hit mux entity for easier placement

diff --git a/tdc_releases/tdc_v1.6/hit_mux.vhd b/tdc_releases/tdc_v1.6/hit_mux.vhd
new file mode 100644 (file)
index 0000000..538a2df
--- /dev/null
+++ b/tdc_releases/tdc_v1.6/hit_mux.vhd
@@ -0,0 +1,81 @@
+-------------------------------------------------------------------------------
+-- Title      : Hit Multiplexer
+-- Project    : FPGA TDC
+-------------------------------------------------------------------------------
+-- File       : hit_mux.vhd
+-- Author     : Cahit Ugur  <c.ugur@gsi.de>
+-- Created    : 2014-03-26
+-- Last update: 2014-03-27
+-------------------------------------------------------------------------------
+-- Description: Entity to decide the hit for the channels between physical or
+-- calibration hits.
+-------------------------------------------------------------------------------
+-- Copyright (c) 2014 
+-------------------------------------------------------------------------------
+-- Revisions  :
+-- Date        Version  Author  Description
+-- 2014-03-26  1.0      cugur   Created
+-------------------------------------------------------------------------------
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+
+
+entity hit_mux is
+  
+  port (
+    CH_EN_IN           : in  std_logic;  -- channel enable signal
+    CALIBRATION_EN_IN  : in  std_logic;  -- calibration enable signal
+    HIT_CALIBRATION_IN : in  std_logic;  -- hit signal for calibration purposes
+    HIT_PHYSICAL_IN    : in  std_logic;  -- physical hit signal
+    HIT_OUT            : out std_logic);  -- hit signal to the delay lines
+end entity hit_mux;
+
+architecture behavioral of hit_mux is
+
+  signal ch_en_i           : std_logic;
+  signal calibration_en_i  : std_logic;
+  signal hit_calibration_i : std_logic;
+  signal hit_physical_i    : std_logic;
+  signal hit_i             : std_logic;
+
+  attribute syn_keep                      : boolean;
+  attribute syn_keep of ch_en_i           : signal is true;
+  attribute syn_keep of calibration_en_i  : signal is true;
+  attribute syn_keep of hit_calibration_i : signal is true;
+  attribute syn_keep of hit_physical_i    : signal is true;
+  attribute syn_keep of hit_i             : signal is true;
+  --attribute syn_preserve                        : boolean;
+  --attribute syn_preserve of coarse_cntr         : signal is true;
+  attribute nomerge                       : string;
+  attribute nomerge of ch_en_i            : signal is "true";
+  attribute nomerge of calibration_en_i   : signal is "true";
+  attribute nomerge of hit_calibration_i  : signal is "true";
+  attribute nomerge of hit_physical_i     : signal is "true";
+  attribute nomerge of hit_i              : signal is "true";
+
+  
+begin  -- architecture behavioral
+
+  ch_en_i           <= CH_EN_IN;
+  calibration_en_i  <= CALIBRATION_EN_IN;
+  hit_calibration_i <= HIT_CALIBRATION_IN;
+  hit_physical_i    <= HIT_PHYSICAL_IN;
+  
+  process (ch_en_i, calibration_en_i, hit_calibration_i, hit_physical_i)
+  begin
+    if ch_en_i = '1' then
+      if calibration_en_i = '1' then
+        hit_i <= hit_calibration_i;
+      else
+        hit_i <= hit_physical_i;
+      end if;
+    else
+      hit_i <= '0';
+    end if;
+  end process;
+
+  HIT_OUT <= hit_i;
+
+end architecture behavioral;