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[/] [epc_rfid_transponder/] [trunk/] [InvSelFlags.vhd] - Blame information for rev 2

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1 2 erwing 
-------------------------------------------------------------------------------
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--     Politecnico di Torino
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--     Dipartimento di Automatica e Informatica
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-------------------------------------------------------------------------------
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-------------------------------------------------------------------------------
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--
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--     Title          : EPC Class1 Gen2 RFID Tag - Inventoried and Selected Flags Model
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--
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--     File name      : InvSelFlags.vhd
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--
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--     Description    : Simulation model of Inventoried and Selected Flags. It
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--                      includes persistence time as described in the EPC
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--                      standard v. 1.09.
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--
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--     Authors        : Erwing R. Sanchez <erwing.sanchezsanchez@polito.it>
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--
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--     Rev. History   : 29 June 06
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--
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-------------------------------------------------------------------------------
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-------------------------------------------------------------------------------
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library IEEE;
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use IEEE.STD_LOGIC_1164.all;
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use IEEE.std_logic_unsigned.all;
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entity InvSelFlag is
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  port (
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    S1i : in  std_logic;
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    S2i : in  std_logic;
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    S3i : in  std_logic;
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    SLi : in  std_logic;
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    S1o : out std_logic;
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    S2o : out std_logic;
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    S3o : out std_logic;
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    SLo : out std_logic);
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end InvSelFlag;
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architecture Flags1 of InvSelFlag is
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-- synopsys synthesis_off
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  constant S1INV_PERSISTENCE_TIME : time := 500 ms;
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  constant S2INV_PERSISTENCE_TIME : time := 2 sec;
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  constant S3INV_PERSISTENCE_TIME : time := 2 sec;
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  constant SL_PERSISTENCE_TIME    : time := 2 sec;
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  constant TM_STEP          : time      := 10 ns;
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  signal   S1_time_cnt      : time      := 1 ns;
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  signal   S2_time_cnt      : time      := 1 ns;
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  signal   S3_time_cnt      : time      := 1 ns;
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  signal   SL_time_cnt      : time      := 1 ns;
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  signal   S1_time_cnt_flag : std_logic := '0';
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  signal   S2_time_cnt_flag : std_logic := '0';
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  signal   S3_time_cnt_flag : std_logic := '0';
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  signal   SL_time_cnt_flag : std_logic := '0';
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  -- synopsys synthesis_on
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begin  -- Flags1
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-- synopsys synthesis_off
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  S1FLAG : process (S1_time_cnt_flag, S1i)
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  begin  -- process S1FLAG
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    if S1i'event and (S1i = '0' or S1i = '1') then
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      S1o         <= S1i;
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      S1_time_cnt <= 0 ns after TM_STEP;
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    elsif S1_time_cnt_flag'event then
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      if S1_time_cnt = S1INV_PERSISTENCE_TIME then
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        S1o         <= 'X';
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        S1_time_cnt <= 0 ns after TM_STEP;
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      else
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        S1_time_cnt <= S1_time_cnt + TM_STEP after TM_STEP;
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      end if;
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    end if;
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  end process S1FLAG;
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  S1FLAG_flag : process (S1_time_cnt)
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  begin  -- process S1FLAG_MIRROR
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    S1_time_cnt_flag <= not S1_time_cnt_flag;
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  end process S1FLAG_flag;
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  S2FLAG : process (S2_time_cnt_flag, S2i)
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  begin  -- process S2FLAG
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    if S2i'event and (S2i = '0' or S2i = '1') then
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      S2o         <= S2i;
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      S2_time_cnt <= 0 ns after TM_STEP;
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    elsif S2_time_cnt_flag'event then
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      if S2_time_cnt = S2INV_PERSISTENCE_TIME then
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        S2o         <= 'X';
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        S2_time_cnt <= 0 ns after TM_STEP;
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      else
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        S2_time_cnt <= S2_time_cnt + TM_STEP after TM_STEP;
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      end if;
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    end if;
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  end process S2FLAG;
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  S2FLAG_flag : process (S2_time_cnt)
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  begin  -- process S2FLAG_MIRROR
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    S2_time_cnt_flag <= not S2_time_cnt_flag;
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  end process S2FLAG_flag;
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  S3FLAG : process (S3_time_cnt_flag, S3i)
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  begin  -- process S3FLAG
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    if S3i'event and (S3i = '0' or S3i = '1') then
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      S3o         <= S3i;
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      S3_time_cnt <= 0 ns after TM_STEP;
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    elsif S3_time_cnt_flag'event then
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      if S3_time_cnt = S3INV_PERSISTENCE_TIME then
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        S3o         <= 'X';
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        S3_time_cnt <= 0 ns after TM_STEP;
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      else
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        S3_time_cnt <= S3_time_cnt + TM_STEP after TM_STEP;
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      end if;
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    end if;
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  end process S3FLAG;
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  S3FLAG_flag : process (S3_time_cnt)
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  begin  -- process S3FLAG_MIRROR
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    S3_time_cnt_flag <= not S3_time_cnt_flag;
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  end process S3FLAG_flag;
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  SLFLAG : process (SL_time_cnt_flag, SLi)
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  begin  -- process SLFLAG
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    if SLi'event and (SLi = '0' or SLi = '1') then
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      SLo         <= SLi;
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      SL_time_cnt <= 0 ns after TM_STEP;
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    elsif SL_time_cnt_flag'event then
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      if SL_time_cnt = SL_PERSISTENCE_TIME then
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        SLo         <= 'X';
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        SL_time_cnt <= 0 ns after TM_STEP;
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      else
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        SL_time_cnt <= SL_time_cnt + TM_STEP after TM_STEP;
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      end if;
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    end if;
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  end process SLFLAG;
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  SLFLAG_flag : process (SL_time_cnt)
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  begin  -- process SLFLAG_MIRROR
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    SL_time_cnt_flag <= not SL_time_cnt_flag;
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  end process SLFLAG_flag;
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-- synopsys synthesis_on
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end Flags1;

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