//////////////////////////////////////////////////////////////////////
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//////////////////////////////////////////////////////////////////////
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//// ////
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//// ////
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//// adbg_or1k_module.v ////
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//// adbg_or1k_module.v ////
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//// ////
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//// ////
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//// ////
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//// ////
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//// This file is part of the SoC Advanced Debug Interface. ////
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//// This file is part of the SoC Advanced Debug Interface. ////
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//// ////
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//// ////
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//// Author(s): ////
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//// Author(s): ////
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//// Nathan Yawn (nathan.yawn@opencores.org) ////
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//// Nathan Yawn (nathan.yawn@opencores.org) ////
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//// ////
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//// ////
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//// ////
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//// ////
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//// ////
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//// ////
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//////////////////////////////////////////////////////////////////////
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//////////////////////////////////////////////////////////////////////
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//// ////
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//// ////
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//// Copyright (C) 2008 Authors ////
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//// Copyright (C) 2008 Authors ////
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//// ////
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//// ////
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//// This source file may be used and distributed without ////
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//// This source file may be used and distributed without ////
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//// restriction provided that this copyright statement is not ////
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//// restriction provided that this copyright statement is not ////
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//// removed from the file and that any derivative work contains ////
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//// removed from the file and that any derivative work contains ////
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//// the original copyright notice and the associated disclaimer. ////
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//// the original copyright notice and the associated disclaimer. ////
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//// ////
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//// ////
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//// This source file is free software; you can redistribute it ////
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//// This source file is free software; you can redistribute it ////
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//// and/or modify it under the terms of the GNU Lesser General ////
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//// and/or modify it under the terms of the GNU Lesser General ////
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//// Public License as published by the Free Software Foundation; ////
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//// Public License as published by the Free Software Foundation; ////
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//// either version 2.1 of the License, or (at your option) any ////
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//// either version 2.1 of the License, or (at your option) any ////
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//// later version. ////
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//// later version. ////
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//// ////
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//// ////
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//// This source is distributed in the hope that it will be ////
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//// This source is distributed in the hope that it will be ////
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//// useful, but WITHOUT ANY WARRANTY; without even the implied ////
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//// useful, but WITHOUT ANY WARRANTY; without even the implied ////
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//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////
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//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////
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//// PURPOSE. See the GNU Lesser General Public License for more ////
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//// PURPOSE. See the GNU Lesser General Public License for more ////
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//// details. ////
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//// details. ////
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//// ////
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//// ////
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//// You should have received a copy of the GNU Lesser General ////
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//// You should have received a copy of the GNU Lesser General ////
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//// Public License along with this source; if not, download it ////
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//// Public License along with this source; if not, download it ////
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//// from http://www.opencores.org/lgpl.shtml ////
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//// from http://www.opencores.org/lgpl.shtml ////
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//// ////
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//// ////
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//////////////////////////////////////////////////////////////////////
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//////////////////////////////////////////////////////////////////////
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//
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//
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// CVS Revision History
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// CVS Revision History
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//
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//
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// $Log: adbg_or1k_module.v,v $
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// $Log: adbg_or1k_module.v,v $
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// Revision 1.2 2009/05/17 20:54:56 Nathan
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// Revision 1.2 2009/05/17 20:54:56 Nathan
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// Changed email address to opencores.org
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// Changed email address to opencores.org
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//
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//
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// Revision 1.1 2008/07/22 20:28:31 Nathan
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// Revision 1.1 2008/07/22 20:28:31 Nathan
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// Changed names of all files and modules (prefixed an a, for advanced). Cleanup, indenting. No functional changes.
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// Changed names of all files and modules (prefixed an a, for advanced). Cleanup, indenting. No functional changes.
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//
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//
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// Revision 1.7 2008/07/11 08:13:29 Nathan
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// Revision 1.7 2008/07/11 08:13:29 Nathan
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// Latch opcode on posedge, like other signals. This fixes a problem
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// Latch opcode on posedge, like other signals. This fixes a problem
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// when the module is used with a Xilinx BSCAN TAP. Added signals to
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// when the module is used with a Xilinx BSCAN TAP. Added signals to
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// allow modules to inhibit latching of a new active module by the top
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// allow modules to inhibit latching of a new active module by the top
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// module. This allows the sub-modules to force the top level module
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// module. This allows the sub-modules to force the top level module
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// to ignore the command present in the input shift register after e.g.
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// to ignore the command present in the input shift register after e.g.
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// a burst read.
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// a burst read.
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//
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//
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`include "adbg_or1k_defines.v"
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`include "adbg_or1k_defines.v"
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// Module interface
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// Module interface
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module adbg_or1k_module (
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module adbg_or1k_module (
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// JTAG signals
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// JTAG signals
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tck_i,
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tck_i,
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module_tdo_o,
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module_tdo_o,
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tdi_i,
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tdi_i,
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// TAP states
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// TAP states
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capture_dr_i,
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capture_dr_i,
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shift_dr_i,
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shift_dr_i,
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update_dr_i,
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update_dr_i,
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data_register_i, // the data register is at top level, shared between all modules
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data_register_i, // the data register is at top level, shared between all modules
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module_select_i,
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module_select_i,
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top_inhibit_o,
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top_inhibit_o,
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rst_i,
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rst_i,
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// Interfate to the OR1K debug unit
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// Interfate to the OR1K debug unit
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cpu_clk_i,
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cpu_clk_i,
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cpu_addr_o,
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cpu_addr_o,
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cpu_data_i,
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cpu_data_i,
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cpu_data_o,
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cpu_data_o,
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cpu_bp_i,
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cpu_bp_i,
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cpu_stall_o,
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cpu_stall_o,
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cpu_stb_o,
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cpu_stb_o,
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cpu_we_o,
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cpu_we_o,
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cpu_ack_i,
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cpu_ack_i,
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cpu_rst_o
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cpu_rst_o
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);
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);
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// JTAG signals
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// JTAG signals
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input tck_i;
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input tck_i;
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output module_tdo_o;
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output module_tdo_o;
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input tdi_i; // This is only used by the CRC module - data_register_i[MSB] is delayed a cycle
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input tdi_i; // This is only used by the CRC module - data_register_i[MSB] is delayed a cycle
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// TAP states
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// TAP states
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input capture_dr_i;
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input capture_dr_i;
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input shift_dr_i;
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input shift_dr_i;
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input update_dr_i;
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input update_dr_i;
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input [52:0] data_register_i;
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input [52:0] data_register_i;
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input module_select_i;
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input module_select_i;
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output top_inhibit_o;
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output top_inhibit_o;
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input rst_i;
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input rst_i;
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// WISHBONE master interface
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// WISHBONE master interface
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input cpu_clk_i; // 'bus' style interface to SPRs
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input cpu_clk_i; // 'bus' style interface to SPRs
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output [31:0] cpu_addr_o;
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output [31:0] cpu_addr_o;
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input [31:0] cpu_data_i;
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input [31:0] cpu_data_i;
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output [31:0] cpu_data_o;
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output [31:0] cpu_data_o;
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output cpu_stb_o;
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output cpu_stb_o;
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output cpu_we_o;
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output cpu_we_o;
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input cpu_ack_i;
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input cpu_ack_i;
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output cpu_rst_o; // control lines
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output cpu_rst_o; // control lines
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input cpu_bp_i;
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input cpu_bp_i;
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output cpu_stall_o;
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output cpu_stall_o;
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// Declare inputs / outputs as wires / registers
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// Declare inputs / outputs as wires / registers
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reg module_tdo_o;
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reg module_tdo_o;
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reg top_inhibit_o;
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reg top_inhibit_o;
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// Registers to hold state etc.
