from migen import *


class IOLoopBack(Module):
    def __init__(self, pads):
        self.o = Signal(4)
        self.i = Signal(4)
        self.t = Signal(4)

        for i in range(4):
            self.specials += Instance("IOBUFDS",
                o_O=self.o[i],
                io_IO=pads[i].p,
                io_IOB=pads[i].n,
                i_I=self.i[i],
                # Always enable input buffer, so it is actually a loop back
                i_T=self.t[i],
            )


class SingleIOLoopback(Module):
    def __init__(self, pad):
        self.o = Signal()
        self.i = Signal()
        self.t = Signal()

        self.specials += Instance(
            # "IOBUFDS_DCIEN",
            "IOBUFDS",
            # p_DIFF_TERM="TRUE",
            # p_IBUF_LOW_PWR="TRUE",
            # p_USE_IBUFDISABLE="TRUE",
            o_O=self.o,
            io_IO=pad.p,
            io_IOB=pad.n,
            i_I=self.i,
            # Always enable input buffer, so it is actually a loop back
            i_T=self.t,
            # i_IBUFDISABLE=~self.t,
            # i_DCITERMDISABLE=~self.t,
        )