phy: Improve clock accuracy at 0.5 dividers at the cost of some jitter

Actually, assuming that each clock domain is fast enough for 10 MBit/s,
there is no problem running crazy ratios.

.externalToolBuilders/com.sigasi.hdt.toolchains.vunit.builder.launch

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<launchConfiguration type="org.eclipse.ui.externaltools.ProgramBuilderLaunchConfigurationType">
+    <booleanAttribute key="org.eclipse.ui.externaltools.ATTR_BUILDER_ENABLED" value="false"/>
+    <stringAttribute key="org.eclipse.ui.externaltools.ATTR_DISABLED_BUILDER" value="com.sigasi.hdt.toolchains.vunit.builder"/>
+    <mapAttribute key="org.eclipse.ui.externaltools.ATTR_TOOL_ARGUMENTS"/>
+    <booleanAttribute key="org.eclipse.ui.externaltools.ATTR_TRIGGERS_CONFIGURED" value="true"/>
+</launchConfiguration>

.gitignore

@@ -1 +1,12 @@
+# VUnit
 vunit_out
+
+# Cocotb
+__pycache__
+*.o
+cocotb/results.xml
+cocotb/sim_build
+cocotb/wave.ghw
+
+cocotb/cocotb_top_mac_test
+cocotb/cocotb_top_hwitl

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "cocotb/cocotb_helpers"]
+	path = cocotb/cocotb_helpers
+	url = https://git.notsyncing.net/fpga/cocotb_helpers.git

.library_mapping.xml

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<com.sigasi.hdt.shared.librarymapping.model:LibraryMappings xmlns:com.sigasi.hdt.shared.librarymapping.model="com.sigasi.hdt.vhdl.scoping.librarymapping" Version="2">
+  <Mappings Location="bench" Library="bench"/>
+  <Mappings Location="cocotb" Library="cocotb"/>
+  <Mappings Location="design" Library="design"/>
+  <Mappings Location="Common Libraries/IEEE" Library="ieee"/>
+  <Mappings Location="Common Libraries/IEEE Synopsys" Library="ieee"/>
+  <Mappings Location="" Library="not mapped"/>
+  <Mappings Location="Common Libraries" Library="not mapped"/>
+  <Mappings Location="Common Libraries/vunit" Library="not mapped"/>
+  <Mappings Location="cocotb/__pycache__" Library="not mapped"/>
+  <Mappings Location="cocotb/sim_build" Library="not mapped"/>
+  <Mappings Location="Common Libraries/STD" Library="std"/>
+  <Mappings Location="trashernet" Library="trashernet"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/IP_complete_nomac.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/IPv4.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/IPv4_RX.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/IPv4_TX.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/UDP_Complete_nomac.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/UDP_RX.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/UDP_TX.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/arp.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/arp_REQ.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/arp_RX.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/arp_STORE_br.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/arp_SYNC.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/arp_TX.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/arp_types.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/arpv2.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/axi.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/ipv4_types.vhd" Library="udpip"/>
+  <Mappings Location="udp_ip_stack/rtl/vhdl/tx_arbitrator.vhd" Library="udpip"/>
+  <Mappings Location="Common Libraries/vunit/vunit/vhdl" Library="vunit_lib"/>
+  <Mappings Location="Common Libraries/src" Library="xp2"/>
+</com.sigasi.hdt.shared.librarymapping.model:LibraryMappings>

.project

@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>trashernet</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.ui.externaltools.ExternalToolBuilder</name>
+			<triggers>full,incremental,</triggers>
+			<arguments>
+				<dictionary>
+					<key>LaunchConfigHandle</key>
+					<value>&lt;project&gt;/.externalToolBuilders/com.sigasi.hdt.toolchains.vunit.builder.launch</value>
+				</dictionary>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.xtext.ui.shared.xtextBuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>com.sigasi.hdt.vhdl.ui.vhdlNature</nature>
+		<nature>org.eclipse.xtext.ui.shared.xtextNature</nature>
+		<nature>com.sigasi.hdt.toolchains.vunit.nature</nature>
+	</natures>
+	<linkedResources>
+		<link>
+			<name>Common Libraries</name>
+			<type>2</type>
+			<locationURI>virtual:/virtual</locationURI>
+		</link>
+		<link>
+			<name>Common Libraries/DRAG_REUSABLE_LIBRARIES_HERE.txt</name>
+			<type>1</type>
+			<locationURI>sigasiresource:/vhdl/readme.txt</locationURI>
+		</link>
+		<link>
+			<name>Common Libraries/IEEE</name>
+			<type>2</type>
+			<locationURI>sigasiresource:/vhdl/2008/IEEE</locationURI>
+		</link>
+		<link>
+			<name>Common Libraries/IEEE Synopsys</name>
+			<type>2</type>
+			<locationURI>sigasiresource:/vhdl/2008/IEEE%20Synopsys</locationURI>
+		</link>
+		<link>
+			<name>Common Libraries/STD</name>
+			<type>2</type>
+			<locationURI>sigasiresource:/vhdl/2008/STD</locationURI>
+		</link>
+		<link>
+			<name>Common Libraries/src</name>
+			<type>2</type>
+			<location>/usr/local/diamond/3.12/cae_library/simulation/vhdl/xp2/src</location>
+		</link>
+		<link>
+			<name>Common Libraries/vunit</name>
+			<type>2</type>
+			<locationURI>PARENT-1-PROJECT_LOC/vunit</locationURI>
+		</link>
+	</linkedResources>
+</projectDescription>

.settings/com.sigasi.hdt.toolchains.vunit.prefs

@@ -0,0 +1,2 @@
+VUnitScriptLocation=vunit/run.py
+eclipse.preferences.version=1

.settings/com.sigasi.hdt.vhdl.version.prefs

@@ -0,0 +1 @@
+<project>=2008

.settings/org.eclipse.core.resources.prefs

@@ -0,0 +1,5 @@
+eclipse.preferences.version=1
+encoding//Common\ Libraries/IEEE=utf-8
+encoding//Common\ Libraries/IEEE\ Synopsys=utf-8
+encoding//Common\ Libraries/STD=utf-8
+encoding/Common\ Libraries=utf-8

README.MD

@@ -5,7 +5,8 @@
 Trashernet is a very trashy Ethernet stack for FPGAs written in VHDL aiming to cover all OSI layers:
 
 * Layer 1, Physical: `trashernet_phy`
-* Layer 2, Data link: `trashernet_mac`
+* Layer 2, Data link: `trashernet_mac`, `trashernet_eth`, `trashernet_arp`
+* Layer 3, Network: `trashernet_ipv4`, `trashernet_ipv4prot`, `trashernet_icmp`
 
 When writing it, the following were the main design philosophies:
 
@@ -27,6 +28,23 @@ Notes:
 * The RX pull up/downs are probably not the best idea, and fixable in a better way. But for now, this shall work -- and suffice!
 * On the TX side, I'm grossly overloading the drivers. A line driver would probably be a good idea. Or you can just parallel multiple outputs ;D
 
+## Stats
+
+Sythesized for a Lattice LFXP2-5E FPGA using LSE / Diamond v3.12:
+
+| Configuration    | Slices | LUT4 | Registers |
+| ---------------- | ------ | ---- | --------- |
+| `trashernet_phy` | 115    | 188  | 91        |
+
 ## License
 
 This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
+
+The Trashernet logo uses graphics from [svgrepo.com](https://svgrepo.com), which are released under the Creative Commons CC0 license, granting the right to freely adapt and use them in any context. Thank you for making these available:
+
+* Trash can: https://www.svgrepo.com/svg/66604/trash
+* Ethernet jack: https://www.svgrepo.com/svg/292518/ethernet
+
+The font used in the logo, "White Rabbit" by Matthew Welch, is also released on a free-to-use basis. Thank you!
+
+* White Rabbit: https://www.fontsquirrel.com/fonts/white-rabbit

bench/bench_trashernet_phy.vhd

@@ -18,10 +18,10 @@ use work.bench_pkg.all;
 library trashernet;
 use trashernet.trashernet_pkg.all;
 
-entity cocotb_trashernet_phy is
+entity bench_trashernet_phy is
-end entity cocotb_trashernet_phy;
+end entity bench_trashernet_phy;
 
-architecture bench of cocotb_trashernet_phy is
+architecture bench of bench_trashernet_phy is
 	signal clk            : std_logic;
 	signal phy_clk        : std_logic;
 	signal rst            : std_logic;

bench/pll0.vhd

@@ -0,0 +1,42 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- pll0.vhd : Simulates the PLL component present in some demo designs
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+entity pll0 is
+	port(
+		CLK   : in  std_logic;
+		CLKOP : out std_logic;
+		LOCK  : out std_logic
+	);
+end entity pll0;
+
+architecture bench of pll0 is
+begin
+	clock_driver : process
+		constant period : time := 7.1429 ns; -- 140 MHz configured clock
+	begin
+		CLKOP <= '0';
+		LOCK  <= '0';
+
+		wait until CLK'event;
+		wait for 12 ns;
+		LOCK <= '1';
+
+		loop
+			CLKOP <= '0';
+			wait for period / 2;
+			CLKOP <= '1';
+			wait for period / 2;
+		end loop;
+	end process clock_driver;
+end architecture bench;

cocotb/.gitignore

@@ -1,4 +0,0 @@
-*.pyc
-*.o
-results.xml
-*.cf

cocotb/Makefile

@@ -1,14 +1,19 @@
 # defaults
+
 SIM ?= ghdl
 TOPLEVEL_LANG ?= vhdl
 BASE = $(PWD)/..
+BENCHTOP ?= cocotb_top_mac_test
 
 COMPILE_ARGS=--std=08
+# SIM_ARGS ?= --wave=wave.ghw
 
 VHDL_SOURCES_trashernet += $(BASE)/trashernet/*.vhd
+VHDL_SOURCES_design += $(BASE)/design/*.vhd
+VHDL_SOURCES_design += $(BASE)/bench/pll0.vhd
 VHDL_SOURCES += $(BASE)/cocotb/*.vhd
 
-TOPLEVEL = cocotb_trashernet_phy
+TOPLEVEL ?= $(BENCHTOP)
-MODULE = cocotb_trashernet_phy
+MODULE ?= $(BENCHTOP)
 
 include $(shell cocotb-config --makefiles)/Makefile.sim

cocotb/cocotb_helpers

@@ -0,0 +1 @@
+Subproject commit e2c72ef61d7742fbcb7e048bc928446ed4b56a82

cocotb/cocotb_top_hwitl.vhd

@@ -0,0 +1,90 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- cocotb_top_hwitl.vhd : Test bench for cocotb HW-in-the-loop tests
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+library design;
+use design.all;
+
+entity cocotb_top_hwitl is
+end entity cocotb_top_hwitl;
+
+architecture bench of cocotb_top_hwitl is
+	-- DUT signals
+	signal clk        : std_logic;
+	signal rst_n      : std_logic;
+	signal rx_p       : std_logic;
+	signal tx_p       : std_logic;
+	signal tx_n       : std_logic;
+	signal led_n      : std_logic_vector(7 downto 0);
+	signal button_n   : std_logic_vector(3 downto 0);
+	signal debug_data : std_logic_vector(7 downto 0);
+
+	-- Generic test bench
+	signal bench_ready : std_logic := '0';
+begin
+	top_mac_test_inst : entity top_hwitl(eth) -- TODO: I haven't managed to get configurations working with cocotb yet, so changing this line changes the test case :(
+		port map(
+			clk        => clk,
+			rst_n      => rst_n,
+			rx_p       => rx_p,
+			tx_p       => tx_p,
+			tx_n       => tx_n,
+			led_n      => led_n,
+			button_n   => button_n,
+			debug_data => debug_data
+		);
+
+	clock_driver : process
+		constant period : time := 20 ns;
+	begin
+		clk <= '0';
+		wait for period / 2;
+		clk <= '1';
+		wait for period / 2;
+	end process clock_driver;
+
+	rstsim : process is
+	begin
+		rst_n       <= '0';
+		wait for 400 ns;
+		rst_n       <= '1';
+		wait for 100 ns;
+		wait until rising_edge(clk);
+		bench_ready <= '1';
+		wait;
+	end process rstsim;
+
+	cocovc_eth_inst : entity work.cocovc_eth
+		port map(
+			rx_p => tx_p,
+			rx_n => tx_n,
+			tx_p => rx_p,
+			tx_n => open
+		);
+
+	test_seq : process is
+	begin
+		wait until bench_ready = '1';
+
+		button_n <= (others => '1');
+		wait for 1 us;
+
+		wait until rising_edge(clk);
+		button_n(0) <= '0';
+		wait until rising_edge(clk);
+		button_n(0) <= '1';
+
+		wait;
+	end process test_seq;
+
+end architecture bench;

cocotb/cocotb_top_mac_test.py

@@ -0,0 +1,48 @@
+#!/usr/bin/env python
+
+import cocotb
+from cocotb.triggers import *
+from cocotb.result import *
+
+from cocotb.queue import Queue
+
+from cocotb_helpers import buffers
+
+ETH_HEAD = b'\x55\x55\x55\x55\xD5'
+
+async def timeout(dut):
+	await Timer(1, units="ms")
+	assert False, "Timeout"
+
+async def rxprinter(dut, rx):
+	while True:
+		frame = await rx.queue.get()
+		dut._log.info("RX Frame: " + str(frame))
+
+@cocotb.test()
+async def my_test(dut):
+	"""TBD description."""
+
+	# Start verification components
+	eth_tx = buffers.tx_buffer(dut, "cocovc_eth_inst.cocotb_tx_")
+	await eth_tx.start()
+	eth_rx = buffers.rx_buffer(dut, "cocovc_eth_inst.cocotb_rx_")
+	await eth_rx.start()
+
+	# Start local monitors
+	await cocotb.start(rxprinter(dut, eth_rx))
+
+	# Start timeout
+	await cocotb.start(timeout(dut))
+
+	# Wait for VHDL part to be ready
+	await Edge(dut.bench_ready)
+
+	# Start test procedure
+	await Timer(400, units="us") # The device will send a frame at startup
+
+	dut._log.info("Send first frame"); # This will trigger a response frame
+	await eth_tx.send(ETH_HEAD + b'\x00\xff\xff\x11"3\x00\xff\xff\xaa\xbb\xcc\x00\n\n\t\x08\x07\x06\x05\x04\x03\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00!\x10\x90\xe0');
+	dut._log.info("Send second frame");
+	await eth_tx.send(ETH_HEAD + b'World');
+	await Timer(400, units="us") # Wait for response

cocotb/cocotb_top_mac_test.vhd

@@ -0,0 +1,77 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- cocotb_top_mac_test.vhd : Test bench for the MAC test demo.
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+library design;
+use design.all;
+
+entity cocotb_top_mac_test is
+end entity cocotb_top_mac_test;
+
+architecture bench of cocotb_top_mac_test is
+	-- DUT signals
+	signal clk        : std_logic;
+	signal rst_n      : std_logic;
+	signal rx_p       : std_logic;
+	signal tx_p       : std_logic;
+	signal tx_n       : std_logic;
+	signal led_n      : std_logic_vector(7 downto 0);
+	signal button_n   : std_logic_vector(3 downto 0);
+	signal debug_data : std_logic_vector(7 downto 0);
+
+	-- Generic test bench
+	signal bench_ready : std_logic := '0';
+begin
+	top_mac_test_inst : entity design.top_mac_test
+		port map(
+			clk        => clk,
+			rst_n      => rst_n,
+			rx_p       => rx_p,
+			tx_p       => tx_p,
+			tx_n       => tx_n,
+			led_n      => led_n,
+			button_n   => button_n,
+			debug_data => debug_data
+		);
+
+	clock_driver : process
+		constant period : time := 20 ns;
+	begin
+		clk <= '0';
+		wait for period / 2;
+		clk <= '1';
+		wait for period / 2;
+	end process clock_driver;
+
+	rstsim : process is
+	begin
+		rst_n       <= '0';
+		wait for 400 ns;
+		rst_n       <= '1';
+		wait for 100 ns;
+		wait until rising_edge(clk);
+		bench_ready <= '1';
+		wait;
+	end process rstsim;
+
+	cocovc_eth_inst : entity work.cocovc_eth
+		port map(
+			rx_p => tx_p,
+			rx_n => tx_n,
+			tx_p => rx_p,
+			tx_n => open
+		);
+
+	button_n <= (others => '1');
+
+end architecture bench;

