Merge branch 'dev' into ppu-interface

1 files changed, 116 insertions, 0 deletions

diff --git a/basys3/basys3.srcs/er_ram_tb.vhd b/basys3/basys3.srcs/er_ram_tb.vhd
new file mode 100644
index 0000000..d360442
--- /dev/null
+++ b/basys3/basys3.srcs/er_ram_tb.vhd
@@ -0,0 +1,116 @@
+library ieee;
+library unisim;
+
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+use unisim.vcomponents.all;
+
+entity er_ram_tb is
+end er_ram_tb;
+
+architecture behavioral of er_ram_tb is
+	component er_ram
+		generic(
+			ADDR_W : natural := 2; -- ADDR line width
+			DATA_W : natural := 2; -- DATA line width
+			ADDR_LOW : natural := 16#0000#; -- starting address
+			ADDR_RANGE : natural := 16#0002#); -- amount of valid addresses after ADDR_LOW
+		port(
+			CLK : in std_logic; -- clock
+			RST : in std_logic; -- async memory clear
+			WEN : in std_logic; -- write enable
+			ADDR : in std_logic_vector(ADDR_W-1 downto 0);
+			DATA : in std_logic_vector(DATA_W-1 downto 0);
+			REG : out std_logic_vector((ADDR_W*DATA_W)-1 downto 0));
+	end component;
+
+	signal CLK, RST, WEN : std_logic := '0';
+	signal ADDR : std_logic_vector(3 downto 0);
+	signal DATA : std_logic_vector(7 downto 0);
+	signal REG : std_logic_vector(31 downto 0);
+begin
+	uut : component er_ram
+		generic map(
+			ADDR_W => 4,
+			DATA_W => 8,
+			ADDR_LOW => 0,
+			ADDR_RANGE => 4)
+		port map(
+			CLK => CLK,
+			RST => RST,
+			WEN => WEN,
+			ADDR => ADDR,
+			DATA => DATA,
+			REG => REG);
+
+	tb : process
+	begin
+		wait for 5 ns;
+
+		-- async reset (safety)
+		RST <= '1';
+		wait for 5 ns;
+		RST <= '0';
+		wait for 5 ns;
+
+		-- set 0xef at address 0x1 (exists)
+		DATA <= x"ef";
+		ADDR <= x"1";
+		WEN <= '1';
+
+		CLK <= '1';
+		wait for 5 ns;
+		CLK <= '0';
+		wait for 5 ns;
+
+		-- set 0x34 at address 0x4 (doesn't exist)
+		ADDR <= x"4";
+		DATA <= x"34";
+
+		CLK <= '1';
+		wait for 5 ns;
+		CLK <= '0';
+		wait for 5 ns;
+
+		-- reset
+		RST <= '1';
+		wait for 5 ns;
+		RST <= '0';
+		wait for 5 ns;
+
+		-- set REG to 0x12345678
+		ADDR <= x"0";
+		DATA <= x"12";
+
+		CLK <= '1';
+		wait for 1 ns;
+		CLK <= '0';
+		wait for 1 ns;
+
+		ADDR <= x"1";
+		DATA <= x"34";
+
+		CLK <= '1';
+		wait for 1 ns;
+		CLK <= '0';
+		wait for 1 ns;
+
+		ADDR <= x"2";
+		DATA <= x"56";
+
+		CLK <= '1';
+		wait for 1 ns;
+		CLK <= '0';
+		wait for 1 ns;
+
+		ADDR <= x"3";
+		DATA <= x"78";
+
+		CLK <= '1';
+		wait for 1 ns;
+		CLK <= '0';
+		wait for 1 ns;
+
+		wait; -- stop for simulator
+	end process;
+end;