-- --------------------------------------------------------------------------
--
-- Title      : Draft Standard VHDL 1076.1.1 Packages for Multiple Energy 
--            : Domain Support.
--
-- Library    : This package shall be compiled into a library symbolically
--            : named IEEE.
--
-- Developers : IEEE 1076.1.1 Working Group
--
-- Purpose    : This package contains fundamental constants known to be
--            : standard. It also contains common engineering scale factors.
--
-- Note       :
--
-- --------------------------------------------------------------------------
--   Modification History :
--
--   Version   Date           Description
--     1.0     31 Aug 2002    Original version.
--     1.1     30 Sep 2002    FDL 2002 revisions
-- --------------------------------------------------------------------------

library IEEE;
    use IEEE.MATH_REAL.all;

package FUNDAMENTAL_CONSTANTS is

-- some declarations
  attribute SYMBOL : STRING;
  attribute UNIT   : STRING;

-- PHYSICAL CONSTANTS

   -- electron charge <COULOMB>
   -- NIST value: 1.602 176 462e-19 coulomb
   -- uncertainty: 0.000 000 063e-19
   -- Date obtained: 
   constant PHYS_Q : REAL :=  1.602_176_462e-19;

   -- permittivity of vacuum <FARADS/METER>
   -- NIST value: 8.854 187 817e-12 farads/meter
   -- uncertainty: exact
   -- Date obtained: 
   constant PHYS_EPS0 : REAL := 8.854_187_817e-12;

   -- permeability of vacuum <HENRIES/METER>
   -- NIST value: 4e-7*pi henries/meter
   -- uncertainty: exact
   -- Date obtained: 
   constant PHYS_MU0 : REAL := 4.0e-7 * MATH_PI;

   -- Boltzmann's constant <JOULES/KELVIN>
   -- NIST value: 1.380 6503e-23 joules/kelvin
   -- uncertainty: 0.000 0024e-23
   -- Date obtained: 
   constant PHYS_K : REAL :=  1.380_6503e-23;

   -- Acceleration due to gravity <METERS/SECOND_SQUARED>
   -- NIST value: 9.806 65 meters/square second
   -- uncertainty: exact
   -- Date obtained: 
   constant PHYS_GRAVITY : REAL := 9.806_65;

   -- Conversion between Kelvin and degree Celsius
   -- NIST value: 273.15
   -- uncertainty: exact
   -- Date obtained: 
   constant PHYS_CTOK : REAL := 273.15;

   -- object declarations
   -- common scaling factors
   constant  YOCTO : REAL := 1.0e-24;
   constant  ZEPTO : REAL := 1.0e-21;
   constant  ATTO  : REAL := 1.0e-18;
   constant  FEMTO : REAL := 1.0e-15;
   constant  PICO  : REAL := 1.0e-12;
   constant  NANO  : REAL := 1.0e-9;
   constant  MICRO : REAL := 1.0e-6;
   constant  MILLI : REAL := 1.0e-3;
   constant  CENTI : REAL := 1.0e-2;
   constant  DECI  : REAL := 1.0e-1;
   constant  DEKA  : REAL := 1.0e+1;
   constant  HECTO : REAL := 1.0e+2;
   constant  KILO  : REAL := 1.0e+3;
   constant  MEGA  : REAL := 1.0e+6;
   constant  GIGA  : REAL := 1.0e+9;
   constant  TERA  : REAL := 1.0e+12;
   constant  PETA  : REAL := 1.0e+15;
   constant  EXA   : REAL := 1.0e+18;
   constant  ZETTA : REAL := 1.0e+21;
   constant  YOTTA : REAL := 1.0e+24;
   alias DECA is DEKA;

end package FUNDAMENTAL_CONSTANTS;