From 9121ccfdbecb16979991f8bce42ae4793562465a Mon Sep 17 00:00:00 2001
From: Xiretza <xiretza@xiretza.xyz>
Date: Sun, 5 Jun 2022 21:34:31 +0200
Subject: [PATCH] vhdl: implement setting LEDs via UDP

---
 vhdl/arty_a7.vhdl | 36 +++++++++++++++++++++++++++--------
 vhdl/splink.vhdl  | 48 ++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 71 insertions(+), 13 deletions(-)

diff --git a/vhdl/arty_a7.vhdl b/vhdl/arty_a7.vhdl
index 1a8aebd..061690a 100644
--- a/vhdl/arty_a7.vhdl
+++ b/vhdl/arty_a7.vhdl
@@ -116,6 +116,16 @@ architecture a of arty_a7 is
 	signal pixel_sink_ready : std_logic;
 	signal pixel_sink_data : std_logic_vector(31 downto 0);
 
+	signal pixel_source_src_ip_address : std_logic_vector(31 downto 0);
+	signal pixel_source_src_port : std_logic_vector(15 downto 0);
+
+	signal pixel_source_length : std_logic_vector(15 downto 0);
+	signal pixel_source_valid : std_logic;
+	signal pixel_source_last : std_logic;
+	signal pixel_source_last_be : std_logic_vector(3 downto 0);
+	signal pixel_source_ready : std_logic;
+	signal pixel_source_data : std_logic_vector(31 downto 0);
+
 	component PLLE2_BASE
 		generic (
 			CLKFBOUT_MULT : integer;
@@ -232,15 +242,15 @@ begin
 		pixel_sink_data => pixel_sink_data,
 
 		-- source
-		pixel_source_src_ip_address => open,
-		pixel_source_src_port => open,
+		pixel_source_src_ip_address => pixel_source_src_ip_address,
+		pixel_source_src_port => pixel_source_src_port,
 
-		pixel_source_length => open,
-		pixel_source_valid => open,
-		pixel_source_last => open,
-		pixel_source_last_be => open,
-		pixel_source_ready => '1',
-		pixel_source_data => open
+		pixel_source_length => pixel_source_length,
+		pixel_source_valid => pixel_source_valid,
+		pixel_source_last => pixel_source_last,
+		pixel_source_last_be => pixel_source_last_be,
+		pixel_source_ready => pixel_source_ready,
+		pixel_source_data => pixel_source_data
 	);
 
 	-- 800 MHz VCO
@@ -323,6 +333,16 @@ begin
 			clk => sys_clk,
 			reset => sys_reset,
 
+			udp_src_ip_address => pixel_source_src_ip_address,
+			udp_src_port => pixel_source_src_port,
+
+			udp_length => pixel_source_length,
+			udp_valid => pixel_source_valid,
+			udp_last => pixel_source_last,
+			udp_last_be => pixel_source_last_be,
+			udp_ready => pixel_source_ready,
+			udp_data => pixel_source_data,
+
 			drivers => drivers
 		);
 end architecture;
diff --git a/vhdl/splink.vhdl b/vhdl/splink.vhdl
index 5462f81..81f6e69 100644
--- a/vhdl/splink.vhdl
+++ b/vhdl/splink.vhdl
@@ -11,16 +11,34 @@ entity splink is
 		clk : in std_logic;
 		reset : in std_logic;
 
+		udp_src_ip_address : in std_logic_vector(31 downto 0);
+		udp_src_port : in std_logic_vector(15 downto 0);
+
+		udp_length : in std_logic_vector(15 downto 0);
+		udp_valid : in std_logic;
+		udp_last : in std_logic;
+		udp_last_be : in std_logic_vector(3 downto 0);
+		udp_ready : out std_logic;
+		udp_data : in std_logic_vector(31 downto 0);
+
 		drivers : out std_logic_vector(NUM_STRANDS-1 downto 0)
 	);
 end entity;
 
 architecture a of splink is
 	signal driver_out : std_logic;
+
+	constant BITS_PER_LED: natural := 24;
+	subtype color_t is std_logic_vector(BITS_PER_LED-1 downto 0);
+	type strand_store_t is array(0 to MAX_STRAND_LEN) of color_t;
+	signal strand_store: strand_store_t;
+
+	signal led_addr : std_logic_vector(7 downto 0);
+	signal current_color : color_t;
 begin
 	ws2812_inst: entity work.ws2812
 		generic map (
-			NUM_LEDS => 20,
+			NUM_LEDS => MAX_STRAND_LEN,
 			COLOR_ORDER => "GRB",
 			T_CLK => 12.5 ns,
 
@@ -35,15 +53,35 @@ begin
 			n_reset => not reset,
 			clk     => clk,
 
-			led_addr => open,
+			led_addr => led_addr,
 
-			led_red   => x"ff",
-			led_green => x"00",
-			led_blue  => x"ff",
+			led_red   => current_color(7 downto 0),
+			led_green => current_color(15 downto 8),
+			led_blue  => current_color(23 downto 16),
 
 			dout => driver_out
 		);
 
 	-- https://github.com/YosysHQ/yosys/issues/3360
 	drivers <= (19 => driver_out, others => '0');
+
+	writer: process(clk)
+		variable store_counter: natural range 0 to MAX_STRAND_LEN-1;
+	begin
+		if rising_edge(clk) then
+			current_color <= strand_store(to_integer(unsigned(led_addr)));
+
+			if udp_valid then
+				strand_store(store_counter) <= udp_data(23 downto 0);
+
+				if udp_last then
+					store_counter := 0;
+				elsif store_counter /= MAX_STRAND_LEN-1 then
+					store_counter := store_counter + 1;
+				end if;
+			end if;
+		end if;
+	end process;
+
+	udp_ready <= '1';
 end architecture;