MCC execution control unit added

diff --git a/mcc_exec.vhd b/mcc_exec.vhd
new file mode 100644 (file)
index 0000000..8c39167
--- /dev/null
+++ b/mcc_exec.vhd
@@ -0,0 +1,49 @@
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.std_logic_arith.all;
+use ieee.std_logic_unsigned.all;
+
+--------------------------------------------------------------------------------
+
+entity mcc_exec is
+  port (
+    -- Clock & reset
+    CLK_I      : in  std_logic;
+    RST_I      : in  std_logic;
+    -- MCC execution
+    MCC_EN_I   : in  std_logic;
+    MCC_EXEC_I : in  std_logic;
+    MCC_ERR_O  : out std_logic;
+    -- MCC master interface
+    MCC_ACK_I  : in  std_logic;
+    MCC_STB_O  : out std_logic);
+end entity mcc_exec;
+
+--------------------------------------------------------------------------------
+
+architecture behavioral of mcc_exec is
+
+  signal mcc_stb : std_logic := '0';
+  
+--------------------------------------------------------------------------------
+
+begin
+
+  MCC_STB_O <= mcc_stb;
+  
+  MCC_ERR_O <= MCC_EXEC_I and (mcc_stb or MCC_ACK_I);
+
+  
+  process (CLK_I, RST_I) is
+  begin
+    if rising_edge(CLK_I) then
+      if RST_I = '1' or MCC_ACK_I = '1' then
+        mcc_stb <= '0';
+      elsif MCC_EN_I = '1' and MCC_EXEC_I = '1' then
+        mcc_stb <= '1';
+      end if;
+    end if;
+  end process;
+  
+end architecture behavioral;
+