I am partially involved in a project involving operating a small motor with an encoder. The motor is being powered through a grblshield v3, which has worked just fine for the previous motor it was used with, which didn't have an encoder. The problem is I'd like to take the pulse-data the encoder gives us to track the motor's orientation, as shown in some sketch examples here:
However, these all involve using the Uno interrupt pins (2 and 3), which, when the grlbshield is plugged on top of it, seem to be used for grbl-specific things (in this case I think the pins are labeled 'Xstep' and 'Ystep'). So, I was hesitant about plugging the motor wires into these labeled pins for fear that it would interact with the grblshield strangely. Researching further I learned that grlbshield apparently operates using its own kind of code for motor-control specific applications, effectively hijacking the Arduino microcontroller in the process. We have no particular interest in using the grblshield in this way (it is currently being used for powering purposes, as far as I can tell).
My question is this: if we do not do any special Grbl coding, simply upload a sketch to the Uno, mount the grblshield on top, and plug the motor outputs into the grblshield pins corresponding to Uno pins 2 and 3, will this have any particular effect on the grblshield/Arduino? Will it be functionally the same as plugging the motor output directly into Uno pins 2 and 3? My first instinct is yes it would, but the grblshield seems to be a somewhat special case.
Sorry if the answer to this question seems obvious or easily learned: I'm afraid I don't know much about grblshield or motor control and was not able to find the answer with relevant searches. I also understand that using the grblshield in this way may not be strictly necessary/efficient, but it's kind of the constraint I'm working in right now. If the answer is effectively no, I can still implement ways around it.
Thanks for your time!