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Altera_Forum's avatar
Altera_Forum
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16 years ago

lpm_decode output

I am trying to use the lpm_decode ip core to generate a 7 input to 128 output decoder but it keeps generating 128 individual outputs eq0 - eq128. How do I get it to generate a single 128 bit wide eq signal as indicated by the documentation. Any assitance would be greatly appreciated.

Thanks,

Steve

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    The lpm_decode MegaFunction has a std_logic_vector output, but the MegaWizard is generating individual outputs in the instantiation. If you you want std_logic_vector, you should instantiate the MegaFunction directly in your code. 

    LIBRARY lpm;
USE lpm.all;
-- ....
COMPONENT lpm_decode
GENERIC (
  lpm_decodes : NATURAL;
  lpm_type       : STRING;
  lpm_width     : NATURAL
);
PORT (
  eq   : OUT STD_LOGIC_VECTOR (lpm_decodes-1 DOWNTO 0);
  data : IN STD_LOGIC_VECTOR (3 DOWNTO 0)
);
END COMPONENT;
-- ..
lpm_decode_component : lpm_decode
  GENERIC MAP (
  lpm_decodes => 128,
  lpm_type => "LPM_DECODE",
  lpm_width => 7
)
PORT MAP (
  data => your_inputdata,
  eq => your_decodeddata
);