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//////////////////////////////////////////////////////////////////////

////                                                              ////

////  can_top.v                                                   ////

////                                                              ////

////                                                              ////

////  This file is part of the CAN Protocol Controller            ////

////  http://www.opencores.org/projects/can/                      ////

////                                                              ////

////                                                              ////

////  Author(s):                                                  ////

////       Igor Mohor                                             ////

////       igorm@opencores.org                                    ////

////                                                              ////

////                                                              ////

////  All additional information is available in the README.txt   ////

////  file.                                                       ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

////                                                              ////

//// Copyright (C) 2002, 2003 Authors                             ////

////                                                              ////

//// This source file may be used and distributed without         ////

//// restriction provided that this copyright statement is not    ////

//// removed from the file and that any derivative work contains  ////

//// the original copyright notice and the associated disclaimer. ////

////                                                              ////

//// This source file is free software; you can redistribute it   ////

//// and/or modify it under the terms of the GNU Lesser General   ////

//// Public License as published by the Free Software Foundation; ////

//// either version 2.1 of the License, or (at your option) any   ////

//// later version.                                               ////

////                                                              ////

//// This source 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 Lesser General Public License for more ////

//// details.                                                     ////

////                                                              ////

//// You should have received a copy of the GNU Lesser General    ////

//// Public License along with this source; if not, download it   ////

//// from http://www.opencores.org/lgpl.shtml                     ////

////                                                              ////

//// The CAN protocol is developed by Robert Bosch GmbH and       ////

//// protected by patents. Anybody who wants to implement this    ////

//// CAN IP core on silicon has to obtain a CAN protocol license  ////

//// from Bosch.                                                  ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

//

// CVS Revision History

//

// $Log: not supported by cvs2svn $

// Revision 1.30  2003/03/20 17:01:17  mohor

// unix.

//

// Revision 1.28  2003/03/14 19:36:48  mohor

// can_cs signal used for generation of the cs.

//

// Revision 1.27  2003/03/12 05:56:33  mohor

// Bidirectional port_0_i changed to port_0_io.

// input cs_can changed to cs_can_i.

//

// Revision 1.26  2003/03/12 04:39:40  mohor

// rd_i and wr_i are active high signals. If 8051 is connected, these two signals

// need to be negated one level higher.

//

// Revision 1.25  2003/03/12 04:17:36  mohor

// 8051 interface added (besides WISHBONE interface). Selection is made in

// can_defines.v file.

//

// Revision 1.24  2003/03/10 17:24:40  mohor

// wire declaration added.

//

// Revision 1.23  2003/03/05 15:33:13  mohor

// tx_o is now tristated signal. tx_oen and tx_o combined together.

//

// Revision 1.22  2003/03/05 15:01:56  mohor

// Top level signal names changed.

//

// Revision 1.21  2003/03/01 22:53:33  mohor

// Actel APA ram supported.

//

// Revision 1.20  2003/02/19 15:09:02  mohor

// Incomplete sensitivity list fixed.

//

// Revision 1.19  2003/02/19 15:04:14  mohor

// Typo fixed.

//

// Revision 1.18  2003/02/19 14:44:03  mohor

// CAN core finished. Host interface added. Registers finished.

// Synchronization to the wishbone finished.

//

// Revision 1.17  2003/02/18 00:10:15  mohor

// Most of the registers added. Registers "arbitration lost capture", "error code

// capture" + few more still need to be added.

//

// Revision 1.16  2003/02/14 20:17:01  mohor

// Several registers added. Not finished, yet.

//

// Revision 1.15  2003/02/12 14:25:30  mohor

// abort_tx added.

//

// Revision 1.14  2003/02/11 00:56:06  mohor

// Wishbone interface added.

//

// Revision 1.13  2003/02/09 18:40:29  mohor

// Overload fixed. Hard synchronization also enabled at the last bit of

// interframe.

//

// Revision 1.12  2003/02/09 02:24:33  mohor

// Bosch license warning added. Error counters finished. Overload frames

// still need to be fixed.

//

// Revision 1.11  2003/02/04 14:34:52  mohor

// *** empty log message ***

//

// Revision 1.10  2003/01/31 01:13:38  mohor

// backup.

//

// Revision 1.9  2003/01/15 13:16:48  mohor

// When a frame with "remote request" is received, no data is stored to

// fifo, just the frame information (identifier, ...). Data length that

// is stored is the received data length and not the actual data length

// that is stored to fifo.

//

// Revision 1.8  2003/01/14 17:25:09  mohor

// Addresses corrected to decimal values (previously hex).

