paulvdhoeven
commented
4 years ago I have cobbled something together with a Blue Pill and some 74LS244 TTL driver chips on a piece of Vero-board. The TTL chips drive the opto couplers from external stepper motor drivers.
Boards such as in your link are usually pre-loaded with some variant of CNC firmware. (In this case GRBL) Personally I would never buy such a board if it does not: A). Specify which processor is used. B). Does not have a link to source code.
AtMega328 is also too near it's limits and cracking at it's seams for GRBL. There are multiple on-going efforts for ports to more capable microcontrollers, and my closest guess is that AtMega328 is "Legacy".
"Bigtreetech" may be a nice company to deal with, and still is quite affordable. It is maybe not the cheapest clone you can find, but good (Does BigTreeTech do 4 layer?) PCB's are worth something too, and making documentation available also costs time, and thus money for a commercial company.
Here is a link to one of such boards from Bigtreetech: https://github.com/bigtreetech/BIGTREETECH-SKR-V1.3/tree/master/BTT%20SKR%20V1.4
For a more general overview of GRBL compatibility with different processors, have a look at: https://github.com/terjeio/grblHAL/
andyb749
Is there a list available with compatible boards? I'm interested if this board is compatible with the latest grbl version? https://www.amazon.de/QPX-Triaxiale-Steuerplatine-Controller-Bildschirm/dp/B07D211NKD/