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//////////////////////////////////////////////////////////////////////
////                                                              ////
////  dbg_wb.v                                                    ////
////                                                              ////
////                                                              ////
////  This file is part of the SoC/OpenRISC Development Interface ////
////  http://www.opencores.org/projects/DebugInterface/           ////
////                                                              ////
////  Author(s):                                                  ////
////       Igor Mohor (igorm@opencores.org)                       ////
////                                                              ////
////                                                              ////
////  All additional information is avaliable in the README.txt   ////
////  file.                                                       ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// Copyright (C) 2000 - 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                     ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
//
// CVS Revision History
//
// $Log: not supported by cvs2svn $
// Revision 1.13  2004/01/15 12:09:43  mohor
// Working.
//
// Revision 1.12  2004/01/14 22:59:18  mohor
// Temp version.
//
// Revision 1.11  2004/01/14 12:29:40  mohor
// temp version. Resets will be changed in next version.
//
// Revision 1.10  2004/01/13 11:28:14  mohor
// tmp version.
//
// Revision 1.9  2004/01/10 07:50:24  mohor
// temp version.
//
// Revision 1.8  2004/01/09 12:48:44  mohor
// tmp version.
//
// Revision 1.7  2004/01/08 17:53:36  mohor
// tmp version.
//
// Revision 1.6  2004/01/07 11:58:56  mohor
// temp4 version.
//
// Revision 1.5  2004/01/06 17:15:19  mohor
// temp3 version.
//
// Revision 1.4  2004/01/05 12:16:00  mohor
// tmp2 version.
//
// Revision 1.3  2003/12/23 16:22:46  mohor
// Tmp version.
//
// Revision 1.2  2003/12/23 15:26:26  mohor
// Small fix.
//
// Revision 1.1  2003/12/23 15:09:04  mohor
// New directory structure. New version of the debug interface.
//
//
//
 
// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
`include "dbg_wb_defines.v"
 
// Top module
module dbg_wb(
                // JTAG signals
                tck_i,
                tdi_i,
                tdo_o,
 
                // TAP states
                shift_dr_i,
                pause_dr_i,
                update_dr_i,
 
                wishbone_ce_i,
                crc_match_i,
                crc_en_o,
                shift_crc_o,
                rst_i,
 
                // WISHBONE common signals
                wb_clk_i,
 
                // WISHBONE master interface
                wb_adr_o, wb_dat_o, wb_dat_i, wb_cyc_o, wb_stb_o, wb_sel_o,
                wb_we_o, wb_ack_i, wb_cab_o, wb_err_i, wb_cti_o, wb_bte_o
 
              );
 
// JTAG signals
input         tck_i;
input         tdi_i;
output        tdo_o;
 
// TAP states
input         shift_dr_i;
input         pause_dr_i;
input         update_dr_i;
 
input         wishbone_ce_i;
input         crc_match_i;
output        crc_en_o;
output        shift_crc_o;
input         rst_i;
// WISHBONE common signals
input         wb_clk_i;
 
// WISHBONE master interface
output [31:0] wb_adr_o;
output [31:0] wb_dat_o;
input  [31:0] wb_dat_i;
output        wb_cyc_o;
output        wb_stb_o;
output  [3:0] wb_sel_o;
output        wb_we_o;
input         wb_ack_i;
output        wb_cab_o;
input         wb_err_i;
output  [2:0] wb_cti_o;
output  [1:0] wb_bte_o;
 
reg           wb_cyc_o;
reg    [31:0] wb_adr_o;
reg    [31:0] wb_dat_o;
reg     [3:0] wb_sel_o;
 
reg           tdo_o;
 
reg    [50:0] dr;
wire          enable;
wire          cmd_cnt_en;
reg     [1:0] cmd_cnt;
wire          cmd_cnt_end;
reg           cmd_cnt_end_q;
wire          addr_len_cnt_en;
reg     [5:0] addr_len_cnt;
reg     [5:0] addr_len_cnt_limit;
wire          addr_len_cnt_end;
wire          crc_cnt_en;
reg     [5:0] crc_cnt;
wire          crc_cnt_end;
reg           crc_cnt_end_q;
wire          data_cnt_en;
reg    [18:0] data_cnt;
reg    [18:0] data_cnt_limit;
wire          data_cnt_end;
reg           data_cnt_end_q;
reg           status_reset_en;
 
reg           crc_match_reg;
 
reg     [2:0] cmd, cmd_old, dr_cmd_latched;
reg    [31:0] adr;
reg    [15:0] len;
reg           start_rd_tck;
reg           rd_tck_started;
reg           start_rd_sync1;
reg           start_wb_rd;
reg           start_wb_rd_q;
reg           start_wr_tck;
reg           start_wr_sync1;
reg           start_wb_wr;
reg           start_wb_wr_q;
 
wire          dr_read;
wire          dr_write;
wire          dr_go;
 
reg           dr_write_latched;
reg           dr_read_latched;
reg           dr_go_latched;
 
wire          status_cnt_end;
 
wire          byte, half, long;
reg           byte_q, half_q, long_q;
reg           byte_q2, half_q2, long_q2;
reg           cmd_read;
reg           cmd_write;
reg           cmd_go;
 
reg           status_cnt1, status_cnt2, status_cnt3, status_cnt4;
 
reg [`STATUS_LEN -1:0] status;
 
reg           wb_error, wb_error_sync, wb_error_tck;
reg           wb_overrun, wb_overrun_sync, wb_overrun_tck;
reg           underrun_tck;
 
reg           busy_wb;
reg           busy_tck;
reg           wb_end;
reg           wb_end_rst;
reg           wb_end_rst_sync;
reg           wb_end_sync;
reg           wb_end_tck, wb_end_tck_q;
reg           busy_sync;
reg   [799:0] tdo_text;
reg   [399:0] latching_data_text;
reg           latch_data;
reg   [199:0] status_text;
 
reg           set_addr, set_addr_sync, set_addr_wb, set_addr_wb_q;
reg           read_cycle;
reg           write_cycle;
reg     [2:0] rw_type;
wire   [31:0] input_data;
 
wire          len_eq_0;
wire          crc_cnt_31;
 
reg     [1:0] ptr;
reg     [2:0] fifo_cnt;
wire          fifo_full;
wire          fifo_empty;
reg     [7:0] mem [0:3];
reg     [2:0] mem_ptr;
reg           wishbone_ce_sync;
reg           wishbone_ce_rst;
wire          go_prelim;
 
 
 
assign enable = wishbone_ce_i & shift_dr_i;
assign crc_en_o = enable & crc_cnt_end & (~status_cnt_end);
assign shift_crc_o = enable & status_cnt_end;  // Signals dbg module to shift out the CRC
 
 
// Selecting where to take the data from 
always @ (posedge tck_i)
begin
  if (update_dr_i)
    ptr <= #1 2'h0;
  else if (read_cycle & crc_cnt_31) // first latch
    ptr <= #1 ptr + 1'b1;
  else if (read_cycle & byte & (~byte_q))
    ptr <= ptr + 1'd1;
end
 
