UART jitter issues

[olliw42]

thx for replying to this post

yes, moving to SERIALn_RTSCTS does make sense

very glad to hear that this appears more possible now

well, “issues least likely” is hard to define.

not really, as mcu’s have only a limited clear defined set of features it’s usually not difficult to figure out

we do by default enable pullup on both RX and CTS pins

great to hear this.

I’m then very much confused however what these OPTIONS bits reflect and how these actually work.
If the rx pullup is set by default I would have then expected to see the respective flag set. But it isn’t but you say it is set, so the OPTIONS bit does not reflect the situation.
Since the OPTIONS is just one bit per option it can’t represent something like ‘default’,‘no’,‘up’ but only ‘no’,‘up’; there is also no ‘apply options’ ,‘do not apply options’ or other thing which could achieve selecting what should be applied.
I don’t understand this.
anyway, I don’t want to more pollute this thread, so I’m happy to accept this as this special ArduPilot magic

cheers

[tridge]

have you tested if the PR fixes the issue for you?

[olliw42]

no
I started trying to port the PR but realized that the files affected in this PR have more changes compared to the files in my test environment (ap41beta) and being quite unfamiliar with these code parts it was not so clear to me, and what issues I would create if I would just naively make changes, so I stopped here (i.e. I could do it in reasonable time). I also concluded that, since you were not using your above test bed or mine, that you must have done the testing otherwise to come to the conclusion you describe in the PR. So I concluded all good, and spending much effort to get me up isn’t worthwhile. Not sure these words describe my reasoning.
Anyway, I’m out of town for a couple of days, but if it’s relevant I could give it another try next weekend. I may have to ask back concerning some code line changes, to ensure I’m not doing nonsense.