from migen import *


class BiDirectionalIO(Module):
    def __init__(self, i_pads, o_pads):
        self.i = Signal(4)
        self.o = Signal(4)
        self.t = Signal(4)

        for i in range(4):
            self.specials += Instance("OBUFTDS",
                i_I=self.i[i],
                o_O=o_pads[i].p,
                o_OB=o_pads[i].n,
                # Always chain the 3-states input to serializer
                # Vivado will complain otherwise
                i_T=self.t[i],
            )
        
        for i in range(4):
            self.specials += Instance("IBUFDS",
                i_I=i_pads[i].p,
                i_IB=i_pads[i].n,
                o_O=self.o[i],
            )