 
// Shift register for shifting in and out the data
always @ (posedge tck_i)
begin
  if (read_cycle & crc_cnt_31)
    begin
      dr[31:0] <= #1 input_data[31:0];
      latch_data <= #1 1'b1;
      latching_data_text <= #1 "First latch";
    end
  else if (read_cycle & crc_cnt_end)
    begin
      case (rw_type)  // synthesis parallel_case full_case
        `WB_READ8 : begin
                      if(byte & (~byte_q))
                        begin
                          case (ptr)    // synthesis parallel_case
                            2'b00 : dr[31:24] <= #1 input_data[31:24];
                            2'b01 : dr[31:24] <= #1 input_data[23:16];
                            2'b10 : dr[31:24] <= #1 input_data[15:8];
                            2'b11 : dr[31:24] <= #1 input_data[7:0];
                          endcase
                          latch_data <= #1 1'b1;
                          latching_data_text <= #1 "8 bit latched";
                        end
                      else
                        begin
                          dr[31:24] <= #1 {dr[30:24], 1'b0};
                          latch_data <= #1 1'b0;
                          latching_data_text <= #1 "8 bit shifted";
                        end
                    end
        `WB_READ16: begin
                      if(half & (~half_q))
                        begin
                          if (ptr[1])
                            dr[31:16] <= #1 input_data[15:0];
                          else
                            dr[31:16] <= #1 input_data[31:16];
                          latching_data_text <= #1 "16 bit latched";
                          latch_data <= #1 1'b1;
                        end
                      else
                        begin
                          dr[31:16] <= #1 {dr[30:16], 1'b0};
                          latch_data <= #1 1'b0;
                          latching_data_text <= #1 "16 bit shifted";
                        end
                    end
        `WB_READ32: begin
                      if(long & (~long_q))
                        begin
                          dr[31:0] <= #1 input_data[31:0];
                          latch_data <= #1 1'b1;
                          latching_data_text <= #1 "32 bit latched";
                        end
                      else
                        begin
                          dr[31:0] <= #1 {dr[30:0], 1'b0};
                          latch_data <= #1 1'b0;
                          latching_data_text <= #1 "32 bit shifted";
                        end
                    end
      endcase
    end
  else if (enable & ((~addr_len_cnt_end) | (~cmd_cnt_end) | ((~data_cnt_end) & write_cycle)))
    begin
      dr <= #1 {dr[49:0], tdi_i};
      latch_data <= #1 1'b0;
      latching_data_text <= #1 "tdi shifted in";
    end
  else
    latching_data_text <= #1 "nothing";
end
 
 
assign cmd_cnt_en = enable & (~cmd_cnt_end);
 
 
// Command counter
always @ (posedge tck_i or posedge rst_i)
begin
  if (rst_i)
    cmd_cnt <= #1 'h0;
  else if (update_dr_i)
    cmd_cnt <= #1 'h0;
  else if (cmd_cnt_en)
    cmd_cnt <= #1 cmd_cnt + 1'b1;
end
 
 
assign addr_len_cnt_en = enable & cmd_cnt_end & (~addr_len_cnt_end);
 
 
// Address/length counter
always @ (posedge tck_i or posedge rst_i)
begin
  if (rst_i)
    addr_len_cnt <= #1 'h0;
  else if (update_dr_i)
    addr_len_cnt <= #1 'h0;
  else if (addr_len_cnt_en)
    addr_len_cnt <= #1 addr_len_cnt + 1'b1;
end
 
 
assign data_cnt_en = enable & (~data_cnt_end) & (cmd_cnt_end & write_cycle | crc_cnt_end & read_cycle);
 
 
// Data counter
always @ (posedge tck_i or posedge rst_i)
begin
  if (rst_i)
    data_cnt <= #1 'h0;
  else if (update_dr_i)
    data_cnt <= #1 'h0;
  else if (data_cnt_en)
    data_cnt <= #1 data_cnt + 1'b1;
end
 
 
 
assign byte = data_cnt[2:0] == 3'd7;
assign half = data_cnt[3:0] == 4'd15;
assign long = data_cnt[4:0] == 5'd31;
 
 
always @ (posedge tck_i)
begin
  byte_q <= #1 byte;
  half_q <= #1 half;
  long_q <= #1 long;
  byte_q2 <= #1 byte_q;
  half_q2 <= #1 half_q;
  long_q2 <= #1 long_q;
end
 
 
assign dr_read = (dr[2:0] == `WB_READ8) | (dr[2:0] == `WB_READ16) | (dr[2:0] == `WB_READ32);
assign dr_write = (dr[2:0] == `WB_WRITE8) | (dr[2:0] == `WB_WRITE16) | (dr[2:0] == `WB_WRITE32);
assign dr_go = dr[2:0] == `WB_GO;
 
 
// Latching instruction
always @ (posedge tck_i)
begin
  if (update_dr_i)
    begin
      dr_cmd_latched <= #1 3'h0;
      dr_read_latched  <= #1 1'b0;
      dr_write_latched  <= #1 1'b0;
      dr_go_latched  <= #1 1'b0;
    end
  else if (cmd_cnt_end & (~cmd_cnt_end_q))
    begin
      dr_cmd_latched <= #1 dr[2:0];
      dr_read_latched <= #1 dr_read;
      dr_write_latched <= #1 dr_write;
      dr_go_latched <= #1 dr_go;
    end
end
 
 
// Upper limit. Address/length counter counts until this value is reached
always @ (posedge tck_i)
begin
  if (cmd_cnt == 2'h2)
    begin
      if ((~dr[0])  & (~tdi_i))                                   // (current command is WB_STATUS or WB_GO)
        addr_len_cnt_limit <= #1 6'd0;
      else                                                        // (current command is WB_WRITEx or WB_READx)
        addr_len_cnt_limit <= #1 6'd48;
    end
end
 
 
assign go_prelim = (cmd_cnt == 2'h2) & dr[1] & (~dr[0]) & (~tdi_i);
 
 
// Upper limit. Data counter counts until this value is reached.
always @ (posedge tck_i)
begin
  if (update_dr_i)
    data_cnt_limit <= #1 {len, 3'b000};
end
 
 
assign crc_cnt_en = enable & (~crc_cnt_end) & (cmd_cnt_end & addr_len_cnt_end  & (~write_cycle) | (data_cnt_end & write_cycle));
 