cocotb/cocotb_trashernet_phy.py

@@ -1,90 +0,0 @@
-#!/usr/bin/env python
-
-import cocotb
-from cocotb.triggers import *
-from cocotb.result import *
-
-from cocotb.queue import Queue
-
-# DUT interface (internal)
-tb_rx_queue = Queue()
-tb_rx_queue_done_ev = Event()
-
-async def dut_receiver(dut):
-	scoreboard = tb_rx_queue
-	while True:
-		await Edge(dut.coco_dut_rxs)
-		byte = dut.coco_dut_rxd.value
-		dut._log.info("[DT:RX <-] Byte %02X", byte)
-		assert not scoreboard.empty(), "Data was provided on the RX interface even though none was expected"
-		if not scoreboard.empty():
-			sb_byte = await scoreboard.get()
-			assert byte == sb_byte, f"Received {byte} instead of {sb_byte}"
-
-async def dut_rxa(dut):
-	scoreboard = tb_rx_queue
-	await Edge(dut.coco_dut_rxa) # TODO: Workaround for some stupid bug somewhere
-	while True:
-		await Edge(dut.coco_dut_rxa)
-		if dut.coco_dut_rxa.value:
-			dut._log.info("[DT:RX <-] Start of frame")
-		else:
-			dut._log.info("[DT:RX <-] End of frame")
-			if scoreboard.empty():
-				tb_rx_queue_done_ev.set()
-
-# TB / ETH interface (external)
-tb_tx_queue = Queue()
-
-async def tb_transmitter(dut):
-	queue = tb_tx_queue
-	while True:
-		byte = await queue.get()
-		if byte == -1:
-			dut._log.info("[TB:TX ->] Wait IPG")
-			await Timer(16, units="us") # IPG
-		else:	# TX byte
-			dut._log.info("[TB:TX ->] Byte %02X", byte)
-			dut.coco_tb_txd.value = byte
-			dut.coco_tb_txs.value = not dut.coco_tb_txs.value
-			await Edge(dut.coco_tb_txa);
-
-async def tb_send_packet(dut, data):
-	queue = tb_tx_queue
-	scoreboard = tb_rx_queue
-
-	queue.put_nowait(0x55)
-	queue.put_nowait(0x55)
-	queue.put_nowait(0x55)
-	queue.put_nowait(0xD5)
-
-	for byte in data:
-		scoreboard.put_nowait(byte)
-		queue.put_nowait(byte)
-
-	queue.put_nowait(-1)
-
-async def timeout(dut):
-	await Timer(50, units="us")
-	assert False, "Timeout"
-
-@cocotb.test()
-async def simple_rx(dut):
-	"""Receive a packet using trashernet."""
-
-	await cocotb.start(timeout(dut))
-
-	await cocotb.start(dut_receiver(dut))
-	await cocotb.start(dut_rxa(dut))
-	await cocotb.start(tb_transmitter(dut))
-
-	dut.rst.value = 1
-	await Timer(20, units="ns")
-	dut.rst.value = 0
-	await Timer(20, units="ns")
-
-	await tb_send_packet(dut, b'\x02\x03\x05\x07')
-
-	await cocotb.start(timeout(dut))
-
-	await tb_rx_queue_done_ev.wait()

cocotb/cocotb_trashernet_phy.vhd

@@ -1,104 +0,0 @@
--- -------------------------------------------------------------------------- --
---               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
--- -------------------------------------------------------------------------- --
--- bench_trashernet_phy.vhd : Cocotb test bench for the PHY
--- -------------------------------------------------------------------------- --
--- Author       : Markus Koch <markus@notsyncing.net>
--- Contributors : None
--- License      : Mozilla Public License (MPL) Version 2
--- -------------------------------------------------------------------------- --
-
-library ieee;
-use ieee.std_logic_1164.all;
-use ieee.numeric_std.all;
-
-library trashernet;
-use trashernet.trashernet_pkg.all;
-
-entity cocotb_trashernet_phy is
-end entity cocotb_trashernet_phy;
-
-architecture bench of cocotb_trashernet_phy is
-	signal clk     : std_logic;
-	signal phy_clk : std_logic;
-	signal rst     : std_logic;
-	signal phy_out : phy_out_t;
-	signal phy_in  : phy_in_t;
-	signal rx_p    : std_logic;
-	signal tx_p    : std_logic;
-	signal tx_n    : std_logic;
-
-	-- Cocotb interface
-	signal coco_dut_rxd : std_logic_vector(7 downto 0); -- RX data
-	signal coco_dut_rxs : std_logic := '0'; -- RX toggle
-	signal coco_dut_rxa : std_logic;    -- RX active
-
-	signal coco_tb_txd : std_logic_vector(7 downto 0); -- TX data
-	signal coco_tb_txs : std_logic := '0'; -- TX toggle
-	signal coco_tb_txa : std_logic := '0'; -- TX done toggle
-
-begin
-	-- Instantiate design
-	trashernet_phy_cdc_inst : entity trashernet.trashernet_phy_cdc
-		generic map(
-			F_CLK     => 49000000,
-			F_CLK_PHY => 100000000
-		)
-		port map(
-			clk     => clk,
-			phy_clk => phy_clk,
-			rst     => rst,
-			phy_out => phy_out,
-			phy_in  => phy_in,
-			rx_p    => rx_p,
-			tx_p    => tx_p,
-			tx_n    => tx_n
-		);
-
-	-- Create infrastructure
-	clock_driver : process
-		constant period : time := 20 ns;
-	begin
-		clk <= '0';
-		wait for period / 2;
-		clk <= '1';
-		wait for period / 2;
-	end process clock_driver;
-
-	phy_clock_driver : process
-		constant period : time := 10 ns;
-	begin
-		phy_clk <= '0';
-		wait for period / 2;
-		phy_clk <= '1';
-		wait for period / 2;
-	end process phy_clock_driver;
-
-	-- Cocotb adapter (ETH)
-	test : process is
-	begin
-		rx_p <= '0';
-
-		loop
-			wait on coco_tb_txs;
-
-			for j in coco_tb_txd'low to coco_tb_txd'high loop
-				rx_p <= not coco_tb_txd(j);
-				wait for 50 ns;
-				rx_p <= coco_tb_txd(j);
-				wait for 50 ns;
-			end loop;
-			coco_tb_txa <= not coco_tb_txa;
-		end loop;
-	end process test;
-
-	receiver : process is
-	begin
-		wait until rising_edge(clk);
-		if phy_out.rx_data_valid then
-			coco_dut_rxd <= phy_out.rx_data;
-			coco_dut_rxs <= not coco_dut_rxs;
-		end if;
-	end process receiver;
-	coco_dut_rxa <= phy_out.rx_active;
-end architecture bench;

cocotb/cocovc_eth.vhd

@@ -0,0 +1,123 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- cocovc_eth.vhd : Cocotb-based verification component for 10M Ethernet.
+--   Note: This is cheapskated to work with Trashernet. It may not work with
+--   every PHY.
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+entity cocovc_eth is
+	port(
+		rx_p : in  std_logic;
+		rx_n : in  std_logic;
+		tx_p : out std_logic;
+		tx_n : out std_logic
+	);
+end entity cocovc_eth;
+
+architecture bench of cocovc_eth is
+	-- Ethernet TX (TB/Python to DUT/VHDL)
+	signal cocotb_tx_d  : std_logic_vector(7 downto 0) := x"00"; -- Data to be transferred to VHDL
+	signal cocotb_tx_dv : std_logic                    := '0'; -- '1' when `d` holds valid data that is to be processed by VHDL
+	signal cocotb_tx_da : std_logic                    := '0'; -- Toggles when VHDL has latched `d`, Python must advance data or deassert `dv`
+
+	-- Ethernet RX (DUT/VHDL to TB/Python)
+	signal cocotb_rx_d  : std_logic_vector(7 downto 0); -- Data to be transferred to Python
+	signal cocotb_rx_dt : std_logic := '0'; -- Toggles to announce new data (Python has to latch immediately)
+	signal cocotb_rx_a  : std_logic := '0'; -- Block active indicator (rising on block start, falling on block end)
+begin
+	-- Ethernet TX
+	eth_tx_proc : process is
+		variable d : std_logic_vector(cocotb_rx_d'range);
+	begin
+		tx_p <= '0';
+		wait until cocotb_tx_dv = '1';
+
+		loop
+			exit when not cocotb_tx_dv;
+
+			d            := cocotb_tx_d;
+			cocotb_tx_da <= not cocotb_tx_da;
+
+			for j in d'low to d'high loop
+				tx_p <= not d(j);
+				wait for 50 ns;
+				tx_p <= d(j);
+				wait for 50 ns;
+			end loop;
+		end loop;
+
+		wait for 16 us;                 -- Wait IPG
+		cocotb_tx_da <= not cocotb_tx_da; -- Signal that end-of-block was latched
+
+	end process eth_tx_proc;
+	tx_n <= not tx_p;
+
+	-- Ethernet RX
+	eth_rx_proc : process is
+		constant SYM_TIME : time                                := 50 ns;
+		variable d        : std_logic_vector(cocotb_rx_d'range) := x"00";
+		variable cnt      : integer range d'low to d'high;
+		variable bit      : std_logic;
+		variable ignore   : boolean;
+		variable first    : boolean;    -- Just a cheap workaround because the weather is too nice to implement it properly this afternoon
+		procedure latch(value : std_logic) is
+		begin
+			d(cnt) := value;
+			if (cnt = 7) then
+				cocotb_rx_d  <= d;
+				cocotb_rx_dt <= not cocotb_rx_dt;
+				cnt          := 0;
+			else
+				cnt := cnt + 1;
+			end if;
+		end procedure latch;
+
+	begin
+		cocotb_rx_a <= '0';
+
+		loop
+			wait on rx_p;
+			exit when (rx_p'last_value = '0' or rx_p'last_value = '1');
+		end loop;
+
+		cocotb_rx_a <= '1';
+		wait for 0 ns;
+
+		cnt    := 0;
+		bit    := '0';
+		ignore := false;
+		first  := true;
+		loop
+			wait on rx_p for SYM_TIME * 1.5;
+			exit when rx_p'last_event > 2.5 * SYM_TIME;
+
+			if rx_p'event then          -- short
+				if not ignore then
+					latch(bit);
+				end if;
+				ignore := not ignore;
+			else                        -- long
+				if (first) then
+					bit  := '1';
+					cnt  := 1;
+					d(0) := '1';
+				end if;
+				bit    := not bit;
+				latch(bit);
+				ignore := true;
+			end if;
+
+			first := false;
+		end loop;
+	end process eth_rx_proc;
+
+end architecture bench;

cocotb/hw_itl.py

@@ -0,0 +1,94 @@
+#!/usr/bin/env python3
+
+import cocotb
+from cocotb.triggers import *
+from cocotb.result import *
+from cocotb.queue import Queue
+from cocotb_helpers import buffers
+
+import sys
+import threading
+import socket
+import time
+import os
+import asyncio
+import fcntl
+import zlib
+
+'''
+# Set up virtual device using
+sudo ip link add dev veth1 type veth peer name veth2
+sudo ip link set up veth1
+sudo ip link set up veth2
+sudo ip addr add 192.168.2.1/24 dev veth1
+sudo ip link set promisc on dev veth1
+'''
+
+class MacDevReceiver():
+	def __init__(self, dut, eth_tx, eth_rx, dev):
+		self.dut = dut
+		self.eth_tx = eth_tx
+		self.eth_rx = eth_rx
+		self.dev = dev
+		self.mac_rx_ev = Event()
+
+		ETH_P_ALL=3
+		self.macdev=socket.socket(socket.AF_PACKET, socket.SOCK_RAW, socket.htons(ETH_P_ALL))
+		self.macdev.bind((dev, 0))
+		fcntl.fcntl(self.macdev, fcntl.F_SETFL, os.O_NONBLOCK) # Not the best way to poll, but I couldn't get asyncio to play nicely with threading...
+
+	def eth_fcs(self, data):
+		crc = zlib.crc32(data) & 0xFFFF_FFFF
+		return crc.to_bytes(4, byteorder='little')
+
+	async def main(self):
+		ETH_HEAD = b'\x55\x55\x55\x55\xD5'
+		while True:
+			try:
+				r = self.macdev.recv(2000)
+				if len(r) < 60:
+					r += b'\x00' * (60 - len(r))
+				r += self.eth_fcs(r)
+				self.dut._log.debug("DUT RX: " + str(r))
+				await self.eth_tx.send(ETH_HEAD + r);
+			except:
+				await Timer(1, "us")
+				pass
+	async def main_rx(self):
+		while True:
+			frame = await self.eth_rx.queue.get()
+			try:
+				while (frame[0] != 0xD5):
+					frame = frame[1:]
+				frame = frame[1:]
+			except:
+				self.dut._log.debug("NLP / Invalid frame")
+				continue
+			self.dut._log.debug("DUT TX: " + str(frame))
+			self.macdev.send(frame)
+
+	async def start(self):
+		await cocotb.start(self.main())
+		await cocotb.start(self.main_rx())
+
+@cocotb.test()
+async def hwitl(dut):
+	"""Real-Ethernet-hardware in the loop test"""
+
+	# Start verification components
+	eth_tx = buffers.tx_buffer(dut, "cocovc_eth_inst.cocotb_tx_")
+	await eth_tx.start()
+	eth_rx = buffers.rx_buffer(dut, "cocovc_eth_inst.cocotb_rx_")
+	await eth_rx.start()
+
+	# Start local monitors
+	macdev_receiver = MacDevReceiver(dut, eth_tx, eth_rx, "veth2")
+
+	# Wait for VHDL part to be ready
+	await Edge(dut.bench_ready)
+
+	print("beep")
+	await macdev_receiver.start()
+
+	print("Press Ctrl+C to stop the test.")
+	await Timer(100, "sec")

cocotb/hw_itl.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+echo Hardware in the loop test
+
+make TOPLEVEL=cocotb_top_hwitl MODULE=hw_itl

demo/lattice_brevia2/pingable/pingable.ldf

@@ -0,0 +1,68 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<BaliProject version="3.2" title="pingable" device="LFXP2-5E-6TN144C" default_implementation="impl1">
+    <Options/>
+    <Implementation title="impl1" dir="impl1" description="impl1" synthesis="lse" default_strategy="Strategy1">
+        <Options def_top="trashernet.fifo" lib="work" top="top_pingable"/>
+        <Source name="../ip/pll0.vhd" type="VHDL" type_short="VHDL">
+            <Options/>
+        </Source>
+        <Source name="../../../design/ledcon.vhd" type="VHDL" type_short="VHDL">
+            <Options/>
+        </Source>
+        <Source name="../../../trashernet/cdc_strobe.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="../../../trashernet/crc.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="../../../trashernet/synchronizer.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="../../../trashernet/trashernet_eth.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="../../../trashernet/trashernet_mac.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="../../../trashernet/trashernet_phy.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="../../../trashernet/trashernet_phy_cdc.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="../../../trashernet/trashernet_pkg.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="../../../trashernet/trashernet_arp.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="../../../design/top_hwitl.vhd" type="VHDL" type_short="VHDL">
+            <Options/>
+        </Source>
+        <Source name="../../../trashernet/timer.vhd" type="VHDL" type_short="VHDL">
+            <Options/>
+        </Source>
+        <Source name="../../../design/top_pingable.vhd" type="VHDL" type_short="VHDL">
+            <Options top_module="top_pingable"/>
+        </Source>
+        <Source name="../../../trashernet/fifo.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="../../../trashernet/trashernet_icmp.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="../../../trashernet/trashernet_ipv4.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="../../../trashernet/trashernet_ipv4prot.vhd" type="VHDL" type_short="VHDL">
+            <Options lib="trashernet"/>
+        </Source>
+        <Source name="impl1/impl1.xcf" type="Programming Project File" type_short="Programming">
+            <Options/>
+        </Source>
+        <Source name="pingable.lpf" type="Logic Preference" type_short="LPF">
+            <Options/>
+        </Source>
+    </Implementation>
+    <Strategy name="Strategy1" file="pingable1.sty"/>
+</BaliProject>

demo/lattice_brevia2/pingable/pingable.lpf

@@ -0,0 +1,47 @@
+BLOCK RESETPATHS ;
+BLOCK ASYNCPATHS ;
+LOCATE COMP "clk" SITE "21" ;
+LOCATE COMP "rst_n" SITE "19" ;
+LOCATE COMP "rx_p" SITE "94" ;
+LOCATE COMP "led_n[0]" SITE "37" ;
+LOCATE COMP "led_n[1]" SITE "38" ;
+LOCATE COMP "led_n[2]" SITE "39" ;
+LOCATE COMP "led_n[3]" SITE "40" ;
+LOCATE COMP "led_n[4]" SITE "43" ;
+LOCATE COMP "led_n[5]" SITE "44" ;
+LOCATE COMP "led_n[6]" SITE "45" ;
+LOCATE COMP "led_n[7]" SITE "46" ;
+IOBUF PORT "rx_p" IO_TYPE=LVPECL33 ;
+IOBUF PORT "clk" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "rst_n" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "debug_data[0]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "debug_data[1]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "debug_data[2]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "debug_data[3]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "debug_data[4]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "debug_data[5]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "debug_data[6]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "debug_data[7]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "led_n[0]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "led_n[1]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "led_n[2]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "led_n[3]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "led_n[4]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "led_n[5]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "led_n[6]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "led_n[7]" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "tx_n" IO_TYPE=LVCMOS33 ;
+IOBUF PORT "tx_p" IO_TYPE=LVCMOS33 ;
+LOCATE COMP "tx_n" SITE "114" ;
+LOCATE COMP "tx_p" SITE "116" ;
+LOCATE COMP "button_n[0]" SITE "54" ;
+LOCATE COMP "debug_data[0]" SITE "73" ;
+LOCATE COMP "debug_data[1]" SITE "74" ;
+LOCATE COMP "debug_data[2]" SITE "77" ;
+LOCATE COMP "debug_data[3]" SITE "87" ;
+LOCATE COMP "debug_data[4]" SITE "88" ;
+LOCATE COMP "debug_data[5]" SITE "89" ;
+LOCATE COMP "debug_data[6]" SITE "90" ;
+LOCATE COMP "debug_data[7]" SITE "91" ;
+BLOCK PATH FROM CLKNET "clk_c" TO CLKNET "clk_phy" ;
+BLOCK PATH FROM CLKNET "clk_phy" TO CLKNET "clk_c" ;

