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[/] [ccsds_rxtxsoc/] [trunk/] [ccsds_tx_mapper_bits_symbols.vhd] - Blame information for rev 2

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1 2 zguig52 
-------------------------------
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---- Project: EurySPACE CCSDS RX/TX with wishbone interface
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---- Design Name: ccsds_tx_mapper_bits_symbols
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---- Version: 1.0.0
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---- Description:
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---- Map input bits to complex I&Q symbols depending on modulation type
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-------------------------------
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---- Author(s):
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---- Guillaume REMBERT
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-------------------------------
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---- Licence:
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---- MIT
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-------------------------------
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---- Changes list:
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---- 2016/11/05: initial release
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-------------------------------
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-- libraries used
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library ieee;
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use ieee.std_logic_1164.all;
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--=============================================================================
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-- Entity declaration for ccsds_tx / unitary tx bits to symbols mapper inputs and outputs
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--=============================================================================
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entity ccsds_tx_mapper_bits_symbols is
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  generic(
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    constant CCSDS_TX_MAPPER_BITS_PER_SYMBOL: integer := 1; -- For QAM - 1 bit/symbol <=> QPSK/4-QAM - 2 bits/symbol <=> 16-QAM - 3 bits/symbol <=> 64-QAM - ... - N bits/symbol <=> 2^(N*2)-QAM
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    constant CCSDS_TX_MAPPER_GRAY_CODER: std_logic := '1'; -- Gray coder activation
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    constant CCSDS_TX_MAPPER_MODULATION_TYPE: integer := 1; -- 1=QPSK/QAM - 2=BPSK
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    constant CCSDS_TX_MAPPER_DATA_BUS_SIZE: integer -- in bits
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  );
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  port(
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    -- inputs
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    clk_i: in std_logic;
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    dat_i: in std_logic_vector(CCSDS_TX_MAPPER_DATA_BUS_SIZE-1 downto 0);
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    dat_val_i: in std_logic;
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    rst_i: in std_logic;
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    -- outputs
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    sym_val_o: out std_logic;
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    sym_i_o: out std_logic_vector(CCSDS_TX_MAPPER_BITS_PER_SYMBOL-1 downto 0);
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    sym_q_o: out std_logic_vector(CCSDS_TX_MAPPER_BITS_PER_SYMBOL-1 downto 0)
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  );
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end ccsds_tx_mapper_bits_symbols;
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--=============================================================================
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-- architecture declaration / internal components and connections
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--=============================================================================
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architecture rtl of ccsds_tx_mapper_bits_symbols is
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-- internal constants
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  constant MAPPER_SYMBOL_NUMBER_PER_CHANNEL: integer := CCSDS_TX_MAPPER_DATA_BUS_SIZE*CCSDS_TX_MAPPER_MODULATION_TYPE/(2*CCSDS_TX_MAPPER_BITS_PER_SYMBOL);
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-- internal variable signals
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-- components instanciation and mapping
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  begin
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-- presynthesis checks
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     CHKMAPPERP0 : if (CCSDS_TX_MAPPER_DATA_BUS_SIZE mod (CCSDS_TX_MAPPER_BITS_PER_SYMBOL*2*CCSDS_TX_MAPPER_MODULATION_TYPE) /= 0) generate
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      process
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      begin
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        report "ERROR: DATA BUS SIZE HAS TO BE A MULTIPLE OF 2*BITS PER SYMBOLS (EXCEPT FOR BPSK MODULATION)" severity failure;
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              wait;
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      end process;
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    end generate CHKMAPPERP0;
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     CHKMAPPERP1: if (CCSDS_TX_MAPPER_BITS_PER_SYMBOL /= 1) and (CCSDS_TX_MAPPER_MODULATION_TYPE = 2) generate
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      process
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      begin
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        report "ERROR: BPSK MODULATION REQUIRES 1 BIT PER SYMBOL" severity failure;
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              wait;
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      end process;
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    end generate CHKMAPPERP1;
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     CHKMAPPERP2 : if (CCSDS_TX_MAPPER_MODULATION_TYPE /= 1) and (CCSDS_TX_MAPPER_MODULATION_TYPE /= 2) generate
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      process
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      begin
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        report "ERROR: UNKNOWN MODULATION TYPE - 1=QPSK/QAM / 2=BPSK" severity failure;
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              wait;
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      end process;
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    end generate CHKMAPPERP2;
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-- internal processing
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    --=============================================================================
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    -- Begin of mapperp
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    -- Map bits to symbols
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    --=============================================================================
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    -- read: rst_i, dat_i, dat_val_i
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    -- write: sym_i_o, sym_q_o, sym_val_o
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    -- r/w:
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    MAPPERP: process (clk_i)
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    variable symbol_counter: integer range 1 to MAPPER_SYMBOL_NUMBER_PER_CHANNEL := MAPPER_SYMBOL_NUMBER_PER_CHANNEL;
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    begin
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      -- on each clock rising edge
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      if rising_edge(clk_i) then
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        -- reset signal received
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        if (rst_i = '1') then
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          sym_i_o <= (others => '0');
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          sym_q_o <= (others => '0');
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          symbol_counter := MAPPER_SYMBOL_NUMBER_PER_CHANNEL;
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          sym_val_o <= '0';
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        else
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          if (dat_val_i = '1') then
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            sym_val_o <= '1';
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            -- BPSK mapping
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            if (CCSDS_TX_MAPPER_BITS_PER_SYMBOL = 1) and (CCSDS_TX_MAPPER_MODULATION_TYPE = 2) then
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              sym_q_o(0) <= '0';
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              sym_i_o(0) <= dat_i(symbol_counter-1);
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            -- QPSK/QAM mapping
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            else
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              sym_i_o <= dat_i(symbol_counter*CCSDS_TX_MAPPER_BITS_PER_SYMBOL*2-1 downto symbol_counter*2*CCSDS_TX_MAPPER_BITS_PER_SYMBOL-CCSDS_TX_MAPPER_BITS_PER_SYMBOL);
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              sym_q_o <= dat_i(symbol_counter*2*CCSDS_TX_MAPPER_BITS_PER_SYMBOL-CCSDS_TX_MAPPER_BITS_PER_SYMBOL-1 downto symbol_counter*2*CCSDS_TX_MAPPER_BITS_PER_SYMBOL-2*CCSDS_TX_MAPPER_BITS_PER_SYMBOL);
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            end if;
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            if (symbol_counter = 1) then
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              symbol_counter := MAPPER_SYMBOL_NUMBER_PER_CHANNEL;
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            else
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              symbol_counter := symbol_counter - 1;
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            end if;
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          else
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            sym_val_o <= '0';
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          end if;
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        end if;
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      end if;
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    end process;
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end rtl;

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