 
// crc counter
always @ (posedge tck_i or posedge rst_i)
begin
  if (rst_i)
    crc_cnt <= #1 'h0;
  else if(crc_cnt_en)
    crc_cnt <= #1 crc_cnt + 1'b1;
  else if (update_dr_i)
    crc_cnt <= #1 'h0;
end
 
assign cmd_cnt_end  = cmd_cnt  == 2'h3;
assign addr_len_cnt_end = addr_len_cnt == addr_len_cnt_limit;
assign crc_cnt_end  = crc_cnt  == 6'd32;
assign crc_cnt_31 = crc_cnt  == 6'd31;
assign data_cnt_end = (data_cnt == data_cnt_limit);
 
always @ (posedge tck_i)
begin
  crc_cnt_end_q  <= #1 crc_cnt_end;
  cmd_cnt_end_q  <= #1 cmd_cnt_end;
  data_cnt_end_q <= #1 data_cnt_end;
end
 
 
// Status counter is made of 4 serialy connected registers
always @ (posedge tck_i or posedge rst_i)
begin
  if (rst_i)
    status_cnt1 <= #1 1'b0;
  else if (update_dr_i)
    status_cnt1 <= #1 1'b0;
  else if (data_cnt_end & read_cycle |
           crc_cnt_end & (~read_cycle)
          )
    status_cnt1 <= #1 1'b1;
end
 
 
always @ (posedge tck_i or posedge rst_i)
begin
  if (rst_i)
    begin
      status_cnt2 <= #1 1'b0;
      status_cnt3 <= #1 1'b0;
      status_cnt4 <= #1 1'b0;
    end
  else if (update_dr_i)
    begin
      status_cnt2 <= #1 1'b0;
      status_cnt3 <= #1 1'b0;
      status_cnt4 <= #1 1'b0;
    end
  else
    begin
      status_cnt2 <= #1 status_cnt1;
      status_cnt3 <= #1 status_cnt2;
      status_cnt4 <= #1 status_cnt3;
    end
end
 
 
assign status_cnt_end = status_cnt4;
 
 
// Status register
always @ (posedge tck_i or posedge rst_i)
begin
  if (rst_i)
    begin
    status <= #1 'h0;
    status_text <= #1 "reset";
    end
  else if(crc_cnt_end & (~crc_cnt_end_q) & (~read_cycle))
    begin
    status <= #1 {crc_match_i, wb_error_tck, wb_overrun_tck, busy_tck};
    status_text <= #1 "!!!READ";
    end
  else if (data_cnt_end & (~data_cnt_end_q) & read_cycle)
    begin
    status <= #1 {crc_match_reg, wb_error_tck, underrun_tck, busy_tck};
    status_text <= #1 "READ";
    end
  else if (shift_dr_i & (~status_cnt_end))
    begin
    status <= #1 {status[0], status[`STATUS_LEN -1:1]};
    status_text <= #1 "shift";
    end
end
// Following status is shifted out:
// 1. bit:          1 if crc is OK, else 0
// 2. bit:          1 while WB access is in progress (busy_tck), else 0
// 3. bit:          1 if overrun occured during write (data couldn't be written fast enough)
//                    or underrun occured during read (data couldn't be read fast enough)
// 4. bit:          1 if WB error occured, else 0
 
 
// TDO multiplexer
always @ (pause_dr_i or busy_tck or crc_cnt_end or crc_cnt_end_q or cmd_read or crc_match_i or
          data_cnt_end or data_cnt_end_q or read_cycle or crc_match_reg or status or dr or cmd_go)
begin
  if (pause_dr_i)
    begin
    tdo_o = busy_tck;
    tdo_text = "busy_tck";
    end
  else if (crc_cnt_end & (~crc_cnt_end_q) & (~(read_cycle)))
    begin
      tdo_o = crc_match_i;
      tdo_text = "crc_match_i";
    end
  else if (read_cycle & crc_cnt_end & (~data_cnt_end))
    begin
    tdo_o = dr[31];
    tdo_text = "read data";
    end
  else if (read_cycle & data_cnt_end & (~data_cnt_end_q))     // cmd is already updated
    begin
      tdo_o = crc_match_reg;
      tdo_text = "crc_match_reg";
    end
  else if (crc_cnt_end & data_cnt_end)  // cmd is already updated
    begin
      tdo_o = status[0];
      tdo_text = "status";
    end
  else
    begin
      tdo_o = 1'b0;
      tdo_text = "zero while CRC is shifted in";
    end
end
 
 
 
always @ (posedge tck_i)
begin
  if(crc_cnt_end & (~crc_cnt_end_q))
    crc_match_reg <= #1 crc_match_i;
end
 
 
// Latching instruction
always @ (posedge tck_i or posedge rst_i)
begin
  if (rst_i)
    begin
      cmd <= #1 'h0;
      cmd_old <= #1 'h0;
      cmd_read <= #1 1'b0;
      cmd_write <= #1 1'b0;
      cmd_go <= #1 1'b0;
    end
  else if(crc_cnt_end & (~crc_cnt_end_q) & crc_match_i)
    begin
      cmd <= #1 dr_cmd_latched;
      cmd_old <= #1 cmd;
      cmd_read <= #1 dr_read_latched;
      cmd_write <= #1 dr_write_latched;
      cmd_go <= #1 dr_go_latched;
    end
end
 
 
// Latching address
always @ (posedge tck_i)
begin
  if(crc_cnt_end & (~crc_cnt_end_q) & crc_match_i)
    begin
      if (dr_write_latched | dr_read_latched)
        begin
          adr <= #1 dr[47:16];
          set_addr <= #1 1'b1;
        end
    end
  else
    set_addr <= #1 1'b0;
end
 
 
// Length counter
always @ (posedge tck_i)
begin
  if(crc_cnt_end & (~crc_cnt_end_q) & crc_match_i & (dr_write_latched | dr_read_latched))
    len <= #1 dr[15:0];
  else if (start_rd_tck)
    begin
      case (rw_type)  // synthesis parallel_case full_case
        `WB_READ8 : len <= #1 len - 1'd1;
        `WB_READ16: len <= #1 len - 2'd2;
        `WB_READ32: len <= #1 len - 3'd4;
      endcase
    end
end
 
 
assign len_eq_0 = len == 16'h0;
 
 
// Start wishbone read cycle
always @ (posedge tck_i)
begin
  if (read_cycle & (~dr_go_latched) & (~len_eq_0))              // First read after cmd is entered
    start_rd_tck <= #1 1'b1;
  else if ((~start_rd_tck) & read_cycle & (~len_eq_0) & (~fifo_full) & (~rd_tck_started))
    start_rd_tck <= #1 1'b1;
  else
    start_rd_tck <= #1 1'b0;
end
 
 
always @ (posedge tck_i)
begin
  if (update_dr_i)
    rd_tck_started <= #1 1'b0;
  else if (start_rd_tck)
    rd_tck_started <= #1 1'b1;
  else if (wb_end_tck & (~wb_end_tck_q))
    rd_tck_started <= #1 1'b0;
end
 
 
always @ (posedge tck_i)
begin
  if (update_dr_i)
    read_cycle <= #1 1'b0;
  else if (cmd_read & go_prelim)
    read_cycle <= #1 1'b1;
end
 
 
always @ (posedge tck_i)
begin
  if ((cmd_read | cmd_write) & go_prelim)
    rw_type <= #1 cmd;
end
 
 
always @ (posedge tck_i)
begin
  if (update_dr_i)
    write_cycle <= #1 1'b0;
  else if (cmd_write & go_prelim)
    write_cycle <= #1 1'b1;
end
 
