I recently purchased a SKR v1.3 to be used in my CR-10S Pro and was running into issues where I could not connect to the board similar to what was described here, and I was able to solve my issue by toggling a couple of settings within octoprint itself.
I documented my findings below
https://github.com/MarlinFirmware/Marlin/issues/14004#issuecomment-544280218
Initially could connect SKR 1.3 and octoprint 1.3.12 without problems, but - after quite while of perfect cooperation got lots of serial connection losses: "SerialException: device reports readiness to read but returned no data (device disconnected or multiple access on port?)"
None of the solutions here: " https://faq.octoprint.org/serialerror" did help.
The solution (and reason) I found: For termistor calibration I had turned on #define SHOW_TEMP_ADC_VALUES in Marlins configuration_adv.h and didn´t disable it afterwards. Now beeing disabled again - serial exceptions are gone. It seems octoprint could not really handle that in addition send out ADC values during a normal print job.
The particular error message you described is generated a layer below OctoPrint and about inherent properties of the serial connection itself, outside of OctoPrint's control. So I'm fairly sure the ADC values themselves are not the issue here but something else that was related to them being sent.
Hey guys. I've been away for a long time. Too busy with work. I've upgraded my printer from MKS base 1.4 8-bit to SKR 1.3 32-bit. It's almost good, but I'm having a weird issue about connecting it.
It's using Marlin 2.0 fw, and set to 115200 baudrate.
What happens is that if I try to connect it set to 115200 on octoprint it fails, but if I set to AUTO it connects, and detects 115200!!!! Does anyone saw something similar?