//

// Revision 1.7  2003/01/10 17:51:34  mohor

// Temporary version (backup).

//

// Revision 1.6  2003/01/09 21:54:45  mohor

// rx fifo added. Not 100 % verified, yet.

//

// Revision 1.5  2003/01/08 02:10:56  mohor

// Acceptance filter added.

//

// Revision 1.4  2002/12/28 04:13:23  mohor

// Backup version.

//

// Revision 1.3  2002/12/27 00:12:52  mohor

// Header changed, testbench improved to send a frame (crc still missing).

//

// Revision 1.2  2002/12/26 16:00:34  mohor

// Testbench define file added. Clock divider register added.

//

// Revision 1.1.1.1  2002/12/20 16:39:21  mohor

// Initial

//

//

//

// synopsys translate_off

`include "timescale.v"

// synopsys translate_on

`include "can_defines.v"

module can_top

(

  `ifdef CAN_WISHBONE_IF

    wb_clk_i,

    wb_rst_i,

    wb_dat_i,

    wb_dat_o,

    wb_cyc_i,

    wb_stb_i,

    wb_we_i,

    wb_adr_i,

    wb_ack_o,

  `else

    rst_i,

    ale_i,

    rd_i,

    wr_i,

    port_0_io,

  `endif

  cs_can_i,

  clk_i,

  rx_i,

  tx_o,

  irq_on,

  clkout_o

);

parameter Tp = 1;

`ifdef CAN_WISHBONE_IF

  input        wb_clk_i;

  input        wb_rst_i;

  input  [7:0] wb_dat_i;

  output [7:0] wb_dat_o;

  input        wb_cyc_i;

  input        wb_stb_i;

  input        wb_we_i;

  input  [7:0] wb_adr_i;

  output       wb_ack_o;

  reg          wb_ack_o;

  reg          cs_sync1;

  reg          cs_sync2;

  reg          cs_sync3;

  reg          cs_ack1;

  reg          cs_ack2;

  reg          cs_ack3;

  reg          cs_sync_rst1;

  reg          cs_sync_rst2;

`else

  input        rst_i;

  input        ale_i;

  input        rd_i;

  input        wr_i;

  inout  [7:0] port_0_io;

  reg    [7:0] addr_latched;

  reg          wr_i_q;

  reg          rd_i_q;

`endif

input        cs_can_i;

input        clk_i;

input        rx_i;

output       tx_o;

output       irq_on;

output       clkout_o;

reg          data_out_fifo_selected;

wire         irq_o;

wire   [7:0] data_out_fifo;

wire   [7:0] data_out_regs;

/* Mode register */

wire         reset_mode;

wire         listen_only_mode;

wire         acceptance_filter_mode;

wire         self_test_mode;

/* Command register */

wire         release_buffer;

wire         tx_request;

wire         abort_tx;

wire         self_rx_request;

wire         single_shot_transmission;

/* Arbitration Lost Capture Register */

wire         read_arbitration_lost_capture_reg;

/* Error Code Capture Register */

wire         read_error_code_capture_reg;

wire   [7:0] error_capture_code;

/* Bus Timing 0 register */

wire   [5:0] baud_r_presc;

wire   [1:0] sync_jump_width;

/* Bus Timing 1 register */

wire   [3:0] time_segment1;

wire   [2:0] time_segment2;

wire         triple_sampling;

/* Error Warning Limit register */

wire   [7:0] error_warning_limit;

/* Rx Error Counter register */

wire         we_rx_err_cnt;

/* Tx Error Counter register */

wire         we_tx_err_cnt;

/* Clock Divider register */

wire         extended_mode;

/* This section is for BASIC and EXTENDED mode */

/* Acceptance code register */

wire   [7:0] acceptance_code_0;

/* Acceptance mask register */

wire   [7:0] acceptance_mask_0;

/* End: This section is for BASIC and EXTENDED mode */

/* This section is for EXTENDED mode */

/* Acceptance code register */

wire   [7:0] acceptance_code_1;

wire   [7:0] acceptance_code_2;

wire   [7:0] acceptance_code_3;

/* Acceptance mask register */

wire   [7:0] acceptance_mask_1;

wire   [7:0] acceptance_mask_2;

wire   [7:0] acceptance_mask_3;

/* End: This section is for EXTENDED mode */

/* Tx data registers. Holding identifier (basic mode), tx frame information (extended mode) and data */

wire   [7:0] tx_data_0;

wire   [7:0] tx_data_1;

wire   [7:0] tx_data_2;

wire   [7:0] tx_data_3;

wire   [7:0] tx_data_4;

wire   [7:0] tx_data_5;

wire   [7:0] tx_data_6;

wire   [7:0] tx_data_7;

wire   [7:0] tx_data_8;

wire   [7:0] tx_data_9;

wire   [7:0] tx_data_10;

wire   [7:0] tx_data_11;

wire   [7:0] tx_data_12;