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// Registers to hold state etc.
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reg [31:0] address_counter; // Holds address for next Wishbone access
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reg [31:0] address_counter; // Holds address for next Wishbone access
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reg [5:0] bit_count; // How many bits have been shifted in/out
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reg [5:0] bit_count; // How many bits have been shifted in/out
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reg [15:0] word_count; // bytes remaining in current burst command
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reg [15:0] word_count; // bytes remaining in current burst command
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reg [3:0] operation; // holds the current command (rd/wr, word size)
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reg [3:0] operation; // holds the current command (rd/wr, word size)
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reg [31:0] data_out_shift_reg; // parallel-load output shift register
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reg [31:0] data_out_shift_reg; // parallel-load output shift register
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reg [`DBG_OR1K_REGSELECT_SIZE-1:0] internal_register_select; // Holds index of currently selected register
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reg [`DBG_OR1K_REGSELECT_SIZE-1:0] internal_register_select; // Holds index of currently selected register
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wire [1:0] internal_reg_status; // Holds CPU stall and reset status - signal is output of separate module
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wire [1:0] internal_reg_status; // Holds CPU stall and reset status - signal is output of separate module
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// Control signals for the various counters / registers / state machines
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// Control signals for the various counters / registers / state machines
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reg addr_sel; // Selects data for address_counter. 0 = data_register_i, 1 = incremented address count
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reg addr_sel; // Selects data for address_counter. 0 = data_register_i, 1 = incremented address count
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reg addr_ct_en; // Enable signal for address counter register
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reg addr_ct_en; // Enable signal for address counter register
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reg op_reg_en; // Enable signal for 'operation' register
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reg op_reg_en; // Enable signal for 'operation' register
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reg bit_ct_en; // enable bit counter
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reg bit_ct_en; // enable bit counter
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reg bit_ct_rst; // reset (zero) bit count register
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reg bit_ct_rst; // reset (zero) bit count register
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reg word_ct_sel; // Selects data for byte counter. 0 = data_register_i, 1 = decremented byte count
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reg word_ct_sel; // Selects data for byte counter. 0 = data_register_i, 1 = decremented byte count
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reg word_ct_en; // Enable byte counter register
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reg word_ct_en; // Enable byte counter register
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reg out_reg_ld_en; // Enable parallel load of data_out_shift_reg
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reg out_reg_ld_en; // Enable parallel load of data_out_shift_reg
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reg out_reg_shift_en; // Enable shift of data_out_shift_reg
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reg out_reg_shift_en; // Enable shift of data_out_shift_reg
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reg out_reg_data_sel; // 0 = BIU data, 1 = internal register data
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reg out_reg_data_sel; // 0 = BIU data, 1 = internal register data
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reg [1:0] tdo_output_sel; // Selects signal to send to TDO. 0 = ready bit, 1 = output register, 2 = CRC match, 3 = CRC shift reg.
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reg [1:0] tdo_output_sel; // Selects signal to send to TDO. 0 = ready bit, 1 = output register, 2 = CRC match, 3 = CRC shift reg.
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reg biu_strobe; // Indicates that the bus unit should latch data and start a transaction
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reg biu_strobe; // Indicates that the bus unit should latch data and start a transaction
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reg crc_clr; // resets CRC module
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reg crc_clr; // resets CRC module
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reg crc_en; // does 1-bit iteration in CRC module
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reg crc_en; // does 1-bit iteration in CRC module
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reg crc_in_sel; // selects incoming write data (=0) or outgoing read data (=1)as input to CRC module
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reg crc_in_sel; // selects incoming write data (=0) or outgoing read data (=1)as input to CRC module
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reg crc_shift_en; // CRC reg is also it's own output shift register; this enables a shift
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reg crc_shift_en; // CRC reg is also it's own output shift register; this enables a shift
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reg regsel_ld_en; // Reg. select register load enable
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reg regsel_ld_en; // Reg. select register load enable
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reg intreg_ld_en; // load enable for internal registers
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reg intreg_ld_en; // load enable for internal registers
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// Status signals
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// Status signals
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wire word_count_zero; // true when byte counter is zero
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wire word_count_zero; // true when byte counter is zero
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wire bit_count_max; // true when bit counter is equal to current word size
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wire bit_count_max; // true when bit counter is equal to current word size
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wire module_cmd; // inverse of MSB of data_register_i. 1 means current cmd not for top level (but is for us)
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wire module_cmd; // inverse of MSB of data_register_i. 1 means current cmd not for top level (but is for us)
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wire biu_ready; // indicates that the BIU has finished the last command
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wire biu_ready; // indicates that the BIU has finished the last command
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wire burst_instruction; // True when the input_data_i reg has a valid burst instruction for this module
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wire burst_instruction; // True when the input_data_i reg has a valid burst instruction for this module
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wire intreg_instruction; // True when the input_data_i reg has a valid internal register instruction
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wire intreg_instruction; // True when the input_data_i reg has a valid internal register instruction
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wire intreg_write; // True when the input_data_i reg has an internal register write op
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wire intreg_write; // True when the input_data_i reg has an internal register write op
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wire rd_op; // True when operation in the opcode reg is a read, false when a write
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wire rd_op; // True when operation in the opcode reg is a read, false when a write
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wire crc_match; // indicates whether data_register_i matches computed CRC
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wire crc_match; // indicates whether data_register_i matches computed CRC
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wire bit_count_32; // true when bit count register == 32, for CRC after burst writes
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wire bit_count_32; // true when bit count register == 32, for CRC after burst writes
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// Intermediate signals
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// Intermediate signals
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wire [5:0] word_size_bits; // 8,16, or 32. Decoded from 'operation'
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wire [5:0] word_size_bits; // 8,16, or 32. Decoded from 'operation'
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wire [2:0] address_increment; // How much to add to the address counter each iteration
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wire [2:0] address_increment; // How much to add to the address counter each iteration
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wire [32:0] incremented_address; // value of address counter plus 'word_size'
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wire [32:0] incremented_address; // value of address counter plus 'word_size'
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wire [31:0] data_to_addr_counter; // output of the mux in front of the address counter inputs
