Hi,
I am trying to use a CNC V3 shield with a UNO, to drive a stepper using DRV 8825 for a non 3D printer use. I am starting with 1, but I might need upto 2 sockets on the board for 2 motors. The problem is, I need to change the step mode pins sometimes. The CNC shields seem to have only jumpers for the mode pins. I was wondering if instead of using jumpers on the M1/2/3 pins, could I connect them to the Step/Dir pins of the the unused 3rd socket? I will be using my own sketch (not GRBL) to drive the motors. I see the X,Y,Z Step/Dir pins available on the shield. Can I just connect them to the M pins. Will it work electrically? I think I can get by with 2 pins per motor, and I might be able to use the same mode connections for both the motors. What other pins on the board could I use which I could control from the Arduino?
Alternatively are there any shields for 1 or 2 drivers, that have pins for the mode bits? All the single driver shields I see have dip switches for the mode bits and not exposed pins.
Any other options?
I make my own carrier boards for the drivers.
Looks good.
My soldering skills are not very good, but I did solder a perfboard with wires for this, and it worked for about a year 
But poor soldering and rough usage, broke some of the connections so I am looking at the shield option now.
Maybe I can leave the dip swtiches open and solder wires to the dip switch pins of the single driver shield and drive the mode pins that way
The M0, M1 and M2 pins have internal pulldowns so the DIP switches pull the Mx input on the driver high to set microstepping. That means that one side of each DIP switch connects to Vcc and the other side of the DIP switch goes to the Mx input on the driver. Find the side of the DIP switch that connects to the inputs and solder wires to those terminals. Connect those wires to Arduino outputs to control microstepping.
groundFungus:
The M0, M1 and M2 pins have internal pulldowns so the DIP switches pull the Mx input on the driver high to set microstepping. That means that one side of each DIP switch connects to Vcc and the other side of the DIP switch goes to the Mx input on the driver. Find the side of the DIP switch that connects to the inputs and solder wires to those terminals. Connect those wires to Arduino outputs to control microstepping.
Yeah, that was my plan. Either that or get right angled headers for the mode pins on the CNC shield and connect those to unused Step/Dir pins. The mode pins which are under the driver chip and the headers would make them easy to connect.
You could do the same thing with the CNC shield. Solder wires to the exposed Mx jumper header pins, accessible from the bottom of the board.
groundFungus:
You could do the same thing with the CNC shield. Solder wires to the exposed Mx jumper header pins, accessible from the bottom of the board.
You are right, hadn't thought about that. It looks a little scary to solder on the bottom of the board though with my skills. Might be an option if the rt angled headers dont work out because of their height.