/* End: Tx data registers */

wire         cs;

/* Output signals from can_btl module */

wire         clk_en;

wire         sample_point;

wire         sampled_bit;

wire         sampled_bit_q;

wire         tx_point;

wire         hard_sync;

wire         resync;

/* output from can_bsp module */

wire         rx_idle;

wire         transmitting;

wire         last_bit_of_inter;

wire         set_reset_mode;

wire         node_bus_off;

wire         error_status;

wire   [7:0] rx_err_cnt;

wire   [7:0] tx_err_cnt;

wire         rx_err_cnt_dummy;  // The MSB is not displayed. It is just used for easier calculation (no counter overflow).

wire         tx_err_cnt_dummy;  // The MSB is not displayed. It is just used for easier calculation (no counter overflow).

wire         transmit_status;

wire         receive_status;

wire         tx_successful;

wire         need_to_tx;

wire         overrun;

wire         info_empty;

wire         set_bus_error_irq;

wire         set_arbitration_lost_irq;

wire   [4:0] arbitration_lost_capture;

wire         node_error_passive;

wire         node_error_active;

wire   [6:0] rx_message_counter;

wire         tx_out;

wire         tx_oen;

wire         rst;

wire         we;

wire   [7:0] addr;

wire   [7:0] data_in;

reg    [7:0] data_out;

/* Connecting can_registers module */

can_registers i_can_registers

(

  .clk(clk_i),

  .rst(rst),

  .cs(cs),

  .we(we),

  .addr(addr),

  .data_in(data_in),

  .data_out(data_out_regs),

  .irq(irq_o),

  .sample_point(sample_point),

  .transmitting(transmitting),

  .set_reset_mode(set_reset_mode),

  .node_bus_off(node_bus_off),

  .error_status(error_status),

  .rx_err_cnt(rx_err_cnt),

  .tx_err_cnt(tx_err_cnt),

  .transmit_status(transmit_status),

  .receive_status(receive_status),

  .tx_successful(tx_successful),

  .need_to_tx(need_to_tx),

  .overrun(overrun),

  .info_empty(info_empty),

  .set_bus_error_irq(set_bus_error_irq),

  .set_arbitration_lost_irq(set_arbitration_lost_irq),

  .arbitration_lost_capture(arbitration_lost_capture),

  .node_error_passive(node_error_passive),

  .node_error_active(node_error_active),

  .rx_message_counter(rx_message_counter),

  /* Mode register */

  .reset_mode(reset_mode),

  .listen_only_mode(listen_only_mode),

  .acceptance_filter_mode(acceptance_filter_mode),

  .self_test_mode(self_test_mode),

  /* Command register */

  .clear_data_overrun(),

  .release_buffer(release_buffer),

  .abort_tx(abort_tx),

  .tx_request(tx_request),

  .self_rx_request(self_rx_request),

  .single_shot_transmission(single_shot_transmission),

  /* Arbitration Lost Capture Register */

  .read_arbitration_lost_capture_reg(read_arbitration_lost_capture_reg),

  /* Error Code Capture Register */

  .read_error_code_capture_reg(read_error_code_capture_reg),

  .error_capture_code(error_capture_code),

  /* Bus Timing 0 register */

  .baud_r_presc(baud_r_presc),

  .sync_jump_width(sync_jump_width),

  /* Bus Timing 1 register */

  .time_segment1(time_segment1),

  .time_segment2(time_segment2),

  .triple_sampling(triple_sampling),

  /* Error Warning Limit register */

  .error_warning_limit(error_warning_limit),

  /* Rx Error Counter register */

  .we_rx_err_cnt(we_rx_err_cnt),

  /* Tx Error Counter register */

  .we_tx_err_cnt(we_tx_err_cnt),

  /* Clock Divider register */

  .extended_mode(extended_mode),

  .clkout(clkout_o),

  /* This section is for BASIC and EXTENDED mode */

  /* Acceptance code register */

  .acceptance_code_0(acceptance_code_0),

  /* Acceptance mask register */

  .acceptance_mask_0(acceptance_mask_0),

  /* End: This section is for BASIC and EXTENDED mode */

  /* This section is for EXTENDED mode */

  /* Acceptance code register */

  .acceptance_code_1(acceptance_code_1),

  .acceptance_code_2(acceptance_code_2),

  .acceptance_code_3(acceptance_code_3),

  /* Acceptance mask register */

  .acceptance_mask_1(acceptance_mask_1),

  .acceptance_mask_2(acceptance_mask_2),

  .acceptance_mask_3(acceptance_mask_3),

  /* End: This section is for EXTENDED mode */

  /* Tx data registers. Holding identifier (basic mode), tx frame information (extended mode) and data */