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wire [31:0] data_to_addr_counter; // output of the mux in front of the address counter inputs
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wire [15:0] data_to_word_counter; // output of the mux in front of the byte counter input
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wire [15:0] data_to_word_counter; // output of the mux in front of the byte counter input
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wire [15:0] decremented_word_count;
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wire [15:0] decremented_word_count;
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wire [31:0] address_data_in; // from data_register_i
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wire [31:0] address_data_in; // from data_register_i
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wire [15:0] count_data_in; // from data_register_i
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wire [15:0] count_data_in; // from data_register_i
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wire [3:0] operation_in; // from data_register_i
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wire [3:0] operation_in; // from data_register_i
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wire [31:0] data_to_biu; // from data_register_i
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wire [31:0] data_to_biu; // from data_register_i
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wire [31:0] data_from_biu; // to data_out_shift_register
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wire [31:0] data_from_biu; // to data_out_shift_register
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wire [31:0] crc_data_out; // output of CRC module, to output shift register
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wire [31:0] crc_data_out; // output of CRC module, to output shift register
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wire crc_data_in; // input to CRC module, either data_register_i[52] or data_out_shift_reg[0]
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wire crc_data_in; // input to CRC module, either data_register_i[52] or data_out_shift_reg[0]
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wire crc_serial_out;
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wire crc_serial_out;
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wire [`DBG_OR1K_REGSELECT_SIZE-1:0] reg_select_data; // from data_register_i, input to internal register select register
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wire [`DBG_OR1K_REGSELECT_SIZE-1:0] reg_select_data; // from data_register_i, input to internal register select register
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wire [31:0] out_reg_data; // parallel input to the output shift register
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wire [31:0] out_reg_data; // parallel input to the output shift register
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reg [31:0] data_from_internal_reg; // data from internal reg. MUX to output shift register
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reg [31:0] data_from_internal_reg; // data from internal reg. MUX to output shift register
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wire status_reg_wr;
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wire status_reg_wr;
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/////////////////////////////////////////////////
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/////////////////////////////////////////////////
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// Combinatorial assignments
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// Combinatorial assignments
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assign module_cmd = ~(data_register_i[52]);
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assign module_cmd = ~(data_register_i[52]);
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assign operation_in = data_register_i[51:48];
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assign operation_in = data_register_i[51:48];
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assign address_data_in = data_register_i[47:16];
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assign address_data_in = data_register_i[47:16];
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assign count_data_in = data_register_i[15:0];
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assign count_data_in = data_register_i[15:0];
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assign data_to_biu = data_register_i[52:21];
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assign data_to_biu = data_register_i[52:21];
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assign reg_select_data = data_register_i[47:(47-(`DBG_OR1K_REGSELECT_SIZE-1))];
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assign reg_select_data = data_register_i[47:(47-(`DBG_OR1K_REGSELECT_SIZE-1))];
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////////////////////////////////////////////////
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////////////////////////////////////////////////
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// Operation decoder
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// Operation decoder
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// These are only used before the operation is latched, so decode them from operation_in
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// These are only used before the operation is latched, so decode them from operation_in
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assign burst_instruction = (operation_in == `DBG_OR1K_CMD_BWRITE32) | (operation_in == `DBG_OR1K_CMD_BREAD32);
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assign burst_instruction = (operation_in == `DBG_OR1K_CMD_BWRITE32) | (operation_in == `DBG_OR1K_CMD_BREAD32);
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assign intreg_instruction = ((operation_in == `DBG_OR1K_CMD_IREG_WR) | (operation_in == `DBG_OR1K_CMD_IREG_SEL));
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assign intreg_instruction = ((operation_in == `DBG_OR1K_CMD_IREG_WR) | (operation_in == `DBG_OR1K_CMD_IREG_SEL));
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assign intreg_write = (operation_in == `DBG_OR1K_CMD_IREG_WR);
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assign intreg_write = (operation_in == `DBG_OR1K_CMD_IREG_WR);
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|
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// These are constant, the CPU module only does 32-bit accesses
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// These are constant, the CPU module only does 32-bit accesses
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assign word_size_bits = 5'd31; // Bits is actually bits-1, to make the FSM easier
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assign word_size_bits = 5'd31; // Bits is actually bits-1, to make the FSM easier
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assign address_increment = 3'd1; // This is only used to increment the address. SPRs are word-addressed.
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assign address_increment = 3'd1; // This is only used to increment the address. SPRs are word-addressed.
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|
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// This is the only thing that actually needs to be saved and 'decoded' from the latched opcode
|
// This is the only thing that actually needs to be saved and 'decoded' from the latched opcode
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// It goes to the BIU each time a transaction is started.
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// It goes to the BIU each time a transaction is started.
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assign rd_op = operation[2];
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assign rd_op = operation[2];
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|
|
|
|
////////////////////////////////////////////////
|
////////////////////////////////////////////////
|
// Module-internal register select register (no, that's not redundant.)
|
// Module-internal register select register (no, that's not redundant.)
|
// Also internal register output MUX
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// Also internal register output MUX
|
|
|
always @ (posedge tck_i or posedge rst_i)
|
always @ (posedge tck_i or posedge rst_i)
|
begin
|
begin
|
if(rst_i) internal_register_select = 1'h0;
|
if(rst_i) internal_register_select = 1'h0;
|
else if(regsel_ld_en) internal_register_select = reg_select_data;
|
else if(regsel_ld_en) internal_register_select = reg_select_data;
|
end
|
end
|
|
|
// This is completely unnecessary here, since the module has only 1 internal
|
// This is completely unnecessary here, since the module has only 1 internal
|
// register. However, to make the module expandable, it is included anyway.
|
// register. However, to make the module expandable, it is included anyway.
|
always @ (internal_register_select or internal_reg_status)
|
always @ (internal_register_select or internal_reg_status)
|
begin
|
begin
|
case(internal_register_select)
|
case(internal_register_select)
|
`DBG_OR1K_INTREG_STATUS: data_from_internal_reg = {30'h0, internal_reg_status};
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`DBG_OR1K_INTREG_STATUS: data_from_internal_reg = {30'h0, internal_reg_status};
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default: data_from_internal_reg = {30'h0, internal_reg_status};
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default: data_from_internal_reg = {30'h0, internal_reg_status};
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endcase
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endcase
|
end
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end
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|
|
|
|
|
////////////////////////////////////////////////////////////////////
|
////////////////////////////////////////////////////////////////////
|
// Module-internal registers
|
// Module-internal registers
|
// These have generic read/write/select code, but
|
// These have generic read/write/select code, but
|
// individual registers may have special behavior, defined here.
|
// individual registers may have special behavior, defined here.
|
|
|
// This is the status register, which holds the reset and stall states.
|
// This is the status register, which holds the reset and stall states.
