I have 2 control boards running in Multi MCU with Klipper, I have a need for one board to power the other up after the system boots.
Is there any way to have klipper start with only 1 MCU active as the second needs a powercycle or delayed power to detect and operate correctly
Currently Klipper shuts down when it cant see both MCU’s active, but I need to control the first one to switch on the second one via a select output.
I have resorted to using a toggle switch, to power up the second board after the system has booted, then I can restart Klipper and everything works fine, but on a reboot, I will loose the second MCU again and I need to cycle its power once the system is backup.
It seems to be an issue with the THR36 tool boards, on a slower system they seem to be fine ona cold boot, but not on a warm boot, they always need to have the power cycled, but on a faster system they are very problematic and require thier power to be fully cut and reinstated to detect properly.
I have the wiring as I want it, but the fact that Klipper has a hissy fit and wont allow me to control the primary control board until it sees the second tool board, I’m kind of stuck.
If I cant accomplish this, I will have to built a timer to control the relay and cycle its power that way.
Anyone else looking at something like this, I plan to use a CH340 usb relay to power on and off the printer via a script on Klipper startup and shutdown, this will resolve the issue for me.
Once I have this tested and operational, I will post a how to here so others can do this if they need to.
The Klipper code does not currently support what you are looking for. It is possible that it could be done with host code changes, but it may be painful to implement that. (The current Klipper code performs initialization in phases - one phase to read and validate the configs, one phase to connect to the mcus, and another phase to configure those mcus - it could be tricky to configure one mcu prior to connecting to another.)
Thanks for the response Kevin, much appreciated, I thought this might have been the case, I will go down the path of using a relay controlled by a script on startup and shutdown, Ill just have that control the main power feed for for the printer and all control boards, I can manually simulate this with a switch and it works fine, once I have it working I will let others know how to do it as others are having issues on a warm reboot with Multi MCU and certain combinations of hardware not detecting, cold booting has no issue.