#!/usr/bin/env python3 # # This file is part of LiteX-Boards. # # Copyright (c) 2021 Michael T. Mayers # SPDX-License-Identifier: BSD-2-Clause import math from migen import * from litex.gen import * from litex.build.io import CRG from litex_boards.platforms import digilent_nexys4 from litex.soc.cores.clock import * from litex.soc.integration.soc_core import * from litex.soc.integration.soc import SoCRegion from litex.soc.integration.builder import * from litex.soc.cores.led import LedChaser from litex.soc.interconnect import wishbone from litex.soc.integration.soc import colorer from litex.soc.cores.video import VideoVGAPHY from liteeth.phy.rmii import LiteEthPHYRMII # CRG ---------------------------------------------------------------------------------------------- class _CRG(LiteXModule): def __init__(self, platform, sys_clk_freq): self.rst = Signal() self.cd_sys = ClockDomain() self.cd_sys2x = ClockDomain() self.cd_sys2x_dqs = ClockDomain() self.cd_idelay = ClockDomain() self.cd_eth = ClockDomain() self.cd_vga = ClockDomain() # # # self.pll = pll = S7MMCM(speedgrade=-1) self.comb += pll.reset.eq(~platform.request("cpu_reset") | self.rst) pll.register_clkin(platform.request("clk100"), 100e6) pll.create_clkout(self.cd_sys, sys_clk_freq) pll.create_clkout(self.cd_sys2x, 2*sys_clk_freq) pll.create_clkout(self.cd_sys2x_dqs, 2*sys_clk_freq, phase=90) pll.create_clkout(self.cd_idelay, 200e6) pll.create_clkout(self.cd_eth, 50e6) 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. self.idelayctrl = S7IDELAYCTRL(self.cd_idelay) # CellularRAM (https://media.digikey.com/PDF/Data%20Sheets/Micron%20Technology%20Inc%20PDFs/MT45W8MW16BGX.pdf) class CellularRAM(LiteXModule): def __init__(self, soc, platform): sys_clk_freq = soc.sys_clk_freq addr_width = 23 data_width = 16 delay_for_70ns = (70e-9) / (1.0/sys_clk_freq) delay_for_70ns = int(math.ceil(delay_for_70ns))+1 #print("sys_clk_freq<%g> delay_for_70ns<%g>\n"%(sys_clk_freq,delay_for_70ns)) self.bus = wishbone.Interface(data_width=data_width,adr_width=addr_width) self.delaycounter = Signal(5) cellram = platform.request("cellularram") addr = cellram.addr data = cellram.data wen = cellram.wen oen = cellram.oen cen = cellram.cen clk = cellram.clk cre = cellram.cre adv = cellram.adv # address valid (low) lb = cellram.lb ub = cellram.ub ######################## tristate_data = TSTriple(data_width) self.specials += tristate_data.get_tristate(data) ######################## i_rst = ResetSignal("sys") fsm = FSM(reset_state="RESET") fsm = ResetInserter()(fsm) self.fsm = fsm self.sync += fsm.reset.eq(i_rst) ######################## fsm.act("RESET", NextState("INIT")) ######################## fsm.act("INIT", NextValue(self.delaycounter,0), NextValue(self.bus.ack,0), NextValue(cen,1), NextValue(adv,1), NextValue(lb,1), NextValue(ub,1), NextValue(clk,0), NextValue(cre,0), NextValue(tristate_data.oe,0), NextState("IDLE")) ######################## fsm.act("IDLE", If(self.bus.stb & self.bus.cyc, NextValue(lb,~self.bus.sel[0]), NextValue(ub,~self.bus.sel[1]), NextValue(self.delaycounter,0), NextValue(cen,0), NextValue(adv,0), NextValue(addr,self.bus.adr[:addr_width]), If(self.bus.we, NextValue(wen,0), NextValue(oen,1), NextValue(tristate_data.oe,1), NextValue(tristate_data.o,self.bus.dat_w[:data_width]), NextState("WRITE") ).Else( NextValue(wen,1), NextValue(oen,0), NextValue(tristate_data.oe,0), NextState("READ") ) ) ) ######################## fsm.act("WRITE", NextValue(self.delaycounter,self.delaycounter+1), If(self.delaycounter==delay_for_70ns, NextValue(self.bus.ack,1), NextState("INIT")) ) ######################## fsm.act("READ", NextValue(self.delaycounter,self.delaycounter+1), NextValue(self.bus.dat_r,tristate_data.i[:data_width]), If(self.delaycounter==delay_for_70ns, NextValue(self.bus.ack,1), NextState("INIT")) ) ######################## def