|
|
|
assign status_reg_wr = (intreg_ld_en & (reg_select_data == `DBG_OR1K_INTREG_STATUS));
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assign status_reg_wr = (intreg_ld_en & (reg_select_data == `DBG_OR1K_INTREG_STATUS));
|
|
|
adbg_or1k_status_reg or1k_statusreg_i (
|
adbg_or1k_status_reg or1k_statusreg_i (
|
.data_i(data_register_i[(47-`DBG_OR1K_REGSELECT_SIZE):(47-(`DBG_OR1K_REGSELECT_SIZE+1))]),
|
.data_i(data_register_i[(47-`DBG_OR1K_REGSELECT_SIZE):(47-(`DBG_OR1K_REGSELECT_SIZE+1))]),
|
.we_i(status_reg_wr),
|
.we_i(status_reg_wr),
|
.tck_i(tck_i),
|
.tck_i(tck_i),
|
.bp_i(cpu_bp_i),
|
.bp_i(cpu_bp_i),
|
.rst_i(rst_i),
|
.rst_i(rst_i),
|
.cpu_clk_i(cpu_clk_i),
|
.cpu_clk_i(cpu_clk_i),
|
.ctrl_reg_o(internal_reg_status),
|
.ctrl_reg_o(internal_reg_status),
|
.cpu_stall_o(cpu_stall_o),
|
.cpu_stall_o(cpu_stall_o),
|
.cpu_rst_o(cpu_rst_o)
|
.cpu_rst_o(cpu_rst_o)
|
);
|
);
|
|
|
|
|
///////////////////////////////////////////////
|
///////////////////////////////////////////////
|
// Address counter
|
// Address counter
|
|
|
assign data_to_addr_counter = (addr_sel) ? incremented_address[31:0] : address_data_in;
|
assign data_to_addr_counter = (addr_sel) ? incremented_address[31:0] : address_data_in;
|
assign incremented_address = address_counter + address_increment;
|
assign incremented_address = address_counter + address_increment;
|
|
|
// Technically, since this data (sometimes) comes from the input shift reg, we should latch on
|
// Technically, since this data (sometimes) comes from the input shift reg, we should latch on
|
// negedge, per the JTAG spec. But that makes things difficult when incrementing.
|
// negedge, per the JTAG spec. But that makes things difficult when incrementing.
|
always @ (posedge tck_i or posedge rst_i) // JTAG spec specifies latch on negative edge in UPDATE_DR state
|
always @ (posedge tck_i or posedge rst_i) // JTAG spec specifies latch on negative edge in UPDATE_DR state
|
begin
|
begin
|
if(rst_i)
|
if(rst_i)
|
address_counter <= 32'h0;
|
address_counter <= 32'h0;
|
else if(addr_ct_en)
|
else if(addr_ct_en)
|
address_counter <= data_to_addr_counter;
|
address_counter <= data_to_addr_counter;
|
end
|
end
|
|
|
////////////////////////////////////////
|
////////////////////////////////////////
|
// Opcode latch
|
// Opcode latch
|
|
|
always @ (posedge tck_i or posedge rst_i) // JTAG spec specifies latch on negative edge in UPDATE_DR state
|
always @ (posedge tck_i or posedge rst_i) // JTAG spec specifies latch on negative edge in UPDATE_DR state
|
begin
|
begin
|
if(rst_i)
|
if(rst_i)
|
operation <= 4'h0;
|
operation <= 4'h0;
|
else if(op_reg_en)
|
else if(op_reg_en)
|
operation <= operation_in;
|
operation <= operation_in;
|
end
|
end
|
|
|
//////////////////////////////////////
|
//////////////////////////////////////
|
// Bit counter
|
// Bit counter
|
|
|
always @ (posedge tck_i or posedge rst_i)
|
always @ (posedge tck_i or posedge rst_i)
|
begin
|
begin
|
|
|
if(rst_i) bit_count <= 6'h0;
|
if(rst_i) bit_count <= 6'h0;
|
else if(bit_ct_rst) bit_count <= 6'h0;
|
else if(bit_ct_rst) bit_count <= 6'h0;
|
else if(bit_ct_en) bit_count <= bit_count + 6'h1;
|
else if(bit_ct_en) bit_count <= bit_count + 6'h1;
|
|
|
end
|
end
|
|
|
assign bit_count_max = (bit_count == word_size_bits) ? 1'b1 : 1'b0 ;
|
assign bit_count_max = (bit_count == word_size_bits) ? 1'b1 : 1'b0 ;
|
assign bit_count_32 = (bit_count == 6'h20) ? 1'b1 : 1'b0;
|
assign bit_count_32 = (bit_count == 6'h20) ? 1'b1 : 1'b0;
|
|
|
////////////////////////////////////////
|
////////////////////////////////////////
|
// Word counter
|
// Word counter
|
|
|
assign data_to_word_counter = (word_ct_sel) ? decremented_word_count : count_data_in;
|
assign data_to_word_counter = (word_ct_sel) ? decremented_word_count : count_data_in;
|
assign decremented_word_count = word_count - 16'h1;
|
assign decremented_word_count = word_count - 16'h1;
|
|
|
// Technically, since this data (sometimes) comes from the input shift reg, we should latch on
|
// Technically, since this data (sometimes) comes from the input shift reg, we should latch on
|
// negedge, per the JTAG spec. But that makes things difficult when incrementing.
|
// negedge, per the JTAG spec. But that makes things difficult when incrementing.
