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[/] [zipcpu/] [trunk/] [rtl/] [zipbones.v] - Rev 176
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/////////////////////////////////////////////////////////////////////////// // // Filename: zipbones.v // // Project: Zip CPU -- a small, lightweight, RISC CPU soft core // // Purpose: In the spirit of keeping the Zip CPU small, this implements a // Zip System with no peripherals: Any peripherals you wish will // need to be implemented off-module. // // Creator: Dan Gisselquist, Ph.D. // Gisselquist Technology, LLC // /////////////////////////////////////////////////////////////////////////// // // Copyright (C) 2015, Gisselquist Technology, LLC // // This program is free software (firmware): you can redistribute it and/or // modify it under the terms of the GNU General Public License as published // by the Free Software Foundation, either version 3 of the License, or (at // your option) any later version. // // This program is distributed in the hope that it will be useful, but WITHOUT // ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License // for more details. // // License: GPL, v3, as defined and found on www.gnu.org, // http://www.gnu.org/licenses/gpl.html // // /////////////////////////////////////////////////////////////////////////// // `include "cpudefs.v" // module zipbones(i_clk, i_rst, // Wishbone master interface from the CPU o_wb_cyc, o_wb_stb, o_wb_we, o_wb_addr, o_wb_data, i_wb_ack, i_wb_stall, i_wb_data, i_wb_err, // Incoming interrupts i_ext_int, // Our one outgoing interrupt o_ext_int, // Wishbone slave interface for debugging purposes i_dbg_cyc, i_dbg_stb, i_dbg_we, i_dbg_addr, i_dbg_data, o_dbg_ack, o_dbg_stall, o_dbg_data `ifdef DEBUG_SCOPE , o_zip_debug `endif ); parameter RESET_ADDRESS=32'h0100000, ADDRESS_WIDTH=32, LGICACHE=6, START_HALTED=0, AW=ADDRESS_WIDTH; input i_clk, i_rst; // Wishbone master output wire o_wb_cyc, o_wb_stb, o_wb_we; output wire [(AW-1):0] o_wb_addr; output wire [31:0] o_wb_data; input i_wb_ack, i_wb_stall; input [31:0] i_wb_data; input i_wb_err; // Incoming interrupts input i_ext_int; // Outgoing interrupt output wire o_ext_int; // Wishbone slave input i_dbg_cyc, i_dbg_stb, i_dbg_we, i_dbg_addr; input [31:0] i_dbg_data; output reg o_dbg_ack; output wire o_dbg_stall; output wire [31:0] o_dbg_data; // `ifdef DEBUG_SCOPE output wire [31:0] o_zip_debug; `endif // // // wire sys_cyc, sys_stb, sys_we; wire [4:0] sys_addr; wire [(AW-1):0] cpu_addr; wire [31:0] sys_data; wire sys_ack, sys_stall; // // The external debug interface // // We offer only a limited interface here, requiring a pre-register // write to set the local address. This interface allows access to // the Zip System on a debug basis only, and not to the rest of the // wishbone bus. Further, to access these registers, the control // register must first be accessed to both stop the CPU and to // set the following address in question. Hence all accesses require // two accesses: write the address to the control register (and halt // the CPU if not halted), then read/write the data from the data // register. // wire cpu_break, dbg_cmd_write; reg cmd_reset, cmd_halt, cmd_step, cmd_clear_pf_cache; reg [4:0] cmd_addr; wire [3:0] cpu_dbg_cc; assign dbg_cmd_write = (i_dbg_cyc)&&(i_dbg_stb)&&(i_dbg_we)&&(~i_dbg_addr); // // Always start us off with an initial reset // initial cmd_reset = 1'b1; always @(posedge i_clk) cmd_reset <= ((dbg_cmd_write)&&(i_dbg_data[6])); // initial cmd_halt = START_HALTED; always @(posedge i_clk) if (i_rst) cmd_halt <= (START_HALTED == 1)? 1'b1 : 1'b0; else if (dbg_cmd_write) cmd_halt <= ((i_dbg_data[10])||(i_dbg_data[8])); else if ((cmd_step)||(cpu_break)) cmd_halt <= 1'b1; initial cmd_clear_pf_cache = 1'b0; always @(posedge i_clk) if (i_rst) cmd_clear_pf_cache <= 1'b0; else if (dbg_cmd_write) cmd_clear_pf_cache <= i_dbg_data[11]; else cmd_clear_pf_cache <= 1'b0; // initial cmd_step = 1'b0; always @(posedge i_clk) cmd_step <= (dbg_cmd_write)&&(i_dbg_data[8]); // initial cmd_addr = 5'h0; always @(posedge i_clk) if (dbg_cmd_write) cmd_addr <= i_dbg_data[4:0]; wire cpu_reset; assign cpu_reset = (cmd_reset)||(i_rst); wire cpu_halt, cpu_dbg_stall; assign cpu_halt = (i_rst)||((cmd_halt)&&(~cmd_step)); wire [31:0] cmd_data; // Values: // 0x0003f -> cmd_addr mask // 0x00040 -> reset // 0x00080 -> PIC interrrupts enabled // 0x00100 -> cmd_step // 0x00200 -> cmd_stall // 0x00400 -> cmd_halt // 0x00800 -> cmd_clear_pf_cache // 0x01000 -> cc.sleep // 0x02000 -> cc.gie // 0x10000 -> External interrupt line is high assign cmd_data = { 7'h00, 8'h00, i_ext_int, cpu_dbg_cc, 1'b0, cmd_halt, (~cpu_dbg_stall), 1'b0, 1'b0, cpu_reset, 1'b0, cmd_addr }; // // The CPU itself // wire cpu_gbl_stb, cpu_lcl_cyc, cpu_lcl_stb, cpu_we, cpu_dbg_we, cpu_op_stall, cpu_pf_stall, cpu_i_count; wire [31:0] cpu_data; wire [31:0] cpu_dbg_data; assign cpu_dbg_we = ((i_dbg_cyc)&&(i_dbg_stb) &&(i_dbg_we)&&(i_dbg_addr)); zipcpu #(RESET_ADDRESS,ADDRESS_WIDTH,LGICACHE) thecpu(i_clk, cpu_reset, i_ext_int, cpu_halt, cmd_clear_pf_cache, cmd_addr[4:0], cpu_dbg_we, i_dbg_data, cpu_dbg_stall, cpu_dbg_data, cpu_dbg_cc, cpu_break, o_wb_cyc, o_wb_stb, cpu_lcl_cyc, cpu_lcl_stb, o_wb_we, o_wb_addr, o_wb_data, i_wb_ack, i_wb_stall, i_wb_data, (i_wb_err)||((cpu_lcl_cyc)&&(cpu_lcl_stb)), cpu_op_stall, cpu_pf_stall, cpu_i_count `ifdef DEBUG_SCOPE , o_zip_debug `endif ); // Return debug response values assign o_dbg_data = (~i_dbg_addr)?cmd_data :cpu_dbg_data; initial o_dbg_ack = 1'b0; always @(posedge i_clk) o_dbg_ack <= (i_dbg_cyc)&&((~i_dbg_addr)||(~o_dbg_stall)); assign o_dbg_stall=(i_dbg_cyc)&&(cpu_dbg_stall)&&(i_dbg_addr); assign o_ext_int = (cmd_halt) && (~i_wb_stall); endmodule
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