reflected power interlock

[hartytp]

This is currently exposed to the user. I don't feel too strongly about this + am very open to feedback, but previously we concluded it was better to just hard-code this to a value and not expose. (a) it's not trivial to accurately calibrate this so it's not going to be as accurate as the other two interlocks (b) none of the interlocks work well under high VSWR anyway (due to the couplers not seeing 50Ohm) (c) unlike the other interlocks, this does not help to protect the load, only the amplifier. IIRC @gkasprow was happy setting the reflected power to a fixed 1W, which should be safe for the chip and simplifies things for the user. That way there is only one interlock for the user to play with.

[ryan-summers]

This would certainly simplify the firmware design. If it's not useful for the end user to configure (as you note, the whole principle of it seems to be to protect booster, so this value should be set due to hardware constraints), it's definitely worth removing. If we settle on a logical interlock threshold, I can update the firmware and remove configuration.

I'll perform a review of hardware later as well, but input from @jordens would also be appreciated here (if you have any preferences).

[hartytp]

If we settle on a logical interlock threshold, I can update the firmware and remove configuration.

cf sinara-hw/Booster#202

I don't think there was ever a totally principled decision here, but Greg was pretty convinced that it could take 1W reverse power continuously without issue. I recall him testing that out and posting results in an issue, but I couldn't find it on a quick search.

Fixing this to 1W would be totally fine for all the applications I have in mind (can't speak for use cases that I'm not aware of though).

It's worth reiterating that the power readings can be pretty inaccurate with high VSWR; Booster isn't a VNA.

[jordens]

Ack. If the transforms are correct, let's fix the threshold at 1 W and remove the getter and setter API (for the thresholds).