|
always @ (posedge tck_i or posedge rst_i) // JTAG spec specifies latch on negative edge in UPDATE_DR state
|
always @ (posedge tck_i or posedge rst_i) // JTAG spec specifies latch on negative edge in UPDATE_DR state
|
begin
|
begin
|
if(rst_i)
|
if(rst_i)
|
word_count <= 16'h0;
|
word_count <= 16'h0;
|
else if(word_ct_en)
|
else if(word_ct_en)
|
word_count <= data_to_word_counter;
|
word_count <= data_to_word_counter;
|
end
|
end
|
|
|
assign word_count_zero = (word_count == 16'h0);
|
assign word_count_zero = (word_count == 16'h0);
|
|
|
/////////////////////////////////////////////////////
|
/////////////////////////////////////////////////////
|
// Output register and TDO output MUX
|
// Output register and TDO output MUX
|
|
|
assign out_reg_data = (out_reg_data_sel) ? data_from_internal_reg : data_from_biu;
|
assign out_reg_data = (out_reg_data_sel) ? data_from_internal_reg : data_from_biu;
|
|
|
always @ (posedge tck_i or posedge rst_i)
|
always @ (posedge tck_i or posedge rst_i)
|
begin
|
begin
|
if(rst_i) data_out_shift_reg <= 32'h0;
|
if(rst_i) data_out_shift_reg <= 32'h0;
|
else if(out_reg_ld_en) data_out_shift_reg <= out_reg_data;
|
else if(out_reg_ld_en) data_out_shift_reg <= out_reg_data;
|
else if(out_reg_shift_en) data_out_shift_reg <= {1'b0, data_out_shift_reg[31:1]};
|
else if(out_reg_shift_en) data_out_shift_reg <= {1'b0, data_out_shift_reg[31:1]};
|
end
|
end
|
|
|
|
|
always @ (tdo_output_sel or data_out_shift_reg[0] or biu_ready or crc_match or crc_serial_out)
|
always @ (tdo_output_sel or data_out_shift_reg[0] or biu_ready or crc_match or crc_serial_out)
|
begin
|
begin
|
if(tdo_output_sel == 2'h0) module_tdo_o <= biu_ready;
|
if(tdo_output_sel == 2'h0) module_tdo_o <= biu_ready;
|
else if(tdo_output_sel == 2'h1) module_tdo_o <= data_out_shift_reg[0];
|
else if(tdo_output_sel == 2'h1) module_tdo_o <= data_out_shift_reg[0];
|
else if(tdo_output_sel == 2'h2) module_tdo_o <= crc_match;
|
else if(tdo_output_sel == 2'h2) module_tdo_o <= crc_match;
|
else module_tdo_o <= crc_serial_out;
|
else module_tdo_o <= crc_serial_out;
|
end
|
end
|
|
|
////////////////////////////////////////
|
////////////////////////////////////////
|
// Bus Interface Unit (to OR1K SPR bus)
|
// Bus Interface Unit (to OR1K SPR bus)
|
// It is assumed that the BIU has internal registers, and will
|
// It is assumed that the BIU has internal registers, and will
|
// latch address, operation, and write data on rising clock edge
|
// latch address, operation, and write data on rising clock edge
|
// when strobe is asserted
|
// when strobe is asserted
|
|
|
adbg_or1k_biu or1k_biu_i (
|
adbg_or1k_biu or1k_biu_i (
|
// Debug interface signals
|
// Debug interface signals
|
.tck_i (tck_i),
|
.tck_i (tck_i),
|
.rst_i (rst_i),
|
.rst_i (rst_i),
|
.data_i (data_to_biu),
|
.data_i (data_to_biu),
|
.data_o (data_from_biu),
|
.data_o (data_from_biu),
|
.addr_i (address_counter),
|
.addr_i (address_counter),
|
.strobe_i (biu_strobe),
|
.strobe_i (biu_strobe),
|
.rd_wrn_i (rd_op), // If 0, then write op
|
.rd_wrn_i (rd_op), // If 0, then write op
|
.rdy_o (biu_ready),
|
.rdy_o (biu_ready),
|
// This bus has no error signal
|
// This bus has no error signal
|
|
|
// OR1K SPR bus signals
|
// OR1K SPR bus signals
|
.cpu_clk_i(cpu_clk_i),
|
.cpu_clk_i(cpu_clk_i),
|
.cpu_addr_o(cpu_addr_o),
|
.cpu_addr_o(cpu_addr_o),
|
.cpu_data_i(cpu_data_i),
|
.cpu_data_i(cpu_data_i),
|
.cpu_data_o(cpu_data_o),
|
.cpu_data_o(cpu_data_o),
|
.cpu_stb_o(cpu_stb_o),
|
.cpu_stb_o(cpu_stb_o),
|
.cpu_we_o(cpu_we_o),
|
.cpu_we_o(cpu_we_o),
|
.cpu_ack_i(cpu_ack_i)
|
.cpu_ack_i(cpu_ack_i)
|
);
|
);
|
|
|
|
|
|
|
/////////////////////////////////////
|
/////////////////////////////////////
|
// CRC module
|
// CRC module
|
|
|
assign crc_data_in = (crc_in_sel) ? tdi_i : data_out_shift_reg[0]; // MUX, write or read data
|
assign crc_data_in = (crc_in_sel) ? tdi_i : data_out_shift_reg[0]; // MUX, write or read data
|
|
|
adbg_crc32 or1k_crc_i
|
adbg_crc32 or1k_crc_i
|
(
|
(
|
.clk(tck_i),
|
.clk(tck_i),
|
.data(crc_data_in),
|
.data(crc_data_in),
|
.enable(crc_en),
|
.enable(crc_en),
|
.shift(crc_shift_en),
|
.shift(crc_shift_en),
|
.clr(crc_clr),
|
.clr(crc_clr),
|
.rst(rst_i),
|
.rst(rst_i),
|
.crc_out(crc_data_out),
|
.crc_out(crc_data_out),
|
.serial_out(crc_serial_out)
|
.serial_out(crc_serial_out)
|
);
|
);
|
|
|
assign crc_match = (data_register_i[52:21] == crc_data_out) ? 1'b1 : 1'b0;
|
assign crc_match = (data_register_i[52:21] == crc_data_out) ? 1'b1 : 1'b0;
|
|
|
////////////////////////////////////////
|
////////////////////////////////////////
|
// Control FSM
|
// Control FSM
|
|
|
// Definition of machine state values.
|
// Definition of machine state values.
|
// Don't worry too much about the state encoding, the synthesis tool
|
// Don't worry too much about the state encoding, the synthesis tool
|
// will probably re-encode it anyway.
|
// will probably re-encode it anyway.
|
|
|
`define STATE_idle 4'h0
|
`define STATE_idle 4'h0
|
`define STATE_Rbegin 4'h1
|
`define STATE_Rbegin 4'h1
|
`define STATE_Rready 4'h2
|
`define STATE_Rready 4'h2
|
`define STATE_Rstatus 4'h3
|
`define STATE_Rstatus 4'h3
|
`define STATE_Rburst 4'h4
|
`define STATE_Rburst 4'h4
|
`define STATE_Wready 4'h5
|
`define STATE_Wready 4'h5
|
`define STATE_Wwait 4'h6
|
`define STATE_Wwait 4'h6
|
`define STATE_Wburst 4'h7
|
`define STATE_Wburst 4'h7
|
`define STATE_Wstatus 4'h8
|
`define STATE_Wstatus 4'h8
|
`define STATE_Rcrc 4'h9
|
`define STATE_Rcrc 4'h9
|
`define STATE_Wcrc 4'ha
|
`define STATE_Wcrc 4'ha
|
`define STATE_Wmatch 4'hb
|
`define STATE_Wmatch 4'hb
|
|
|
reg [3:0] module_state; // FSM state
|
reg [3:0] module_state; // FSM state
|
reg [3:0] module_next_state; // combinatorial signal, not actually a register
|
reg [3:0] module_next_state; // combinatorial signal, not actually a register
|
|
|
|
|
|
|
// sequential part of the FSM
|
// sequential part of the FSM
|
always @ (posedge tck_i or posedge rst_i)
|
always @ (posedge tck_i or posedge rst_i)
|
begin
|
begin
|
if(rst_i)
|
if(rst_i)
|
module_state <= `STATE_idle;
|
module_state <= `STATE_idle;
|
else
|
else
|
module_state <= module_next_state;
|
module_state <= module_next_state;
|
end
|
end
|
|
|
|
|
// Determination of next state; purely combinatorial
|
// Determination of next state; purely combinatorial
|
always @ (module_state or module_select_i or update_dr_i or capture_dr_i or shift_dr_i or operation_in[2]
|
always @ (module_state or module_select_i or update_dr_i or capture_dr_i or shift_dr_i or operation_in[2]
|
or word_count_zero or bit_count_max or data_register_i[52] or bit_count_32 or biu_ready
|
or word_count_zero or bit_count_max or data_register_i[52] or bit_count_32 or biu_ready
|
or module_cmd or intreg_write or decremented_word_count or burst_instruction)
|
or module_cmd or intreg_write or decremented_word_count or burst_instruction)
|
begin
|
begin
|
case(module_state)
|
case(module_state)
|
`STATE_idle:
|
`STATE_idle:
|
begin
|
begin
|
if(module_cmd && module_select_i && update_dr_i && burst_instruction && operation_in[2]) module_next_state <= `STATE_Rbegin;
|
if(module_cmd && module_select_i && update_dr_i && burst_instruction && operation_in[2]) module_next_state <= `STATE_Rbegin;
|
else if(module_cmd && module_select_i && update_dr_i && burst_instruction) module_next_state <= `STATE_Wready;
|
else if(module_cmd && module_select_i && update_dr_i && burst_instruction) module_next_state <= `STATE_Wready;
|
else module_next_state <= `STATE_idle;
|
else module_next_state <= `STATE_idle;
|
end
|
end
|
|
|
`STATE_Rbegin:
|
`STATE_Rbegin:
|
begin
|
begin
|
if(word_count_zero) module_next_state <= `STATE_idle; // set up a burst of size 0, illegal.
