a_e115fb: new board

It's a core board with EP4CE115 by a random vendor on Taobao.

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>

litex_boards/platforms/a_e115fb.py

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+#
+# This file is part of LiteX-Boards.
+#
+# Copyright (c) 2022 Icenowy Zheng <uwu@icenowy.me>
+# SPDX-License-Identifier: BSD-2-Clause
+
+from litex.build.generic_platform import *
+from litex.build.altera import AlteraPlatform
+from litex.build.altera.programmer import USBBlaster
+
+# IOs ----------------------------------------------------------------------------------------------
+
+_io = [
+    # Clk
+    ("clk25", 0, Pins("AB11"), IOStandard("3.3-V LVTTL")),
+    ("clk27", 0, Pins("A11"), IOStandard("3.3-V LVTTL")),
+
+    # Rst
+    ("cpu_reset_n", 0, Pins("N21"), IOStandard("1.8-V")), # N21
+
+    # Serial
+    ("serial", 0,
+        Subsignal("tx", Pins("V3"), IOStandard("3.3-V LVTTL")), # GPIOs close to voltage selector
+        Subsignal("rx", Pins("AA1"), IOStandard("3.3-V LVTTL"))
+    ),
+
+    # LEDs
+    ("user_led_n", 0, Pins("A5"), IOStandard("3.3-V LVTTL")), # D3
+    ("user_led_n", 1, Pins("B5"), IOStandard("3.3-V LVTTL")), # D4
+    ("user_led_n", 2, Pins("C4"), IOStandard("3.3-V LVTTL")), # D5
+    ("user_led_n", 3, Pins("C3"), IOStandard("3.3-V LVTTL")), # D6
+
+    # Buttons
+    ("user_btn_n", 0, Pins("T1"),  IOStandard("3.3-V LVTTL")),  # K3
+    ("user_btn_n", 1, Pins("N22"),  IOStandard("3.3-V LVTTL")), # K4
+]
+
+# Platform -----------------------------------------------------------------------------------------
+
+class Platform(AlteraPlatform):
+    default_clk_name   = "clk25"
+    default_clk_period = 1e9/25e6
+
+    def __init__(self, toolchain="quartus"):
+        AlteraPlatform.__init__(self, "EP4CE115F23I7", _io, toolchain=toolchain)
+
+    def create_programmer(self):
+        return USBBlaster()
+
+    def do_finalize(self, fragment):
+        AlteraPlatform.do_finalize(self, fragment)
+        self.add_period_constraint(self.lookup_request("clk25", loose=True), 1e9/25e6)
+        self.add_period_constraint(self.lookup_request("clk27", loose=True), 1e9/27e6)

litex_boards/targets/a_e115fb.py

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+#!/usr/bin/env python3
+
+#
+# This file is part of LiteX-Boards.
+#
+# Copyright (c) 2022 Icenowy Zheng <icenowy@aosc.io>
+# SPDX-License-Identifier: BSD-2-Clause
+
+from migen import *
+from migen.genlib.resetsync import AsyncResetSynchronizer
+
+from litex_boards.platforms import a_e115fb
+
+from litex.soc.cores.clock import CycloneIVPLL
+from litex.soc.cores.led import LedChaser
+from litex.soc.integration.soc_core import *
+from litex.soc.integration.builder import *
+
+# CRG ----------------------------------------------------------------------------------------------
+
+class _CRG(Module):
+    def __init__(self, platform, sys_clk_freq):
+        self.rst = Signal()
+        self.clock_domains.cd_sys    = ClockDomain()
+
+        # # #
+
+        # Clk / Rst
+        clk25 = platform.request("clk25")
+        rst_n  = platform.request("cpu_reset_n")
+
+        # PLL
+        self.submodules.pll = pll = CycloneIVPLL(speedgrade="-7")
+        self.comb += pll.reset.eq(~rst_n | self.rst)
+        pll.register_clkin(clk25, 25e6)
+        pll.create_clkout(self.cd_sys,    sys_clk_freq)
+
+# BaseSoC ------------------------------------------------------------------------------------------
+
+class BaseSoC(SoCCore):
+    def __init__(self, sys_clk_freq=int(50e6), with_led_chaser=True,
+                 **kwargs):
+        platform = a_e115fb.Platform()
+
+        # CRG --------------------------------------------------------------------------------------
+        self.submodules.crg = _CRG(platform, sys_clk_freq)
+
+        # SoCCore ----------------------------------------------------------------------------------
+        SoCCore.__init__(self, platform, sys_clk_freq, ident="LiteX SoC on A-E115FB", **kwargs)
+
+        # Leds -------------------------------------------------------------------------------------
+        if with_led_chaser:
+            ledn = platform.request_all("user_led_n")
+            self.submodules.leds = LedChaser(pads=ledn, sys_clk_freq=sys_clk_freq)
+
+# Build --------------------------------------------------------------------------------------------
+
+def main():
+    from litex.soc.integration.soc import LiteXSoCArgumentParser
+    parser = LiteXSoCArgumentParser(description="LiteX SoC on A-E115FB")
+    target_group = parser.add_argument_group(title="Target options")
+    target_group.add_argument("--build",        action="store_true", help="Build design.")
+    target_group.add_argument("--load",         action="store_true", help="Load bitstream.")
+    target_group.add_argument("--sys-clk-freq", default=50e6,        help="System clock frequency.")
+    builder_args(parser)
+    soc_core_args(parser)
+    args = parser.parse_args()
+
+    soc = BaseSoC(
+        sys_clk_freq = int(float(args.sys_clk_freq)),
+        **soc_core_argdict(args)
+    )
+    builder = Builder(soc, **builder_argdict(args))
+    if args.build:
+        builder.build()
+
+    if args.load:
+        prog = soc.platform.create_programmer()
+        prog.load_bitstream(builder.get_bitstream_filename(mode="sram"))
+
+if __name__ == "__main__":
+    main()