Subversion Repositories spacewire_light

--

--  Test of spwstream on Digilent XC3S200 board.

--  60 MHz system clock, 200 MHz receive clock and transmit clock.

--

--  LED 0 = link started

--  LED 1 = link connecting

--  LED 2 = link run

--  LED 3 = link error (sticky until clear button)

--  LED 4 = gotdata

--  LED 5 = off

--  LED 6 = data error (sticky until reset)

--  LED 7 = time code error (sticky until reset)

--

--  Button 0 = reset

--  Button 1 = clear LED 3

--

--  Switch 0 = link autostart

--  Switch 1 = link start

--  Switch 2 = link disable

--  Switch 3 = send data and time codes

--  Switch 4-7 = bits 0-3 of tx bit rate scale factor

--

--  SpaceWire signals on A2 expansion connector:

--    Data In    pos,neg  =  B5,C5  =  pin 19,6

--    Strobe In  pos,neg  =  D6,E6  =  pin 7,4

--    Data Out   pos,neg  =  B6,C6  =  pin 21,8

--    Strobe Out pos,neg  =  D7,E7  =  pin 11,9

--

--  Note: these are not true LVDS signals; they are configured as LVDS25

--  but powered from 3.3V instead of 2.5V, not differentially routed and

--  not properly terminated.

--

--  The SpaceWire port should be looped back to itself with wires from

--  outputs to corresponding inputs.

--

library ieee;

use ieee.std_logic_1164.all, ieee.numeric_std.all;

library unisim;

use unisim.vcomponents.all;

use work.spwpkg.all;

entity streamtest_top is

    port (

        clk50:      in  std_logic;

        button:     in  std_logic_vector(3 downto 0);

        switch:     in  std_logic_vector(7 downto 0);

        led:        out std_logic_vector(7 downto 0);

        spw_di_p:   in  std_logic;

        spw_di_n:   in  std_logic;

        spw_si_p:   in  std_logic;

        spw_si_n:   in  std_logic;

        spw_do_p:   out std_logic;

        spw_do_n:   out std_logic;

        spw_so_p:   out std_logic;

        spw_so_n:   out std_logic );

end entity streamtest_top;

architecture streamtest_top_arch of streamtest_top is

    -- Clock generation.

    signal boardclk:        std_logic;

    signal sysclk:          std_logic;

    signal fastclk:         std_logic;

    -- Synchronize buttons

    signal s_resetbtn:      std_logic := '0';

    signal s_clearbtn:      std_logic := '0';

    -- Sticky LED

    signal s_linkerrorled:  std_logic := '0';

    -- Interface signals.

    signal s_rst:           std_logic := '1';

    signal s_linkstart:     std_logic := '0';

    signal s_autostart:     std_logic := '0';

    signal s_linkdisable:   std_logic := '0';

    signal s_senddata:      std_logic := '0';

    signal s_txdivcnt:      std_logic_vector(7 downto 0) := "00000000";

    signal s_linkstarted:   std_logic;

    signal s_linkconnecting: std_logic;

    signal s_linkrun:       std_logic;

    signal s_linkerror:     std_logic;

    signal s_gotdata:       std_logic;

    signal s_dataerror:     std_logic;

    signal s_tickerror:     std_logic;

    signal s_spwdi:         std_logic;

    signal s_spwsi:         std_logic;

    signal s_spwdo:         std_logic;

    signal s_spwso:         std_logic;

    -- Make clock nets visible to UCF file.

    attribute KEEP: string;

    attribute KEEP of sysclk: signal is "SOFT";

    attribute KEEP of fastclk: signal is "SOFT";

    component streamtest is

        generic (

            sysfreq:    real;

            txclkfreq:  real;

            tickdiv:    integer range 12 to 24 := 20;

            rximpl:     spw_implementation_type := impl_generic;

            rxchunk:    integer range 1 to 4 := 1;

            tximpl:     spw_implementation_type := impl_generic;

            rxfifosize_bits: integer range 6 to 14 := 11;

            txfifosize_bits: integer range 2 to 14 := 11 );

        port (

            clk:        in  std_logic;

            rxclk:      in  std_logic;

            txclk:      in  std_logic;

            rst:        in  std_logic;

            linkstart:  in  std_logic;

            autostart:  in  std_logic;

            linkdisable: in std_logic;

            senddata:   in  std_logic;

            sendtick:   in  std_logic;

            txdivcnt:   in  std_logic_vector(7 downto 0);

            linkstarted: out std_logic;

            linkconnecting: out std_logic;

            linkrun:    out std_logic;

            linkerror:  out std_logic;

            gotdata:    out std_logic;

            dataerror:  out std_logic;

            tickerror:  out std_logic;

            spw_di:     in  std_logic;

            spw_si:     in  std_logic;

            spw_do:     out std_logic;

            spw_so:     out std_logic );

    end component;

begin

    -- Buffer incoming clock.

