Marlin 2.0.x support

[sean97140]

I would love to use the MMU2S (with your incredible firmware) on printers other than a Prusa. Marlin 2 includes support for the mmu2s, but it is for the stock communication protocol and firmware.

I would like the ability to use the stock communication protocol (if this is remotely possible) to enable me to use your mmu2s firmware with Marlin 2.

The alternative option would be to port your communication protocol over to Marlin 2 but again, don’t know how extensive the work would be to have this realized. The Marlin code for the mmu2 is here https://github.com/MarlinFirmware/Marlin/blob/2.0.x/Marlin/src/feature/mmu/mmu2.cpp

I’ve considered going back to stock firmware… This would let me run Marlin 2 with the mmu2s, but your firmware works so much better, so this isn’t something I’d even want to contemplate.

I sent you an email touching on this before I started drilling into the source and recognizing you reworked the communication protocol. I’d be happy to contribute funds and share my time helping to make this happen.

I am at the point where I don’t run stock firmware on any of my printers and gaining the capacity to use your mmu2s firmware with Marlin 2 would be incredible.

[sean97140]

I can settle on better documentation/some flow charts of your communication protocol and how the interactions changed from stock, error-correcting, etc if you have any spare time. I am at the point I am just going to implement it myself soon and any info you can provide on your thought process and control flow would save me a ton of time getting started on this.