Hello, I want to upgrade my laser with a Z table and need several motors, so I connected the BTT-EXP-MOT to the SKR3 EZ in UARD mode. I only use TMC2209 drivers, but they are not recognized correctly on the BTT-EXP-MOT. Only the motor on Drive 7 moves, but only in one direction.
I suspect an error in Board.txt
@tidal root
#SKR 3 EZ with BTT-EXP-MOT
severe temple
rare tulip
you will need to increase stepper.numSmartDrivers to 8 I guess, and add the pins for the extra drivers.
ah, I see you did the latter further down
severe temple
@rare tulip Yes, but I'm not sure if everything is correct. There are no instructions yet on how to connect this board to the BTT-EXP-MOT. I had to pick out the pins myself
tidal root
You can compare the pins used on the SKR2 and map them to the SKR3
Unfortunately i dont have the time to do this for you but it shouldnt be difficult
rare tulip
either way you need to increase numSmartDrivers
https://github.com/bigtreetech/BTT-Expansion-module/blob/master/BTT EXP-MOT/BTT EXP-MOT V1.0-BOT.pdf has a mapping of the exp headers to the driver slots. note that this is the view from the back
map via matching GND
The pins for m1 as the rightmost slot, which would be the 6th driver, seem correct to me. But to use it, you need to increase numSmartDrivers to 6. I would suggest bringing up the slots one by one, checking that the drivers work correctly. Make sure the exp1/exp2 connections aren't flipped, and that either exp is plugged in the right way around.
(also double check the voltage selector and chip select jumpers are properly set)
severe temple
@rare tulip @tidal root Thank you very much, I'll give it a try this weekend
tidal root
<@406091071186272256> <@561307644841689092> Thank you very much, I'll give it a ...
if you get it working, please send the board.txt details so I can get them added to the wiki
severe temple
@rare tulip Why do I need to increase the NumSmartDrivers to 6? In total I have 8 drivers. And which TMCdiagPins are included? I assumed that this was only in the context of sensorless homing
@tidal root ok
rare tulip
@severe temple needs to increased to 8 for all of them, I suggested you bring up the drivers one by one, so you would set it to 6, then 7, then 8. Diag pins are only for stall detect/sensorless homing so I omitted them for now since the first order is to get the drivers driving
severe temple
@rare tulip Ok, I was thinking that if I increase the NumSmartDriver, the DiagPins must also be specified. But they probably won't be led out to the additional board at all.
final magnetBOT
GG @severe temple, you just advanced to level 3!
tidal root
Smart drivers are unconnected to the diag pin
rare tulip
the diag pins are clearly mapped to the ext2/ext1 connectors on the BTT-EXP-MOT. The smart part is about programmable current settings and driver registers though. I.e. 2208s are smart drivers, but they don't have a diag pin
severe temple
@rare tulip @tidal root Today I increased the NumSmartDriver to 8 for a quick test and it works. So the pins in my file are correct. I use TMC2209 drivers, but I don't need the sensorless.
Many thanks for your help.
rare tulip
@tidal root board.txt above seems to work
tidal root
i'll look at adding a page for the SKR3 boards when i get back at the weekend