I am seeing some strange behavior in slow decay mode. Right now, I have slow decay when Current increases (quadrant 1 & 3) and mixed when Current decreases (quadrant 2 & 4).
Background. We are using a hybrid stepper motor. Vref is used to set the peak Current. I[4:0] is used to control the percentage of peak that is outputted (via micro-stepping, right now 1/4 stepping).
If I use the slow/mixed scheme, during the slow decay portion, the current does not step properly. It goes to full scale (as if Vref is at its peak value, which it is not) and stays there for all of steps until we transition to mixed mode quadrant . If we use only mixed or fast decay for all of quadrants, it single steps correctly.
Dan