If moving multiple steppers one at a time is ok for your project, is it ok to parallel drivers like the a4988 and use the enable line to pick the one you want? To save on io pins.
Sometimes /ENABLE just disables the output drive.
From the A4988 datasheet:
"The translator inputs STEP, DIR, and MSx, as well as the internal sequencing logic, all remain active, independent of the /ENABLE input state."
You can share DIR pin and give each driver its own STEP input. That would save a pin.
Yes, I'd confirm that - you should provide a separate step signal for each driver. You can share direction and enable if you want (unless you need separate enables anyway for some reason).
You might even be able to use the AccelStepper library unchanged with direction pins common, though I've not actually tried this.
[ to be pedantic this is multiplexing rather than paralleling I think ]
Thank you much!