 
// Start wishbone write cycle
always @ (posedge tck_i)
begin
  if (write_cycle)
    begin
      case (rw_type)  // synthesis parallel_case full_case
        `WB_WRITE8  : begin
                        if (byte_q & (~byte_q2))
                          begin
                            start_wr_tck <= #1 1'b1;
                            wb_dat_o <= #1 {4{dr[7:0]}};
                          end
                        else
                          begin
                            start_wr_tck <= #1 1'b0;
                          end
                      end
        `WB_WRITE16 : begin
                        if (half_q & (~half_q2))
                          begin
                            start_wr_tck <= #1 1'b1;
                            wb_dat_o <= #1 {2{dr[15:0]}};
                          end
                        else
                          begin
                            start_wr_tck <= #1 1'b0;
                          end
                      end
        `WB_WRITE32 : begin
                        if (long_q & (~long_q2))
                          begin
                            start_wr_tck <= #1 1'b1;
                            wb_dat_o <= #1 dr[31:0];
                          end
                        else
                          begin
                            start_wr_tck <= #1 1'b0;
                          end
                      end
      endcase
    end
  else
    start_wr_tck <= #1 1'b0;
end
 
 
always @ (posedge wb_clk_i)
begin
  start_rd_sync1  <= #1 start_rd_tck;
  start_wb_rd     <= #1 start_rd_sync1;
  start_wb_rd_q   <= #1 start_wb_rd;
 
  start_wr_sync1  <= #1 start_wr_tck;
  start_wb_wr     <= #1 start_wr_sync1;
  start_wb_wr_q   <= #1 start_wb_wr;
 
  set_addr_sync   <= #1 set_addr;
  set_addr_wb     <= #1 set_addr_sync;
  set_addr_wb_q   <= #1 set_addr_wb;
end
 
 
// wb_cyc_o
always @ (posedge wb_clk_i or posedge rst_i)
begin
  if (rst_i)
    wb_cyc_o <= #1 1'b0;
  else if ((start_wb_wr & (~start_wb_wr_q)) | (start_wb_rd & (~start_wb_rd_q)))
    wb_cyc_o <= #1 1'b1;
  else if (wb_ack_i | wb_err_i)
    wb_cyc_o <= #1 1'b0;
end
 
 
// wb_adr_o logic
always @ (posedge wb_clk_i)
begin
  if (set_addr_wb & (~set_addr_wb_q)) // Setting starting address
    wb_adr_o <= #1 adr;
  else if (wb_ack_i)
    begin
      if ((rw_type == `WB_WRITE8) | (rw_type == `WB_READ8))
        wb_adr_o <= #1 wb_adr_o + 1'd1;
      else if ((rw_type == `WB_WRITE16) | (rw_type == `WB_READ16))
        wb_adr_o <= #1 wb_adr_o + 2'd2;
      else
        wb_adr_o <= #1 wb_adr_o + 3'd4;
    end
end
 
 
 
//    adr   byte  |  short  |  long
//     0    1000     1100      1111
//     1    0100     err       err
//     2    0010     0011      err
//     3    0001     err       err
// wb_sel_o logic
always @ (posedge wb_clk_i or posedge rst_i)
begin
  if (rst_i)
    wb_sel_o[3:0] <= #1 4'h0;
  else
    begin
      wb_sel_o[0] <= #1 (rw_type[1:0] == 2'b11) & (wb_adr_o[1:0] == 2'b00) | (rw_type[1:0] == 2'b01) & (wb_adr_o[1:0] == 2'b11) |
                        (rw_type[1:0] == 2'b10) & (wb_adr_o[1:0] == 2'b10);
      wb_sel_o[1] <= #1 (rw_type[1:0] == 2'b11) & (wb_adr_o[1:0] == 2'b00) | (rw_type[1] ^ rw_type[0]) & (wb_adr_o[1:0] == 2'b10);
      wb_sel_o[2] <= #1 (rw_type[1]) & (wb_adr_o[1:0] == 2'b00) | (rw_type[1:0] == 2'b01) & (wb_adr_o[1:0] == 2'b01);
      wb_sel_o[3] <= #1 (wb_adr_o[1:0] == 2'b00);
    end
end
 
 
assign wb_we_o = write_cycle;
assign wb_cab_o = 1'b0;
assign wb_stb_o = wb_cyc_o;
assign wb_cti_o = 3'h0;     // always performing single access
assign wb_bte_o = 2'h0;     // always performing single access
 
 
// Logic for detecting end of transaction
always @ (posedge wb_clk_i or posedge rst_i)
begin
  if (rst_i)
    wb_end <= #1 1'b0;
  else if (wb_ack_i | wb_err_i)
    wb_end <= #1 1'b1;
  else if (wb_end_rst)
    wb_end <= #1 1'b0;
end
 
 
always @ (posedge tck_i or posedge rst_i)
begin
  if (rst_i)
    begin
      wb_end_sync <= #1 1'b0;
      wb_end_tck  <= #1 1'b0;
      wb_end_tck_q<= #1 1'b0;
    end
  else
    begin
      wb_end_sync <= #1 wb_end;
      wb_end_tck  <= #1 wb_end_sync;
      wb_end_tck_q<= #1 wb_end_tck;
    end
end
 
 
always @ (posedge wb_clk_i or posedge rst_i)
begin
  if (rst_i)
    busy_wb <= #1 1'b0;
  else if (wb_end_rst)
    busy_wb <= #1 1'b0;
  else if (wb_cyc_o)
    busy_wb <= #1 1'b1;
end
 
 
always @ (posedge tck_i or posedge rst_i)
begin
  if (rst_i)
    begin
      busy_sync <= #1 1'b0;
      busy_tck <= #1 1'b0;
    end
  else
    begin
      busy_sync <= #1 busy_wb;
      busy_tck <= #1 busy_sync;
    end
end
 
 
always @ (posedge wb_clk_i)
begin
  wb_end_rst_sync <= #1 wb_end_tck;
  wb_end_rst  <= #1 wb_end_rst_sync;
end
 
 
// Detecting WB error
always @ (posedge wb_clk_i or posedge rst_i)
begin
  if (rst_i)
    wb_error <= #1 1'b0;
  else if(wb_err_i)
    wb_error <= #1 1'b1;
  else if(wb_ack_i & status_reset_en) // error remains active until STATUS read is performed
    wb_error <= #1 1'b0;
end
 
 
always @ (posedge tck_i)
begin
  wb_error_sync <= #1 wb_error;
  wb_error_tck  <= #1 wb_error_sync;
end
 
