-- Interactive Audio Manipulation Processor
--
-- file: constants.vhd
-- status: compiled - no errors
--
-- author: Stephen Tang
--
-- Constants_Pkg contains constants that are used throughout the iAMP design

library ieee;
use ieee.std_logic_1164.all;

package Constants_Pkg is

-- mouse constants

  constant MOUSEWIDTH: positive := 9;

-- video constants
  
  constant DISPLAY_X: positive := 10;
  constant DISPLAY_Y: positive := 10;

  constant MIN_X_COORD: std_logic_vector(DISPLAY_X-1 downto 0) := "0000000000";
  constant MIN_Y_COORD: std_logic_vector(DISPLAY_X-1 downto 0) := "0000000000";
  constant MAX_X_COORD: std_logic_vector(DISPLAY_X-1 downto 0) := "1001111111";
   -- X"27F", 640-1
  constant MAX_Y_COORD: std_logic_vector(DISPLAY_X-1 downto 0) := "0111011111";
   -- X"1DF", 480-1

-- audio constants

  constant SOURCE_WIDTH: positive := 4;
  
  constant MIN_SOUND: positive := 1;
  constant MAX_SOUND: positive := 15;
  constant MIN_SOUND_COORD:std_logic_vector(SOURCE_WIDTH-1 downto 0):="0001"; -- 1
  constant MAX_SOUND_COORD:std_logic_vector(SOURCE_WIDTH-1 downto 0):="1111"; -- 15

  constant SAMPLE_WIDTH: positive := 24;
    -- ADC provides a 24-bit sample, but...
  constant EFFECTIVE_SAMPLE_WIDTH: positive := 8;
    -- ...we only use the 8 most significant bits.

  constant DELAY_WIDTH: positive := 5;
  constant NO_DELAY: std_logic_vector(DELAY_WIDTH-1 downto 0) := "00000";

-- RAM constants

  constant RAM_ADDRESS_WIDTH: positive := 18;
  constant RAM_DATA_WIDTH: positive := 8;
  constant RAM_MAX_ADDRESS: std_logic_vector(RAM_ADDRESS_WIDTH-1 downto 0)
    := "000000000000000100";  -- temp maximum of 4 addresses, for testing
--    := "000000000100000000";  -- RAM is 512x8, so max address is 512

  constant RAM_ADDRESS_UNDERFLOW: std_logic_vector(RAM_ADDRESS_WIDTH-1 downto 0)
    := "111111111111111111";
    -- if address is "000000000000001000", subtracting '1' will give this
    -- value, which is NOT the same as RAM_MAX_ADDRESS in general; this
    -- number indicates an arithmetic underflow


end Constants_Pkg;