root_a.vhd

USBHostSlave is a USB 1.1 host and Device IP core. – Supports full speed (12Mbps) and low speed (1.

library ieee;
use ieee.std_logic_1164.all;

library work;
use work.usbpkg.all;

library std;
use std.textio.all;


architecture a of root is


  signal timer :boolean;
  signal wakeup :boolean;

  type boolvec is array (natural range <>) of boolean;


  procedure clrdata (variable s: inout string) is
  begin

    for i in s'range loop
      s(i) := NUL;
    end loop;

  end clrdata;

begin



 process (timer,dport)
    begin

      wakeup <= not wakeup;
      
    end process;

  process

    variable id: natural := 0;
    variable ll  : line;
    variable endpts: boolvec(0 to MAXENDPT-1);
    variable j :integer := 0;
    variable local_data:string(1 to 80);

    begin

      -- let things stabilize
      wait for 10 ns;

      for i in 1 to 31 loop
	-- look for end points
	-- send an 'OUT' packet
	dport.id <= POUT;
	dport.dest <= i;
	clrdata(local_data);
	dport.data <= local_data;
	wait for PTIME ;
	dport.id <= NONE;
	dport.dest <= i;
	wait for RTIME;
	timer <= not (timer) after 2*PTIME;  -- timer signal
	wait on wakeup;
	if (dport.id /= PACK) then
	  next;
	end if;
	write(ll,string'("Found Endpoint "));
	write(ll,i);
	write(ll,string'(", data is "));
	write(ll,dport.data);
	writeline(OUTPUT,ll);
	local_data := dport.data;
	endpts(i) := TRUE;
	-- wait until line is released
	wait on dport;
	-- now modify packet
	-- find end of string
	j := 1;
	while (local_data(j) /= NUL) loop
	  j := j + 1;
	end loop;
	j := j+1;
	local_data(j to j+4) := "FOUND";
	dport.data <= local_data;
	write(ll,string'("Modifying Endpoint"));
	writeline(OUTPUT,ll);
	dport.id <= PIN;
	dport.dest <= i;
	wait for PTIME ;
	dport.id <= NONE;
	dport.dest <= i;
	wait for RTIME;
	timer <= not (timer) after 2*PTIME;  -- timer signal
	wait on wakeup;
	if (dport.id /= PACK) then
	  write(ll,string'("Endpoint did not respond to PIN packet!!! Modify failed!"));
	  writeline(OUTPUT,ll);
	  next;
	end if;
	-- wait until line is released
	wait on dport;

	-- read data again
	dport.id <= POUT;
	dport.dest <= i;
	clrdata(local_data);
	dport.data <= local_data;
	wait for PTIME ;
	dport.id <= NONE;
	dport.dest <= i;
	wait for RTIME;
	timer <= not (timer) after 2*PTIME;  -- timer signal
	wait on wakeup;
	if (dport.id /= PACK) then
	  write(ll,string'("Endpoint did not respond to second POUT packet!!! Modify failed!"));
	  writeline(OUTPUT,ll);
	  next;
	end if;

	write(ll,string'("Modified Endpoint data: "));
	write(ll,dport.data);
	writeline(OUTPUT,ll);
	-- wait until line is released
	wait on dport;

      end loop;

      write(ll,string'("Finished Scan for Endpoints "));
      writeline(OUTPUT,ll);
      wait;

  
  end process;


end a;