blinky.py

import itertools

from nmigen import *
from nmigen.build import ResourceError

from pym.icesugar_nano import *

__all__ = ["Blinky"]

class Blinky(Elaboratable):
    def elaborate(self, platform):
        m = Module()

        def get_all_resources(name):
            resources = []
            for number in itertools.count():
                try:
                    resources.append(platform.request(name, number))
                except ResourceError:
                    break
            return resources

        leds     = [res.o for res in get_all_resources("led")]

        clk_freq = platform.default_clk_frequency
        timer = Signal(range(int(clk_freq//2)), reset=int(clk_freq//2) - 1)
        flops = Signal(len(leds))

        inverts  = [0 for _ in leds]
        m.d.comb += Cat(leds).eq(flops ^ Cat(inverts))

        with m.If(timer == 0):
            m.d.sync += timer.eq(timer.reset)
            m.d.sync += flops.eq(~flops)
        with m.Else():
            m.d.sync += timer.eq(timer - 1)

        return m

if __name__ == "__main__":
    p = iCESugarNanoPlatform()
    p.add_resources(p.pmod_led)
    p.build(Blinky(), do_program=True)