63 lines
1.7 KiB
Verilog
63 lines
1.7 KiB
Verilog
/*
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* Milkymist-NG SoC
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* Copyright (C) 2007, 2008, 2009, 2010, 2011 Sebastien Bourdeauducq
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 3 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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module m1reset(
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input sys_clk,
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input trigger_reset,
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output reg sys_rst,
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output ac97_rst_n,
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output videoin_rst_n,
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output flash_rst_n
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);
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reg [19:0] rst_debounce;
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initial rst_debounce <= 20'hFFFFF;
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initial sys_rst <= 1'b1;
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always @(posedge sys_clk) begin
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if(trigger_reset)
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rst_debounce <= 20'hFFFFF;
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else if(rst_debounce != 20'd0)
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rst_debounce <= rst_debounce - 20'd1;
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sys_rst <= rst_debounce != 20'd0;
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end
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assign ac97_rst_n = ~sys_rst;
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assign videoin_rst_n = ~sys_rst;
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/*
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* We must release the Flash reset before the system reset
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* because the Flash needs some time to come out of reset
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* and the CPU begins fetching instructions from it
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* as soon as the system reset is released.
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* From datasheet, minimum reset pulse width is 100ns
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* and reset-to-read time is 150ns.
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*/
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reg [7:0] flash_rstcounter;
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initial flash_rstcounter <= 8'd0;
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always @(posedge sys_clk) begin
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if(trigger_reset)
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flash_rstcounter <= 8'd0;
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else if(~flash_rstcounter[7])
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flash_rstcounter <= flash_rstcounter + 8'd1;
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end
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assign flash_rst_n = flash_rstcounter[7];
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endmodule
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