digilent_basys3.py

#!/usr/bin/env python3

#
# This file is part of LiteX-Boards.
#
# Copyright (c) 2020-2021 Xuanyu Hu <xuanyu.hu@whu.edu.cn>
# SPDX-License-Identifier: BSD-2-Clause

import os
import argparse

from migen import *

from litex_boards.platforms import basys3

from litex.soc.cores.clock import *
from litex.soc.integration.soc import SoCRegion
from litex.soc.integration.soc_core import *
from litex.soc.integration.builder import *
from litex.soc.cores.video import VideoVGAPHY
from litex.soc.cores.led import LedChaser

# CRG ----------------------------------------------------------------------------------------------

class _CRG(Module):
    def __init__(self, platform, sys_clk_freq):
        self.rst = Signal()
        self.clock_domains.cd_sys       = ClockDomain()
        self.clock_domains.cd_vga       = ClockDomain(reset_less=True)

        self.submodules.pll = pll = S7MMCM(speedgrade=-1)
        self.comb += pll.reset.eq(platform.request("user_btnc") | self.rst)

        pll.register_clkin(platform.request("clk100"), 100e6)
        pll.create_clkout(self.cd_sys, sys_clk_freq)
        pll.create_clkout(self.cd_vga, 40e6)
        platform.add_false_path_constraints(self.cd_sys.clk, pll.clkin) # Ignore sys_clk to pll.clkin path created by SoC's rst.
        #platform.add_platform_command("set_property CLOCK_DEDICATED_ROUTE FALSE [get_nets clk100_IBUF]")

# BaseSoC ------------------------------------------------------------------------------------------

class BaseSoC(SoCCore):
    def __init__(self, sys_clk_freq=int(75e6), with_led_chaser=True, with_video_terminal=False, **kwargs):
        platform = basys3.Platform()

        # SoCCore ----------------------------------_-----------------------------------------------
        SoCCore.__init__(self, platform, sys_clk_freq,
            ident          = "LiteX SoC on Basys3",
            ident_version  = True,
            **kwargs)

        # CRG --------------------------------------------------------------------------------------
        self.submodules.crg = _CRG(platform, sys_clk_freq)

        # Video ------------------------------------------------------------------------------------
        if with_video_terminal:
            self.submodules.videophy = VideoVGAPHY(platform.request("vga"), clock_domain="vga")
            if with_video_terminal:
                self.add_video_terminal(phy=self.videophy, timings="800x600@60Hz", clock_domain="vga")

        # Leds -------------------------------------------------------------------------------------
        if with_led_chaser:
            self.submodules.leds = LedChaser(
                pads         = platform.request_all("user_led"),
                sys_clk_freq = sys_clk_freq)

# Build --------------------------------------------------------------------------------------------  
def main():
    parser = argparse.ArgumentParser(description="LiteX SoC on Basys3")
    parser.add_argument("--build",               action="store_true", help="Build bitstream")
    parser.add_argument("--load",                action="store_true", help="Load bitstream")
    parser.add_argument("--sys-clk-freq",        default=75e6,        help="System clock frequency (default: 75MHz)")
    sdopts = parser.add_mutually_exclusive_group()
    sdopts.add_argument("--with-spi-sdcard",     action="store_true", help="Enable SPI-mode SDCard support")
    sdopts.add_argument("--with-sdcard",         action="store_true", help="Enable SDCard support")
    parser.add_argument("--sdcard-adapter",      type=str,            help="SDCard PMOD adapter: digilent (default) or numato")
    viopts = parser.add_mutually_exclusive_group()
    viopts.add_argument("--with-video-terminal", action="store_true", help="Enable Video Terminal (VGA)")
    builder_args(parser)
    soc_core_args(parser)
    args = parser.parse_args()

    soc = BaseSoC(
        sys_clk_freq           = int(float(args.sys_clk_freq)),
        with_video_terminal    = args.with_video_terminal,
        **soc_core_argdict(args)
    )
    soc.platform.add_extension(basys3._sdcard_pmod_io)
    if args.with_spi_sdcard:
        soc.add_spi_sdcard()
    if args.with_sdcard:
        soc.add_sdcard()
    if args.with_spi_sdcard:
        soc.add_spi_sdcard()
    if args.with_sdcard:
        soc.add_sdcard()
    builder = Builder(soc, **builder_argdict(args))
    builder.build(run=args.build)

    if args.load:
        prog = soc.platform.create_programmer()
        prog.load_bitstream(os.path.join(builder.gateware_dir, soc.build_name + ".bit"))

if __name__ == "__main__":
    main()