I’m trying to set the VREF to the above board. The equation is:
current limit = VREF * 5 A/V. What is A? i’m guessing is not the current limit. What is V? the voltage of the motor? the Logic power supply?
These terms are not identified, at least i’m reading something wrong, on your web page : https://www.pololu.com/product/2876
The motor that i have requires 3.4V at 1.7A.

The A/V at the end of the equation denotes the units of the constant 5; Amps divided by Volts. So, if you measure VREF as 0.1V, the current limit would be 0.5A (0.1 x 5). Since your motor can handle more current than the STSPIN220 carrier, I recommend setting the limit to 1.1A (the maximum the carrier can handle continuously). That corresponds to a VREF of 0.22V.