  .tx_data_0(tx_data_0),

  .tx_data_1(tx_data_1),

  .tx_data_2(tx_data_2),

  .tx_data_3(tx_data_3),

  .tx_data_4(tx_data_4),

  .tx_data_5(tx_data_5),

  .tx_data_6(tx_data_6),

  .tx_data_7(tx_data_7),

  .tx_data_8(tx_data_8),

  .tx_data_9(tx_data_9),

  .tx_data_10(tx_data_10),

  .tx_data_11(tx_data_11),

  .tx_data_12(tx_data_12)

  /* End: Tx data registers */

);

assign irq_on = ~irq_o;

/* Connecting can_btl module */

can_btl i_can_btl

(

  .clk(clk_i),

  .rst(rst),

  .rx(rx_i),

  /* Mode register */

  .reset_mode(reset_mode),

  /* Bus Timing 0 register */

  .baud_r_presc(baud_r_presc),

  .sync_jump_width(sync_jump_width),

  /* Bus Timing 1 register */

  .time_segment1(time_segment1),

  .time_segment2(time_segment2),

  .triple_sampling(triple_sampling),

  /* Output signals from this module */

  .clk_en(clk_en),

  .sample_point(sample_point),

  .sampled_bit(sampled_bit),

  .sampled_bit_q(sampled_bit_q),

  .tx_point(tx_point),

  .hard_sync(hard_sync),

  .resync(resync),

  /* output from can_bsp module */

  .rx_idle(rx_idle),

  .transmitting(transmitting),

  .last_bit_of_inter(last_bit_of_inter)

);

can_bsp i_can_bsp

(

  .clk(clk_i),

  .rst(rst),

  /* From btl module */

  .sample_point(sample_point),

  .sampled_bit(sampled_bit),

  .sampled_bit_q(sampled_bit_q),

  .tx_point(tx_point),

  .hard_sync(hard_sync),

  .addr(addr),

  .data_in(data_in),

  .data_out(data_out_fifo),

  .fifo_selected(data_out_fifo_selected),

  /* Mode register */

  .reset_mode(reset_mode),

  .listen_only_mode(listen_only_mode),

  .acceptance_filter_mode(acceptance_filter_mode),

  .self_test_mode(self_test_mode),

  /* Command register */

  .release_buffer(release_buffer),

  .tx_request(tx_request),

  .abort_tx(abort_tx),

  .self_rx_request(self_rx_request),

  .single_shot_transmission(single_shot_transmission),

  /* Arbitration Lost Capture Register */

  .read_arbitration_lost_capture_reg(read_arbitration_lost_capture_reg),

  /* Error Code Capture Register */

  .read_error_code_capture_reg(read_error_code_capture_reg),

  .error_capture_code(error_capture_code),

  /* Error Warning Limit register */

  .error_warning_limit(error_warning_limit),

  /* Rx Error Counter register */

  .we_rx_err_cnt(we_rx_err_cnt),

  /* Tx Error Counter register */

  .we_tx_err_cnt(we_tx_err_cnt),

  /* Clock Divider register */

  .extended_mode(extended_mode),

  /* output from can_bsp module */

  .rx_idle(rx_idle),

  .transmitting(transmitting),

  .last_bit_of_inter(last_bit_of_inter),

  .set_reset_mode(set_reset_mode),

  .node_bus_off(node_bus_off),

  .error_status(error_status),

  .rx_err_cnt({rx_err_cnt_dummy, rx_err_cnt[7:0]}),   // The MSB is not displayed. It is just used for easier calculation (no counter overflow).

  .tx_err_cnt({tx_err_cnt_dummy, tx_err_cnt[7:0]}),   // The MSB is not displayed. It is just used for easier calculation (no counter overflow).