demo/lattice_brevia2/pingable/pingable1.sty

@@ -0,0 +1,206 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE strategy>
+<Strategy version="1.0" predefined="0" description="" label="Strategy1">
+    <Property name="PROP_BD_CmdLineArgs" value="" time="0"/>
+    <Property name="PROP_BD_EdfHardtimer" value="Enable" time="0"/>
+    <Property name="PROP_BD_EdfInBusNameConv" value="None" time="0"/>
+    <Property name="PROP_BD_EdfInLibPath" value="" time="0"/>
+    <Property name="PROP_BD_EdfInRemLoc" value="Off" time="0"/>
+    <Property name="PROP_BD_EdfMemPath" value="" time="0"/>
+    <Property name="PROP_BD_ParSearchPath" value="" time="0"/>
+    <Property name="PROP_BIT_AddressBitGen" value="Increment" time="0"/>
+    <Property name="PROP_BIT_AllowReadBitGen" value="Disable" time="0"/>
+    <Property name="PROP_BIT_ByteWideBitMirror" value="Disable" time="0"/>
+    <Property name="PROP_BIT_CapReadBitGen" value="Disable" time="0"/>
+    <Property name="PROP_BIT_ConModBitGen" value="Disable" time="0"/>
+    <Property name="PROP_BIT_CreateBitFile" value="True" time="0"/>
+    <Property name="PROP_BIT_DisRAMResBitGen" value="True" time="0"/>
+    <Property name="PROP_BIT_DisableUESBitgen" value="False" time="0"/>
+    <Property name="PROP_BIT_DonePinBitGen" value="Pullup" time="0"/>
+    <Property name="PROP_BIT_DoneSigBitGen" value="4" time="0"/>
+    <Property name="PROP_BIT_EnIOBitGen" value="TriStateDuringReConfig" time="0"/>
+    <Property name="PROP_BIT_EnIntOscBitGen" value="Disable" time="0"/>
+    <Property name="PROP_BIT_ExtClockBitGen" value="False" time="0"/>
+    <Property name="PROP_BIT_GSREnableBitGen" value="True" time="0"/>
+    <Property name="PROP_BIT_GSRRelOnBitGen" value="DoneIn" time="0"/>
+    <Property name="PROP_BIT_GranTimBitGen" value="0" time="0"/>
+    <Property name="PROP_BIT_IOTriRelBitGen" value="Cycle 2" time="0"/>
+    <Property name="PROP_BIT_JTAGEnableBitGen" value="False" time="0"/>
+    <Property name="PROP_BIT_LenBitsBitGen" value="24" time="0"/>
+    <Property name="PROP_BIT_MIFFileBitGen" value="" time="0"/>
+    <Property name="PROP_BIT_NoHeader" value="False" time="0"/>
+    <Property name="PROP_BIT_OutFormatBitGen" value="Bit File (Binary)" time="0"/>
+    <Property name="PROP_BIT_OutFormatBitGen_REF" value="Bit File (Binary)" time="0"/>
+    <Property name="PROP_BIT_OutFormatPromGen" value="Intel Hex 32-bit" time="0"/>
+    <Property name="PROP_BIT_ParityCheckBitGen" value="True" time="0"/>
+    <Property name="PROP_BIT_ReadBackBitGen" value="Flash" time="0"/>
+    <Property name="PROP_BIT_ReadCaptureBitGen" value="Disable" time="0"/>
+    <Property name="PROP_BIT_RemZeroFramesBitGen" value="False" time="0"/>
+    <Property name="PROP_BIT_RunDRCBitGen" value="True" time="0"/>
+    <Property name="PROP_BIT_SearchPthBitGen" value="" time="0"/>
+    <Property name="PROP_BIT_StartUpClkBitGen" value="Cclk" time="0"/>
+    <Property name="PROP_BIT_SynchIOBitGen" value="True" time="0"/>
+    <Property name="PROP_BIT_SysClockConBitGen" value="Reset" time="0"/>
+    <Property name="PROP_BIT_SysConBitGen" value="Reset" time="0"/>
+    <Property name="PROP_BIT_UFMOrder" value="Normal" time="0"/>
+    <Property name="PROP_BIT_WaitStTimBitGen" value="5" time="0"/>
+    <Property name="PROP_IOTIMING_AllSpeed" value="False" time="0"/>
+    <Property name="PROP_LST_AllowDUPMod" value="False" time="0"/>
+    <Property name="PROP_LST_CarryChain" value="True" time="0"/>
+    <Property name="PROP_LST_CarryChainLength" value="0" time="0"/>
+    <Property name="PROP_LST_CmdLineArgs" value="" time="0"/>
+    <Property name="PROP_LST_DSPStyle" value="DSP" time="0"/>
+    <Property name="PROP_LST_DSPUtil" value="100" time="0"/>
+    <Property name="PROP_LST_DecodeUnreachableStates" value="False" time="0"/>
+    <Property name="PROP_LST_DisableDistRam" value="False" time="0"/>
+    <Property name="PROP_LST_EBRUtil" value="100" time="0"/>
+    <Property name="PROP_LST_EdfFrequency" value="200" time="0"/>
+    <Property name="PROP_LST_EdfHardtimer" value="Enable" time="0"/>
+    <Property name="PROP_LST_EdfInLibPath" value="" time="0"/>
+    <Property name="PROP_LST_EdfInRemLoc" value="Off" time="0"/>
+    <Property name="PROP_LST_EdfMemPath" value="" time="0"/>
+    <Property name="PROP_LST_FIXGATEDCLKS" value="True" time="0"/>
+    <Property name="PROP_LST_FSMEncodeStyle" value="Auto" time="0"/>
+    <Property name="PROP_LST_ForceGSRInfer" value="No" time="0"/>
+    <Property name="PROP_LST_IOInsertion" value="True" time="0"/>
+    <Property name="PROP_LST_InterFileDump" value="False" time="0"/>
+    <Property name="PROP_LST_LoopLimit" value="1950" time="0"/>
+    <Property name="PROP_LST_MaxFanout" value="1000" time="0"/>
+    <Property name="PROP_LST_MuxStyle" value="Auto" time="0"/>
+    <Property name="PROP_LST_NumCriticalPaths" value="" time="0"/>
+    <Property name="PROP_LST_OptimizeGoal" value="Timing" time="0"/>
+    <Property name="PROP_LST_PropagatConst" value="True" time="0"/>
+    <Property name="PROP_LST_RAMStyle" value="Auto" time="0"/>
+    <Property name="PROP_LST_ROMStyle" value="Auto" time="0"/>
+    <Property name="PROP_LST_RemoveDupRegs" value="True" time="0"/>
+    <Property name="PROP_LST_ResolvedMixedDrivers" value="False" time="0"/>
+    <Property name="PROP_LST_ResourceShare" value="True" time="0"/>
+    <Property name="PROP_LST_UseIOReg" value="Auto" time="0"/>
+    <Property name="PROP_LST_UseLPF" value="True" time="0"/>
+    <Property name="PROP_LST_VHDL2008" value="True" time="0"/>
+    <Property name="PROP_MAPSTA_AnalysisOption" value="Standard Setup and Hold Analysis" time="0"/>
+    <Property name="PROP_MAPSTA_AutoTiming" value="True" time="0"/>
+    <Property name="PROP_MAPSTA_CheckUnconstrainedConns" value="False" time="0"/>
+    <Property name="PROP_MAPSTA_CheckUnconstrainedPaths" value="False" time="0"/>
+    <Property name="PROP_MAPSTA_FullName" value="False" time="0"/>
+    <Property name="PROP_MAPSTA_NumUnconstrainedPaths" value="0" time="0"/>
+    <Property name="PROP_MAPSTA_ReportStyle" value="Verbose Timing Report" time="0"/>
+    <Property name="PROP_MAPSTA_RouteEstAlogtithm" value="0" time="0"/>
+    <Property name="PROP_MAPSTA_RptAsynTimLoop" value="False" time="0"/>
+    <Property name="PROP_MAPSTA_WordCasePaths" value="1" time="0"/>
+    <Property name="PROP_MAP_IgnorePreErr" value="True" time="0"/>
+    <Property name="PROP_MAP_MAPIORegister" value="Auto" time="0"/>
+    <Property name="PROP_MAP_MAPInferGSR" value="True" time="0"/>
+    <Property name="PROP_MAP_MapModArgs" value="" time="0"/>
+    <Property name="PROP_MAP_OvermapDevice" value="False" time="0"/>
+    <Property name="PROP_MAP_PackLogMapDes" value="" time="0"/>
+    <Property name="PROP_MAP_RegRetiming" value="False" time="0"/>
+    <Property name="PROP_MAP_SigCrossRef" value="False" time="0"/>
+    <Property name="PROP_MAP_SymCrossRef" value="False" time="0"/>
+    <Property name="PROP_MAP_TimingDriven" value="False" time="0"/>
+    <Property name="PROP_MAP_TimingDrivenNodeRep" value="False" time="0"/>
+    <Property name="PROP_MAP_TimingDrivenPack" value="False" time="0"/>
+    <Property name="PROP_PARSTA_AnalysisOption" value="Standard Setup and Hold Analysis" time="0"/>
+    <Property name="PROP_PARSTA_AutoTiming" value="True" time="0"/>
+    <Property name="PROP_PARSTA_CheckUnconstrainedConns" value="False" time="0"/>
+    <Property name="PROP_PARSTA_CheckUnconstrainedPaths" value="False" time="0"/>
+    <Property name="PROP_PARSTA_FullName" value="False" time="0"/>
+    <Property name="PROP_PARSTA_NumUnconstrainedPaths" value="0" time="0"/>
+    <Property name="PROP_PARSTA_ReportStyle" value="Verbose Timing Report" time="0"/>
+    <Property name="PROP_PARSTA_RptAsynTimLoop" value="False" time="0"/>
+    <Property name="PROP_PARSTA_SpeedForHoldAnalysis" value="m" time="0"/>
+    <Property name="PROP_PARSTA_SpeedForSetupAnalysis" value="default" time="0"/>
+    <Property name="PROP_PARSTA_WordCasePaths" value="10" time="0"/>
+    <Property name="PROP_PAR_CrDlyStFileParDes" value="False" time="0"/>
+    <Property name="PROP_PAR_DisableTDParDes" value="False" time="0"/>
+    <Property name="PROP_PAR_EffortParDes" value="5" time="0"/>
+    <Property name="PROP_PAR_MultiSeedSortMode" value="Worst Slack" time="0"/>
+    <Property name="PROP_PAR_NewRouteParDes" value="NBR" time="0"/>
+    <Property name="PROP_PAR_PARClockSkew" value="Off" time="0"/>
+    <Property name="PROP_PAR_PARModArgs" value="" time="0"/>
+    <Property name="PROP_PAR_ParMultiNodeList" value="" time="0"/>
+    <Property name="PROP_PAR_ParRunPlaceOnly" value="False" time="0"/>
+    <Property name="PROP_PAR_PlcIterParDes" value="1" time="0"/>
+    <Property name="PROP_PAR_PlcStCostTblParDes" value="1" time="0"/>
+    <Property name="PROP_PAR_PrefErrorOut" value="True" time="0"/>
+    <Property name="PROP_PAR_RemoveDir" value="True" time="0"/>
+    <Property name="PROP_PAR_RouteDlyRedParDes" value="0" time="0"/>
+    <Property name="PROP_PAR_RoutePassParDes" value="6" time="0"/>
+    <Property name="PROP_PAR_RouteResOptParDes" value="0" time="0"/>
+    <Property name="PROP_PAR_RoutingCDP" value="Auto" time="0"/>
+    <Property name="PROP_PAR_RoutingCDR" value="1" time="0"/>
+    <Property name="PROP_PAR_RunParWithTrce" value="False" time="0"/>
+    <Property name="PROP_PAR_RunTimeReduction" value="True" time="0"/>
+    <Property name="PROP_PAR_SaveBestRsltParDes" value="1" time="0"/>
+    <Property name="PROP_PAR_StopZero" value="False" time="0"/>
+    <Property name="PROP_PAR_parHold" value="On" time="0"/>
+    <Property name="PROP_PAR_parPathBased" value="Off" time="0"/>
+    <Property name="PROP_PRE_CmdLineArgs" value="" time="0"/>
+    <Property name="PROP_PRE_EdfArrayBoundsCase" value="False" time="0"/>
+    <Property name="PROP_PRE_EdfAutoResOfRam" value="False" time="0"/>
+    <Property name="PROP_PRE_EdfClockDomainCross" value="False" time="0"/>
+    <Property name="PROP_PRE_EdfDSPAcrossHie" value="False" time="0"/>
+    <Property name="PROP_PRE_EdfFullCase" value="False" time="0"/>
+    <Property name="PROP_PRE_EdfIgnoreRamRWCol" value="False" time="0"/>
+    <Property name="PROP_PRE_EdfMissConstraint" value="False" time="0"/>
+    <Property name="PROP_PRE_EdfNetFanout" value="True" time="0"/>
+    <Property name="PROP_PRE_EdfParaCase" value="False" time="0"/>
+    <Property name="PROP_PRE_EdfReencodeFSM" value="True" time="0"/>
+    <Property name="PROP_PRE_EdfResSharing" value="True" time="0"/>
+    <Property name="PROP_PRE_EdfTimingViolation" value="True" time="0"/>
+    <Property name="PROP_PRE_EdfUseSafeFSM" value="False" time="0"/>
+    <Property name="PROP_PRE_EdfVlog2001" value="True" time="0"/>
+    <Property name="PROP_PRE_VSynComArea" value="False" time="0"/>
+    <Property name="PROP_PRE_VSynCritcal" value="3" time="0"/>
+    <Property name="PROP_PRE_VSynFSM" value="Auto" time="0"/>
+    <Property name="PROP_PRE_VSynFreq" value="200" time="0"/>
+    <Property name="PROP_PRE_VSynGSR" value="False" time="0"/>
+    <Property name="PROP_PRE_VSynGatedClk" value="False" time="0"/>
+    <Property name="PROP_PRE_VSynIOPad" value="False" time="0"/>
+    <Property name="PROP_PRE_VSynOutNetForm" value="None" time="0"/>
+    <Property name="PROP_PRE_VSynOutPref" value="True" time="0"/>
+    <Property name="PROP_PRE_VSynRepClkFreq" value="True" time="0"/>
+    <Property name="PROP_PRE_VSynRetime" value="True" time="0"/>
+    <Property name="PROP_PRE_VSynTimSum" value="10" time="0"/>
+    <Property name="PROP_PRE_VSynTransform" value="True" time="0"/>
+    <Property name="PROP_PRE_VSyninpd" value="0" time="0"/>
+    <Property name="PROP_PRE_VSynoutd" value="0" time="0"/>
+    <Property name="PROP_SYN_ClockConversion" value="True" time="0"/>
+    <Property name="PROP_SYN_CmdLineArgs" value="" time="0"/>
+    <Property name="PROP_SYN_DisableRegisterRep" value="False" time="0"/>
+    <Property name="PROP_SYN_EdfAllowDUPMod" value="False" time="0"/>
+    <Property name="PROP_SYN_EdfArea" value="False" time="0"/>
+    <Property name="PROP_SYN_EdfArrangeVHDLFiles" value="True" time="0"/>
+    <Property name="PROP_SYN_EdfDefEnumEncode" value="Default" time="0"/>
+    <Property name="PROP_SYN_EdfFanout" value="1000" time="0"/>
+    <Property name="PROP_SYN_EdfFrequency" value="200" time="0"/>
+    <Property name="PROP_SYN_EdfGSR" value="False" time="0"/>
+    <Property name="PROP_SYN_EdfInsertIO" value="False" time="0"/>
+    <Property name="PROP_SYN_EdfNumCritPath" value="" time="0"/>
+    <Property name="PROP_SYN_EdfNumStartEnd" value="" time="0"/>
+    <Property name="PROP_SYN_EdfOutNetForm" value="None" time="0"/>
+    <Property name="PROP_SYN_EdfPushTirstates" value="True" time="0"/>
+    <Property name="PROP_SYN_EdfResSharing" value="True" time="0"/>
+    <Property name="PROP_SYN_EdfRunRetiming" value="Pipelining Only" time="0"/>
+    <Property name="PROP_SYN_EdfSymFSM" value="True" time="0"/>
+    <Property name="PROP_SYN_EdfUnconsClk" value="False" time="0"/>
+    <Property name="PROP_SYN_EdfVerilogInput" value="Verilog 2001" time="0"/>
+    <Property name="PROP_SYN_ExportSetting" value="No" time="0"/>
+    <Property name="PROP_SYN_LibPath" value="" time="0"/>
+    <Property name="PROP_SYN_ResolvedMixedDrivers" value="False" time="0"/>
+    <Property name="PROP_SYN_UpdateCompilePtTimData" value="False" time="0"/>
+    <Property name="PROP_SYN_UseLPF" value="True" time="0"/>
+    <Property name="PROP_SYN_VHDL2008" value="True" time="0"/>
+    <Property name="PROP_THERMAL_DefaultFreq" value="0" time="0"/>
+    <Property name="PROP_TIM_MaxDelSimDes" value="" time="0"/>
+    <Property name="PROP_TIM_MinSpeedGrade" value="False" time="0"/>
+    <Property name="PROP_TIM_ModPreSimDes" value="" time="0"/>
+    <Property name="PROP_TIM_NegStupHldTim" value="True" time="0"/>
+    <Property name="PROP_TIM_TimSimGenPUR" value="True" time="0"/>
+    <Property name="PROP_TIM_TimSimGenX" value="False" time="0"/>
+    <Property name="PROP_TIM_TimSimHierSep" value="" time="0"/>
+    <Property name="PROP_TIM_TransportModeOfPathDelay" value="False" time="0"/>
+    <Property name="PROP_TIM_TrgtSpeedGrade" value="" time="0"/>
+    <Property name="PROP_TIM_WriteVerboseNetlist" value="False" time="0"/>
+    <Property name="PROP_TMCHK_EnableCheck" value="True" time="0"/>
+</Strategy>