|
if(word_count_zero) module_next_state <= `STATE_idle; // set up a burst of size 0, illegal.
|
else module_next_state <= `STATE_Rready;
|
else module_next_state <= `STATE_Rready;
|
end
|
end
|
`STATE_Rready:
|
`STATE_Rready:
|
begin
|
begin
|
if(module_select_i && capture_dr_i) module_next_state <= `STATE_Rstatus;
|
if(module_select_i && capture_dr_i) module_next_state <= `STATE_Rstatus;
|
else module_next_state <= `STATE_Rready;
|
else module_next_state <= `STATE_Rready;
|
end
|
end
|
`STATE_Rstatus:
|
`STATE_Rstatus:
|
begin
|
begin
|
if(update_dr_i) module_next_state <= `STATE_idle;
|
if(update_dr_i) module_next_state <= `STATE_idle;
|
else if (biu_ready) module_next_state <= `STATE_Rburst;
|
else if (biu_ready) module_next_state <= `STATE_Rburst;
|
else module_next_state <= `STATE_Rstatus;
|
else module_next_state <= `STATE_Rstatus;
|
end
|
end
|
`STATE_Rburst:
|
`STATE_Rburst:
|
begin
|
begin
|
if(update_dr_i) module_next_state <= `STATE_idle;
|
if(update_dr_i) module_next_state <= `STATE_idle;
|
else if(bit_count_max && word_count_zero) module_next_state <= `STATE_Rcrc;
|
else if(bit_count_max && word_count_zero) module_next_state <= `STATE_Rcrc;
|
else if(bit_count_max) module_next_state <= `STATE_Rstatus;
|
else if(bit_count_max) module_next_state <= `STATE_Rstatus;
|
else module_next_state <= `STATE_Rburst;
|
else module_next_state <= `STATE_Rburst;
|
end
|
end
|
`STATE_Rcrc:
|
`STATE_Rcrc:
|
begin
|
begin
|
if(update_dr_i) module_next_state <= `STATE_idle;
|
if(update_dr_i) module_next_state <= `STATE_idle;
|
// This doubles as the 'recovery' state, so stay here until update_dr_i.
|
// This doubles as the 'recovery' state, so stay here until update_dr_i.
|
else module_next_state <= `STATE_Rcrc;
|
else module_next_state <= `STATE_Rcrc;
|
end
|
end
|
|
|
`STATE_Wready:
|
`STATE_Wready:
|
begin
|
begin
|
if(word_count_zero) module_next_state <= `STATE_idle;
|
if(word_count_zero) module_next_state <= `STATE_idle;
|
else if(module_select_i && capture_dr_i) module_next_state <= `STATE_Wwait;
|
else if(module_select_i && capture_dr_i) module_next_state <= `STATE_Wwait;
|
else module_next_state <= `STATE_Wready;
|
else module_next_state <= `STATE_Wready;
|
end
|
end
|
`STATE_Wwait:
|
`STATE_Wwait:
|
begin
|
begin
|
if(update_dr_i) module_next_state <= `STATE_idle; // client terminated early
|
if(update_dr_i) module_next_state <= `STATE_idle; // client terminated early
|
else if(module_select_i && data_register_i[52]) module_next_state <= `STATE_Wburst; // Got a start bit
|
else if(module_select_i && data_register_i[52]) module_next_state <= `STATE_Wburst; // Got a start bit
|
else module_next_state <= `STATE_Wwait;
|
else module_next_state <= `STATE_Wwait;
|
end
|
end
|
`STATE_Wburst:
|
`STATE_Wburst:
|
begin
|
begin
|
if(update_dr_i) module_next_state <= `STATE_idle; // client terminated early
|
if(update_dr_i) module_next_state <= `STATE_idle; // client terminated early
|
else if(bit_count_max) module_next_state <= `STATE_Wstatus;
|
else if(bit_count_max) module_next_state <= `STATE_Wstatus;
|
else module_next_state <= `STATE_Wburst;
|
else module_next_state <= `STATE_Wburst;
|
end
|
end
|
`STATE_Wstatus:
|
`STATE_Wstatus:
|
begin
|
begin
|
if(update_dr_i) module_next_state <= `STATE_idle; // client terminated early
|
if(update_dr_i) module_next_state <= `STATE_idle; // client terminated early
|
else if(word_count_zero) module_next_state <= `STATE_Wcrc;
|
else if(word_count_zero) module_next_state <= `STATE_Wcrc;
|
// can't wait until bus ready if multiple devices in chain...
|
// can't wait until bus ready if multiple devices in chain...
|
// Would have to read postfix_bits, then send another start bit and push it through
|
// Would have to read postfix_bits, then send another start bit and push it through
|
// prefix_bits...potentially very inefficient.
|
// prefix_bits...potentially very inefficient.
|
else module_next_state <= `STATE_Wburst;
|
else module_next_state <= `STATE_Wburst;
|
end
|
end
|
|
|
`STATE_Wcrc:
|
`STATE_Wcrc:
|
begin
|
begin
|
if(update_dr_i) module_next_state <= `STATE_idle; // client terminated early
|
if(update_dr_i) module_next_state <= `STATE_idle; // client terminated early
|
else if(bit_count_32) module_next_state <= `STATE_Wmatch;
|
else if(bit_count_32) module_next_state <= `STATE_Wmatch;
|
else module_next_state <= `STATE_Wcrc;
|
else module_next_state <= `STATE_Wcrc;
|
end
|
end
|
|
|
`STATE_Wmatch:
|
`STATE_Wmatch:
|
begin
|
begin
|
if(update_dr_i) module_next_state <= `STATE_idle;
|
if(update_dr_i) module_next_state <= `STATE_idle;
|
// This doubles as our recovery state, stay here until update_dr_i
|
// This doubles as our recovery state, stay here until update_dr_i
|
else module_next_state <= `STATE_Wmatch;
|
else module_next_state <= `STATE_Wmatch;
|
end
|
end
|
|
|
default: module_next_state <= `STATE_idle; // shouldn't actually happen...
