Sense resistors S1, S2 are marked R100. I checked the resistance of the two but my multimeter was reading between 0.2 ohm and 0.3 ohm. R100 is 0.1 ohm by SMD code calculator.
A = VREF / (8 x RS)
= VREF / (8 x 0.1)
= VREF / 0.8
To set 1A current
VREF = 1.0 x 0.8 = 0.8V (800 mV)