design/top_hwitl.vhd

@@ -0,0 +1,445 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- top_hwitl.vhd: Top level design for hardware-in-the-loop tests
+--
+--   Target: Simulation
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+use ieee.math_real.all;
+
+library trashernet;
+use trashernet.trashernet_pkg.all;
+
+entity top_hwitl is
+	port(
+		clk        : in  std_logic;
+		rst_n      : in  std_logic;
+		rx_p       : in  std_logic;
+		tx_p       : out std_logic;
+		tx_n       : out std_logic;
+		led_n      : out std_logic_vector(7 downto 0); -- @suppress: Used in different architectures
+		button_n   : in  std_logic_vector(3 downto 0); -- @suppress: Used in different architectures
+		debug_data : out std_logic_vector(7 downto 0) -- @suppress: Used in different architectures
+	);
+end entity top_hwitl;
+
+architecture mac of top_hwitl is
+	component pll0
+		port(
+			CLK   : in  std_logic;
+			CLKOP : out std_logic;
+			LOCK  : out std_logic
+		);
+	end component pll0;
+
+	constant F_CLK     : integer := 50000000;
+	constant F_CLK_PHY : integer := 140000000;
+
+	constant ETH_CONFIG : configuration_t := (
+		mac_address => (x"00", x"ff", x"ff", x"11", x"22", x"33")
+	);
+
+	signal rst     : std_logic;
+	signal clk_phy : std_logic;
+
+	signal phy_out : phy_out_t;
+	signal phy_in  : phy_in_t;
+
+	signal mac_out : mac_out_t;
+	signal mac_in  : mac_in_t;
+
+	type status_t is (IDLE, TX);
+	signal state          : status_t;
+	constant BYTE_CNT_MAX : integer := 100;
+	signal byte_cnt       : integer range 0 to BYTE_CNT_MAX;
+
+	constant TMO_MAX : integer := integer(round((real(F_CLK) * 0.25))) - 1;
+	signal tmo       : integer range 0 to TMO_MAX;
+begin
+	trashernet_mac_inst : entity trashernet.trashernet_mac
+		port map(
+			clk     => clk,
+			rst     => rst,
+			phy_out => phy_out,
+			phy_in  => phy_in,
+			mac_out => mac_out,
+			mac_in  => mac_in
+		);
+
+	pll0_inst : pll0
+		port map(
+			CLK   => clk,
+			CLKOP => clk_phy,
+			LOCK  => open
+		);
+
+	trashernet_phy_cdc_inst : entity trashernet.trashernet_phy_cdc
+		generic map(
+			F_CLK     => F_CLK,
+			F_CLK_PHY => F_CLK_PHY
+		)
+		port map(
+			clk     => clk,
+			phy_clk => clk_phy,
+			rst     => rst,
+			phy_out => phy_out,
+			phy_in  => phy_in,
+			rx_p    => rx_p,
+			tx_p    => tx_p,
+			tx_n    => tx_n
+		);
+
+	reset_sync : process(clk, rst_n) is
+	begin
+		if (rst_n = '0') then
+			rst <= '1';
+		elsif (rising_edge(clk)) then
+			rst <= '0';
+		end if;
+	end process reset_sync;
+
+	receiver : process(clk, rst) is
+	begin
+		if rst then
+			state                 <= IDLE;
+			mac_in.tx_mac_data_en <= '0';
+			tmo                   <= 0;
+		elsif rising_edge(clk) then
+			if (tmo /= 0) then
+				tmo <= tmo - 1;
+			end if;
+			case state is
+				when IDLE =>
+					if mac_out.rx_mac_crc_ok then
+						if (mac_out.rx_header.mac_destination = ETH_CONFIG.mac_address) then -- Note: We won't respond to broadcasts!
+							state                            <= TX;
+							byte_cnt                         <= BYTE_CNT_MAX;
+							mac_in.tx_header.mac_destination <= mac_out.rx_header.mac_source;
+						end if;
+					end if;
+
+					if tmo = 0 then
+						state                            <= TX;
+						byte_cnt                         <= BYTE_CNT_MAX;
+						mac_in.tx_header.mac_destination <= (others => x"FF");
+					end if;
+				when TX =>
+					tmo                            <= TMO_MAX;
+					mac_in.tx_header.mac_ethertype <= (x"00", std_logic_vector(to_unsigned(BYTE_CNT_MAX, 8)));
+					mac_in.tx_mac_data_en          <= '1';
+					mac_in.tx_mac_data             <= std_logic_vector(to_unsigned(byte_cnt, 8));
+					if mac_out.tx_mac_data_ack then
+						if byte_cnt = 1 then
+							mac_in.tx_mac_data_en <= '0';
+							state                 <= IDLE;
+						else
+							byte_cnt <= byte_cnt - 1;
+						end if;
+					end if;
+			end case;
+
+		end if;
+	end process receiver;
+
+	mac_in.tx_header.mac_source <= ETH_CONFIG.mac_address;
+
+	debug_data(0) <= tx_p;
+	debug_data(1) <= tx_n;
+
+end architecture mac;
+
+-- -------------------------------------------------------------------------- --
+-- top_hwitl (eth)
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+use ieee.math_real.all;
+
+library trashernet;
+use trashernet.trashernet_pkg.all;
+
+architecture eth of top_hwitl is
+	component pll0
+		port(
+			CLK   : in  std_logic;
+			CLKOP : out std_logic;
+			LOCK  : out std_logic
+		);
+	end component pll0;
+
+	constant F_CLK     : integer := 50000000;
+	constant F_CLK_PHY : integer := 140000000;
+
+	constant ETH_CONFIG : configuration_t      := (
+		mac_address => (x"00", x"FF", x"FF", x"11", x"22", x"33")
+	);
+	constant IP_CONFIG  : ipv4_configuration_t := (
+		ip_address  => (x"C0", x"A8", x"02", x"02"),
+		subnet_mask => (x"FF", x"FF", x"FF", x"00"),
+		gateway     => (x"C0", x"A8", x"02", x"01")
+	);
+
+	signal rst     : std_logic;
+	signal clk_phy : std_logic;
+
+	signal phy_out : phy_out_t;
+	signal phy_in  : phy_in_t;
+
+	signal mac_out : mac_out_t;
+	signal mac_in  : mac_in_t;
+
+	constant PROT_ARP              : integer                     := 0;
+	constant PROT_IPV4             : integer                     := 1;
+	constant ETHERNET_II_PROTOCOLS : ethernet_ii_protocol_vector := (
+		PROT_ARP  => ETHERNET_II_PROTOCOL_ARP,
+		PROT_IPV4 => ETHERNET_II_PROTOCOL_IPV4
+	);
+	signal ethernet_i_out          : ethernet_i_out_t;
+	signal ethernet_i_in           : ethernet_i_in_t;
+	signal ethernet_ii_out         : ethernet_ii_out_vector(ETHERNET_II_PROTOCOLS'range);
+	signal ethernet_ii_in          : ethernet_ii_in_vector(ETHERNET_II_PROTOCOLS'range);
+
+	signal arp_out : arp_out_t;
+	signal arp_in  : arp_in_t;
+
+	signal ipv4_out : ipv4_out_t;
+	signal ipv4_in  : ipv4_in_t;
+
+	constant IPROT_ICMP      : integer              := 0;
+	constant IPROT_UDP       : integer              := 1;
+	constant IPV4_PROTOCOLS  : ipv4_protocol_vector := (
+		IPROT_ICMP => IPV4_PROTOCOL_ICMP,
+		IPROT_UDP  => IPV4_PROTOCOL_UDP
+	);
+	signal ipv4_protocol_out : ipv4_protocol_out_vector(IPV4_PROTOCOLS'range);
+	signal ipv4_protocol_in  : ipv4_protocol_in_vector(IPV4_PROTOCOLS'range);
+begin
+	trashernet_icmp_inst : entity trashernet.trashernet_icmp
+		port map(
+			clk               => clk,
+			rst               => rst,
+			ipv4_protocol_out => ipv4_protocol_out(IPROT_ICMP),
+			ipv4_protocol_in  => ipv4_protocol_in(IPROT_ICMP)
+		);
+
+	trashernet_ipv4prot_inst : entity trashernet.trashernet_ipv4prot
+		generic map(
+			IPV4_PROTOCOLS => IPV4_PROTOCOLS
+		)
+		port map(
+			clk               => clk,
+			rst               => rst,
+			ipv4_out          => ipv4_out,
+			ipv4_in           => ipv4_in,
+			ipv4_protocol_out => ipv4_protocol_out,
+			ipv4_protocol_in  => ipv4_protocol_in
+		);
+
+	trashernet_ipv4_inst : entity trashernet.trashernet_ipv4
+		port map(
+			clk             => clk,
+			rst             => rst,
+			ipv4_config     => IP_CONFIG,
+			arp_out         => arp_out,
+			arp_in          => arp_in,
+			ethernet_ii_out => ethernet_ii_out(PROT_IPV4),
+			ethernet_ii_in  => ethernet_ii_in(PROT_IPV4),
+			ipv4_out        => ipv4_out,
+			ipv4_in         => ipv4_in
+		);
+
+	trashernet_arp_inst : entity trashernet.trashernet_arp
+		generic map(
+			SYSTICK_FREQ => F_CLK
+		)
+		port map(
+			clk             => clk,
+			rst             => rst,
+			systick         => '1',
+			mac_config      => ETH_CONFIG,
+			ip_config       => IP_CONFIG,
+			arp_out         => arp_out,
+			arp_in          => arp_in,
+			ethernet_ii_out => ethernet_ii_out(PROT_ARP),
+			ethernet_ii_in  => ethernet_ii_in(PROT_ARP)
+		);
+
+	ethernet_i_in <= ethernet_i_in_t'(
+		tx_mac_address => (others => (others => '-')),
+		tx_data        => (others => '-'),
+		tx_en          => '0',
+		tx_length      => (others => '-')
+	);
+
+	trashernet_eth_inst : entity trashernet.trashernet_eth
+		generic map(
+			ETHERNET_II_PROTOCOLS => ETHERNET_II_PROTOCOLS
+		)
+		port map(
+			clk             => clk,
+			rst             => rst,
+			mac_out         => mac_out,
+			mac_in          => mac_in,
+			config          => ETH_CONFIG,
+			ethernet_i_out  => ethernet_i_out,
+			ethernet_i_in   => ethernet_i_in,
+			ethernet_ii_out => ethernet_ii_out,
+			ethernet_ii_in  => ethernet_ii_in
+		);
+
+	trashernet_mac_inst : entity trashernet.trashernet_mac
+		port map(
+			clk     => clk,
+			rst     => rst,
+			phy_out => phy_out,
+			phy_in  => phy_in,
+			mac_out => mac_out,
+			mac_in  => mac_in
+		);
+
+	pll0_inst : pll0
+		port map(
+			CLK   => clk,
+			CLKOP => clk_phy,
+			LOCK  => open
+		);
+
+	trashernet_phy_cdc_inst : entity trashernet.trashernet_phy_cdc
+		generic map(
+			F_CLK     => F_CLK,
+			F_CLK_PHY => F_CLK_PHY
+		)
+		port map(
+			clk     => clk,
+			phy_clk => clk_phy,
+			rst     => rst,
+			phy_out => phy_out,
+			phy_in  => phy_in,
+			rx_p    => rx_p,
+			tx_p    => tx_p,
+			tx_n    => tx_n
+		);
+
+	reset_sync : process(clk, rst_n) is
+	begin
+		if (rst_n = '0') then
+			rst <= '1';
+		elsif (rising_edge(clk)) then
+			rst <= '0';
+		end if;
+	end process reset_sync;
+
+	receiver : process(clk, rst) is
+	begin
+		if rst then
+
+		elsif rising_edge(clk) then
+			if ethernet_i_out.rx_header_rcv then
+				report "RX ETH-I: " & to_string(to_integer(ethernet_i_out.rx_length));
+			end if;
+			if (ethernet_ii_out(PROT_ARP).rx_header_rcv) then
+				report "RX ARP";
+			end if;
+
+			if ipv4_out.rx_ok_stb then
+				report "RX IP OK";
+			end if;
+			if ipv4_out.rx_error_stb then
+				report "RX IP error";
+			end if;
+			if ipv4_out.rx_header_rcv then
+				report "RX IP start. PROT=" & to_hstring(ipv4_out.rx_protocol) & ", FROM=" & ip_to_string(ipv4_out.rx_ip_address);
+			end if;
+		end if;
+	end process receiver;
+
+	udp : process(clk) is
+	begin
+		if rising_edge(clk) then
+			if ipv4_protocol_out(IPROT_UDP).rx_header_rcv then
+				report "Receive UDP";
+			end if;
+		end if;
+	end process udp;
+
+	tx_udp_p : block
+		type state_t is (IDLE, TX, DONE);
+		signal state : state_t;
+
+		constant PACKET : byte_vector := (
+			x"10", x"00",               -- Source port
+			x"04", x"00",               -- Destination port
+			x"00", x"15",               -- Length
+			x"00", x"00",               -- Checksum (not used)
+			x"48", x"65", x"6C", x"6C", x"6F", x"20", x"57", x"6F", x"72", x"6C", x"64", x"21", x"0a" -- Payload
+		);
+		signal sr  : byte_vector(PACKET'range);
+		signal cnt : integer range 0 to sr'length - 1;
+
+	begin
+		tx_udp : process(clk, rst) is
+		begin
+			if rst then
+				state <= IDLE;
+
+			elsif rising_edge(clk) then
+				case state is
+					when IDLE =>
+						if button_n(0) = '0' then
+							state <= TX;
+							sr    <= PACKET;
+							cnt   <= sr'length - 1;
+							report "UDP: Start TX";
+						end if;
+
+					when TX =>
+						if ipv4_protocol_out(IPROT_UDP).tx_data_ack then
+							sr <= sr(sr'low + 1 to sr'high) & x"00";
+							if cnt = 0 then
+								state <= DONE;
+							else
+								cnt <= cnt - 1;
+							end if;
+						end if;
+						if ipv4_protocol_out(IPROT_UDP).tx_err_stb then
+							report "UDP: TX ERROR";
+							state <= DONE;
+						end if;
+						if ipv4_protocol_out(IPROT_UDP).tx_ok_stb then
+							report "UDP: TX OK stb in TX state -- that shouldn't happen, right?";
+						end if;
+
+					when DONE =>
+						null;
+
+				end case;
+			end if;
+		end process tx_udp;
+		ipv4_protocol_in(IPROT_UDP).tx_en         <= '1' when state = TX else '0';
+		ipv4_protocol_in(IPROT_UDP).tx_ip_address <= (x"C0", x"A8", x"02", x"01");
+		ipv4_protocol_in(IPROT_UDP).tx_length     <= to_unsigned(sr'length, 16);
+		ipv4_protocol_in(IPROT_UDP).tx_data       <= sr(0);
+	end block tx_udp_p;
+
+	icmp : process(clk) is
+	begin
+		if rising_edge(clk) then
+			if ipv4_protocol_out(IPROT_ICMP).rx_header_rcv then
+				report "Receive ICMP";
+			end if;
+		end if;
+	end process icmp;
+
+end architecture eth;