|
default: module_next_state <= `STATE_idle; // shouldn't actually happen...
|
endcase
|
endcase
|
end
|
end
|
|
|
|
|
// Outputs of state machine, pure combinatorial
|
// Outputs of state machine, pure combinatorial
|
always @ (module_state or module_next_state or module_select_i or update_dr_i or capture_dr_i or shift_dr_i or operation_in[2]
|
always @ (module_state or module_next_state or module_select_i or update_dr_i or capture_dr_i or shift_dr_i or operation_in[2]
|
or word_count_zero or bit_count_max or data_register_i[52] or biu_ready or intreg_instruction
|
or word_count_zero or bit_count_max or data_register_i[52] or biu_ready or intreg_instruction
|
or module_cmd or intreg_write or decremented_word_count)
|
or module_cmd or intreg_write or decremented_word_count)
|
begin
|
begin
|
// Default everything to 0, keeps the case statement simple
|
// Default everything to 0, keeps the case statement simple
|
addr_sel <= 1'b1; // Selects data for address_counter. 0 = data_register_i, 1 = incremented address count
|
addr_sel <= 1'b1; // Selects data for address_counter. 0 = data_register_i, 1 = incremented address count
|
addr_ct_en <= 1'b0; // Enable signal for address counter register
|
addr_ct_en <= 1'b0; // Enable signal for address counter register
|
op_reg_en <= 1'b0; // Enable signal for 'operation' register
|
op_reg_en <= 1'b0; // Enable signal for 'operation' register
|
bit_ct_en <= 1'b0; // enable bit counter
|
bit_ct_en <= 1'b0; // enable bit counter
|
bit_ct_rst <= 1'b0; // reset (zero) bit count register
|
bit_ct_rst <= 1'b0; // reset (zero) bit count register
|
word_ct_sel <= 1'b1; // Selects data for byte counter. 0 = data_register_i, 1 = decremented byte count
|
word_ct_sel <= 1'b1; // Selects data for byte counter. 0 = data_register_i, 1 = decremented byte count
|
word_ct_en <= 1'b0; // Enable byte counter register
|
word_ct_en <= 1'b0; // Enable byte counter register
|
out_reg_ld_en <= 1'b0; // Enable parallel load of data_out_shift_reg
|
out_reg_ld_en <= 1'b0; // Enable parallel load of data_out_shift_reg
|
out_reg_shift_en <= 1'b0; // Enable shift of data_out_shift_reg
|
out_reg_shift_en <= 1'b0; // Enable shift of data_out_shift_reg
|
tdo_output_sel <= 2'b1; // 1 = data reg, 0 = biu_ready, 2 = crc_match, 3 = CRC data
|
tdo_output_sel <= 2'b1; // 1 = data reg, 0 = biu_ready, 2 = crc_match, 3 = CRC data
|
biu_strobe <= 1'b0;
|
biu_strobe <= 1'b0;
|
crc_clr <= 1'b0;
|
crc_clr <= 1'b0;
|
crc_en <= 1'b0; // add the input bit to the CRC calculation
|
crc_en <= 1'b0; // add the input bit to the CRC calculation
|
crc_in_sel <= 1'b0; // 0 = tdo, 1 = tdi
|
crc_in_sel <= 1'b0; // 0 = tdo, 1 = tdi
|
crc_shift_en <= 1'b0;
|
crc_shift_en <= 1'b0;
|
out_reg_data_sel <= 1'b1; // 0 = BIU data, 1 = internal register data
|
out_reg_data_sel <= 1'b1; // 0 = BIU data, 1 = internal register data
|
regsel_ld_en <= 1'b0;
|
regsel_ld_en <= 1'b0;
|
intreg_ld_en <= 1'b0;
|
intreg_ld_en <= 1'b0;
|
top_inhibit_o <= 1'b0; // Don't disable the top-level module in the default case
|
top_inhibit_o <= 1'b0; // Don't disable the top-level module in the default case
|
|
|
case(module_state)
|
case(module_state)
|
`STATE_idle:
|
`STATE_idle:
|
begin
|
begin
|
addr_sel <= 1'b0;
|
addr_sel <= 1'b0;
|
word_ct_sel <= 1'b0;
|
word_ct_sel <= 1'b0;
|
|
|
// Operations for internal registers - stay in idle state
|
// Operations for internal registers - stay in idle state
|
if(module_select_i & shift_dr_i) out_reg_shift_en <= 1'b1; // For module regs
|
if(module_select_i & shift_dr_i) out_reg_shift_en <= 1'b1; // For module regs
|
if(module_select_i & capture_dr_i)
|
if(module_select_i & capture_dr_i)
|
begin
|
begin
|
out_reg_data_sel <= 1'b1; // select internal register data
|
out_reg_data_sel <= 1'b1; // select internal register data
|
out_reg_ld_en <= 1'b1; // For module regs
|
out_reg_ld_en <= 1'b1; // For module regs
|
end
|
end
|
if(module_select_i & module_cmd & update_dr_i) begin
|
if(module_select_i & module_cmd & update_dr_i) begin
|
if(intreg_instruction) regsel_ld_en <= 1'b1; // For module regs
|
if(intreg_instruction) regsel_ld_en <= 1'b1; // For module regs
|
if(intreg_write) intreg_ld_en <= 1'b1; // For module regs
|
if(intreg_write) intreg_ld_en <= 1'b1; // For module regs
|
end
|
end
|
|
|
// Burst operations
|
// Burst operations
|
if(module_next_state != `STATE_idle) begin // Do the same to receive read or write opcode
|
if(module_next_state != `STATE_idle) begin // Do the same to receive read or write opcode
|
addr_ct_en <= 1'b1;
|
addr_ct_en <= 1'b1;
|
op_reg_en <= 1'b1;
|
op_reg_en <= 1'b1;
|
bit_ct_rst <= 1'b1;
|
bit_ct_rst <= 1'b1;
|
word_ct_en <= 1'b1;
|
word_ct_en <= 1'b1;
|
crc_clr <= 1'b1;
|
crc_clr <= 1'b1;
|
end
|
end
|
end
|
end
|
|
|
`STATE_Rbegin:
|
`STATE_Rbegin:
|
begin
|
begin
|
if(!word_count_zero) begin // Start a biu read transaction
|
if(!word_count_zero) begin // Start a biu read transaction
|
biu_strobe <= 1'b1;
|
biu_strobe <= 1'b1;
|
