tests to see if this issue actually manifests on the other radios from Semtech, because we only have it confirmed on the SX126x series so far. So if it doesn't actually manifest there it doesn't make that much sense to be including the AGC reset methods for the other radios IMO. And if it does manifest, then we will know for a fact whether AGC reset resolves it or not.

I'm fairly certain the LR1110 is prone to the same issue, but it's just seen/reported less because it's mainly integrated in more "mobile" applications where power and form factor are most important (hence sub-ghz, GNSS and WiFi in 1 chip) . Whereas the SX1262 is a workhorse in many boards that are also used as repeaters etc.

Most people aren't running repeaters on their LR1110. The calibration reset is valid though, would be good having it in I guess for those few users who might need it.