IceStorm Improvements Test File

rot.py

#!/usr/bin/env python3

from migen import *
from migen.build.platforms import icestick
from migen.build.generic_platform import *
from migen.genlib.io import DifferentialOutput
from migen.genlib.resetsync import AsyncResetSynchronizer

class Rot(Module):
    def __init__(self):
        self.clk_freq = 12000000
        self.ready = Signal()
        self.rot = Signal(4)
        self.divider = Signal(max=self.clk_freq)
        self.d1 = Signal()
        self.d2 = Signal()
        self.d3 = Signal()
        self.d4 = Signal()
        self.d5 = Signal()

        self.dummy = Signal()
        self.dummy.attr.add("keep")

        ###
        self.comb += [j.eq(self.rot[i]) for i, j in enumerate([self.d1, self.d2, self.d3, self.d4])]
        self.comb += [self.d5.eq(1)]
        self.comb += [self.dummy.eq(1)]

        self.sync += [
            If(self.ready,
                If(self.divider == int(self.clk_freq) - 1,
                    self.divider.eq(0),
                    self.rot.eq(Cat(self.rot[-1], self.rot[:-1]))
                ).Else(
                    self.divider.eq(self.divider + 1)
                )
            ).Else(
                self.ready.eq(1),
                self.rot.eq(1),
                self.divider.eq(0)
            )
        ]

        self.clock_domains.cd_sys = ClockDomain()

if __name__ == "__main__":
    plat = icestick.Platform()
    m = Rot()
    plat.add_extension([("rst", 0, Pins("PMOD:0"), IOStandard("LVCMOS33"))])
    m.comb += [plat.request("user_led").eq(m.d1)]
    m.comb += [plat.request("user_led").eq(m.d2)]
    m.comb += [plat.request("user_led").eq(m.d3)]
    led4 = plat.request("user_led")
    led5 = plat.request("user_led")
    m.specials += [DifferentialOutput(m.d4, led4, led5)]


    rst = plat.request("rst")
    clk12 = plat.request("clk12")
    m.specials += [AsyncResetSynchronizer(m.cd_sys, rst)]
    # m.specials += [AsyncResetSynchronizer(ClockDomain("sys"), rst)]
    m.comb += [m.cd_sys.clk.eq(clk12)]

    plat.toolchain.pre_synthesis_commands.append("hierarchy -top top")
    # plat.toolchain.synthesis_commands.append("synth_ice40 -blif {build_name}.blif")
    plat.toolchain.post_synthesis_commands.append("show top")

    plat.build(m, run=True, build_dir="rot", build_name="rot_migen")
    plat.create_programmer().flash(0, "rot/rot_migen.bin")