design/top_pingable.vhd

@@ -0,0 +1,248 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- top_mac_test.vhd: Test design to verify the functionality of the MAC core
+--   Sends a broadcast with 100 decrementing numbers every 250 ms or when a
+--   button is pushed. It will also directly reply with that content to any
+--   packet addressed to us.
+--
+--   Target: Lattice Brevia 2 (LFXP2-5E)
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+use ieee.math_real.all;
+
+library trashernet;
+use trashernet.trashernet_pkg.all;
+
+entity top_pingable is
+	port(
+		clk        : in  std_logic;
+		rst_n      : in  std_logic;
+		rx_p       : in  std_logic;
+		tx_p       : out std_logic;
+		tx_n       : out std_logic;
+		led_n      : out std_logic_vector(7 downto 0);
+		button_n   : in  std_logic_vector(3 downto 0);
+		debug_data : out std_logic_vector(7 downto 0)
+	);
+end entity top_pingable;
+
+architecture rtl of top_pingable is
+	component pll0
+		port(
+			CLK   : in  std_logic;
+			CLKOP : out std_logic;
+			LOCK  : out std_logic
+		);
+	end component pll0;
+
+	constant F_CLK     : integer := 50000000;
+	constant F_CLK_PHY : integer := 140000000;
+
+	constant LED_BLINK : boolean_vector(led_n'range) := (
+		6 downto 2 => true,
+		others     => false
+	);
+
+	constant ETH_CONFIG : configuration_t      := (
+		mac_address => (x"00", x"FF", x"FF", x"11", x"22", x"44")
+	);
+	constant IP_CONFIG  : ipv4_configuration_t := (
+		ip_address  => (x"C0", x"A8", x"02", x"02"),
+		subnet_mask => (x"FF", x"FF", x"FF", x"00"),
+		gateway     => (x"C0", x"A8", x"02", x"01")
+	);
+
+	signal rst          : std_logic;
+	signal clk_phy      : std_logic;
+	signal phy_pll_lock : std_logic;
+
+	signal led_sig : std_logic_vector(led_n'range);
+
+	signal phy_out : phy_out_t;
+	signal phy_in  : phy_in_t;
+
+	signal mac_out : mac_out_t;
+	signal mac_in  : mac_in_t;
+
+	constant PROT_ARP              : integer                     := 0;
+	constant PROT_IPV4             : integer                     := 1;
+	constant ETHERNET_II_PROTOCOLS : ethernet_ii_protocol_vector := (
+		PROT_ARP  => ETHERNET_II_PROTOCOL_ARP,
+		PROT_IPV4 => ETHERNET_II_PROTOCOL_IPV4
+	);
+	signal ethernet_i_out          : ethernet_i_out_t;
+	signal ethernet_i_in           : ethernet_i_in_t;
+	signal ethernet_ii_out         : ethernet_ii_out_vector(ETHERNET_II_PROTOCOLS'range);
+	signal ethernet_ii_in          : ethernet_ii_in_vector(ETHERNET_II_PROTOCOLS'range);
+
+	signal arp_out : arp_out_t;
+	signal arp_in  : arp_in_t;
+
+	signal ipv4_out : ipv4_out_t;
+	signal ipv4_in  : ipv4_in_t;
+
+	constant IPROT_ICMP      : integer              := 0;
+	constant IPV4_PROTOCOLS  : ipv4_protocol_vector := (
+		IPROT_ICMP => IPV4_PROTOCOL_ICMP
+	);
+	signal ipv4_protocol_out : ipv4_protocol_out_vector(IPV4_PROTOCOLS'range);
+	signal ipv4_protocol_in  : ipv4_protocol_in_vector(IPV4_PROTOCOLS'range);
+
+	signal button_n_sync : std_logic_vector(button_n'range);
+	signal button        : std_logic_vector(button_n'range);
+begin
+	trashernet_icmp_inst : entity trashernet.trashernet_icmp
+		port map(
+			clk               => clk,
+			rst               => rst,
+			ipv4_protocol_out => ipv4_protocol_out(IPROT_ICMP),
+			ipv4_protocol_in  => ipv4_protocol_in(IPROT_ICMP)
+		);
+
+	trashernet_ipv4prot_inst : entity trashernet.trashernet_ipv4prot
+		generic map(
+			IPV4_PROTOCOLS => IPV4_PROTOCOLS
+		)
+		port map(
+			clk               => clk,
+			rst               => rst,
+			ipv4_out          => ipv4_out,
+			ipv4_in           => ipv4_in,
+			ipv4_protocol_out => ipv4_protocol_out,
+			ipv4_protocol_in  => ipv4_protocol_in
+		);
+
+	trashernet_ipv4_inst : entity trashernet.trashernet_ipv4
+		port map(
+			clk             => clk,
+			rst             => rst,
+			ipv4_config     => IP_CONFIG,
+			arp_out         => arp_out,
+			arp_in          => arp_in,
+			ethernet_ii_out => ethernet_ii_out(PROT_IPV4),
+			ethernet_ii_in  => ethernet_ii_in(PROT_IPV4),
+			ipv4_out        => ipv4_out,
+			ipv4_in         => ipv4_in
+		);
+
+	trashernet_arp_inst : entity trashernet.trashernet_arp
+		generic map(
+			SYSTICK_FREQ => F_CLK
+		)
+		port map(
+			clk             => clk,
+			rst             => rst,
+			systick         => '1',
+			mac_config      => ETH_CONFIG,
+			ip_config       => IP_CONFIG,
+			arp_out         => arp_out,
+			arp_in          => arp_in,
+			ethernet_ii_out => ethernet_ii_out(PROT_ARP),
+			ethernet_ii_in  => ethernet_ii_in(PROT_ARP)
+		);
+
+	ethernet_i_in <= ETHERNET_I_IN_UNUSED;
+
+	trashernet_eth_inst : entity trashernet.trashernet_eth
+		generic map(
+			ETHERNET_II_PROTOCOLS => ETHERNET_II_PROTOCOLS
+		)
+		port map(
+			clk             => clk,
+			rst             => rst,
+			mac_out         => mac_out,
+			mac_in          => mac_in,
+			config          => ETH_CONFIG,
+			ethernet_i_out  => ethernet_i_out,
+			ethernet_i_in   => ethernet_i_in,
+			ethernet_ii_out => ethernet_ii_out,
+			ethernet_ii_in  => ethernet_ii_in
+		);
+
+	trashernet_mac_inst : entity trashernet.trashernet_mac
+		port map(
+			clk     => clk,
+			rst     => rst,
+			phy_out => phy_out,
+			phy_in  => phy_in,
+			mac_out => mac_out,
+			mac_in  => mac_in
+		);
+
+	pll0_inst : pll0
+		port map(
+			CLK   => clk,
+			CLKOP => clk_phy,
+			LOCK  => phy_pll_lock
+		);
+
+	trashernet_phy_cdc_inst : entity trashernet.trashernet_phy_cdc
+		generic map(
+			F_CLK     => F_CLK,
+			F_CLK_PHY => F_CLK_PHY
+		)
+		port map(
+			clk     => clk,
+			phy_clk => clk_phy,
+			rst     => rst,
+			phy_out => phy_out,
+			phy_in  => phy_in,
+			rx_p    => rx_p,
+			tx_p    => tx_p,
+			tx_n    => tx_n
+		);
+
+	reset_sync : process(clk, rst_n) is
+	begin
+		if (rst_n = '0') then
+			rst <= '1';
+		elsif (rising_edge(clk)) then
+			rst <= '0';
+		end if;
+	end process reset_sync;
+
+	ledcon_inst : entity work.ledcon
+		generic map(
+			F_CLK => F_CLK,
+			BLINK => LED_BLINK
+		)
+		port map(
+			clk   => clk,
+			rst   => rst,
+			sig   => led_sig,
+			led_n => led_n
+		);
+
+	led_sig <= (
+		0 => phy_pll_lock,
+		1 => phy_out.carrier_detect,
+		2 => phy_out.rx_active,
+		3 => phy_out.rx_error,
+		4 => mac_out.rx_mac_crc_ok,
+		5 => mac_out.rx_mac_crc_error,
+		6 => mac_out.tx_active,
+		7 => '0'
+	);
+
+	synchronizer_inst : entity trashernet.synchronizer
+		generic map(
+			SIZE => 2
+		)
+		port map(
+			clk      => clk,
+			rst      => rst,
+			data_in  => button_n(0),
+			data_out => button_n_sync(0)
+		);
+
+	button <= not button_n_sync;
+end architecture rtl;

micobu.sh

@@ -1,9 +0,0 @@
-#!/bin/bash
-
-cd cocotb
-make
-RET=$?
-
-mv ./* -t $MCB_ARTEFACTS/
-
-exit $RET

trashernet/fifo.vhd

@@ -0,0 +1,98 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- fifo.vhd : Basic single-clock FIFO
+--   Implements a basic single-clock FIFO
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+entity fifo is
+	generic(
+		DEPTH : natural                 -- Number of elements the FIFO can hold
+	);
+	port(
+		-- Global
+		clk      : in  std_logic;       -- Global clock
+		rst      : in  std_logic;       -- Asynchronous reset
+
+		-- FIFO
+		clear    : in  std_logic;       -- Synchronous reset (clear FIFO)
+		data_in  : in  std_logic_vector; -- Data into the FIFO (automatically constrains width)
+		push     : in  std_logic;       -- Push `data_in` into the FIFO
+		full     : out std_logic;       -- No further elements can be pushed into the FIFO
+		data_out : out std_logic_vector; -- Data out of the FIFO
+		pop      : in  std_logic;       -- Get an element from the FIFO
+		empty    : out std_logic        -- FIFO is empty
+	);
+end entity fifo;
+
+architecture rtl of fifo is
+	type memory_t is array (natural range <>) of std_logic_vector(data_in'range);
+	signal memory : memory_t(0 to DEPTH - 1);
+
+	subtype memory_pointer_t is integer range 0 to DEPTH - 1;
+	subtype usage_counter_t is integer range 0 to DEPTH;
+
+	signal read_pointer  : memory_pointer_t;
+	signal write_pointer : memory_pointer_t;
+	signal usage_counter : usage_counter_t;
+begin
+	fifo_proc : process(clk, rst) is
+		procedure increment_pointer(signal pointer : inout memory_pointer_t) is
+		begin
+			if pointer = pointer'subtype'high then
+				pointer <= 0;
+			else
+				pointer <= pointer + 1;
+			end if;
+		end procedure increment_pointer;
+
+		variable pushed : boolean;
+		variable popped : boolean;
+	begin
+		if rst then
+			read_pointer  <= 0;
+			write_pointer <= 0;
+			usage_counter <= 0;
+
+		elsif rising_edge(clk) then
+			pushed := false;
+			popped := false;
+
+			if push and not full then
+				memory(write_pointer) <= data_in;
+				increment_pointer(write_pointer);
+				usage_counter         <= usage_counter + 1;
+				pushed                := true;
+			end if;
+
+			if pop and not empty then
+				increment_pointer(read_pointer);
+				usage_counter <= usage_counter - 1;
+				popped        := true;
+			end if;
+
+			if pushed and popped then
+				usage_counter <= usage_counter;
+			end if;
+
+			if clear then
+				read_pointer  <= 0;
+				write_pointer <= 0;
+				usage_counter <= 0;
+			end if;
+		end if;
+	end process fifo_proc;
+
+	data_out <= memory(read_pointer);
+	empty    <= '1' when usage_counter = 0 else '0';
+	full     <= '1' when usage_counter = DEPTH else '0';
+
+end architecture rtl;

trashernet/timer.vhd

@@ -0,0 +1,64 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- timer.vhd : Simple Timer
+--   Implements a very simple integer timer
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+entity timer is
+	generic(
+		F_TICK    : integer;            -- Frequency of `tick` (or `clk` if tick is tied to '1')
+		DURATION  : time;               -- Duration of the timer
+		AUTOSTART : boolean := false    -- Automatically start the timer after reset
+	);
+	port(
+		clk         : in  std_logic;    -- Global clock
+		rst         : in  std_logic;    -- Asynchronous reset
+
+		tick        : in  std_logic;    -- Timer enable
+		start       : in  std_logic;    -- (Re-)start timer
+
+		expired     : out std_logic;    -- Timer is expired
+		expired_stb : out std_logic     -- Strobe when timer reaches zero
+	);
+end entity timer;
+
+architecture rtl of timer is
+	constant PERIOD : time    := 1 sec / real(F_TICK);
+	constant TICKS  : integer := integer(DURATION / PERIOD);
+
+	signal counter : integer range 0 to TICKS;
+begin
+	timer_p : process(clk, rst) is
+	begin
+		if rst then
+			counter     <= TICKS when AUTOSTART else 0;
+			expired_stb <= '0';
+
+		elsif rising_edge(clk) then
+			expired_stb <= '0';
+			if tick then
+				if counter = 1 then
+					expired_stb <= '1';
+				end if;
+				if counter /= 0 then
+					counter <= counter - 1;
+				end if;
+			end if;
+
+			if start then
+				counter <= TICKS;
+			end if;
+		end if;
+	end process timer_p;
+
+	expired <= not start when counter = 0 else '0';
+end architecture rtl;

