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------------------------------------------------------------------------------- -- -- Interface Timing Checker. -- -- $Id: if_timing.vhd,v 1.4 2004-10-25 19:33:13 arniml Exp $ -- -- Copyright (c) 2004, Arnim Laeuger (arniml@opencores.org) -- -- All rights reserved -- -- Redistribution and use in source and synthezised forms, with or without -- modification, are permitted provided that the following conditions are met: -- -- Redistributions of source code must retain the above copyright notice, -- this list of conditions and the following disclaimer. -- -- Redistributions in synthesized form must reproduce the above copyright -- notice, this list of conditions and the following disclaimer in the -- documentation and/or other materials provided with the distribution. -- -- Neither the name of the author nor the names of other contributors may -- be used to endorse or promote products derived from this software without -- specific prior written permission. -- -- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" -- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, -- THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR -- PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE -- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR -- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF -- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS -- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN -- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) -- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -- POSSIBILITY OF SUCH DAMAGE. -- -- Please report bugs to the author, but before you do so, please -- make sure that this is not a derivative work and that -- you have the latest version of this file. -- -- The latest version of this file can be found at: -- http://www.opencores.org/cvsweb.shtml/t48/ -- ------------------------------------------------------------------------------- library ieee; use ieee.std_logic_1164.all; entity if_timing is port ( xtal_i : in std_logic; ale_i : in std_logic; psen_n_i : in std_logic; rd_n_i : in std_logic; wr_n_i : in std_logic; prog_n_i : in std_logic; db_bus_i : in std_logic_vector(7 downto 0); p2_i : in std_logic_vector(7 downto 0) ); end if_timing; architecture behav of if_timing is signal last_xtal_rise_s : time; signal period_s : time; signal last_ale_rise_s, last_ale_fall_s : time; signal last_psen_n_rise_s, last_psen_n_fall_s : time; signal last_rd_n_rise_s, last_rd_n_fall_s : time; signal last_wr_n_rise_s, last_wr_n_fall_s : time; signal last_prog_n_rise_s, last_prog_n_fall_s : time; signal last_bus_change_s, bus_change_ale_s : time; signal last_p2_change_s : time; signal t_CY : time; begin t_CY <= 15 * period_s; ----------------------------------------------------------------------------- -- Check RD -- rd_check: process (rd_n_i) begin case rd_n_i is -- RD active when '0' => -- tLAFC1: ALE to Control RD assert (now - last_ale_fall_s) > (t_CY / 5 - 75 ns) report "Timing violation of tLAFC1 on RD!" severity error; -- tAFC1: Addr Float to RD assert (now - last_bus_change_s) > (t_CY * 2/15 - 40 ns) report "Timing violation of tAFC1 on RD!" severity error; -- RD inactive when '1' => -- tCC1: Control Pulse Width RD assert (now - last_rd_n_fall_s) > (t_CY / 2 - 200 ns) report "Timing violation of tCC1 on RD!" severity error; when others => null; end case; end process rd_check; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Check WR -- wr_check: process (wr_n_i) begin case wr_n_i is -- WR active when '0' => -- tLAFC1: ALE to Control WR assert (now - last_ale_fall_s) > (t_CY / 5 - 75 ns) report "Timing violation of tLAFC1 on WR!" severity error; -- tAW: Addr Setup to WR assert (now - bus_change_ale_s) > (t_CY / 3 - 150 ns) report "Timing violation