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[/] [openrisc/] [trunk/] [or1200/] [rtl/] [verilog/] [or1200_tt.v] - Rev 717
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////////////////////////////////////////////////////////////////////// //// //// //// OR1200's Tick Timer //// //// //// //// This file is part of the OpenRISC 1200 project //// //// http://www.opencores.org/cores/or1k/ //// //// //// //// Description //// //// TT according to OR1K architectural specification. //// //// //// //// To Do: //// //// None //// //// //// //// Author(s): //// //// - Damjan Lampret, lampret@opencores.org //// //// //// ////////////////////////////////////////////////////////////////////// //// //// //// Copyright (C) 2000 Authors and OPENCORES.ORG //// //// //// //// 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 //// //// //// ////////////////////////////////////////////////////////////////////// // // synopsys translate_off `include "timescale.v" // synopsys translate_on `include "or1200_defines.v" module or1200_tt( // RISC Internal Interface clk, rst, du_stall, spr_cs, spr_write, spr_addr, spr_dat_i, spr_dat_o, intr ); // // RISC Internal Interface // input clk; // Clock input rst; // Reset input du_stall; // DU stall input spr_cs; // SPR CS input spr_write; // SPR Write input [31:0] spr_addr; // SPR Address input [31:0] spr_dat_i; // SPR Write Data output [31:0] spr_dat_o; // SPR Read Data output intr; // Interrupt output `ifdef OR1200_TT_IMPLEMENTED // // TT Mode Register bits (or no register) // `ifdef OR1200_TT_TTMR reg [31:0] ttmr; // TTMR bits `else wire [31:0] ttmr; // No TTMR register `endif // // TT Count Register bits (or no register) // `ifdef OR1200_TT_TTCR reg [31:0] ttcr; // TTCR bits `else wire [31:0] ttcr; // No TTCR register `endif // // Internal wires & regs // wire ttmr_sel; // TTMR select wire ttcr_sel; // TTCR select wire match; // Asserted when TTMR[TP] // is equal to TTCR[27:0] wire restart; // Restart counter when asserted wire stop; // Stop counter when asserted reg [31:0] spr_dat_o; // SPR data out // // TT registers address decoder // assign ttmr_sel = (spr_cs && (spr_addr[`OR1200_TTOFS_BITS] == `OR1200_TT_OFS_TTMR)) ? 1'b1 : 1'b0; assign ttcr_sel = (spr_cs && (spr_addr[`OR1200_TTOFS_BITS] == `OR1200_TT_OFS_TTCR)) ? 1'b1 : 1'b0; // // Write to TTMR or update of TTMR[IP] bit // `ifdef OR1200_TT_TTMR always @(posedge clk or `OR1200_RST_EVENT rst) if (rst == `OR1200_RST_VALUE) ttmr <= 32'b0; else if (ttmr_sel && spr_write) ttmr <= spr_dat_i; else if (ttmr[`OR1200_TT_TTMR_IE]) ttmr[`OR1200_TT_TTMR_IP] <= ttmr[`OR1200_TT_TTMR_IP] | (match & ttmr[`OR1200_TT_TTMR_IE]); `else assign ttmr = {2'b11, 30'b0}; // TTMR[M] = 0x3 `endif // // Write to or increment of TTCR // `ifdef OR1200_TT_TTCR always @(posedge clk or `OR1200_RST_EVENT rst) if (rst == `OR1200_RST_VALUE) ttcr <= 32'b0; else if (restart) ttcr <= 32'b0; else if (ttcr_sel && spr_write) ttcr <= spr_dat_i; else if (!stop) ttcr <= ttcr + 32'd1; `else assign ttcr = 32'b0; `endif // // Read TT registers // always @(spr_addr or ttmr or ttcr) case (spr_addr[`OR1200_TTOFS_BITS]) // synopsys parallel_case `ifdef OR1200_TT_READREGS `OR1200_TT_OFS_TTMR: spr_dat_o = ttmr; `endif default: spr_dat_o = ttcr; endcase // // A match when TTMR[TP] is equal to TTCR[27:0] // assign match = (ttmr[`OR1200_TT_TTMR_TP] == ttcr[27:0]) ? 1'b1 : 1'b0; // // Restart when match and TTMR[M]==0x1 // assign restart = match && (ttmr[`OR1200_TT_TTMR_M] == 2'b01); // // Stop when match and TTMR[M]==0x2 or when TTMR[M]==0x0 or when RISC is stalled by debug unit // assign stop = match & (ttmr[`OR1200_TT_TTMR_M] == 2'b10) | (ttmr[`OR1200_TT_TTMR_M] == 2'b00) | du_stall; // // Generate an interrupt request // assign intr = ttmr[`OR1200_TT_TTMR_IP]; `else // // When TT is not implemented, drive all outputs as would when TT is disabled // assign intr = 1'b0; // // Read TT registers // `ifdef OR1200_TT_READREGS assign spr_dat_o = 32'b0; `endif `endif endmodule
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