addCellularRAM(soc, platform, name, origin): size = 16 * MEGABYTE ram_bus = wishbone.Interface(data_width=soc.bus.data_width) ram = CellularRAM(soc,platform) soc.bus.add_slave(name, ram.bus, SoCRegion(origin=origin, size=size, mode="rw")) soc.check_if_exists(name) soc.logger.info("CELLULARRAM {} {} {}.".format( colorer(name), colorer("added", color="green"), soc.bus.regions[name])) setattr(soc.submodules, name, ram) # BaseSoC ------------------------------------------------------------------------------------------ class BaseSoC(SoCCore): def __init__(self, sys_clk_freq=75e6, with_led_chaser = True, with_ethernet = False, with_etherbone = False, with_video_terminal = False, with_video_framebuffer = False, **kwargs): platform = digilent_nexys4.Platform() # CRG -------------------------------------------------------------------------------------- self.crg = _CRG(platform, sys_clk_freq) # SoCCore ----------------------------------_----------------------------------------------- SoCCore.__init__(self, platform, sys_clk_freq, ident="LiteX SoC on Nexys4", **kwargs) # Cellular RAM ------------------------------------------------------------------------------- addCellularRAM(self,platform,"main_ram", 0x40000000) # Ethernet / Etherbone --------------------------------------------------------------------- if with_ethernet or with_etherbone: self.ethphy = LiteEthPHYRMII( clock_pads = self.platform.request("eth_clocks"), pads = self.platform.request("eth")) if with_ethernet: self.add_ethernet(phy=self.ethphy) if with_etherbone: self.add_etherbone(phy=self.ethphy) # Video ------------------------------------------------------------------------------------ if with_video_terminal or with_video_framebuffer: self.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") if with_video_framebuffer: self.add_video_framebuffer(phy=self.videophy, timings="800x600@60Hz", clock_domain="vga") # Leds ------------------------------------------------------------------------------------- if with_led_chaser: self.leds = LedChaser( pads = platform.request_all("user_led"), sys_clk_freq = sys_clk_freq) # Build -------------------------------------------------------------------------------------------- def main(): from litex.build.parser import LiteXArgumentParser parser = LiteXArgumentParser(platform=digilent_nexys4.Platform, description="LiteX SoC on Nexys4.") parser.add_target_argument("--sys-clk-freq", default=75e6, type=float, help="System clock frequency.") ethopts = parser.target_group.add_mutually_exclusive_group() ethopts.add_argument("--with-ethernet", action="store_true", help="Enable Ethernet support.") ethopts.add_argument("--with-etherbone", action="store_true", help="Enable Etherbone support.") sdopts = parser.target_group.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.") viopts = parser.target_group.add_mutually_exclusive_group() viopts.add_argument("--with-video-terminal", action="store_true", help="Enable Video Terminal (VGA).") viopts.add_argument("--with-video-framebuffer", action="store_true", help="Enable Video Framebuffer (VGA).") args = parser.parse_args() soc = BaseSoC( sys_clk_freq = args.sys_clk_freq, with_ethernet = args.with_ethernet, with_etherbone = args.with_etherbone, with_video_terminal = args.with_video_terminal, with_video_framebuffer = args.with_video_framebuffer, **parser.soc_argdict ) if args.with_spi_sdcard: soc.add_spi_sdcard() if args.with_sdcard: soc.add_sdcard() builder = Builder(soc, **parser.builder_argdict) if args.build: builder.build(**parser.toolchain_argdict) if args.load: prog = soc.platform.create_programmer() prog.load_bitstream(builder.get_bitstream_filename(mode="sram")) if __name__ == "__main__": main()