- added helper functions for DCM frequency synthesis

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git-svn-id: http://moon:8086/svn/vhdl/trunk@576 cc03376c-175c-47c8-b038-4cd826a8556b

lib/misc/utils_pkg.vhd

@@ -1,5 +1,5 @@
 -----------------------------------------------------------------------
--- $Header: /tmp/cvsroot/VHDL/lib/misc/utils_pkg.vhd,v 1.2 2009-01-02 15:28:01 Jens Exp $
+-- $Header: /tmp/cvsroot/VHDL/lib/misc/utils_pkg.vhd,v 1.3 2009-11-03 20:38:30 Jens Exp $
 -----------------------------------------------------------------------
 
 library IEEE;
@@ -18,6 +18,9 @@ package utils_pkg is
 	function NextExpBaseTwo(x : natural) return natural;
 	function GCD(a, b : natural) return natural;
 	function LCM(a, b : natural) return natural;
+	function UTILS_PERIOD_NS(f_in_hz : natural) return real;
+	function UTILS_FREQ_M(f_in_hz, f_out_hz : natural) return natural;
+	function UTILS_FREQ_D(f_in_hz, f_out_hz : natural) return natural;
 	
 end utils_pkg;
 
@@ -71,6 +74,45 @@ package body utils_pkg is
 
 	end LCM;	
 
+	function UTILS_PERIOD_NS(f_in_hz : natural) return real is
+	begin
+		
+		return 1.0E9/real(f_in_hz);
+
+	end UTILS_PERIOD_NS;	
+	
+	function UTILS_FREQ_M(f_in_hz, f_out_hz : natural) return natural is
+	variable f_in_mhz : natural;
+	variable f_out_mhz : natural;
+	variable m : natural;
+	begin
+		f_in_mhz := f_in_hz/1E6;
+		f_out_mhz := f_out_hz/1E6;
+		m := f_out_mhz/GCD(f_in_mhz, f_out_mhz);
+
+		if m = 1 then
+			m := 2;
+		end if;
+		
+		return m;
+		
+	end UTILS_FREQ_M;	
+
+	function UTILS_FREQ_D(f_in_hz, f_out_hz : natural) return natural is
+	variable f_in_mhz : natural;
+	variable f_out_mhz : natural;
+	variable m : natural;
+	variable d : natural;
+	begin
+		m := UTILS_FREQ_M(f_in_hz, f_out_hz);
+		f_in_mhz := f_in_hz/1E6;
+		f_out_mhz := f_out_hz/1E6;
+		d := m*f_in_mhz/f_out_mhz;
+		
+		return d;
+
+	end UTILS_FREQ_D;	
+
 end utils_pkg;