de1_dac_rtl.vhd 3.31 KB
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library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

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-- PLL for 100 MHz speed
library altera_mf;
use altera_mf.all;

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entity de1_dac is 
  port ( CLOCK_50 : in  std_ulogic;         
         SW       : in  std_ulogic_vector(9 downto 0); 
         KEY0     : in  std_ulogic;
         DAC_MODE : out std_ulogic;    --1=dual port, 0=interleaved
         DAC_WRT_A : out std_ulogic;
         DAC_WRT_B : out std_ulogic;
         DAC_CLK_A : out std_ulogic;  -- PLL_OUT_DAC0 in User Manual
         DAC_CLK_B : out std_ulogic;  -- PLL_OUT_DAC1 in User Manual
         DAC_DA   : out std_ulogic_vector(13 downto 0);
         DAC_DB   : out std_ulogic_vector(13 downto 0);
         ADC_CLK_A : out std_ulogic;
         ADC_CLK_B : out std_ulogic;
         POWER_ON  : out std_ulogic;
         ADC_OEB_A : out std_ulogic;
         ADC_OEB_B : out std_ulogic;
         LEDR     : out std_ulogic_vector(9 downto 0));  -- red LEDs
end entity;

architecture rtl of de1_dac is

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  -- Altera PLL
  component altpll
    generic (
      clk0_divide_by         : natural;
      clk0_duty_cycle        : natural;
      clk0_multiply_by       : natural;
--              clk0_phase_shift                : STRING;
--              compensate_clock                : STRING;
      inclk0_input_frequency : natural;
--              intended_device_family          : STRING;
--              lpm_hint                : STRING;
--              lpm_type                : STRING;
      operation_mode         : string;
      port_inclk0            : string;
      port_clk0              : string
      );
    port (
      clk   : out std_logic_vector (5 downto 0);
      inclk : in  std_logic_vector (1 downto 0)
      );
  end component;

  signal pll_inclk : std_logic_vector(1 downto 0);
  signal pll_outclk : std_logic_vector(5 downto 0);

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  signal clk,rst_n : std_ulogic;
  signal cnt : unsigned(13 downto 0);
  signal phase_inc : unsigned(9 downto 0);
  signal dac_a_reg, dac_a_next, dac_b_reg : unsigned(13 downto 0);
  
begin

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  pll_i0 : altpll
    generic map (
      clk0_divide_by         => 1,
      clk0_duty_cycle        => 50,
      clk0_multiply_by       => 2,
--              clk0_phase_shift => "0",
--              compensate_clock => "CLK0",
      inclk0_input_frequency => 20000,
      operation_mode         => "NORMAL",
      port_inclk0            => "PORT_USED",
      port_clk0              => "PORT_USED"
      )
    port map (
      inclk => pll_inclk,
      clk   => pll_outclk
      );

  pll_inclk(0) <= CLOCK_50;
  pll_inclk(1) <= '0';

  clk <= pll_outclk(0);
  rst_n <= '0' when KEY0 = '0' else '1' when rising_edge (clk);
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  LEDR <= SW;
  
  DAC_MODE  <= '1'; --dual port
  DAC_CLK_A <= clk;
  DAC_CLK_B <= clk;
  DAC_WRT_A <= clk;
  DAC_WRT_B <= clk;

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  phase_inc <= unsigned(SW(9 downto 1) & '0');
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  cnt <= (others => '0') when rst_n = '0' else cnt+phase_inc when rising_edge(clk);

  dac_a_next <= (others => '1') when cnt = 0 else (others => '0');
  dac_a_reg <= (others => '0') when rst_n = '0' else dac_a_next when falling_edge(clk);
  dac_b_reg <= (others => '0') when rst_n = '0' else cnt when falling_edge(clk); 
  DAC_DA <= std_ulogic_vector(dac_a_reg);
  DAC_DB <= std_ulogic_vector(dac_b_reg);

  -- ADC Section - switch off everything
  ADC_CLK_A <= '0';
  ADC_CLK_B <= '0';
  ADC_OEB_A <= '1';
  ADC_OEB_B <= '1';
  POWER_ON  <= '1';

end architecture rtl;