 
// Detecting overrun when write operation.
always @ (posedge wb_clk_i or posedge rst_i)
begin
  if (rst_i)
    wb_overrun <= #1 1'b0;
  else if(start_wb_wr & (~start_wb_wr_q) & wb_cyc_o)
    wb_overrun <= #1 1'b1;
  else if((wb_ack_i | wb_err_i) & status_reset_en) // error remains active until STATUS read is performed
    wb_overrun <= #1 1'b0;
end
 
always @ (posedge tck_i)
begin
  wb_overrun_sync <= #1 wb_overrun;
  wb_overrun_tck  <= #1 wb_overrun_sync;
end
 
 
// Detecting underrun when read operation
always @ (posedge tck_i or posedge rst_i)
begin
  if (rst_i)
    underrun_tck <= #1 1'b0;
  else if(latch_data & fifo_empty & (~data_cnt_end))
    underrun_tck <= #1 1'b1;
  else if(read_cycle & status_reset_en) // error remains active until STATUS read is performed
    underrun_tck <= #1 1'b0;
end
 
 
 
// wb_error is locked until WB_STATUS is performed
always @ (posedge tck_i or posedge rst_i)
begin
  if (rst_i)
    status_reset_en <= 1'b0;
  else if((cmd_old == `WB_STATUS) & (cmd !== `WB_STATUS))
    status_reset_en <= #1 1'b1;
  else
    status_reset_en <= #1 1'b0;
end
 
 
always @ (posedge wb_clk_i)
begin
  wishbone_ce_sync <= #1  wishbone_ce_i;
  wishbone_ce_rst  <= #1 ~wishbone_ce_sync;
end
 
 
// Logic for latching data that is read from wishbone
always @ (posedge wb_clk_i)
begin
  if(wishbone_ce_rst)
    mem_ptr <= #1 'h0;
  else if (wb_ack_i)
    begin
      if (rw_type == `WB_READ8)
        mem_ptr <= #1 mem_ptr + 1'd1;
      else if (rw_type == `WB_READ16)
        mem_ptr <= #1 mem_ptr + 2'd2;
    end
end
 
 
// Logic for latching data that is read from wishbone
always @ (posedge wb_clk_i)
begin
  if (wb_ack_i)
    begin
      case (wb_sel_o)    // synthesis parallel_case full_case 
        4'b1000  :  mem[mem_ptr[1:0]] <= #1 wb_dat_i[31:24];            // byte 
        4'b0100  :  mem[mem_ptr[1:0]] <= #1 wb_dat_i[23:16];            // byte
        4'b0010  :  mem[mem_ptr[1:0]] <= #1 wb_dat_i[15:08];            // byte
        4'b0001  :  mem[mem_ptr[1:0]] <= #1 wb_dat_i[07:00];            // byte
 
        4'b1100  :                                                      // half
                    begin
                      mem[mem_ptr[1:0]]      <= #1 wb_dat_i[31:24];
                      mem[mem_ptr[1:0]+1'b1] <= #1 wb_dat_i[23:16];
                    end
        4'b0011  :                                                      // half
                    begin
                      mem[mem_ptr[1:0]]      <= #1 wb_dat_i[15:08];
                      mem[mem_ptr[1:0]+1'b1] <= #1 wb_dat_i[07:00];
                    end
        4'b1111  :                                                      // long
                    begin
                      mem[0] <= #1 wb_dat_i[31:24];
                      mem[1] <= #1 wb_dat_i[23:16];
                      mem[2] <= #1 wb_dat_i[15:08];
                      mem[3] <= #1 wb_dat_i[07:00];
                    end
      endcase
    end
end
 
 
assign input_data = {mem[0], mem[1], mem[2], mem[3]};
 
 
// Fifo counter and empty/full detection
always @ (posedge tck_i)
begin
  if (update_dr_i)
    fifo_cnt <= #1 'h0;
  else if (wb_end_tck & (~wb_end_tck_q) & (~latch_data))  // incrementing
    begin
      case (rw_type)  // synthesis parallel_case full_case
        `WB_READ8 : fifo_cnt <= #1 fifo_cnt + 1'd1;
        `WB_READ16: fifo_cnt <= #1 fifo_cnt + 2'd2;
        `WB_READ32: fifo_cnt <= #1 fifo_cnt + 3'd4;
      endcase
    end
  else if (~(wb_end_tck & (~wb_end_tck_q)) & latch_data)  // decrementing
    begin
      case (rw_type)  // synthesis parallel_case full_case
        `WB_READ8 : fifo_cnt <= #1 fifo_cnt - 1'd1;
        `WB_READ16: fifo_cnt <= #1 fifo_cnt - 2'd2;
        `WB_READ32: fifo_cnt <= #1 fifo_cnt - 3'd4;
      endcase
    end
end
 
 
assign fifo_full = fifo_cnt == 3'h4;
assign fifo_empty = fifo_cnt == 3'h0;
 
 
 
