1 files changed, 137 insertions, 0 deletions
diff --git a/zpu/hdl/zy2000/timer.vhd b/zpu/hdl/zy2000/timer.vhd
new file mode 100644
index 0000000..735d55c
--- /dev/null
+++ b/zpu/hdl/zy2000/timer.vhd
@@ -0,0 +1,137 @@
+library ieee;
+use ieee.std_logic_1164.all;
+use IEEE.STD_LOGIC_UNSIGNED.ALL;
+ 
+entity timer is
+  port(
+       	clk             : in std_logic;
+		areset			: in std_logic;
+		sample			: in std_logic;
+		reset			: in std_logic;
+		counter			: out std_logic_vector(63 downto 0));
+end timer;
+   
+   
+architecture behave of timer is
+
+signal	c			: std_logic_vector(1 to 7);
+
+signal	cnt		: std_logic_vector(63 downto 0);
+signal	cnt_smp	: std_logic_vector(63 downto 0);
+
+begin
+
+	counter <= cnt_smp;
+
+	process(clk, areset)	-- Carry generation
+	begin
+		if areset = '1' then
+			c <= "0000000";
+		elsif (clk'event and clk = '1') then
+			if reset = '1' then
+				c <= "0000000";
+			else
+				if cnt(7 downto 0) = "11111110" then
+					c(1) <= '1';
+				else
+					c(1) <= '0';
+				end if;
+				if cnt(15 downto 8) = "11111111" then
+					c(2) <= '1';
+				else
+					c(2) <= '0';
+				end if;
+				if cnt(23 downto 16) = "11111111" and c(2) = '1' then
+					c(3) <= '1';
+				else
+					c(3) <= '0';
+				end if;
+				if cnt(31 downto 24) = "11111111" and c(3) = '1' then
+					c(4) <= '1';
+				else
+					c(4) <= '0';
+				end if;
+				if cnt(39 downto 32) = "11111111" and c(4) = '1' then
+					c(5) <= '1';
+				else
+					c(5) <= '0';
+				end if;
+				if cnt(47 downto 40) = "11111111" and c(5) = '1' then
+					c(6) <= '1';
+				else
+					c(6) <= '0';
+				end if;
+				if cnt(55 downto 48) = "11111111" and c(6) = '1' then
+					c(7) <= '1';
+				else
+					c(7) <= '0';
+				end if;
+			end if;	
+		end if;
+	end process;
+	
+	process(clk, areset)
+	begin
+		if areset = '1' then
+			cnt <= (others=>'0');
+		elsif (clk'event and clk = '1') then
+			if reset = '1' then
+				cnt <= (others=>'0');
+			else
+				cnt(7 downto 0) <= cnt(7 downto 0) + '1';
+				if c(1) = '1' then
+					cnt(15 downto 8) <= cnt(15 downto 8) + '1';
+				else
+					cnt(15 downto 8) <= cnt(15 downto 8);
+				end if;
+				if c(2) = '1' and c(1) = '1' then
+					cnt(23 downto 16) <= cnt(23 downto 16) + '1';
+				else
+					cnt(23 downto 16) <= cnt(23 downto 16);
+				end if;
+				if c(3) = '1' and c(1) = '1' then
+					cnt(31 downto 24) <= cnt(31 downto 24) + '1';
+				else
+					cnt(31 downto 24) <= cnt(31 downto 24);
+				end if;
+				if c(4) = '1' and c(1) = '1' then
+					cnt(39 downto 32) <= cnt(39 downto 32) + '1';
+				else
+					cnt(39 downto 32) <= cnt(39 downto 32);
+				end if;
+				if c(5) = '1' and c(1) = '1' then
+					cnt(47 downto 40) <= cnt(47 downto 40) + '1';
+				else
+					cnt(47 downto 40) <= cnt(47 downto 40);
+				end if;
+				if c(6) = '1' and c(1) = '1' then
+					cnt(55 downto 48) <= cnt(55 downto 48) + '1';
+				else
+					cnt(55 downto 48) <= cnt(55 downto 48);
+				end if;
+				if c(7) = '1' and c(1) = '1' then
+					cnt(63 downto 56) <= cnt(63 downto 56) + '1';
+				else
+					cnt(63 downto 56) <= cnt(63 downto 56);
+				end if;
+			end if;
+		end if;
+	end process;
+	
+	process(clk, areset)
+	begin
+		if areset = '1' then
+			cnt_smp <= (others=>'0');
+		elsif (clk'event and clk = '1') then
+			if reset = '1' then
+				cnt_smp <= (others=>'0');
+			elsif sample = '1' then
+				cnt_smp <= cnt;
+			else
+				cnt_smp <= cnt_smp;
+			end if;
+		end if;
+	end process;
+	
+end behave;
+