nmigen_boards/test/blinky.py

   1 import itertools
   2
   3 from nmigen import *
   4 from nmigen.build import ResourceError
   5
   6
   7 __all__ = ["Blinky"]
   8
   9
  10 class Blinky(Elaboratable):
  11     def elaborate(self, platform):
  12         m = Module()
  13
  14         def get_all_resources(name):
  15             resources = []
  16             for number in itertools.count():
  17                 try:
  18                     resources.append(platform.request(name, number))
  19                 except ResourceError:
  20                     break
  21             return resources
  22
  23         leds     = [res.o for res in get_all_resources("led")]
  24         buttons  = [res.i for res in get_all_resources("button")]
  25         switches = [res.i for res in get_all_resources("switch")]
  26
  27         inverts  = [0 for _ in leds]
  28         for index, button in zip(itertools.cycle(range(len(inverts))), buttons):
  29             inverts[index] ^= button
  30         for index, switch in zip(itertools.cycle(range(len(inverts))), switches):
  31             inverts[index] ^= switch
  32
  33         clk_freq = platform.default_clk_frequency
  34         timer = Signal(max=int(clk_freq//2), reset=int(clk_freq//2) - 1)
  35         flops = Signal(len(leds))
  36
  37         m.d.comb += Cat(leds).eq(flops ^ Cat(inverts))
  38         with m.If(timer == 0):
  39             m.d.sync += timer.eq(timer.reset)
  40             m.d.sync += flops.eq(~flops)
  41         with m.Else():
  42             m.d.sync += timer.eq(timer - 1)
  43
  44         return m