trashernet/trashernet_arp.vhd

@@ -0,0 +1,317 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- trashernet_arp.vhd : Address Resolution Protocol
+--   Implements simple single-entry cache ARP.
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+use work.trashernet_pkg.all;
+
+entity trashernet_arp is
+	generic(
+		SYSTICK_FREQ : integer
+	);
+	port(
+		-- Global
+		clk             : in  std_logic; -- Global clock
+		rst             : in  std_logic; -- Asynchronous reset
+		systick         : in  std_logic; -- Global time reference for slow events (here: timeout)
+
+		-- Configuration
+		mac_config      : in  configuration_t; -- Trashernet MAC configuration
+		ip_config       : in  ipv4_configuration_t; -- Trashernet IP configuration
+
+		-- ARP application interface
+		arp_out         : out arp_out_t; -- ARP IF (out from ARP)
+		arp_in          : in  arp_in_t; -- ARP IF (into ARP)
+
+		-- Ethernet II application interface
+		ethernet_ii_out : in  ethernet_ii_out_t; -- Ethernet II IF (out from MAC)
+		ethernet_ii_in  : out ethernet_ii_in_t -- Ethernet II IF (into MAC)
+	);
+end entity trashernet_arp;
+
+architecture rtl of trashernet_arp is
+	constant HTYPE        : byte_vector := (x"00", x"01");
+	constant PTYPE        : byte_vector := (x"08", x"00");
+	constant HLEN         : byte        := x"06";
+	constant PLEN         : byte        := x"04";
+	constant OPER_REQUEST : byte_vector := (x"00", x"01");
+	constant OPER_REPLY   : byte_vector := (x"00", x"02");
+
+	constant ARP_TIMEOUT : time := 1 sec;
+
+	signal arp_tx_reply_rq  : std_logic; -- Request to transmit an ARP reply
+	signal arp_tx_reply_tha : mac_addr_t; -- Target MAC to use in reply (SHA in received packet)
+	signal arp_tx_reply_tpa : ip_addr_t; -- Target IP to use in reply (SPA in received packet)
+	signal arp_tx_reply_ack : std_logic; -- ARP reply has been latched and is being sent
+
+	signal arp_tx_request_rq  : std_logic; -- Request to transmit an ARP request
+	signal arp_tx_request_tpa : ip_addr_t; -- IP address that we want to know the MAC address of
+	signal arp_tx_request_ack : std_logic; -- ARP request has been latched and is being sent
+
+	signal arp_rx_reply_stb : std_logic; -- An ARP reply was received (strobe)
+	signal arp_rx_sha       : mac_addr_t; -- The MAC address of the reply sender, valid with arp_rx_reply
+	signal arp_rx_spa       : ip_addr_t; -- The IP address of the reply sender, valid with arp_rx_reply
+
+begin
+	resolver : block
+		type resolver_state_t is (IDLE, QUERY_MAC);
+		signal state : resolver_state_t;
+
+		signal query_mac_found : std_logic;
+		signal query_timeout   : std_logic := '0'; -- TODO: Implement
+
+		signal replied_ip  : ip_addr_t;
+		signal replied_mac : mac_addr_t;
+	begin
+
+		arp_resolver_main : process(rst, clk) is
+		begin
+			if rst then
+				state                <= IDLE;
+				replied_ip           <= (others => x"00"); -- 0.0.0.0
+				arp_out.arp_ok_stb   <= '0';
+				arp_out.arp_fail_stb <= '0';
+				arp_tx_request_rq    <= '0';
+
+			elsif rising_edge(clk) then
+				arp_out.arp_ok_stb   <= '0';
+				arp_out.arp_fail_stb <= '0';
+
+				if arp_rx_reply_stb then
+					if arp_tx_request_tpa = arp_rx_spa then -- If this reply is actually for our request
+						replied_mac <= arp_rx_sha;
+						replied_ip  <= arp_rx_spa;
+					end if;
+				end if;
+
+				case state is
+					when IDLE =>
+						if arp_in.arp_query_stb then
+							if query_mac_found then
+								arp_out.arp_ok_stb <= '1';
+							else
+								arp_tx_request_rq <= '1';
+								state             <= QUERY_MAC;
+							end if;
+						end if;
+
+					when QUERY_MAC =>
+						if arp_tx_request_ack then
+							arp_tx_request_rq <= '0';
+						end if;
+						if query_mac_found or query_timeout then
+							arp_out.arp_ok_stb   <= query_mac_found;
+							arp_out.arp_fail_stb <= not query_mac_found;
+							state                <= IDLE;
+						end if;
+				end case;
+			end if;
+		end process arp_resolver_main;
+		query_mac_found <= '1' when (arp_tx_request_tpa = replied_ip) else '0';
+
+		arp_out.arp_mac    <= replied_mac;
+		arp_tx_request_tpa <= arp_in.arp_ip;
+
+		timeout_timer_inst : entity work.timer
+			generic map(
+				F_TICK    => SYSTICK_FREQ,
+				DURATION  => ARP_TIMEOUT,
+				AUTOSTART => false
+			)
+			port map(
+				clk         => clk,
+				rst         => rst,
+				tick        => systick,
+				start       => arp_tx_request_rq,
+				expired     => query_timeout,
+				expired_stb => open
+			);
+
+	end block resolver;
+
+	rx : block
+		constant BYTECOUNT_HEAD      : integer := 8; -- HTYPE -> OPER
+		constant BYTECOUNT_ADDRESSES : integer := 20; -- SHA -> TPA
+
+		signal sr : byte_vector(0 to BYTECOUNT_ADDRESSES - 1);
+
+		constant SR_HEAD_OFFSET : integer := BYTECOUNT_ADDRESSES - BYTECOUNT_HEAD;
+		alias sr_head_htype is sr(SR_HEAD_OFFSET + 0 to SR_HEAD_OFFSET + 1);
+		alias sr_head_ptype is sr(SR_HEAD_OFFSET + 2 to SR_HEAD_OFFSET + 3);
+		alias sr_head_hlen is sr(SR_HEAD_OFFSET + 4);
+		alias sr_head_plen is sr(SR_HEAD_OFFSET + 5);
+		alias sr_head_oper is sr(SR_HEAD_OFFSET + 6 to SR_HEAD_OFFSET + 7);
+
+		constant SR_ADDRESSES_OFFSET : integer := -8;
+		alias sr_addresses_sha is sr(8 + SR_ADDRESSES_OFFSET to 13 + SR_ADDRESSES_OFFSET);
+		alias sr_addresses_spa is sr(14 + SR_ADDRESSES_OFFSET to 17 + SR_ADDRESSES_OFFSET);
+		alias sr_addresses_tha is sr(18 + SR_ADDRESSES_OFFSET to 23 + SR_ADDRESSES_OFFSET); -- @suppress "Unused declaration": We don't need to check this as this is already done by the MAC
+		alias sr_addresses_tpa is sr(24 + SR_ADDRESSES_OFFSET to 27 + SR_ADDRESSES_OFFSET);
+
+		type state_t is (HEAD, ADDRESSES, WAITCRC, SENDREPLY, IGNORE);
+		signal state     : state_t;
+		signal bytecount : integer range 0 to BYTECOUNT_ADDRESSES;
+		signal shifted   : std_logic;
+
+		signal block_done : std_logic;
+
+		signal header_ok    : std_logic;
+		signal we_are_asked : std_logic;
+
+		signal is_request : std_logic;
+	begin
+
+		block_done <= '1' when shifted = '1' and bytecount = 0 else '0';
+
+		header_ok <= '1' when           --
+		             sr_head_htype = HTYPE and --
+		             sr_head_ptype = PTYPE and --
+		             sr_head_hlen = HLEN and sr_head_plen = PLEN --
+		             else
+		             '0';
+
+		we_are_asked <= '1' when        --
+		                sr_addresses_tpa = ip_config.ip_address else
+		                '0';
+
+		rx_fsm : process(clk, rst) is
+		begin
+			if rst then
+				state            <= HEAD;
+				shifted          <= '0';
+				bytecount        <= BYTECOUNT_HEAD;
+				arp_rx_reply_stb <= '0';
+
+			elsif rising_edge(clk) then
+				arp_rx_reply_stb <= '0';
+
+				if (ethernet_ii_out.rx_crc_ok or ethernet_ii_out.rx_crc_error) then
+					state     <= HEAD;  -- Safe return from any state, may be overridden below
+					bytecount <= BYTECOUNT_HEAD;
+				end if;
+				shifted <= ethernet_ii_out.rx_data_valid;
+				if (ethernet_ii_out.rx_data_valid = '1') and (bytecount > 0) then
+					sr        <= sr(sr'low + 1 to sr'high) & ethernet_ii_out.rx_data;
+					bytecount <= bytecount - 1;
+				end if;
+				case state is
+					when HEAD =>
+						if block_done then
+							if header_ok then
+								bytecount  <= BYTECOUNT_ADDRESSES;
+								state      <= ADDRESSES;
+								is_request <= '1' when (sr_head_oper = OPER_REQUEST) else '0';
+							else
+								state <= IGNORE;
+							end if;
+						end if;
+
+					when ADDRESSES =>
+						if block_done then
+							if (we_are_asked) then
+								state <= WAITCRC;
+							else
+								state <= IGNORE;
+							end if;
+						end if;
+
+					when WAITCRC =>
+						if ethernet_ii_out.rx_crc_ok then
+							if is_request then
+								state <= SENDREPLY;
+							else
+								arp_rx_reply_stb <= '1';
+							end if;
+						end if;
+
+					when SENDREPLY =>
+						if arp_tx_reply_ack then
+							bytecount <= BYTECOUNT_HEAD;
+							state     <= HEAD;
+						end if;
+
+					when IGNORE => -- @suppress "Dead state 'IGNORE'": Outgoing transition provided outside of case statement (on RX ok/err)
+						null;
+				end case;
+			end if;
+		end process rx_fsm;
+		arp_tx_reply_rq  <= '1' when state = SENDREPLY else '0';
+		arp_tx_reply_tha <= sr_addresses_sha;
+		arp_tx_reply_tpa <= sr_addresses_spa;
+		arp_rx_sha       <= sr_addresses_sha;
+		arp_rx_spa       <= sr_addresses_spa;
+	end block rx;
+
+	tx : block
+		signal sr                  : byte_vector(0 to 27);
+		signal arp_reply_preload   : byte_vector(sr'range);
+		signal arp_request_preload : byte_vector(sr'range);
+		constant BYTECOUNT_MAX     : integer := sr'length + 1;
+		signal bytecount           : integer range 0 to BYTECOUNT_MAX;
+
+		type state_t is (IDLE, TRANSMIT);
+		signal state : state_t;
+	begin
+
+		arp_reply_preload <= HTYPE & PTYPE & HLEN & PLEN & OPER_REPLY & -- Header
+		                     mac_config.mac_address & ip_config.ip_address & -- Sender
+		                     arp_tx_reply_tha & arp_tx_reply_tpa; -- Target
+
+		arp_request_preload <= HTYPE & PTYPE & HLEN & PLEN & OPER_REQUEST & -- Header
+		                       mac_config.mac_address & ip_config.ip_address & -- Sender
+		                       mac_addr_t'(x"00", x"00", x"00", x"00", x"00", x"00") & arp_tx_request_tpa; -- Target
+
+		tx_fsm : process(clk, rst) is
+		begin
+			if rst then
+				arp_tx_reply_ack   <= '0';
+				arp_tx_request_ack <= '0';
+
+			elsif rising_edge(clk) then
+				arp_tx_reply_ack   <= '0';
+				arp_tx_request_ack <= '0';
+
+				if (ethernet_ii_out.tx_data_ack = '1') and (bytecount > 0) then
+					sr        <= sr(sr'low + 1 to sr'high) & x"00";
+					bytecount <= bytecount - 1;
+				end if;
+
+				case state is
+					when IDLE =>
+						if arp_tx_reply_rq then
+							state                         <= TRANSMIT;
+							arp_tx_reply_ack              <= '1';
+							sr                            <= arp_reply_preload;
+							ethernet_ii_in.tx_mac_address <= arp_tx_reply_tha;
+						elsif arp_tx_request_rq then
+							state                         <= TRANSMIT;
+							arp_tx_request_ack            <= '1';
+							sr                            <= arp_request_preload;
+							ethernet_ii_in.tx_mac_address <= MAC_ADDR_BROADCAST;
+						end if;
+
+						bytecount <= BYTECOUNT_MAX;
+
+					when TRANSMIT =>
+						if bytecount = 0 then
+							state <= IDLE;
+						end if;
+				end case;
+			end if;
+		end process tx_fsm;
+
+		ethernet_ii_in.tx_en   <= '1' when state = TRANSMIT else '0';
+		ethernet_ii_in.tx_data <= sr(0);
+
+	end block tx;
+end architecture rtl;

trashernet/trashernet_eth.vhd

@@ -0,0 +1,176 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- trashernet_eth.vhd : Ethernet OSI Layer 2, Data Link, ETH I/II Ethertype
+--   Implements arbitration of different ethertypes.
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+use work.trashernet_pkg.all;
+
+entity trashernet_eth is
+	generic(
+		ETHERNET_II_PROTOCOLS : ethernet_ii_protocol_vector := ETHERNET_II_PROTOCOLS_NONE
+	);
+	port(
+		-- Global
+		clk             : in  std_logic; -- Global clock
+		rst             : in  std_logic; -- Asynchronous reset
+
+		-- MAC application interface
+		mac_out         : in  mac_out_t; -- MAC application IF (out of MAC)
+		mac_in          : out mac_in_t; -- MAC application IF (into MAC)
+
+		-- Configuration
+		config          : in  configuration_t; -- Global Trashernet configuration
+
+		-- Ethernet 802.3 application interface
+		ethernet_i_out  : out ethernet_i_out_t; -- Ethernet 802.3 IF (out from MAC)
+		ethernet_i_in   : in  ethernet_i_in_t                                    := ETHERNET_I_IN_UNUSED; -- Ethernet 802.3 IF (out from MAC)
+
+		-- Ethernet II application interface
+		ethernet_ii_out : out ethernet_ii_out_vector(ETHERNET_II_PROTOCOLS'range); -- Ethernet II IF (out from MAC)
+		ethernet_ii_in  : in  ethernet_ii_in_vector(ETHERNET_II_PROTOCOLS'range) := (others => ETHERNET_II_IN_UNUSED) -- Ethernet II IF (into MAC)
+	);
+end entity trashernet_eth;
+
+architecture rtl of trashernet_eth is
+	signal tx_data_ack_ii : std_logic_vector(ethernet_ii_out'range);
+	signal tx_data_ack_i  : std_logic;
+begin
+	rx : block
+		constant SEL_ETH_I               : integer := ethernet_ii_out'low - 1;
+		constant SEL_ETH_NONE            : integer := ethernet_ii_out'low - 2;
+		signal sel                       : integer range SEL_ETH_NONE to ethernet_ii_out'high;
+		signal mac_destination_matches   : std_logic;
+		signal rx_mac_header_rcv_delayed : std_logic;
+
+	begin
+		mac_destination_matches <= '1' when --
+		                           ((mac_out.rx_header.mac_destination = MAC_ADDR_BROADCAST) or --
+		                            (mac_out.rx_header.mac_destination = config.mac_address)) else
+		                           '0';
+
+		mux : process(clk, rst) is
+		begin
+			if rst then
+				sel                       <= SEL_ETH_NONE;
+				rx_mac_header_rcv_delayed <= '0';
+
+			elsif rising_edge(clk) then
+				rx_mac_header_rcv_delayed <= mac_out.rx_mac_header_rcv;
+
+				if mac_out.rx_mac_header_rcv then
+					sel <= SEL_ETH_NONE; -- By default, let's assume it's not for us
+					if mac_destination_matches then
+						if (unsigned(std_logic_vector'(mac_out.rx_header.mac_ethertype(0) & mac_out.rx_header.mac_ethertype(1))) < 1500) then -- Ethernet 802.3 Frame
+							sel <= SEL_ETH_I;
+
+						else            -- Ethernet II Frame
+							for i in ETHERNET_II_PROTOCOLS'range loop
+								if (mac_out.rx_header.mac_ethertype = ETHERNET_II_PROTOCOLS(i).ethertype) then
+									sel <= i;
+								end if;
+							end loop;
+						end if;
+					end if;
+				end if;
+			end if;
+		end process mux;
+
+		-- Shared fields in the Ethernet II application interface
+		shared_fields : for i in ethernet_ii_out'range generate
+			ethernet_ii_out(i).rx_mac_address <= mac_out.rx_header.mac_source;
+			ethernet_ii_out(i).rx_data        <= mac_out.rx_mac_data;
+			ethernet_ii_out(i).rx_data_valid  <= mac_out.rx_mac_valid when sel = i else '0';
+			ethernet_ii_out(i).rx_crc_error   <= mac_out.rx_mac_crc_error when sel = i else '0';
+			ethernet_ii_out(i).rx_crc_ok      <= mac_out.rx_mac_crc_ok when sel = i else '0';
+			ethernet_ii_out(i).rx_header_rcv  <= rx_mac_header_rcv_delayed when sel = i else '0';
+		end generate shared_fields;
+
+		-- Shared fields in the Ethernet application interface
+		ethernet_i_out.rx_data        <= mac_out.rx_mac_data;
+		ethernet_i_out.rx_data_valid  <= mac_out.rx_mac_valid when sel = SEL_ETH_I;
+		ethernet_i_out.rx_crc_error   <= mac_out.rx_mac_crc_error when sel = SEL_ETH_I else '0';
+		ethernet_i_out.rx_crc_ok      <= mac_out.rx_mac_crc_ok when sel = SEL_ETH_I else '0';
+		ethernet_i_out.rx_header_rcv  <= rx_mac_header_rcv_delayed when sel = SEL_ETH_I else '0';
+		ethernet_i_out.rx_mac_address <= mac_out.rx_header.mac_source;
+		ethernet_i_out.rx_length      <= unsigned(mac_out.rx_header.mac_ethertype(0)) & unsigned(mac_out.rx_header.mac_ethertype(1));
+
+		-- TX fields (need to be driven here to avoid multiple drivers (blocks drive ALL signals of a record))
+		tx_fields : for i in ethernet_ii_out'range generate
+			ethernet_ii_out(i).tx_data_ack <= tx_data_ack_ii(i);
+		end generate;
+		ethernet_i_out.tx_data_ack <= tx_data_ack_i;
+	end block rx;
+
+	tx : block
+		type state_t is (IDLE, TXD);
+		signal state       : state_t;
+		constant SEL_ETH_I : integer := ethernet_ii_out'low - 1;
+		signal sel         : integer range SEL_ETH_I to ethernet_ii_in'high;
+	begin
+		arb : process(clk, rst) is
+		begin
+			if rst then
+				sel <= SEL_ETH_I;
+
+			elsif rising_edge(clk) then
+				case state is
+					when IDLE =>
+						if not mac_out.tx_active then
+							if (ethernet_i_in.tx_en) then -- ETH I has priority
+								sel   <= SEL_ETH_I;
+								state <= TXD;
+							else
+								for i in ethernet_ii_in'range loop
+									if ethernet_ii_in(i).tx_en then
+										sel   <= i;
+										state <= TXD;
+										exit; -- Prioritize according to vector
+									end if;
+								end loop;
+							end if;
+						end if;
+
+					when TXD =>
+						state <= IDLE when (not mac_in.tx_mac_data_en or not mac_out.tx_active);
+				end case;
+			end if;
+		end process arb;
+
+		mux : process(all) is
+		begin
+			-- Defaults to avoid latch
+			tx_data_ack_i  <= '0';
+			tx_data_ack_ii <= (others => '0');
+
+			-- Actual MUX
+			if (sel = SEL_ETH_I) then
+				mac_in.tx_mac_data_en            <= ethernet_i_in.tx_en;
+				mac_in.tx_mac_data               <= ethernet_i_in.tx_data;
+				tx_data_ack_i                    <= mac_out.tx_mac_data_ack;
+				mac_in.tx_header.mac_destination <= ethernet_i_in.tx_mac_address;
+				mac_in.tx_header.mac_ethertype   <= byte(ethernet_i_in.tx_length(15 downto 8)) & byte(ethernet_i_in.tx_length(7 downto 0));
+			else
+				mac_in.tx_mac_data_en <= ethernet_ii_in(sel).tx_en;
+				mac_in.tx_mac_data    <= ethernet_ii_in(sel).tx_data;
+				txack : for i in ethernet_ii_out'range loop
+					tx_data_ack_ii(i) <= mac_out.tx_mac_data_ack when sel = i else '0';
+				end loop txack;
+
+				mac_in.tx_header.mac_destination <= ethernet_ii_in(sel).tx_mac_address;
+				mac_in.tx_header.mac_ethertype   <= ETHERNET_II_PROTOCOLS(sel).ethertype;
+			end if;
+
+			mac_in.tx_header.mac_source <= config.mac_address;
+		end process mux;
+	end block tx;
+end architecture rtl;

