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--! @file

--! @brief Test serial_receiver module module

--! Use standard library and import the packages (std_logic_1164,std_logic_unsigned,std_logic_arith)

LIBRARY ieee;

USE ieee.std_logic_1164.ALL;

--! Use CPU Definitions package

use work.pkgDefinitions.all;

ENTITY testSerial_receiver IS

END testSerial_receiver;

--! @brief Test serial_receiver module module

--! @details Receive some simulated byte stream and verify received values

ARCHITECTURE behavior OF testSerial_receiver IS

    -- Component Declaration for the Unit Under Test (UUT)

    COMPONENT serial_receiver

   Port (

                          rst : in STD_LOGIC;                                                                                                   --! Reset input           

                          baudOverSampleClk : in  STD_LOGIC;                                                            --! Baud oversampled 8x (Best way to detect start bit)

           serial_in : in  STD_LOGIC;                                                                                   --! Uart serial input

           data_ready : out  STD_LOGIC;                                                                         --! Data received and ready to be read

           data_byte : out  STD_LOGIC_VECTOR ((nBits-1) downto 0));      --! Data byte received

    END COMPONENT;

   --Inputs

   signal rst : std_logic := '0';                                        --! Signal to connect with UUT

   signal baudClk : std_logic := '0';                            --! Signal to connect with UUT

   signal baudOverSampleClk : std_logic := '0';  --! Signal to connect with UUT

   signal serial_in : std_logic := '0';                  --! Signal to connect with UUT

        --Outputs

   signal data_ready : std_logic;                                                                       --! Signal to connect with UUT

   signal data_byte : std_logic_vector((nBits-1) downto 0);      --! Signal to connect with UUT

   -- Clock period definitions

   constant baudClk_period : time := 8.6805 us;

   constant baudOverSampleClk_period : time :=1.085 us;

BEGIN

        --! Instantiate the Unit Under Test (UUT)

   uut: serial_receiver PORT MAP (

          rst => rst,

          baudOverSampleClk => baudOverSampleClk,

          serial_in => serial_in,

          data_ready => data_ready,

          data_byte => data_byte

        );

   -- Clock process definitions

   baudClk_process :process

   begin

                baudClk <= '0';

                wait for baudClk_period/2;

                baudClk <= '1';

                wait for baudClk_period/2;

   end process;

   baudOverSampleClk_process :process

   begin

                baudOverSampleClk <= '0';

                wait for baudOverSampleClk_period/2;

                baudOverSampleClk <= '1';

                wait for baudOverSampleClk_period/2;

   end process;

   -- Stimulus process

   stim_proc: process

   begin

      rst <= '1';

                serial_in <= '1';       -- Idle

      wait for 3 us;

                rst <= '0';

                wait for baudClk_period * 3;

                -- Receive 0xC4 value (11000100)

                -- Start bit here

                serial_in <= '0';

                wait for baudClk_period;

                serial_in <= '0';

      wait for baudClk_period;

                serial_in <= '0';

      wait for baudClk_period;

                serial_in <= '1';

      wait for baudClk_period;

                serial_in <= '0';

      wait for baudClk_period;

                serial_in <= '0';

      wait for baudClk_period;

                serial_in <= '0';

      wait for baudClk_period;

                serial_in <= '1';

      wait for baudClk_period;

                serial_in <= '1';

      wait for baudClk_period;

                -- Stop bit here

                serial_in <= '1';

                ---wait until data_ready = '1';

                assert data_byte = X"C4" report "Wrong result... expected 0xC4" severity failure;

                wait for baudClk_period * 8;

                -- Receive 0x55 value (01010101)

                -- Start bit here

                serial_in <= '0';

                wait for baudClk_period;

                serial_in <= '1';

      wait for baudClk_period;

                serial_in <= '0';

      wait for baudClk_period;

                serial_in <= '1';

      wait for baudClk_period;

                serial_in <= '0';

      wait for baudClk_period;

                serial_in <= '1';

      wait for baudClk_period;

                serial_in <= '0';

      wait for baudClk_period;

                serial_in <= '1';

      wait for baudClk_period;

                serial_in <= '0';

      wait for baudClk_period;

                -- Stop bit here

                serial_in <= '1';

                wait for baudClk_period * 1;

                ---wait until data_ready = '1';

                assert data_byte = X"55" report "Wrong result... expected 0x55" severity failure;

      -- Stop Simulation

                assert false report "NONE. End of simulation." severity failure;

      wait;

   end process;

END;