----------------------------------------------------------------------------------
-- Company: University of Connecticut
-- Engineer: Igor Senderovich
-- 
-- Create Date:    12:14:27 10/28/2009 
-- Module Name:    ConfigParam - Behavioral 
-- Description:    FPGA firmware fixed parameter file
--
----------------------------------------------------------------------------------
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
--use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;


entity ConfigParam is
    Port ( DAC_Qmax : out  STD_LOGIC_VECTOR (13 downto 0);
	   DAC_Q_GainModeChan : out  STD_LOGIC_VECTOR (13 downto 0);
           dbShort  : out  STD_LOGIC);
end ConfigParam;

architecture Behavioral of ConfigParam is
begin

	-- IMPORTANT: the following sets the maximum allowed
	-- DAC output voltage. Conversion from voltage units:
	--   DAC_Qmax = Vmax * 2^14/(Vref*50)
	-- original board design: Vref=3.3V
	DAC_Qmax <= "01111001000001"; -- = 78V @ Vref=3.3V
	--DAC_Qmax <= "00111111100111"; -- = 41V @ Vref=3.3V     
	--DAC_Qmax   <= "11010001111010"; -- = 41V @ Vref=1.0V
	--DAC_Qmax <= "01100110011001"; -- = 20V @ Vref=1.0V
	--DAC_Qmax <= "11111111111111"; -- = supply is the limit
	--DAC_Qmax   <= "01111111111111"; -- = 25V @ Vref=1.0V

	-- Here we set the binary value corresponding to the 5V
	-- Gain Mode selector channel. As described above, this
	-- binary value depends on the Vref. 
	-- Also, due to systematics in the DAC at low voltages,
	-- greater than 5V values may be used, relying on the 
	-- Zener diode to limit the voltage at 5V
	-- (refer to the diode's spec sheet for maximum allowed)
	--DAC_Q_GainModeChan  <= "00100011110101"; -- = 7V @ Vref=1.0V
	--DAC_Q_GainModeChan  <= "00001010110111"; -- = 7V @ Vref=3.3V
	--DAC_Q_GainModeChan    <= "00101110100010"; -- = 30V @ Vref=3.3V
	DAC_Q_GainModeChan    <= "00010001000100"; -- = 11V @ Vref=3.3V
                             
	
	-- shorts out the mandatory long waiting times when set to '1'
	-- e.g. during Eth. Ctrl physical layer startup
	-- Used only as a convenience for simulations.
	dbShort <= '0';

end Behavioral;