I have a custom stepper controller board based on grbl and the DRV8825. I use NEMA 17 motors with 1.7A maximum current per phase and the machine operates at 12V (essentially the voltage at VMA/B of DRV8825 is 12V). Attached here is an image of how the microswitches are connected on my board. I used this site to calculate the steps/mm value that I need to specify in grbl. If I set M2 at 5V and leave M1 and M0 open, I should see 1/16 steps/mm resolution and based on my pulley tooth count (20) and belt pitch (2mm) the calculated value for grbl is 80. However, this does not seem to be working. With a value of 80 I seem to be halving the total travel distance in any axis. What am I missing? Is the way the microswitches are connected wrong?
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