litex-boards/litex_boards/official/targets/minispartan6.py

#!/usr/bin/env python3

# This file is Copyright (c) 2013-2014 Sebastien Bourdeauducq <sb@m-labs.hk>
# This file is Copyright (c) 2014-2019 Florent Kermarrec <florent@enjoy-digital.fr>
# This file is Copyright (c) 2014 Yann Sionneau <ys@m-labs.hk>
# License: BSD

import argparse
from fractions import Fraction

from migen import *
from migen.genlib.resetsync import AsyncResetSynchronizer

from litex_boards.official.platforms import minispartan6

from litex.soc.cores.clock import *
from litex.soc.integration.soc_sdram import *
from litex.soc.integration.builder import *

from litedram.modules import AS4C16M16
from litedram.phy import GENSDRPHY

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

class _CRG(Module):
    def __init__(self, platform, clk_freq):
        self.clock_domains.cd_sys = ClockDomain()
        self.clock_domains.cd_sys_ps = ClockDomain()

        # # #

        self.cd_sys.clk.attr.add("keep")
        self.cd_sys_ps.clk.attr.add("keep")

        self.submodules.pll = pll = S6PLL(speedgrade=-1)
        pll.register_clkin(platform.request("clk32"), 32e6)
        pll.create_clkout(self.cd_sys, clk_freq)
        pll.create_clkout(self.cd_sys_ps, clk_freq, phase=270)

        self.specials += Instance("ODDR2",
            p_DDR_ALIGNMENT="NONE",
            p_INIT=0, p_SRTYPE="SYNC",
            i_D0=0, i_D1=1, i_S=0, i_R=0, i_CE=1,
            i_C0=self.cd_sys.clk, i_C1=~self.cd_sys.clk,
            o_Q=platform.request("sdram_clock"))

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

class BaseSoC(SoCSDRAM):
    def __init__(self, sys_clk_freq=int(80e6), **kwargs):
        assert sys_clk_freq == int(80e6)
        platform = minispartan6.Platform()
        SoCSDRAM.__init__(self, platform, clk_freq=sys_clk_freq,
                          integrated_rom_size=0x8000,
                          **kwargs)

        self.submodules.crg = _CRG(platform, sys_clk_freq)

        if not self.integrated_main_ram_size:
            self.submodules.sdrphy = GENSDRPHY(platform.request("sdram"))
            sdram_module = AS4C16M16(sys_clk_freq, "1:1")
            self.register_sdram(self.sdrphy,
                                sdram_module.geom_settings,
                                sdram_module.timing_settings)

# Build --------------------------------------------------------------------------------------------

def main():
    parser = argparse.ArgumentParser(description="LiteX SoC on MiniSpartan6")
    builder_args(parser)
    soc_sdram_args(parser)
    args = parser.parse_args()

    soc = BaseSoC(**soc_sdram_argdict(args))
    builder = Builder(soc, **builder_argdict(args))
    builder.build()


if __name__ == "__main__":
    main()