We are using the L6470 in a new design. We have found that when we move to a position then reverse direction we find that the new position comes up short by 2 or 3 steps. After this initail error all future moves in the same direction are correct. If the direction is reversed again we lose the 2 or 3 steps again on the first move. We have an encoder mounted on the stepper shaft which confirms this action. Also we have placed a dial indicator on the belt and confirmed that we are indeed missing these 2 or 3 steps. ST engineers pleas reply as we are out of ideas on how to fix this issue.