Gecko G320X not responding to Direction signal

Hi, I am controlling the Gecko by an Arduino 256 board.

The step signal works great and the motor turns according to pulse train.

Direction signal has no effect and it has been tested on both of the G320X drivers that I have. I was using digitalWrite HIGH and LOW. It always rotates in same direction.

I plugged the direction signal into both the +5v output of the Arduino and GND and it still had no effect on turning direction.
I tried changing the COMMON terminal of the Gecko from +5v and GND of Arduino with no effects in both situations.

I've contacted Gecko and not yet heard back.
Any suggestions? Thanks
Shawn

Hi, I found the answer - the Arduino GND and +5v must also be wired to the encoder logic of the Gecko. I thought they were opto-isolated in the Gecko internally (step/dir from encoder) but apparently not.