  .transmit_status(transmit_status),

  .receive_status(receive_status),

  .tx_successful(tx_successful),

  .need_to_tx(need_to_tx),

  .overrun(overrun),

  .info_empty(info_empty),

  .set_bus_error_irq(set_bus_error_irq),

  .set_arbitration_lost_irq(set_arbitration_lost_irq),

  .arbitration_lost_capture(arbitration_lost_capture),

  .node_error_passive(node_error_passive),

  .node_error_active(node_error_active),

  .rx_message_counter(rx_message_counter),

  /* This section is for BASIC and EXTENDED mode */

  /* Acceptance code register */

  .acceptance_code_0(acceptance_code_0),

  /* Acceptance mask register */

  .acceptance_mask_0(acceptance_mask_0),

  /* End: This section is for BASIC and EXTENDED mode */

  /* This section is for EXTENDED mode */

  /* Acceptance code register */

  .acceptance_code_1(acceptance_code_1),

  .acceptance_code_2(acceptance_code_2),

  .acceptance_code_3(acceptance_code_3),

  /* Acceptance mask register */

  .acceptance_mask_1(acceptance_mask_1),

  .acceptance_mask_2(acceptance_mask_2),

  .acceptance_mask_3(acceptance_mask_3),

  /* End: This section is for EXTENDED mode */

  /* Tx data registers. Holding identifier (basic mode), tx frame information (extended mode) and data */

  .tx_data_0(tx_data_0),

  .tx_data_1(tx_data_1),

  .tx_data_2(tx_data_2),

  .tx_data_3(tx_data_3),

  .tx_data_4(tx_data_4),

  .tx_data_5(tx_data_5),

  .tx_data_6(tx_data_6),

  .tx_data_7(tx_data_7),

  .tx_data_8(tx_data_8),

  .tx_data_9(tx_data_9),

  .tx_data_10(tx_data_10),

  .tx_data_11(tx_data_11),

  .tx_data_12(tx_data_12),

  /* End: Tx data registers */

  /* Tx signal */

  .tx(tx_out),

  .tx_oen(tx_oen)

);

assign tx_o = tx_oen? 1'bz : tx_out;

// Multiplexing wb_dat_o from registers and rx fifo

always @ (extended_mode or addr or reset_mode)

begin

  if (extended_mode & (~reset_mode) & ((addr >= 8'd16) && (addr <= 8'd28)) | (~extended_mode) & ((addr >= 8'd20) && (addr <= 8'd29)))

    data_out_fifo_selected <= 1'b1;

  else

    data_out_fifo_selected <= 1'b0;

end

always @ (posedge clk_i)

begin

//  if (wb_cyc_i & (~wb_we_i))

  if (cs & (~we))

    begin

      if (data_out_fifo_selected)

        data_out <=#Tp data_out_fifo;

      else

        data_out <=#Tp data_out_regs;

    end

end

`ifdef CAN_WISHBONE_IF

  // Combining wb_cyc_i and wb_stb_i signals to cs signal. Than synchronizing to clk_i clock domain. 

  always @ (posedge clk_i or posedge rst)

  begin

    if (rst)

      begin

        cs_sync1     <= 1'b0;

        cs_sync2     <= 1'b0;

        cs_sync3     <= 1'b0;

        cs_sync_rst1 <= 1'b0;

        cs_sync_rst2 <= 1'b0;

      end

    else

      begin

        cs_sync1     <=#Tp wb_cyc_i & wb_stb_i & (~cs_sync_rst2) & cs_can_i;

        cs_sync2     <=#Tp cs_sync1            & (~cs_sync_rst2);

        cs_sync3     <=#Tp cs_sync2            & (~cs_sync_rst2);

        cs_sync_rst1 <=#Tp cs_ack3;

        cs_sync_rst2 <=#Tp cs_sync_rst1;

      end

  end

  assign cs = cs_sync2 & (~cs_sync3);

  always @ (posedge wb_clk_i)

  begin

    cs_ack1 <=#Tp cs_sync3;

    cs_ack2 <=#Tp cs_ack1;

    cs_ack3 <=#Tp cs_ack2;

  end

  // Generating acknowledge signal

  always @ (posedge wb_clk_i)

  begin

    wb_ack_o <=#Tp (cs_ack2 & (~cs_ack3));

  end

  assign rst      = wb_rst_i;

  assign we       = wb_we_i;

  assign addr     = wb_adr_i;

  assign data_in  = wb_dat_i;

  assign wb_dat_o = data_out;

`else

  // Latching address

  always @ (negedge clk_i or posedge rst)

  begin

    if (rst)

      addr_latched <= 8'h0;

    else if (ale_i)

      addr_latched <=#Tp port_0_io;

  end

  // Generating delayed wr_i and rd_i signals

  always @ (posedge clk_i or posedge rst)

  begin

    if (rst)

      begin

        wr_i_q <= 1'b0;

        rd_i_q <= 1'b0;

      end

    else

      begin

        wr_i_q <=#Tp wr_i;

        rd_i_q <=#Tp rd_i;

      end

  end