The printer should be ready soon, but… What I will be doing, if I finish? No…! I had to change something.
I decided to replace X, Y and E stepsticks with TMC2130. The Z motors will be still run by TMC2208. Why?
TMC2208 are great to run quiet the printer in stealthChop2 mode, without (mostly) lose of any steps, but even with the UART interface which are provided, there is no great function called stallGuard, which are available in TMC2130. This, and already a not bad support for this in Marlin, caused me to go for them. As right now the only true advantage is sensorless homing, and it’s only software feature, to add the Prusa MK3 style rehoming while missing step will be detected. For extruder it will also act as additional sensor for the filament – when the filament will be clogged printer can pause the print and trigger the filament change.
I don’t know, why Trinamic didn’t made yet a stepstick with the upgraded stealthChop2 mode and the stallGuard working it it. Maybe the next product from them will be like that? I hope so, as unfortunately the stealthChop in TMC2100 and 2130 are losing steps very often (unless the speeds and acceleration are low), and also to enable stallGuard it’s needed to turn off stealthChop and go for the louder mode, the spreadCycle.
The TMC2130 on MK2Clone r2 will be connected by software SPI from unused ports on RAMPS, to make the connecting easier than soldering cables to LCD expansion board. Additionally, after tests, I figured that connecting TMC to the hardware SPI used also by SD card reader on LCD board, causes random initialization problems for the memory card.
Moreover, not only the TMC2130 is something new. There will be also RRD fan expansion used to control the fans – as I dont like when the printer finish the job and the fans is running, until someone turns off the printer, and external mosfet board for the heated bed – because the mosfests which are installed on most chinese RAMPS boards are not big enough to power the bed.