From 12bbdb42cdcf5e6e39832d75fbbd31e3781d550a Mon Sep 17 00:00:00 2001
From: Pacien TRAN-GIRARD
Date: Fri, 11 Apr 2014 19:29:53 +0200
Subject: Import fichiers projet Quartus

---
 FPGA/vhdl/clock_divider.vhd | 57 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 FPGA/vhdl/clock_divider.vhd

(limited to 'FPGA/vhdl/clock_divider.vhd')

diff --git a/FPGA/vhdl/clock_divider.vhd b/FPGA/vhdl/clock_divider.vhd
new file mode 100644
index 0000000..3a061bb
--- /dev/null
+++ b/FPGA/vhdl/clock_divider.vhd
@@ -0,0 +1,57 @@
+------------------------------------------------------
+--      Clock Divider
+------------------------------------------------------
+-- Creation : A. Exertier, 2005
+------------------------------------------------------
+
+library ieee;
+use ieee.std_logic_1164.all;
+
+------------------------------------------------------
+--                PARAMETRES GENERIQUES
+------------------------------------------------------
+-- board_frequency  : frequency of the FPGA
+-- user_frequency   : desired frequency
+------------------------------------------------------
+--                   INPUTS
+------------------------------------------------------
+-- clk      : main clock
+-- resetn   : asynchronous active low reset
+------------------------------------------------------
+--                   OUTPUT
+------------------------------------------------------
+-- en_user  : signal at user_frequency
+--            set to 1 only 1 main clock cycle
+------------------------------------------------------
+
+
+entity clock_divider is	
+  generic(
+     board_frequency   : real :=50_000_000.0; -- 50 MHz
+	 user_frequency    : real :=4.0);          -- 4 Hz
+  Port (
+    clk           : in  std_logic;  
+    resetn        : in  std_logic;  -- active low
+	en_user       : out std_logic);
+end clock_divider;
+
+architecture RTL of clock_divider is
+  constant max     : natural := integer(board_frequency/user_frequency);  
+begin
+  process(clk,resetn)
+      variable counter : natural range 0 to max-1;
+  begin
+   if resetn='0' then 			 
+     counter := 0;
+     en_user <= '0';
+   elsif rising_edge(clk) then 
+     if counter = max-1 then 
+       counter	:= 0;
+       en_user <= '1';	
+     else 
+       counter := counter+1;
+       en_user <= '0';
+     end if;
+   end if;
+  end process;
+end RTL;
-- 
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