of tAW on WR!" severity error; -- WR inactive when '1' => -- tCC1: Control Pulse Width WR assert (now - last_wr_n_fall_s) > (t_CY / 2 - 200 ns) report "Timing violation of tCC1 on WR!" severity error; -- tDW: Data Setup before WR assert (now - last_bus_change_s) > (t_CY * 13/30 - 200 ns) report "Timing violation of tDW on WR!" severity error; when others => null; end case; end process wr_check; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Check BUS -- bus_check: process (db_bus_i) begin -- RD access -- tAD1 and tRD1 are not checked as they are constraints for the -- external memory, not the t48! -- WR access if wr_n_i = '0' then -- tDW: Data Hold after WR assert (now - last_wr_n_rise_s) > (t_CY / 15 - 50 ns) report "Timing violation of tDW on BUS vs. WR!" severity error; end if; -- Address strobe if ale_i = '0' then -- tLA: Addr Hold from ALE assert (now - last_ale_fall_s) > (t_CY / 15 - 40 ns) report "Timing violation of tLA on BUS vs. ALE!" severity error; end if; -- PSEN if psen_n_i = '0' then -- tRD2: PSEN to Data In assert (now - last_psen_n_fall_s) < (t_CY * 4/15 - 170 ns) report "Timing violation of tRD2 on BUS vs. PSEN!" severity error; end if; end process bus_check; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Check ALE -- ale_check: process (ale_i) variable t_CA1 : time; variable t_AL : time; begin case ale_i is when '0' => t_AL := t_CY * 2/15 - 110 ns; -- tAL: Addr Setup to ALE assert (now - last_bus_change_s) > t_AL report "Timing violation of tAL on BUS vs. ALE!" severity error; assert (now - last_p2_change_s) > t_AL report "Timing violation of tAL on P2 vs. ALE!" severity error; when '1' => -- tCA1: Control to ALE (RD, WR, PROG) t_CA1 := t_CY / 15 - 40 ns; assert (now - last_rd_n_rise_s) > t_CA1 report "Timing violation of tCA1 on RD vs. ALE!" severity error; assert (now - last_wr_n_rise_s) > t_CA1 report "Timing violation of tCA1 on WR vs. ALE!" severity error; assert (now - last_prog_n_rise_s) > t_CA1 report "Timing violation of tCA1 on PROG vs. ALE!" severity error; -- tCA2: Control to ALE (PSEN) assert (now - last_psen_n_rise_s) > (t_CY * 4/15 - 40 ns) report "Timing violation of tCA2 on PSEN vs. ALE!" severity error; -- tPL: Port 2 I/O Setup to ALE assert (now - last_p2_change_s) > (t_CY * 4/15 - 200 ns) report "Timing violation of tPL on P2 vs. ALE!" severity error; when others => null; end case; end process ale_check; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Check P2 -- p2_check: process (p2_i) begin case ale_i is when '0' => -- tLA: Addr Hold from ALE assert ((now - last_ale_fall_s) > (t_CY / 15 - 40 ns)) or now = 0 ns report "Timing violation of tLA on P2 vs. ALE!" severity error; if last_ale_fall_s < last_ale_rise_s then -- tPV: Port Output from ALE assert (now - last_ale_fall_s) < (t_CY * 3/10 + 100 ns) report "Timing violation of tPV on P2 vs. ALE!" severity error; end if; if prog_n_i = '1' then -- tPD: Output Data Hold assert ((now - last_prog_n_rise_s) > (t_CY / 10 - 50 ns)) or now = 0 ns report "Timing violation of tPD on P2 vs. PROG!" severity error; end if; when '1' => -- tLP: Port 2 I/O to ALE assert (now - last_ale_rise_s) > (t_CY / 30 - 30 ns) report "Timing violation of tLP on P2 vs. ALE!" severity error; when others => null; end case; end process p2_check; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Check PROG -- prog_check: process (prog_n_i) begin case prog_n_i is when '1' => -- tPP: PROG Pulse Width assert (now - last_prog_n_fall_s) > (t_CY * 7/10 - 250 ns) report "Timing violation of tPP!" severity error; -- tDP: Output Data Setup assert (now - last_p2_change_s) > (t_CY * 2/5 - 150 ns) report "Timing violation of tDP on P2 vs. PROG!" severity error; when others => null; end case; end process prog_check; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Check PSEN -- psen_check: