On the MP6500, it looks like you need to put B1 and B2 on the same coil, and A1 and A2 on the other coil.
On the A4988, on the other hand, it pairs 2A and 2B for the first coil, and 1A and 1B on the other.
So on one of the controllers you have to match letters, and on the other you match numbers. That seems really confusing to me. I haven’t done anything with steppers before, so I assume there’s a good reason - is there an overarching convention for how these pins get named?