Keep all the above the same for digital input and output, but:

DM[2]  =  0
DM[1]  =  0
DM[0]  =  1.8
INP_DIS = 0
OE_N    = 1.8

IN      = (core signal connection in the 1.8V domain)
IN_H    = (core signal connection in the 3.3V domain)

for input, and

DM[2]  =  1.8
DM[1]  =  1.8
DM[0]  =  0
INP_DIS = 1.8
OE_N    = 0

OUT     = (core signal connection in the 1.8V domain)

for output. Sadly, there's no 3.3V domain digital output function, so if you're using 3.3V logic from the HVL library, you'll need a level shifter.