trashernet/trashernet_icmp.vhd

@@ -0,0 +1,172 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- trashernet_icmp.vhd : Ethernet OSI Layer 3, Network (ICMP)
+--   Implements ICMP echo replies
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+use work.trashernet_pkg.all;
+
+entity trashernet_icmp is
+	port(
+		-- Global
+		clk               : in  std_logic; -- Global clock
+		rst               : in  std_logic; -- Asynchronous reset
+
+		-- IPv4 application interface
+		ipv4_protocol_out : in  ipv4_protocol_out_t; -- IPv4 Protocol IF (out from IP Mux)
+		ipv4_protocol_in  : out ipv4_protocol_in_t -- IPv4 Protocol IF (into IP Mux)
+	);
+end entity trashernet_icmp;
+
+architecture rtl of trashernet_icmp is
+	signal fifo_clear    : std_logic;
+	signal fifo_data_in  : std_logic_vector(byte'range);
+	signal fifo_push     : std_logic;
+	signal fifo_full     : std_logic;   -- TODO: FIFO full error handling
+	signal fifo_data_out : std_logic_vector(fifo_data_in'range);
+	signal fifo_pop      : std_logic;
+	signal fifo_empty    : std_logic;
+
+	signal tx_response : std_logic;
+	signal rx_checksum : std_logic_vector(15 downto 0);
+begin
+	fifo_inst : entity work.fifo
+		generic map(
+			DEPTH => 64
+		)
+		port map(
+			clk      => clk,
+			rst      => rst,
+			clear    => fifo_clear,
+			data_in  => fifo_data_in,
+			push     => fifo_push,
+			full     => fifo_full,
+			data_out => fifo_data_out,
+			pop      => fifo_pop,
+			empty    => fifo_empty
+		);
+
+	rx : block
+		signal sr : byte_vector(0 to 3);
+		alias sr_type is sr(0);
+		alias sr_code is sr(1);
+		alias sr_checksum is sr(2 to 3);
+
+		type state_t is (HEADER, DATA, IGNORE);
+		signal state : state_t;
+
+		signal byte_count : integer range 0 to sr'length;
+
+	begin
+		rx_fsm : process(clk, rst) is
+		begin
+			if rst then
+				state      <= HEADER;
+				byte_count <= byte_count'subtype'high;
+
+			elsif rising_edge(clk) then
+
+				if (ipv4_protocol_out.rx_data_valid = '1') and (byte_count /= 0) then
+					byte_count <= byte_count - 1;
+					if state = HEADER then
+						sr <= sr(sr'low + 1 to sr'high) & ipv4_protocol_out.rx_data;
+					end if;
+				end if;
+
+				if ipv4_protocol_out.rx_header_rcv then
+					byte_count <= byte_count'subtype'high;
+					state      <= HEADER;
+				end if;
+
+				case state is
+					when HEADER =>
+						if byte_count = 0 then
+							if sr_type = x"08" then
+								state <= DATA;
+							else
+								state <= IGNORE;
+							end if;
+						end if;
+
+					when DATA =>
+						null;           -- We just wait here and collect data
+
+					when IGNORE =>      -- Just wait until it's over
+						null;
+				end case;
+			end if;
+		end process rx_fsm;
+		fifo_clear   <= ipv4_protocol_out.rx_header_rcv; -- TODO: This will break things when we get another Ping too soon
+		fifo_push    <= ipv4_protocol_out.rx_data_valid when state = DATA else '0';
+		fifo_data_in <= ipv4_protocol_out.rx_data;
+
+		tx_response <= ipv4_protocol_out.rx_ok_stb when state = DATA else '0';
+		rx_checksum <= sr_checksum(2) & sr_checksum(3);
+	end block rx;
+
+	tx : block
+		signal checksum      : unsigned(16 downto 0);
+		signal checksum_ones : unsigned(15 downto 0);
+
+		type state_t is (IDLE, HEADER, PAYLOAD);
+		signal state : state_t;
+
+		signal sr         : byte_vector(0 to 3);
+		signal byte_count : integer range 0 to sr'subtype'high;
+	begin
+
+		checksum      <= ('0' & not (unsigned(rx_checksum))) - unsigned'('0' & x"0800"); -- The only change is Type 8 changes to Type 0
+		checksum_ones <= not (checksum(15 downto 0) - checksum(16));
+
+		tx_fsm : process(clk, rst) is
+		begin
+			if rst then
+
+			elsif rising_edge(clk) then
+				if (ipv4_protocol_out.tx_data_ack = '1') and (byte_count /= 0) then
+					sr         <= sr(sr'low + 1 to sr'high) & x"00";
+					byte_count <= byte_count - 1;
+				end if;
+
+				case state is
+					when IDLE =>
+						if tx_response then
+							ipv4_protocol_in.tx_ip_address <= ipv4_protocol_out.rx_ip_address; -- TODO: This is technically too late, but ¯\_(ツ)_/¯
+							ipv4_protocol_in.tx_length     <= ipv4_protocol_out.rx_length;
+							sr                             <= byte_vector'(
+								x"00",
+								x"00",
+								std_logic_vector(checksum_ones(15 downto 8)),
+								std_logic_vector(checksum_ones(7 downto 0))
+							);
+							byte_count                     <= sr'subtype'high;
+							state                          <= HEADER;
+						end if;
+
+					when HEADER =>
+						if (byte_count = 0) and (ipv4_protocol_out.tx_data_ack = '1') then
+							state <= PAYLOAD;
+						end if;
+
+					when PAYLOAD =>
+						if fifo_empty then
+							state <= IDLE;
+						end if;
+				end case;
+			end if;
+		end process tx_fsm;
+
+		fifo_pop                 <= ipv4_protocol_out.tx_data_ack when state = PAYLOAD else '0';
+		ipv4_protocol_in.tx_en   <= '1' when (state = HEADER) or (state = PAYLOAD) else '0';
+		ipv4_protocol_in.tx_data <= sr(sr'low) when state = HEADER else fifo_data_out;
+	end block tx;
+end architecture rtl;

trashernet/trashernet_ipv4.vhd

@@ -0,0 +1,249 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- trashernet_ipv4.vhd : Ethernet OSI Layer 3, Network (IPv4)
+--   Implements packet handling and IP-Layer en-/decoding.
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+use work.trashernet_pkg.all;
+
+entity trashernet_ipv4 is
+	port(
+		-- Global
+		clk             : in  std_logic; -- Global clock
+		rst             : in  std_logic; -- Asynchronous reset
+
+		-- Configuration
+		ipv4_config     : in  ipv4_configuration_t; -- Trashernet IP configuration
+
+		-- ARP application interface
+		arp_out         : in  arp_out_t; -- ARP IF (out from ARP)
+		arp_in          : out arp_in_t; -- ARP IF (into ARP)
+
+		-- Ethernet II application interface
+		ethernet_ii_out : in  ethernet_ii_out_t; -- Ethernet II IF (out from MAC)
+		ethernet_ii_in  : out ethernet_ii_in_t; -- Ethernet II IF (into MAC)
+
+		-- IPv4 application interface
+		ipv4_out        : out ipv4_out_t; -- IPv4 IF (out from IP)
+		ipv4_in         : in  ipv4_in_t -- IPv4 IF (into IP)
+	);
+end entity trashernet_ipv4;
+
+architecture rtl of trashernet_ipv4 is
+begin
+	rx : block
+		constant BYTECOUNT_HEADER : integer := 20; -- Mandatory header fields
+
+		signal sr                 : byte_vector(0 to BYTECOUNT_HEADER - 1) := (others => x"00"); -- Init to zero to squelch metavalue warnings
+		alias sr_version is sr(0)(7 downto 4);
+		alias sr_ihl is sr(0)(3 downto 0);
+		alias sr_dscp is sr(1)(7 downto 2);
+		alias sr_ecn is sr(1)(1 downto 0);
+		alias sr_total_length is sr(2 to 3);
+		alias sr_identification is sr(4 to 5);
+		alias sr_flags is sr(6)(7 downto 5);
+		signal sr_fragment_offset : std_logic_vector(12 downto 0);
+		alias sr_ttl is sr(8);
+		alias sr_protocol is sr(9);
+		alias sr_header_cks is sr(10 to 11);
+		alias sr_source_ip is sr(12 to 15);
+		alias sr_destination_ip is sr(16 to 19);
+
+		signal header_ok : std_logic;
+
+		signal bytecount  : integer range 0 to 65535;
+		signal block_done : std_logic;
+
+		type state_t is (HEADER, OPT, PAYLOAD, DONE);
+		signal state : state_t;
+	begin
+		sr_fragment_offset <= sr(6)(4 downto 0) & sr(7);
+
+		block_done <= '1' when bytecount = 0 else '0';
+		header_ok  <= '1' when          --
+		              (std_logic_vector'(sr_flags(7) & sr_flags(5)) = "00") and -- Reserved = 0, MF unset
+		              (to_integer(unsigned(sr_fragment_offset)) = 0) and -- No fragment offset -> not last fragment
+		              (sr_destination_ip = ipv4_config.ip_address) else -- It's addressed to us. TODO: We do not support broadcasts
+		              '0';
+		rx_fsm : process(clk, rst) is
+		begin
+			if rst then
+				state                  <= HEADER;
+				ipv4_out.rx_ok_stb     <= '0';
+				ipv4_out.rx_error_stb  <= '0';
+				ipv4_out.rx_header_rcv <= '0';
+				bytecount              <= BYTECOUNT_HEADER;
+
+			elsif rising_edge(clk) then
+				ipv4_out.rx_ok_stb     <= '0';
+				ipv4_out.rx_error_stb  <= '0';
+				ipv4_out.rx_header_rcv <= '0';
+
+				if (ethernet_ii_out.rx_crc_ok or ethernet_ii_out.rx_crc_error) then
+					state     <= HEADER;
+					bytecount <= BYTECOUNT_HEADER;
+
+					ipv4_out.rx_error_stb <= ethernet_ii_out.rx_crc_error or to_std_logic(state = PAYLOAD);
+					ipv4_out.rx_ok_stb    <= ethernet_ii_out.rx_crc_ok and to_std_logic(state = DONE);
+				end if;
+				if (ethernet_ii_out.rx_data_valid = '1') and (bytecount > 0) then
+					if state = HEADER then
+						sr <= sr(sr'low + 1 to sr'high) & ethernet_ii_out.rx_data;
+					end if;
+					bytecount <= bytecount - 1;
+				end if;
+
+				case state is
+					when HEADER =>
+						if block_done then
+							bytecount <= to_integer(unsigned(sr_ihl) - 5) * 4; -- five 32-bit words is the header itself
+							if header_ok then
+								state                  <= OPT;
+								ipv4_out.rx_header_rcv <= '1';
+							end if;
+						end if;
+
+					when OPT =>
+						if block_done then
+							bytecount <= to_integer(unsigned(std_logic_vector'(sr_total_length(2) & sr_total_length(3)))) - to_integer(unsigned(sr_ihl)) * 4;
+							state     <= PAYLOAD;
+						end if;
+
+					when PAYLOAD =>
+						if block_done then
+							state <= DONE;
+						end if;
+
+					when DONE =>        -- @suppress "Dead state 'DONE'": Outgoing state transition is outside of case statement
+						null;           -- We just wait here until the MAC gives us a CRC OK/error
+				end case;
+			end if;
+		end process rx_fsm;
+
+		ipv4_out.rx_data       <= ethernet_ii_out.rx_data;
+		ipv4_out.rx_data_valid <= ethernet_ii_out.rx_data_valid when state = PAYLOAD else '0';
+		ipv4_out.rx_ip_address <= sr_source_ip;
+		ipv4_out.rx_protocol   <= sr_protocol;
+		ipv4_out.rx_length     <= unsigned(std_logic_vector'(sr_total_length(2) & sr_total_length(3))) - to_integer(unsigned(sr_ihl)) * 4;
+
+	end block rx;
+
+	tx : block
+		type state_t is (IDLE, ARP, CALC_CKS, HEADER, PAYLOAD);
+		signal state : state_t;
+
+		signal full_length : ipv4_length;
+
+		signal sr            : byte_vector(0 to 19);
+		signal byte_cnt      : integer range 0 to sr'length - 1;
+		signal alt_byte      : std_logic;
+		signal checksum      : unsigned(20 downto 0); -- 20 Header fields -> 19 chances for carry -> 5 additional bits
+		signal checksum_ones : unsigned(15 downto 0);
+
+		constant TTL : byte := x"40";
+		impure function get_header(checksum : std_logic_vector(15 downto 0)) return byte_vector is
+			variable ret : byte_vector(sr'range);
+		begin
+			ret :=                      --
+			       byte_vector'(
+				       x"45", x"00", byte(full_length(15 downto 8)), byte(full_length(7 downto 0)), -- Ver/IHL, DSCP/ECN, Len
+				       x"00", x"00", x"00", x"00" -- Identification, Flags/FragOffset
+			       ) & TTL & ipv4_in.tx_protocol & checksum(15 downto 8) & checksum(7 downto 0) & -- TTL, Protocol, Header Checksum
+			       ipv4_config.ip_address & -- Source IP
+			       ipv4_in.tx_ip_address -- Destination IP
+			     ;
+			return ret;
+		end function get_header;
+	begin
+		full_length   <= sr'length + ipv4_in.tx_length;
+		checksum_ones <= checksum(15 downto 0) + checksum(checksum'high downto 16);
+
+		tx_fsm : process(clk, rst) is
+		begin
+			if rst then
+				state                <= IDLE;
+				ipv4_out.tx_data_ack <= '0';
+				arp_in.arp_query_stb <= '0';
+				ipv4_out.tx_err_stb  <= '0';
+
+			elsif rising_edge(clk) then
+				arp_in.arp_query_stb <= '0';
+				ipv4_out.tx_data_ack <= '0';
+				ipv4_out.tx_err_stb  <= '0';
+
+				if (ethernet_ii_out.tx_data_ack = '1') or (state = CALC_CKS) then
+					if byte_cnt > 0 then
+						byte_cnt <= byte_cnt - 1;
+					end if;
+					sr <= sr(sr'low + 1 to sr'high) & x"00";
+				end if;
+
+				case state is
+					when IDLE =>
+						if ipv4_in.tx_en then
+							arp_in.arp_query_stb <= '1';
+							state                <= ARP;
+						end if;
+
+					when ARP =>
+						if arp_out.arp_ok_stb then
+							ethernet_ii_in.tx_mac_address <= arp_out.arp_mac;
+
+							byte_cnt <= sr'length - 1;
+							sr       <= get_header(x"0000");
+							alt_byte <= '1';
+							checksum <= (others => '0');
+							state    <= CALC_CKS;
+						end if;
+						if arp_out.arp_fail_stb then
+							ipv4_out.tx_err_stb <= '1';
+							-- Then we lock up in this state until tx_en is disabled
+						end if;
+
+					when CALC_CKS =>
+						alt_byte <= not alt_byte;
+
+						if alt_byte then
+							checksum <= checksum + unsigned(std_logic_vector'(sr(sr'low) & sr(sr'low + 1)));
+						else
+							if byte_cnt = 0 then
+								state    <= HEADER;
+								byte_cnt <= sr'length - 1;
+								sr       <= get_header(not std_logic_vector(checksum_ones));
+							end if;
+						end if;
+
+					when HEADER =>
+						if byte_cnt = 0 then
+							state <= PAYLOAD;
+						end if;
+
+					when PAYLOAD =>
+						if ethernet_ii_out.tx_data_ack then
+							sr(sr'low)           <= ipv4_in.tx_data;
+							ipv4_out.tx_data_ack <= '1';
+							if not ipv4_in.tx_en then
+								state <= IDLE;
+							end if;
+						end if;
+				end case;
+			end if;
+		end process tx_fsm;
+
+		ethernet_ii_in.tx_data <= sr(sr'low);
+		ethernet_ii_in.tx_en   <= '1' when (state = HEADER) or (state = PAYLOAD) else '0';
+
+		arp_in.arp_ip <= ipv4_in.tx_ip_address;
+
+	end block tx;
+
+end architecture rtl;