addr_sel <= 1'b1;
|
addr_sel <= 1'b1;
|
addr_ct_en <= 1'b1;
|
addr_ct_en <= 1'b1;
|
end
|
end
|
end
|
end
|
|
|
`STATE_Rready:
|
`STATE_Rready:
|
; // Just a wait state
|
; // Just a wait state
|
|
|
`STATE_Rstatus:
|
`STATE_Rstatus:
|
begin
|
begin
|
tdo_output_sel <= 2'h0;
|
tdo_output_sel <= 2'h0;
|
top_inhibit_o <= 1'b1; // in case of early termination
|
top_inhibit_o <= 1'b1; // in case of early termination
|
|
|
if (module_next_state == `STATE_Rburst) begin
|
if (module_next_state == `STATE_Rburst) begin
|
out_reg_data_sel <= 1'b0; // select BIU data
|
out_reg_data_sel <= 1'b0; // select BIU data
|
out_reg_ld_en <= 1'b1;
|
out_reg_ld_en <= 1'b1;
|
bit_ct_rst <= 1'b1;
|
bit_ct_rst <= 1'b1;
|
word_ct_sel <= 1'b1;
|
word_ct_sel <= 1'b1;
|
word_ct_en <= 1'b1;
|
word_ct_en <= 1'b1;
|
if(!(decremented_word_count == 0) && !word_count_zero) begin // Start a biu read transaction
|
if(!(decremented_word_count == 0) && !word_count_zero) begin // Start a biu read transaction
|
biu_strobe <= 1'b1;
|
biu_strobe <= 1'b1;
|
addr_sel <= 1'b1;
|
addr_sel <= 1'b1;
|
addr_ct_en <= 1'b1;
|
addr_ct_en <= 1'b1;
|
end
|
end
|
end
|
end
|
end
|
end
|
|
|
`STATE_Rburst:
|
`STATE_Rburst:
|
begin
|
begin
|
tdo_output_sel <= 2'h1;
|
tdo_output_sel <= 2'h1;
|
out_reg_shift_en <= 1'b1;
|
out_reg_shift_en <= 1'b1;
|
bit_ct_en <= 1'b1;
|
bit_ct_en <= 1'b1;
|
crc_en <= 1'b1;
|
crc_en <= 1'b1;
|
crc_in_sel <= 1'b0; // read data in output shift register LSB (tdo)
|
crc_in_sel <= 1'b0; // read data in output shift register LSB (tdo)
|
top_inhibit_o <= 1'b1; // in case of early termination
|
top_inhibit_o <= 1'b1; // in case of early termination
|
end
|
end
|
|
|
`STATE_Rcrc:
|
`STATE_Rcrc:
|
begin
|
begin
|
// Just shift out the data, don't bother counting, we don't move on until update_dr_i
|
// Just shift out the data, don't bother counting, we don't move on until update_dr_i
|
tdo_output_sel <= 2'h3;
|
tdo_output_sel <= 2'h3;
|
crc_shift_en <= 1'b1;
|
crc_shift_en <= 1'b1;
|
top_inhibit_o <= 1'b1;
|
top_inhibit_o <= 1'b1;
|
end
|
end
|
|
|
`STATE_Wready:
|
`STATE_Wready:
|
; // Just a wait state
|
; // Just a wait state
|
|
|
`STATE_Wwait:
|
`STATE_Wwait:
|
begin
|
begin
|
tdo_output_sel <= 2'h1;
|
tdo_output_sel <= 2'h1;
|
top_inhibit_o <= 1'b1; // in case of early termination
|
top_inhibit_o <= 1'b1; // in case of early termination
|
if(module_next_state == `STATE_Wburst) begin
|
if(module_next_state == `STATE_Wburst) begin
|
bit_ct_en <= 1'b1;
|
bit_ct_en <= 1'b1;
|
word_ct_sel <= 1'b1; // Pre-decrement the byte count
|
word_ct_sel <= 1'b1; // Pre-decrement the byte count
|
word_ct_en <= 1'b1;
|
word_ct_en <= 1'b1;
|
crc_en <= 1'b1; // CRC gets tdi_i, which is 1 cycle ahead of data_register_i, so we need the bit there now in the CRC
|
crc_en <= 1'b1; // CRC gets tdi_i, which is 1 cycle ahead of data_register_i, so we need the bit there now in the CRC
|
crc_in_sel <= 1'b1; // read data from tdi_i
|
crc_in_sel <= 1'b1; // read data from tdi_i
|
end
|
end
|
end
|
end
|
|
|
`STATE_Wburst:
|
`STATE_Wburst:
|
begin
|
begin
|
bit_ct_en <= 1'b1;
|
bit_ct_en <= 1'b1;
|
tdo_output_sel <= 2'h1;
|
tdo_output_sel <= 2'h1;
|
crc_en <= 1'b1;
|
crc_en <= 1'b1;
|
crc_in_sel <= 1'b1; // read data from tdi_i
|
crc_in_sel <= 1'b1; // read data from tdi_i
|
top_inhibit_o <= 1'b1; // in case of early termination
|
top_inhibit_o <= 1'b1; // in case of early termination
|
end
|
end
|
|
|
`STATE_Wstatus:
|
`STATE_Wstatus:
|
begin
|
begin
|
tdo_output_sel <= 2'h0; // Send the status bit to TDO
|
tdo_output_sel <= 2'h0; // Send the status bit to TDO
|
// start transaction
|
// start transaction
|
biu_strobe <= 1'b1; // Start a BIU transaction
|
biu_strobe <= 1'b1; // Start a BIU transaction
|
word_ct_sel <= 1'b1; // Decrement the byte count
|
word_ct_sel <= 1'b1; // Decrement the byte count
|
word_ct_en <= 1'b1;
|
word_ct_en <= 1'b1;
|
bit_ct_rst <= 1'b1; // Zero the bit count
|
bit_ct_rst <= 1'b1; // Zero the bit count
|
addr_ct_en <= 1'b1; // Increment thte address counter
|
addr_ct_en <= 1'b1; // Increment thte address counter
|
top_inhibit_o <= 1'b1; // in case of early termination
|
top_inhibit_o <= 1'b1; // in case of early termination
|
end
|
end
|
|
|
`STATE_Wcrc:
|
`STATE_Wcrc:
|
begin
|
begin
|
bit_ct_en <= 1'b1;
|
bit_ct_en <= 1'b1;
|
top_inhibit_o <= 1'b1; // in case of early termination
|
top_inhibit_o <= 1'b1; // in case of early termination
|
if(module_next_state == `STATE_Wmatch) tdo_output_sel <= 2'h2; // This is when the 'match' bit is actually read
|
if(module_next_state == `STATE_Wmatch) tdo_output_sel <= 2'h2; // This is when the 'match' bit is actually read
|
end
|
end
|
|
|
`STATE_Wmatch:
|
`STATE_Wmatch:
|
begin
|
begin
|
tdo_output_sel <= 2'h2;
|
tdo_output_sel <= 2'h2;
|
top_inhibit_o <= 1'b1; // in case of early termination
|
top_inhibit_o <= 1'b1; // in case of early termination
|
end
|
end
|
|
|
default: ;
|
default: ;
|
endcase
|
endcase
|
end
|
end
|
|
|
|
|
endmodule
|
endmodule
|
|
|
|
|
