Subversion Repositories simple_uart_for_fpga

--------------------------------------------------------------------------------
-- PROJECT: SIMPLE UART FOR FPGA
--------------------------------------------------------------------------------
-- MODULE:  TESTBANCH OF UART LOOPBACK EXAMPLE TOP MODULE
-- AUTHORS: Jakub Cabal <jakubcabal@gmail.com>
-- lICENSE: The MIT License (MIT)
-- WEBSITE: https://github.com/jakubcabal/uart_for_fpga
--------------------------------------------------------------------------------
 
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.NUMERIC_STD.ALL;
 
entity UART_LOOPBACK_TB is
end UART_LOOPBACK_TB;
 
architecture FULL of UART_LOOPBACK_TB is
 
	signal CLK           : std_logic := '0';
	signal RST_N         : std_logic := '0';
	signal tx_uart       : std_logic;
	signal rx_uart       : std_logic := '1';
    signal busy          : std_logic;
    signal frame_error   : std_logic;
 
  	constant clk_period  : time := 20 ns;
	constant uart_period : time := 8680.56 ns;
	constant data_value  : std_logic_vector(7 downto 0) := "10100111";
	constant data_value2 : std_logic_vector(7 downto 0) := "00110110";
 
begin
 
	utt: entity work.UART_LOOPBACK
    generic map (
        CLK_FREQ    => 50e6,
        BAUD_RATE   => 115200,
        PARITY_BIT  => "none"
    )
    port map (
        CLK         => CLK,
        RST_N       => RST_N,
        -- UART INTERFACE
        UART_TXD    => tx_uart,
        UART_RXD    => rx_uart,
        -- DEBUG INTERFACE
        BUSY        => busy,
        FRAME_ERR   => frame_error
    );
 
	clk_process : process
	begin
		CLK <= '0';
		wait for clk_period/2;
		CLK <= '1';
		wait for clk_period/2;
	end process;
 
	test_rx_uart : process
	begin
		rx_uart <= '1';
		RST_N <= '0';
		wait for 100 ns;
    	RST_N <= '1';
 
		wait for uart_period;
 
		rx_uart <= '0'; -- start bit
		wait for uart_period;
 
		for i in 0 to (data_value'LENGTH-1) loop
		    rx_uart <= data_value(i); -- data bits
		    wait for uart_period;
		end loop;
 
		rx_uart <= '1'; -- stop bit
		wait for uart_period;
 
		rx_uart <= '0'; -- start bit
		wait for uart_period;
 
		for i in 0 to (data_value2'LENGTH-1) loop
  			rx_uart <= data_value2(i); -- data bits
        	wait for uart_period;
		end loop;
 
		rx_uart <= '1'; -- stop bit
		wait for uart_period;
 
		rx_uart <= '0'; -- start bit
		wait for uart_period;
 
		for i in 0 to (data_value'LENGTH-1) loop
			rx_uart <= data_value(i); -- data bits
			wait for uart_period;
		end loop;
 
		rx_uart <= '1'; -- stop bit
		wait for uart_period;
 
		rx_uart <= '0'; -- start bit
		wait for uart_period;
 
		for i in 0 to (data_value2'LENGTH-1) loop
			rx_uart <= data_value2(i); -- data bits
			wait for uart_period;
		end loop;
 
		rx_uart <= '1'; -- stop bit
		wait for uart_period;
 
		wait;
 
	end process;
 
end FULL;