 
endmodule
 

Line No.	Rev	Author	Line
1	82	mohor	`//////////////////////////////////////////////////////////////////////`
2			`//// ////`
3			`//// dbg_wb.v ////`
4			`//// ////`
5			`//// ////`
6			`//// This file is part of the SoC/OpenRISC Development Interface ////`
7			`//// http://www.opencores.org/projects/DebugInterface/ ////`
8			`//// ////`
9			`//// Author(s): ////`
10			`//// Igor Mohor (igorm@opencores.org) ////`
11			`//// ////`
12			`//// ////`
13			`//// All additional information is avaliable in the README.txt ////`
14			`//// file. ////`
15			`//// ////`
16			`//////////////////////////////////////////////////////////////////////`
17			`//// ////`
18			`//// Copyright (C) 2000 - 2003 Authors ////`
19			`//// ////`
20			`//// This source file may be used and distributed without ////`
21			`//// restriction provided that this copyright statement is not ////`
22			`//// removed from the file and that any derivative work contains ////`
23			`//// the original copyright notice and the associated disclaimer. ////`
24			`//// ////`
25			`//// This source file is free software; you can redistribute it ////`
26			`//// and/or modify it under the terms of the GNU Lesser General ////`
27			`//// Public License as published by the Free Software Foundation; ////`
28			`//// either version 2.1 of the License, or (at your option) any ////`
29			`//// later version. ////`
30			`//// ////`
31			`//// This source is distributed in the hope that it will be ////`
32			`//// useful, but WITHOUT ANY WARRANTY; without even the implied ////`
33			`//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////`
34			`//// PURPOSE. See the GNU Lesser General Public License for more ////`
35			`//// details. ////`
36			`//// ////`
37			`//// You should have received a copy of the GNU Lesser General ////`
38			`//// Public License along with this source; if not, download it ////`
39			`//// from http://www.opencores.org/lgpl.shtml ////`
40			`//// ////`
41			`//////////////////////////////////////////////////////////////////////`
42			`//`
43			`// CVS Revision History`
44			`//`
45			`// $Log: not supported by cvs2svn $`
46	99	mohor	`// Revision 1.13 2004/01/15 12:09:43 mohor`
47			`// Working.`
48			`//`
49	97	mohor	`// Revision 1.12 2004/01/14 22:59:18 mohor`
50			`// Temp version.`
51			`//`
52	95	mohor	`// Revision 1.11 2004/01/14 12:29:40 mohor`
53			`// temp version. Resets will be changed in next version.`
54			`//`
55	94	mohor	`// Revision 1.10 2004/01/13 11:28:14 mohor`
56			`// tmp version.`
57			`//`
58	93	mohor	`// Revision 1.9 2004/01/10 07:50:24 mohor`
59			`// temp version.`
60			`//`
61	92	mohor	`// Revision 1.8 2004/01/09 12:48:44 mohor`
62			`// tmp version.`
63			`//`
64	91	mohor	`// Revision 1.7 2004/01/08 17:53:36 mohor`
65			`// tmp version.`
66			`//`
67	90	mohor	`// Revision 1.6 2004/01/07 11:58:56 mohor`
68			`// temp4 version.`
69			`//`
70	89	mohor	`// Revision 1.5 2004/01/06 17:15:19 mohor`
71			`// temp3 version.`
72			`//`
73	88	mohor	`// Revision 1.4 2004/01/05 12:16:00 mohor`
74			`// tmp2 version.`
75			`//`
76	87	mohor	`// Revision 1.3 2003/12/23 16:22:46 mohor`
77			`// Tmp version.`
78			`//`
79	86	mohor	`// Revision 1.2 2003/12/23 15:26:26 mohor`
80			`// Small fix.`
81			`//`
82	83	mohor	`// Revision 1.1 2003/12/23 15:09:04 mohor`
83			`// New directory structure. New version of the debug interface.`
84	82	mohor	`//`
85			`//`
86	83	mohor	`//`
87	82	mohor
88			`// synopsys translate_off`
89			`include "timescale.v"
90			`// synopsys translate_on`
91			`include "dbg_wb_defines.v"
92
93			`// Top module`
94			`module dbg_wb(`
95			`// JTAG signals`
96			`tck_i,`
97			`tdi_i,`
98			`tdo_o,`
99
100			`// TAP states`
101			`shift_dr_i,`
102			`pause_dr_i,`
103			`update_dr_i,`
104
105			`wishbone_ce_i,`
106			`crc_match_i,`
107			`crc_en_o,`
108			`shift_crc_o,`
109	95	mohor	`rst_i,`
110	82	mohor
111			`// WISHBONE common signals`
112	95	mohor	`wb_clk_i,`
113	82	mohor
114			`// WISHBONE master interface`
115			`wb_adr_o, wb_dat_o, wb_dat_i, wb_cyc_o, wb_stb_o, wb_sel_o,`
116			`wb_we_o, wb_ack_i, wb_cab_o, wb_err_i, wb_cti_o, wb_bte_o`
117
118			`);`
119
120			`// JTAG signals`
121	97	mohor	`input tck_i;`
122			`input tdi_i;`
123			`output tdo_o;`
124	82	mohor
125			`// TAP states`
126	97	mohor	`input shift_dr_i;`
127			`input pause_dr_i;`
128			`input update_dr_i;`
129	82	mohor
130	97	mohor	`input wishbone_ce_i;`
131			`input crc_match_i;`
132			`output crc_en_o;`
133			`output shift_crc_o;`
134			`input rst_i;`
135	82	mohor	`// WISHBONE common signals`
136	97	mohor	`input wb_clk_i;`
137	82	mohor
138			`// WISHBONE master interface`
139			`output [31:0] wb_adr_o;`
140			`output [31:0] wb_dat_o;`
141			`input [31:0] wb_dat_i;`
142			`output wb_cyc_o;`
143			`output wb_stb_o;`
144			`output [3:0] wb_sel_o;`
145			`output wb_we_o;`
146			`input wb_ack_i;`
147			`output wb_cab_o;`
148			`input wb_err_i;`
149			`output [2:0] wb_cti_o;`
150			`output [1:0] wb_bte_o;`
151
152			`reg wb_cyc_o;`
153			`reg [31:0] wb_adr_o;`
154	88	mohor	`reg [31:0] wb_dat_o;`
155	82	mohor	`reg [3:0] wb_sel_o;`
156
157			`reg tdo_o;`
158
159	88	mohor	`reg [50:0] dr;`
160			`wire enable;`
161	90	mohor	`wire cmd_cnt_en;`
162	88	mohor	`reg [1:0] cmd_cnt;`
163			`wire cmd_cnt_end;`
164			`reg cmd_cnt_end_q;`
165	90	mohor	`wire addr_len_cnt_en;`
166	88	mohor	`reg [5:0] addr_len_cnt;`