process (psen_n_i) begin case psen_n_i is when '1' => -- tCC2: Control Pulse Width PSEN assert (now - last_psen_n_fall_s) > (t_CY * 2/5 - 200 ns) report "Timing violation of tCC2 on PSEN!" severity error; when '0' => -- tLAFC2: ALE to Control PSEN assert (now - last_ale_fall_s) > (t_CY / 10 - 75 ns) report "Timing violation of tLAFC2 on PSEN vs. ALE!" severity error; when others => null; end case; end process psen_check; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Check cycle overlap -- cycle_overlap_check: process (psen_n_i, rd_n_i, wr_n_i) variable tmp_v : std_logic_vector(2 downto 0); begin tmp_v := psen_n_i & rd_n_i & wr_n_i; case tmp_v is when "001" | "010" | "100" | "000" => assert false report "Cycle overlap deteced on PSEN, RD and WR!" severity error; end case; end process cycle_overlap_check; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Monitor XTAL -- xtal_mon: process begin last_xtal_rise_s <= 0 ns; period_s <= 90 ns; while true loop wait on xtal_i; if xtal_i = '1' then period_s <= now - last_xtal_rise_s; last_xtal_rise_s <= now; end if; end loop; end process xtal_mon; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Monitor ALE -- ale_mon: process begin last_ale_rise_s <= 0 ns; last_ale_fall_s <= 0 ns; while true loop wait on ale_i; case ale_i is when '0' => last_ale_fall_s <= now; when '1' => last_ale_rise_s <= now; when others => null; end case; end loop; end process ale_mon; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Monitor PSEN -- psen_mon: process begin last_psen_n_rise_s <= 0 ns; last_psen_n_fall_s <= 0 ns; while true loop wait on psen_n_i; case psen_n_i is when '0' => last_psen_n_fall_s <= now; when '1' => last_psen_n_rise_s <= now; when others => null; end case; end loop; end process psen_mon; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Monitor RD -- rd_mon: process begin last_rd_n_rise_s <= 0 ns; last_rd_n_fall_s <= 0 ns; while true loop wait on rd_n_i; case rd_n_i is when '0' => last_rd_n_fall_s <= now; when '1' => last_rd_n_rise_s <= now; when others => null; end case; end loop; end process rd_mon; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Monitor WR -- wr_mon: process begin last_wr_n_rise_s <= 0 ns; last_wr_n_fall_s <= 0 ns; while true loop wait on wr_n_i; case wr_n_i is when '0' => last_wr_n_fall_s <= now; when '1' => last_wr_n_rise_s <= now; when others => null; end case; end loop; end process wr_mon; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Monitor PROG -- prog_mon: process begin last_prog_n_rise_s <= 0 ns; last_prog_n_fall_s <= 0 ns; while true loop wait on prog_n_i; case prog_n_i is when '0' => last_prog_n_fall_s <= now; when '1' => last_prog_n_rise_s <= now; when others => null; end case; end loop; end process prog_mon; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Monitor BUS -- bus_mon: process begin last_bus_change_s <= 0 ns; bus_change_ale_s <= 0 ns; while true loop wait on db_bus_i; last_bus_change_s <= now; if ale_i = '1' then bus_change_ale_s <= now; end if; end loop; end process bus_mon; -- ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- -- Monitor P2 -- p2_mon: process begin last_p2_change_s <= 0 ns; while true loop wait on p2_i; last_p2_change_s <= now; end loop; end process p2_mon; -- ----------------------------------------------------------------------------- end behav; ------------------------------------------------------------------------------- -- File History: -- -- $Log: not supported by cvs2svn $ -- Revision 1.3 2004/09/12 00:31:50 arniml -- add checks for PSEN -- -- Revision 1.2 2004/04/25 20:40:58 arniml -- check expander timings -- -- Revision 1.1 2004/04/25 16:24:10 arniml -- initial check-in -- -------------------------------------------------------------------------------
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