Stepper motor works erratically with Pololu A4988 drive

In general, it is good practice to set the current limit before connecting the motor because some motors can draw more current than the driver can deliver. Since you are using the stepper motor at its rated voltage, you should be able to set the current limit to be greater than the current ratings for your stepper motors because the motor will only pull up to the rated current at that voltage. However, if the current limit is set far below the rated current, you might experience problems operating the stepper motor. In addition, the current limit must be set appropriately if you want to use microstepping later.


Sorry to step in 6 years too late, but I believe the problem with this driver is that it’s asleep. The SLEEP pin has to be pulled high to for any coil energizing to happen. This can be done by connecting it to the RESET pin (just next door), or by driving it high from an Arduino GPIO pin. Also, I would not advise leaving the DIR pin to float, I can’t remember, maybe it’s pulled low internally, but I would want to drive it one way or the other. Still, pretty sure the problem here is the SLEEP pin.