167			`reg [5:0] addr_len_cnt_limit;`
168			`wire addr_len_cnt_end;`
169	90	mohor	`wire crc_cnt_en;`
170	88	mohor	`reg [5:0] crc_cnt;`
171			`wire crc_cnt_end;`
172			`reg crc_cnt_end_q;`
173	90	mohor	`wire data_cnt_en;`
174	88	mohor	`reg [18:0] data_cnt;`
175			`reg [18:0] data_cnt_limit;`
176			`wire data_cnt_end;`
177	90	mohor	`reg data_cnt_end_q;`
178	88	mohor	`reg status_reset_en;`
179	82	mohor
180	90	mohor	`reg crc_match_reg;`
181	82	mohor
182	92	mohor	`reg [2:0] cmd, cmd_old, dr_cmd_latched;`
183			`reg [31:0] adr;`
184			`reg [15:0] len;`
185			`reg start_rd_tck;`
186	97	mohor	`reg rd_tck_started;`
187	92	mohor	`reg start_rd_sync1;`
188			`reg start_wb_rd;`
189			`reg start_wb_rd_q;`
190			`reg start_wr_tck;`
191			`reg start_wr_sync1;`
192			`reg start_wb_wr;`
193			`reg start_wb_wr_q;`
194	88	mohor
195	92	mohor	`wire dr_read;`
196			`wire dr_write;`
197			`wire dr_go;`
198	88	mohor
199	92	mohor	`reg dr_write_latched;`
200			`reg dr_read_latched;`
201			`reg dr_go_latched;`
202	82	mohor
203	92	mohor	`wire status_cnt_end;`
204	89	mohor
205	92	mohor	`wire byte, half, long;`
206			`reg byte_q, half_q, long_q;`
207	94	mohor	`reg byte_q2, half_q2, long_q2;`
208	92	mohor	`reg cmd_read;`
209			`reg cmd_write;`
210			`reg cmd_go;`
211	90	mohor
212	92	mohor	`reg status_cnt1, status_cnt2, status_cnt3, status_cnt4;`
213	90	mohor
214	92	mohor	reg [`STATUS_LEN -1:0] status;
215
216	97	mohor	`reg wb_error, wb_error_sync, wb_error_tck;`
217			`reg wb_overrun, wb_overrun_sync, wb_overrun_tck;`
218			`reg underrun_tck;`
219	92	mohor
220	97	mohor	`reg busy_wb;`
221			`reg busy_tck;`
222			`reg wb_end;`
223			`reg wb_end_rst;`
224			`reg wb_end_rst_sync;`
225			`reg wb_end_sync;`
226			`reg wb_end_tck, wb_end_tck_q;`
227			`reg busy_sync;`
228			`reg [799:0] tdo_text;`
229			`reg [399:0] latching_data_text;`
230			`reg latch_data;`
231			`reg [199:0] status_text;`
232	92	mohor
233	97	mohor	`reg set_addr, set_addr_sync, set_addr_wb, set_addr_wb_q;`
234			`reg read_cycle;`
235			`reg write_cycle;`
236			`reg [2:0] rw_type;`
237			`wire [31:0] input_data;`
238	92	mohor
239	97	mohor	`wire len_eq_0;`
240			`wire crc_cnt_31;`
241	93	mohor
242	97	mohor	`reg [1:0] ptr;`
243			`reg [2:0] fifo_cnt;`
244			`wire fifo_full;`
245			`wire fifo_empty;`
246			`reg [7:0] mem [0:3];`
247			`reg [2:0] mem_ptr;`
248			`reg wishbone_ce_sync;`
249			`reg wishbone_ce_rst;`
250			`wire go_prelim;`
251
252
253
254	82	mohor	`assign enable = wishbone_ce_i & shift_dr_i;`
255	90	mohor	`assign crc_en_o = enable & crc_cnt_end & (~status_cnt_end);`
256	89	mohor	`assign shift_crc_o = enable & status_cnt_end; // Signals dbg module to shift out the CRC`
257	82	mohor
258
259	97	mohor	`// Selecting where to take the data from`
260	82	mohor	`always @ (posedge tck_i)`
261			`begin`
262	93	mohor	`if (update_dr_i)`
263			`ptr <= #1 2'h0;`
264	95	mohor	`else if (read_cycle & crc_cnt_31) // first latch`
265	93	mohor	`ptr <= #1 ptr + 1'b1;`
266	95	mohor	`else if (read_cycle & byte & (~byte_q))`
267	93	mohor	`ptr <= ptr + 1'd1;`
268			`end`
269
270
271	97	mohor	`// Shift register for shifting in and out the data`
272	93	mohor	`always @ (posedge tck_i)`
273			`begin`
274	95	mohor	`if (read_cycle & crc_cnt_31)`
275	90	mohor	`begin`
276	93	mohor	`dr[31:0] <= #1 input_data[31:0];`
277	97	mohor	`latch_data <= #1 1'b1;`
278	99	mohor	`latching_data_text <= #1 "First latch";`
279	93	mohor	`end`
280			`else if (read_cycle & crc_cnt_end)`
281			`begin`
282	95	mohor	`case (rw_type) // synthesis parallel_case full_case`
283	90	mohor	`WB_READ8 : begin
284			`if(byte & (~byte_q))`
285	92	mohor	`begin`
286	93	mohor	`case (ptr) // synthesis parallel_case`
287			`2'b00 : dr[31:24] <= #1 input_data[31:24];`
288			`2'b01 : dr[31:24] <= #1 input_data[23:16];`
289			`2'b10 : dr[31:24] <= #1 input_data[15:8];`
290			`2'b11 : dr[31:24] <= #1 input_data[7:0];`
291			`endcase`
292	97	mohor	`latch_data <= #1 1'b1;`
293	99	mohor	`latching_data_text <= #1 "8 bit latched";`
294	92	mohor	`end`
295	90	mohor	`else`
296	92	mohor	`begin`
297	93	mohor	`dr[31:24] <= #1 {dr[30:24], 1'b0};`
298	97	mohor	`latch_data <= #1 1'b0;`
299	99	mohor	`latching_data_text <= #1 "8 bit shifted";`
300	92	mohor	`end`
301	90	mohor	`end`
302			`WB_READ16: begin
303			`if(half & (~half_q))`
304	92	mohor	`begin`
305	93	mohor	`if (ptr[1])`
306	97	mohor	`dr[31:16] <= #1 input_data[15:0];`
307			`else`
308	93	mohor	`dr[31:16] <= #1 input_data[31:16];`
309	99	mohor	`latching_data_text <= #1 "16 bit latched";`
310	97	mohor	`latch_data <= #1 1'b1;`
311	92	mohor	`end`
312	90	mohor	`else`
313	92	mohor	`begin`
314	93	mohor	`dr[31:16] <= #1 {dr[30:16], 1'b0};`
315	97	mohor	`latch_data <= #1 1'b0;`
316	99	mohor	`latching_data_text <= #1 "16 bit shifted";`
317	92	mohor	`end`
318	90	mohor	`end`
319			`WB_READ32: begin
320			`if(long & (~long_q))`
321	92	mohor	`begin`
322	93	mohor	`dr[31:0] <= #1 input_data[31:0];`
323	97	mohor	`latch_data <= #1 1'b1;`
324	99	mohor	`latching_data_text <= #1 "32 bit latched";`
325	92	mohor	`end`
326	90	mohor	`else`
327	92	mohor	`begin`
328	93	mohor	`dr[31:0] <= #1 {dr[30:0], 1'b0};`
329	97	mohor	`latch_data <= #1 1'b0;`
330	99	mohor	`latching_data_text <= #1 "32 bit shifted";`
331	92	mohor	`end`
332	90	mohor	`end`
333			`endcase`
334			`end`
335	94	mohor	`else if (enable & ((~addr_len_cnt_end) \| (~cmd_cnt_end) \| ((~data_cnt_end) & write_cycle)))`
