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-- Copyright (C) 2002 Morgan Kaufmann Publishers, Inc
-- This file is part of VESTs (Vhdl tESTs).
-- VESTs is free software; you can redistribute it and/or modify it
-- under the terms of the GNU General Public License as published by the
-- Free Software Foundation; either version 2 of the License, or (at
-- your option) any later version.
-- VESTs is distributed in the hope that it will be useful, but WITHOUT
-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-- FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
-- for more details.
-- You should have received a copy of the GNU General Public License
-- along with VESTs; if not, write to the Free Software Foundation,
-- Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
entity bus_monitor is
end entity bus_monitor;
architecture test of bus_monitor is
subtype byte is bit_vector(7 downto 0);
type byte_array is array (natural range <>) of byte;
function resolve_bytes ( drivers : in byte_array ) return byte is
begin
return drivers(drivers'left);
end function resolve_bytes;
function resolve_bits ( drivers : in bit_vector ) return bit is
begin
return drivers(drivers'left);
end function resolve_bits;
-- code from book (in text)
signal address : bit_vector(15 downto 0);
signal data : resolve_bytes byte;
signal rd, wr, io : bit; -- read, write, io/mem select
signal ready : resolve_bits bit;
-- end code from book
begin
-- code from book
bus_monitor : process is
constant header : string(1 to 44)
:= FF & " Time R/W I/M Address Data";
use std.textio.all;
file log : text open write_mode is "buslog";
variable trace_line : line;
variable line_count : natural := 0;
begin
if line_count mod 60 = 0 then
write ( trace_line, header );
writeline ( log, trace_line );
writeline ( log, trace_line ); -- empty line
end if;
wait until (rd = '1' or wr = '1') and ready = '1';
write ( trace_line, now, justified => right, field => 10, unit => us );
write ( trace_line, string'(" ") );
if rd = '1' then
write ( trace_line, 'R' );
else
write ( trace_line, 'W' );
end if;
write ( trace_line, string'(" ") );
if io = '1' then
write ( trace_line, 'I' );
else
write ( trace_line, 'M' );
end if;
write ( trace_line, string'(" ") );
write ( trace_line, address );
write ( trace_line, ' ');
write ( trace_line, data );
writeline ( log, trace_line );
line_count := line_count + 1;
end process bus_monitor;
-- end code from book
stimulus : process is
begin
wait for 0.4 us - now;
rd <= '1', '0' after 10 ns;
address <= X"0000";
data <= B"10011110";
ready <= '1', '0' after 10 ns;
wait for 0.9 us - now;
rd <= '1', '0' after 10 ns;
address <= X"0001";
data <= B"00010010";
ready <= '1', '0' after 10 ns;
wait for 2.0 us - now;
rd <= '1', '0' after 10 ns;
address <= X"0014";
data <= B"11100111";
ready <= '1', '0' after 10 ns;
wait for 2.7 us - now;
wr <= '1', '0' after 10 ns;
io <= '1', '0' after 10 ns;
address <= X"0007";
data <= X"00";
ready <= '1', '0' after 10 ns;
wait;
end process stimulus;
end architecture test;
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