trashernet/trashernet_ipv4prot.vhd

@@ -0,0 +1,122 @@
+-- -------------------------------------------------------------------------- --
+--               TRASHERNET - A Trashy Ethernet Stack for FPGAs               --
+-- -------------------------------------------------------------------------- --
+-- trashernet_eth.vhd : Ethernet OSI Layer 3, Network, Protocol Muxing
+--   Implements arbitration of different IP protocols.
+-- -------------------------------------------------------------------------- --
+-- Author       : Markus Koch <markus@notsyncing.net>
+-- Contributors : None
+-- License      : Mozilla Public License (MPL) Version 2
+-- -------------------------------------------------------------------------- --
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+use work.trashernet_pkg.all;
+
+entity trashernet_ipv4prot is
+	generic(
+		IPV4_PROTOCOLS : ipv4_protocol_vector
+	);
+	port(
+		-- Global
+		clk               : in  std_logic; -- Global clock
+		rst               : in  std_logic; -- Asynchronous reset
+
+		-- IPv4 application interface
+		ipv4_out          : in  ipv4_out_t; -- IPv4 IF (out from IP)
+		ipv4_in           : out ipv4_in_t; -- IPv4 IF (into IP)
+
+		-- IPv4 protocol interface
+		ipv4_protocol_out : out ipv4_protocol_out_vector(IPV4_PROTOCOLS'range); -- IPv4 Protocol IF (out from IP Mux)
+		ipv4_protocol_in  : in  ipv4_protocol_in_vector(IPV4_PROTOCOLS'range) -- IPv4 Protocol IF (into IP Mux)
+	);
+end entity trashernet_ipv4prot;
+
+architecture rtl of trashernet_ipv4prot is
+	constant SEL_PROTOCOL_NONE : integer := ipv4_protocol_out'low - 1;
+
+	signal rx_sel : integer range SEL_PROTOCOL_NONE to ipv4_protocol_out'high;
+	signal tx_sel : integer range ipv4_protocol_in'low to ipv4_protocol_in'high;
+
+begin
+	rx : block
+		signal rx_header_rcv_delayed : std_logic;
+
+	begin
+		arb : process(clk, rst) is
+		begin
+			if rst then
+				rx_sel                <= SEL_PROTOCOL_NONE;
+				rx_header_rcv_delayed <= '0';
+
+			elsif rising_edge(clk) then
+				rx_header_rcv_delayed <= ipv4_out.rx_header_rcv;
+
+				if ipv4_out.rx_header_rcv then
+					rx_sel <= SEL_PROTOCOL_NONE;
+					for i in IPV4_PROTOCOLS'range loop
+						if (ipv4_out.rx_protocol = IPV4_PROTOCOLS(i)) then
+							rx_sel <= i;
+						end if;
+					end loop;
+				end if;
+			end if;
+		end process arb;
+
+		mux : for i in ipv4_protocol_out'range generate
+			ipv4_protocol_out(i).rx_data       <= ipv4_out.rx_data;
+			ipv4_protocol_out(i).rx_ip_address <= ipv4_out.rx_ip_address;
+			ipv4_protocol_out(i).rx_length     <= ipv4_out.rx_length;
+			ipv4_protocol_out(i).rx_data_valid <= ipv4_out.rx_data_valid when rx_sel = i else '0';
+			ipv4_protocol_out(i).rx_error_stb  <= ipv4_out.rx_error_stb when rx_sel = i else '0';
+			ipv4_protocol_out(i).rx_ok_stb     <= ipv4_out.rx_ok_stb when rx_sel = i else '0';
+			ipv4_protocol_out(i).rx_header_rcv <= rx_header_rcv_delayed when rx_sel = i else '0';
+		end generate mux;
+
+		tx_mux : for i in ipv4_protocol_out'range generate
+			ipv4_protocol_out(i).tx_data_ack <= ipv4_out.tx_data_ack when tx_sel = i else '0';
+			ipv4_protocol_out(i).tx_err_stb  <= ipv4_out.tx_err_stb when tx_sel = i else '0';
+			ipv4_protocol_out(i).tx_ok_stb   <= ipv4_out.tx_ok_stb when tx_sel = i else '0';
+		end generate;
+	end block rx;
+
+	tx : block
+		type state_t is (IDLE, TXD);
+		signal state : state_t;
+
+	begin
+		arb : process(clk, rst) is
+		begin
+			if rst then
+				state  <= IDLE;
+				tx_sel <= ipv4_protocol_in'left;
+
+			elsif rising_edge(clk) then
+				case state is
+					when IDLE =>
+						for i in ipv4_protocol_in'range loop
+							if ipv4_protocol_in(i).tx_en then
+								tx_sel <= i;
+								state  <= TXD;
+								exit;   -- Prioritize according to vector
+							end if;
+						end loop;
+
+					when TXD =>
+						state <= IDLE when (not ipv4_in.tx_en);
+				end case;
+			end if;
+		end process arb;
+
+		demux : block
+		begin
+			ipv4_in.tx_data       <= ipv4_protocol_in(tx_sel).tx_data;
+			ipv4_in.tx_en         <= ipv4_protocol_in(tx_sel).tx_en;
+			ipv4_in.tx_ip_address <= ipv4_protocol_in(tx_sel).tx_ip_address;
+			ipv4_in.tx_length     <= ipv4_protocol_in(tx_sel).tx_length;
+			ipv4_in.tx_protocol   <= IPV4_PROTOCOLS(tx_sel);
+		end block demux;
+	end block tx;
+end architecture rtl;

trashernet/trashernet_mac.vhd

@@ -102,7 +102,7 @@ begin
 								byte_count <= byte_count + 1;
 							end if;
 						end if;
-					when PAYLOAD =>
+					when PAYLOAD => -- @suppress "Dead state 'PAYLOAD'": Outgoing transition provided outside of case statement (RX disabled or error)
 						if phy_out.rx_data_valid then
 							sr_payload <= sr_payload(sr_payload'low + 1 to sr_payload'high) & phy_out.rx_data;
 							if byte_count = CRC_LENGTH then

trashernet/trashernet_phy.vhd

@@ -253,6 +253,7 @@ begin
 		begin
 			if rst then
 				phy_out.rx_data_valid <= '0';
+				phy_out.rx_data <= (others => '0'); -- Needed for yosys to compile
 
 			elsif rising_edge(clk) then
 				phy_out.rx_data_valid <= '0';
@@ -296,7 +297,10 @@ begin
 	-- -------------------------------------------------------------------------
 
 	transmitter : block
-		constant TX_STB_CNT_MAX : integer := integer(round(real(F_CLK) / real((F_ETH * 2)))) - 1;
+		constant TX_STB_CNT_IDEAL   : real    := real(F_CLK) / real((F_ETH * 2));
+		constant TX_STB_SKIP_ERROR  : real    := abs (round(TX_STB_CNT_IDEAL) - TX_STB_CNT_IDEAL);
+		constant TX_STB_CNT_MAX     : integer := integer(round(TX_STB_CNT_IDEAL + 0.25)) - 1; -- Round up starting for error > 0.25
+		constant TX_STB_SKIP_SECOND : boolean := TX_STB_SKIP_ERROR >= 0.25; -- Skip one clock cycle every other symbol to hit clock rate in between when the divider is close to x.5
 		signal tx_stb_cnt           : integer range 0 to TX_STB_CNT_MAX;
 
 		type tx_state_t is (IDLE, NLP, TX, IPG);
@@ -367,6 +371,9 @@ begin
 
 				if tx_stb_cnt = 0 then
 					tx_stb_cnt <= TX_STB_CNT_MAX;
+					if TX_STB_SKIP_SECOND and bit_stage = '1' then
+						tx_stb_cnt <= TX_STB_CNT_MAX - 1;
+					end if;
 				else
 					tx_stb_cnt <= tx_stb_cnt - 1;
 				end if;

trashernet/trashernet_phy_cdc.vhd

@@ -44,12 +44,14 @@ architecture rtl of trashernet_phy_cdc is
 	signal phy_phy_in  : phy_in_t;
 
 	-- Helper signals
-	signal rx_data_valid_i : std_logic;
+	signal rx_data_i : byte;
 
 begin
 	-- -------------------------------------------------------------------------
 	-- Drives: PHY clock domain
 	-- -------------------------------------------------------------------------
+
+	-- Reset synchronizer for PHY
 	rstsync : process(phy_clk, rst) is
 	begin
 		if rst then
@@ -59,6 +61,7 @@ begin
 		end if;
 	end process rstsync;
 
+	-- Operate Trashernet in PHY clock domain
 	trashernet_phy_inst : entity work.trashernet_phy
 		generic map(
 			F_CLK => F_CLK_PHY
@@ -73,6 +76,22 @@ begin
 			tx_n    => tx_n
 		);
 
+	-- Latch data in PHY clock domain when valid is strobed
+	--  If the other clock domain is slower than the time it takes for the strobe to synchronize,
+	--  `phy_phy_out.rx_data` will already have shifted in the next bit and no longer be valid.
+	--  Therefore, we need to latch it here.
+	rxdff : process(phy_clk, rst) is
+	begin
+		if rst then
+			rx_data_i <= (others => '0');
+
+		elsif rising_edge(phy_clk) then
+			if phy_phy_out.rx_data_valid then
+				rx_data_i <= phy_phy_out.rx_data;
+			end if;
+		end if;
+	end process rxdff;
+
 	synchronizer_txen_inst : entity work.synchronizer
 		generic map(
 			SIZE => 5
@@ -96,18 +115,10 @@ begin
 			a_in  => phy_phy_out.rx_data_valid,
 			b_clk => clk,
 			b_rst => rst,
-			b_out => rx_data_valid_i
+			b_out => phy_out.rx_data_valid
 		);
 
-	rxdvff : process(clk, rst) is
+	phy_out.rx_data <= rx_data_i;       -- No need to synchronize in new clock domain as latched data has been stable for a while thanks to the delay in the _valid synchronizer
-	begin
-		if rst then
-			phy_out.rx_data_valid <= '0';
-		elsif rising_edge(clk) then
-			phy_out.rx_data_valid <= rx_data_valid_i;
-			phy_out.rx_data       <= phy_phy_out.rx_data; -- Data should be stable after the time it takes the _valid signal to go through the synchronizer
-		end if;
-	end process rxdvff;
 
 	cdc_strobe_rxer_inst : entity work.cdc_strobe
 		port map(

trashernet/trashernet_pkg.vhd

@@ -10,6 +10,7 @@
 
 library ieee;
 use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
 
 package trashernet_pkg is
 	-- General types
@@ -18,6 +19,8 @@ package trashernet_pkg is
 
 	-- MAC specific types
 	subtype mac_addr_t is byte_vector(0 to 5);
+	constant MAC_ADDR_BROADCAST : mac_addr_t := (others => x"FF");
+	function mac_to_string(constant mac_address : in mac_addr_t) return string;
 	subtype ethertype_t is byte_vector(0 to 1);
 
 	type mac_header_fields is record
@@ -28,6 +31,17 @@ package trashernet_pkg is
 
 	-- IP specific types
 	subtype ip_addr_t is byte_vector(0 to 3);
+	function ip_to_string(constant ip_address : in ip_addr_t) return string;
+
+	-- Configuration interface
+	type configuration_t is record
+		mac_address : mac_addr_t;       -- MAC address of this node
+	end record configuration_t;
+	type ipv4_configuration_t is record
+		ip_address  : ip_addr_t;        -- IP address of this node
+		gateway     : ip_addr_t;        -- Peer to use when target is outside of subnet
+		subnet_mask : ip_addr_t;        -- Subnet mask of this node
+	end record ipv4_configuration_t;
 
 	-- PHY interface
 	type phy_in_t is record
@@ -65,8 +79,149 @@ package trashernet_pkg is
 		rx_mac_crc_error  : std_logic;  -- End of packet, CRC invalid
 	end record mac_out_t;
 
+	-- MAC ETH interface
+	type ethernet_ii_protocol_t is record
+		ethertype : ethertype_t;
+	end record;
+	type ethernet_ii_protocol_vector is array (natural range <>) of ethernet_ii_protocol_t;
+	constant ETHERNET_II_PROTOCOLS_NONE : ethernet_ii_protocol_vector(0 to -1) := (others => (ethertype => (x"00", x"00"))); -- @suppress "Null range": We want a NULL vector here to remove the logic
+	constant ETHERNET_II_PROTOCOL_IPV4  : ethernet_ii_protocol_t               := (ethertype => (x"08", x"00"));
+	constant ETHERNET_II_PROTOCOL_ARP   : ethernet_ii_protocol_t               := (ethertype => (x"08", x"06"));
+
+	type ethernet_i_out_t is record
+		rx_mac_address : mac_addr_t;    -- Source MAC address
+		rx_crc_ok      : std_logic;     -- End of packet, CRC OK
+		rx_crc_error   : std_logic;     -- End of packet, CRC invalid
+
+		rx_data        : byte;          -- RX data
+		rx_data_valid  : std_logic;     -- RX data valid strobe
+		rx_length      : unsigned(15 downto 0); -- RX payload length in bytes
+		rx_header_rcv  : std_logic;     -- Start of reception, `rx_length` is valid
+		tx_data_ack    : std_logic;     -- Give next data byte or disable `tx_en`
+	end record;
+	type ethernet_i_in_t is record
+		tx_mac_address : mac_addr_t;    -- Destination MAC address
+		tx_data        : byte;          -- TX data
+		tx_en          : std_logic;     -- Start and continue transmitting
+		tx_length      : unsigned(15 downto 0); -- TX payload length in bytes
+	end record;
+	constant ETHERNET_I_IN_UNUSED : ethernet_i_in_t := (tx_mac_address => (others => x"00"), tx_data => x"00", tx_length => x"0000", others => '0'); -- TODO
+
+	type ethernet_ii_out_t is record
+		rx_mac_address : mac_addr_t;    -- Source MAC address
+		rx_data        : byte;          -- RX data
+		rx_data_valid  : std_logic;     -- RX data valid strobe
+		rx_crc_ok      : std_logic;     -- End of packet, CRC OK
+		rx_crc_error   : std_logic;     -- End of packet, CRC invalid
+		rx_header_rcv  : std_logic;     -- Start of reception
+		tx_data_ack    : std_logic;     -- Give next data byte or disable `tx_en`
+	end record;
+	type ethernet_ii_in_t is record
+		tx_mac_address : mac_addr_t;    -- Destination MAC address
+		tx_data        : byte;          -- TX data
+		tx_en          : std_logic;     -- Start and continue transmitting
+	end record;
+	type ethernet_ii_out_vector is array (natural range <>) of ethernet_ii_out_t;
+	type ethernet_ii_in_vector is array (natural range <>) of ethernet_ii_in_t;
+	constant ETHERNET_II_IN_UNUSED : ethernet_ii_in_t := (tx_mac_address => (others => x"00"), tx_data => x"00", others => '0');
+
+	-- ARP interface
+	type arp_out_t is record
+		arp_mac      : mac_addr_t;      -- Resulting MAC address for query
+		arp_ok_stb   : std_logic;       -- ARP request successful, `arp_mac` valid
+		arp_fail_stb : std_logic;       -- ARP request failed, `arp_mac` invalid
+	end record arp_out_t;
+	type arp_in_t is record
+		arp_ip        : ip_addr_t;      -- IP address to query
+		arp_query_stb : std_logic;      -- Request MAC for IP
+	end record arp_in_t;
+
+	-- IPv4 interface
+	subtype ipv4_protocol is byte;
+	type ipv4_protocol_vector is array (natural range <>) of ipv4_protocol;
+	constant IPV4_PROTOCOL_ICMP : ipv4_protocol := x"01";
+	constant IPV4_PROTOCOL_TCP  : ipv4_protocol := x"06";
+	constant IPV4_PROTOCOL_UDP  : ipv4_protocol := x"11";
+	subtype ipv4_length is unsigned(15 downto 0);
+
+	type ipv4_out_t is record
+		rx_ip_address : ip_addr_t;      -- Source IP address
+		rx_protocol   : ipv4_protocol;  -- Transport Protocol
+		rx_length     : ipv4_length;    -- Telegram length (excluding header)
+
+		rx_data       : byte;           -- RX data
+		rx_data_valid : std_logic;      -- RX data valid strobe
+		rx_ok_stb     : std_logic;      -- End of packet, checksum OK
+		rx_error_stb  : std_logic;      -- End of packet, checksum invalid
+		rx_header_rcv : std_logic;      -- Start of reception (`rx_ip_address` and `rx_protocol` are valid)
+
+		tx_data_ack   : std_logic;      -- Give next data byte of disable `tx_en`
+		tx_ok_stb     : std_logic;      -- Transmission successful
+		tx_err_stb    : std_logic;      -- Transmission failed
+	end record ipv4_out_t;
+	type ipv4_in_t is record
+		tx_ip_address : ip_addr_t;      -- Destination IP address
+		tx_protocol   : ipv4_protocol;  -- Transport Protocol
+		tx_length     : ipv4_length;    -- Length of payload
+		tx_data       : byte;           -- TX data
+		tx_en         : std_logic;      -- Start and continue transmitting
+	end record ipv4_in_t;
+
+	type ipv4_protocol_out_t is record
+		rx_ip_address : ip_addr_t;      -- Source IP address
+		rx_length     : ipv4_length;    -- Telegram length (excluding header)
+
+		rx_data       : byte;           -- RX data
+		rx_data_valid : std_logic;      -- RX data valid strobe
+		rx_ok_stb     : std_logic;      -- End of packet, checksum OK
+		rx_error_stb  : std_logic;      -- End of packet, checksum invalid
+		rx_header_rcv : std_logic;      -- Start of reception
+
+		tx_data_ack   : std_logic;      -- Give next data byte of disable `tx_en`
+		tx_ok_stb     : std_logic;      -- Transmission successful
+		tx_err_stb    : std_logic;      -- Transmission failed
+	end record ipv4_protocol_out_t;
+	type ipv4_protocol_in_t is record
+		tx_ip_address : ip_addr_t;      -- Destination IP address
+		tx_length     : ipv4_length;    -- Length of payload
+
+		tx_data       : byte;           -- TX data
+		tx_en         : std_logic;      -- Start and continue transmitting
+	end record ipv4_protocol_in_t;
+	type ipv4_protocol_out_vector is array (natural range <>) of ipv4_protocol_out_t;
+	type ipv4_protocol_in_vector is array (natural range <>) of ipv4_protocol_in_t;
+
+	-- General helper functions
+	function to_std_logic(constant bool : boolean) return std_logic;
 end package trashernet_pkg;
 
 package body trashernet_pkg is
+	function mac_to_string(constant mac_address : in mac_addr_t) return string is
+	begin
+		return                          --
+		to_hstring(mac_address(0)) & ":" & --
+		to_hstring(mac_address(1)) & ":" & --
+		to_hstring(mac_address(2)) & ":" & --
+		to_hstring(mac_address(3)) & ":" & --
+		to_hstring(mac_address(4)) & ":" & --
+		to_hstring(mac_address(5))      --
+		;
+	end function mac_to_string;
 
+	function ip_to_string(constant ip_address : in ip_addr_t) return string is
+	begin
+		return                          --
+		to_string(to_integer(unsigned(ip_address(0)))) & "." & --
+		to_string(to_integer(unsigned(ip_address(1)))) & "." & --
+		to_string(to_integer(unsigned(ip_address(2)))) & "." & --
+		to_string(to_integer(unsigned(ip_address(3)))) --
+		;
+	end function ip_to_string;
+
+	function to_std_logic(constant bool : boolean) return std_logic is
+		variable ret : std_logic;
+	begin
+		ret := '1' when bool else '0';
+		return ret;
+	end function to_std_logic;
 end package body trashernet_pkg;