336	92	mohor	`begin`
337	99	mohor	`dr <= #1 {dr[49:0], tdi_i};`
338			`latch_data <= #1 1'b0;`
339			`latching_data_text <= #1 "tdi shifted in";`
340	92	mohor	`end`
341	94	mohor	`else`
342	99	mohor	`latching_data_text <= #1 "nothing";`
343	82	mohor	`end`
344
345
346	90	mohor	`assign cmd_cnt_en = enable & (~cmd_cnt_end);`
347	88	mohor
348	97	mohor
349			`// Command counter`
350	95	mohor	`always @ (posedge tck_i or posedge rst_i)`
351	82	mohor	`begin`
352	95	mohor	`if (rst_i)`
353	87	mohor	`cmd_cnt <= #1 'h0;`
354	82	mohor	`else if (update_dr_i)`
355	87	mohor	`cmd_cnt <= #1 'h0;`
356	90	mohor	`else if (cmd_cnt_en)`
357	87	mohor	`cmd_cnt <= #1 cmd_cnt + 1'b1;`
358	82	mohor	`end`
359
360
361	90	mohor	`assign addr_len_cnt_en = enable & cmd_cnt_end & (~addr_len_cnt_end);`
362
363	97	mohor
364			`// Address/length counter`
365	95	mohor	`always @ (posedge tck_i or posedge rst_i)`
366	87	mohor	`begin`
367	95	mohor	`if (rst_i)`
368	88	mohor	`addr_len_cnt <= #1 'h0;`
369			`else if (update_dr_i)`
370			`addr_len_cnt <= #1 'h0;`
371	90	mohor	`else if (addr_len_cnt_en)`
372	88	mohor	`addr_len_cnt <= #1 addr_len_cnt + 1'b1;`
373			`end`
374
375
376	95	mohor	`assign data_cnt_en = enable & (~data_cnt_end) & (cmd_cnt_end & write_cycle \| crc_cnt_end & read_cycle);`
377	90	mohor
378	97	mohor
379			`// Data counter`
380	95	mohor	`always @ (posedge tck_i or posedge rst_i)`
381	88	mohor	`begin`
382	95	mohor	`if (rst_i)`
383	87	mohor	`data_cnt <= #1 'h0;`
384			`else if (update_dr_i)`
385			`data_cnt <= #1 'h0;`
386	90	mohor	`else if (data_cnt_en)`
387	87	mohor	`data_cnt <= #1 data_cnt + 1'b1;`
388			`end`
389	82	mohor
390	87	mohor
391	88	mohor
392	93	mohor	`assign byte = data_cnt[2:0] == 3'd7;`
393			`assign half = data_cnt[3:0] == 4'd15;`
394			`assign long = data_cnt[4:0] == 5'd31;`
395	88	mohor
396
397			`always @ (posedge tck_i)`
398			`begin`
399	95	mohor	`byte_q <= #1 byte;`
400			`half_q <= #1 half;`
401			`long_q <= #1 long;`
402			`byte_q2 <= #1 byte_q;`
403			`half_q2 <= #1 half_q;`
404			`long_q2 <= #1 long_q;`
405	88	mohor	`end`
406
407
408	89	mohor	assign dr_read = (dr[2:0] == `WB_READ8) \| (dr[2:0] == `WB_READ16) \| (dr[2:0] == `WB_READ32);
409			assign dr_write = (dr[2:0] == `WB_WRITE8) \| (dr[2:0] == `WB_WRITE16) \| (dr[2:0] == `WB_WRITE32);
410			assign dr_go = dr[2:0] == `WB_GO;
411	88	mohor
412
413	97	mohor	`// Latching instruction`
414	88	mohor	`always @ (posedge tck_i)`
415			`begin`
416			`if (update_dr_i)`
417	91	mohor	`begin`
418	99	mohor	`dr_cmd_latched <= #1 3'h0;`
419	91	mohor	`dr_read_latched <= #1 1'b0;`
420			`dr_write_latched <= #1 1'b0;`
421			`dr_go_latched <= #1 1'b0;`
422			`end`
423	88	mohor	`else if (cmd_cnt_end & (~cmd_cnt_end_q))`
424	91	mohor	`begin`
425	99	mohor	`dr_cmd_latched <= #1 dr[2:0];`
426	91	mohor	`dr_read_latched <= #1 dr_read;`
427			`dr_write_latched <= #1 dr_write;`
428			`dr_go_latched <= #1 dr_go;`
429			`end`
430	88	mohor	`end`
431
432
433	97	mohor	`// Upper limit. Address/length counter counts until this value is reached`
434	88	mohor	`always @ (posedge tck_i)`
435			`begin`
436	90	mohor	`if (cmd_cnt == 2'h2)`
437	88	mohor	`begin`
438	95	mohor	`if ((~dr[0]) & (~tdi_i)) // (current command is WB_STATUS or WB_GO)`
439	99	mohor	`addr_len_cnt_limit <= #1 6'd0;`
440	90	mohor	`else // (current command is WB_WRITEx or WB_READx)`
441	99	mohor	`addr_len_cnt_limit <= #1 6'd48;`
442	88	mohor	`end`
443			`end`
444
445
446	94	mohor	`assign go_prelim = (cmd_cnt == 2'h2) & dr[1] & (~dr[0]) & (~tdi_i);`
447
448	88	mohor
449	97	mohor	`// Upper limit. Data counter counts until this value is reached.`
450	94	mohor	`always @ (posedge tck_i)`
451			`begin`
452			`if (update_dr_i)`
453	99	mohor	`data_cnt_limit <= #1 {len, 3'b000};`
454	94	mohor	`end`
455	88	mohor
456	90	mohor
457	94	mohor	`assign crc_cnt_en = enable & (~crc_cnt_end) & (cmd_cnt_end & addr_len_cnt_end & (~write_cycle) \| (data_cnt_end & write_cycle));`
458
459	97	mohor
460	82	mohor	`// crc counter`
461	95	mohor	`always @ (posedge tck_i or posedge rst_i)`
462	82	mohor	`begin`
463	95	mohor	`if (rst_i)`
464	82	mohor	`crc_cnt <= #1 'h0;`
465	90	mohor	`else if(crc_cnt_en)`
466	82	mohor	`crc_cnt <= #1 crc_cnt + 1'b1;`
467			`else if (update_dr_i)`
468			`crc_cnt <= #1 'h0;`
469			`end`
470
471	87	mohor	`assign cmd_cnt_end = cmd_cnt == 2'h3;`
472	88	mohor	`assign addr_len_cnt_end = addr_len_cnt == addr_len_cnt_limit;`
473	87	mohor	`assign crc_cnt_end = crc_cnt == 6'd32;`
474	93	mohor	`assign crc_cnt_31 = crc_cnt == 6'd31;`
475	89	mohor	`assign data_cnt_end = (data_cnt == data_cnt_limit);`
476	82	mohor
477			`always @ (posedge tck_i)`
478			`begin`
479	90	mohor	`crc_cnt_end_q <= #1 crc_cnt_end;`
480			`cmd_cnt_end_q <= #1 cmd_cnt_end;`
481			`data_cnt_end_q <= #1 data_cnt_end;`
482	82	mohor	`end`
483
484	90	mohor
485	97	mohor	`// Status counter is made of 4 serialy connected registers`
486	95	mohor	`always @ (posedge tck_i or posedge rst_i)`
487	82	mohor	`begin`
488	95	mohor	`if (rst_i)`
489	90	mohor	`status_cnt1 <= #1 1'b0;`
490	82	mohor	`else if (update_dr_i)`
491	90	mohor	`status_cnt1 <= #1 1'b0;`
492	94	mohor	`else if (data_cnt_end & read_cycle \|`
493	95	mohor	`crc_cnt_end & (~read_cycle)`
494	90	mohor	`)`
495			`status_cnt1 <= #1 1'b1;`
496	82	mohor	`end`
497
498	90	mohor
499	95	mohor	`always @ (posedge tck_i or posedge rst_i)`
500	90	mohor	`begin`

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