    bufg0: BUFG port map ( I => clk50, O => boardclk );

    -- Generate 60 MHz system clock.

    dcm0: DCM

        generic map (

            CLKFX_DIVIDE        => 5,

            CLKFX_MULTIPLY      => 6,

            CLK_FEEDBACK      => "NONE",

            CLKIN_DIVIDE_BY_2   => false,

            CLKIN_PERIOD        => 20.0,

            CLKOUT_PHASE_SHIFT  => "NONE",

            DESKEW_ADJUST       => "SYSTEM_SYNCHRONOUS",

            DFS_FREQUENCY_MODE  => "LOW",

            DUTY_CYCLE_CORRECTION => true,

            STARTUP_WAIT        => true )

        port map (

            CLKIN       => boardclk,

            RST         => '0',

            CLKFX       => sysclk );

    -- Generate 200 MHz fast clock.

    dcm1: DCM

        generic map (

            CLKFX_DIVIDE        => 1,

            CLKFX_MULTIPLY      => 4,

            CLK_FEEDBACK        => "NONE",

            CLKIN_DIVIDE_BY_2   => false,

            CLKIN_PERIOD        => 20.0,

            CLKOUT_PHASE_SHIFT  => "NONE",

            DESKEW_ADJUST       => "SYSTEM_SYNCHRONOUS",

            DFS_FREQUENCY_MODE  => "LOW",

            DUTY_CYCLE_CORRECTION => true,

            STARTUP_WAIT        => true )

        port map (

            CLKIN       => boardclk,

            RST         => '0',

            CLKFX       => fastclk );

    -- Streamtest instance

    streamtest_inst: streamtest

        generic map (

            sysfreq     => 60.0e6,

            txclkfreq   => 200.0e6,

            tickdiv     => 22,

            rximpl      => impl_fast,

            rxchunk     => 4,

            tximpl      => impl_fast,

            rxfifosize_bits => 11,

            txfifosize_bits => 10 )

        port map (

            clk         => sysclk,

            rxclk       => fastclk,

            txclk       => fastclk,

            rst         => s_rst,

            linkstart   => s_linkstart,

            autostart   => s_autostart,

            linkdisable => s_linkdisable,

            senddata    => s_senddata,

            sendtick    => s_senddata,

            txdivcnt    => s_txdivcnt,

            linkstarted => s_linkstarted,

            linkconnecting => s_linkconnecting,

            linkrun     => s_linkrun,

            linkerror   => s_linkerror,

            gotdata     => s_gotdata,

            dataerror   => s_dataerror,

            tickerror   => s_tickerror,

            spw_di      => s_spwdi,

            spw_si      => s_spwsi,

            spw_do      => s_spwdo,

            spw_so      => s_spwso );

    -- LVDS buffers

    spwdi_pad: IBUFDS

        generic map ( IOSTANDARD => "LVDS_25" )

        port map ( O => s_spwdi, I => spw_di_p, IB => spw_di_n );

    spwsi_pad: IBUFDS

        generic map ( IOSTANDARD => "LVDS_25" )

        port map ( O => s_spwsi, I => spw_si_p, IB => spw_si_n );

    spwdo_pad: OBUFDS

        generic map ( IOSTANDARD => "LVDS_25" )

        port map ( O => spw_do_p, OB => spw_do_n, I => s_spwdo );

    spwso_pad: OBUFDS

        generic map ( IOSTANDARD => "LVDS_25" )

        port map ( O => spw_so_p, OB => spw_so_n, I => s_spwso );

    process (sysclk) is

    begin

        if rising_edge(sysclk) then

            -- Synchronize buttons

            s_resetbtn  <= button(0);

            s_rst       <= s_resetbtn;

            s_clearbtn  <= button(1);

            -- Synchronize switch settings

            s_autostart <= switch(0);

            s_linkstart <= switch(1);

            s_linkdisable <= switch(2);

            s_senddata  <= switch(3);

            s_txdivcnt(7 downto 4) <= "0000";

            s_txdivcnt(3 downto 0) <= switch(7 downto 4);

            -- Sticky link error LED

            s_linkerrorled <= (s_linkerrorled or s_linkerror) and

                              (not s_clearbtn) and

                              (not s_resetbtn);

            -- Drive LEDs

            led(0)  <= s_linkstarted;

            led(1)  <= s_linkconnecting;

            led(2)  <= s_linkrun;

            led(3)  <= s_linkerrorled;

            led(4)  <= s_gotdata;

            led(5)  <= '0';

            led(6)  <= s_dataerror;

            led(7)  <= s_tickerror;

        end if;

    end process;

end architecture streamtest_top_arch;