amaranth/examples/arst.py

from nmigen import *
from nmigen.cli import main


class ClockDivisor:
    def __init__(self, factor):
        self.v = Signal(factor)
        self.o = Signal()

    def get_fragment(self, platform):
        m = Module()
        m.d.sync += self.v.eq(self.v + 1)
        m.d.comb += self.o.eq(self.v[-1])
        return m.lower(platform)


if __name__ == "__main__":
    ctr  = ClockDivisor(factor=16)
    frag = ctr.get_fragment(platform=None)
    frag.add_domains(ClockDomain("sync", async_reset=True))
    main(frag, ports=[ctr.o])