1 files changed, 95 insertions, 0 deletions
diff --git a/zpu/hdl/zpu3/src/io.vhd b/zpu/hdl/zpu3/src/io.vhd
new file mode 100644
index 0000000..6b50ca1
--- /dev/null
+++ b/zpu/hdl/zpu3/src/io.vhd
@@ -0,0 +1,95 @@
+library ieee;
+use ieee.std_logic_1164.all;
+use IEEE.STD_LOGIC_UNSIGNED.ALL;
+
+use std.textio.all;
+
+library zylin;
+use zylin.zpu_config.all;
+use zylin.zpupkg.all;
+use zylin.txt_util.all;
+ 
+entity  zpu_io is
+  generic (
+           log_file:       string  := "log.txt"
+          );
+  port(
+       	clk         : in std_logic;
+       	areset        : in std_logic;
+		busy : out std_logic;
+		writeEnable : in std_logic;
+		readEnable : in std_logic;
+		write	: in std_logic_vector(7 downto 0);
+		read	: out std_logic_vector(7 downto 0);
+		addr : in std_logic_vector(maxAddrBit downto minAddrBit)
+		);
+end zpu_io;
+   
+   
+architecture behave of zpu_io is
+
+
+
+signal timer_read : std_logic_vector(7 downto 0);
+--signal timer_write : std_logic_vector(7 downto 0);
+signal timer_we : std_logic;
+
+file 		l_file		: TEXT open write_mode is log_file;
+
+begin
+
+	
+	timerinst: timer port map (
+       clk => clk,
+		 areset => areset,
+		 we => timer_we,
+		 din => write,
+		 adr => addr(4 downto 2),
+		 dout => timer_read);
+	
+	
+	process(areset, clk)
+	begin
+		if (areset = '1') then
+			timer_we <= '0';
+			busy <= '1';
+		elsif (clk'event and clk = '1') then
+			busy <= '1';
+			timer_we <= '0';
+			if writeEnable = '1' then
+				-- external interface
+				if addr=x"1000" then
+					-- Write to UART
+					-- report "" & character'image(conv_integer(memBint)) severity note;
+				    print(l_file, character'val(conv_integer(write)));
+				    busy <= '0';
+				elsif addr(12)='1' then
+ 					timer_we <= '1';
+				    busy <= '0';
+				else
+					report "Illegal IO write" severity failure;
+				end if;
+				
+			end if;
+			if (readEnable = '1') then
+				if addr=x"1001" then
+					read <= (0=>'1', others => '0'); -- recieve empty
+				    busy <= '0';
+ 				elsif addr(12)='1' then
+ 					read <= timer_read;
+				    busy <= '0';
+ 				elsif addr(11)='1' then
+ 					read <= ZPU_Frequency;
+				    busy <= '0';
+				else
+					report "Illegal IO read" severity failure;
+				end if;
+			else 
+				read <= (others => '1');
+			end if;
+		end if;
+	end process;
+
+
+end behave;
+