TMC2160-based external stepper drivers

The LV8727 boards I’m using in my router aren’t available any more. I was curious what has replaced them, and no big surprise it’s TMC-based boards. I see two form factors:

Logic-level inputs (opto-isolated), with pretty much exactly the form factor of the LV8727 boards I have (both from MKS):

Isolated, supporting open-drain, in the same form factor as the typical TB6600 and DM542T boxes:

I won’t be surprised if versions with TMC5160 come out, but there would be no point in doing that without also exposing an SPI interface, since the difference between 2160 and 5160 is being able to offload planning; the 5160/1 have a motion planner on the chip. So these STEP/DIR cards wouldn’t get any value from moving to the 5160.

Aha, MKS considers this to be a compatible series with different driver chips. And looking at the schematic here:

I see this:


…and this:


It does have a place to solder in DIAG headers.


This makes me think that it’s meant to be able to use in SPI mode. And it looks like you can talk to this board with serial if you want to solder a few more pins in place.


I think there’s no R0 soldered here, so maybe this is actually a surface-mount jumper to select SPI mode?


Looks promising!


Yes, bridge R0, it’s a solder jumper.

Also mentioned elsewhere, you need to turn off all the DIP switches to use SPI mode.