81 lines
3.2 KiB
Verilog
81 lines
3.2 KiB
Verilog
//
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// Copyright 2013 Ettus Research LLC
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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, either version 3 of the License, or
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// (at your option) any later version.
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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 timekeeper
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#(parameter BASE = 0)
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(input clk, input reset, input pps,
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input set_stb, input [7:0] set_addr, input [31:0] set_data,
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output reg [63:0] vita_time, output reg [63:0] vita_time_lastpps);
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//////////////////////////////////////////////////////////////////////////
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// timer settings for this module
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//////////////////////////////////////////////////////////////////////////
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wire [63:0] time_at_next_event;
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wire set_time_pps, set_time_now;
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wire cmd_trigger;
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setting_reg #(.my_addr(BASE), .width()) sr_time_hi
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(.clk(clk), .rst(reset), .strobe(set_stb), .addr(set_addr), .in(set_data),
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.out(time_at_next_event[63:32]), .changed());
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setting_reg #(.my_addr(BASE+1), .width()) sr_time_lo
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(.clk(clk), .rst(reset), .strobe(set_stb), .addr(set_addr), .in(set_data),
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.out(time_at_next_event[31:0]), .changed());
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setting_reg #(.my_addr(BASE+2), .width(2)) sr_ctrl
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(.clk(clk), .rst(reset), .strobe(set_stb), .addr(set_addr), .in(set_data),
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.out({set_time_pps, set_time_now}), .changed(cmd_trigger));
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//////////////////////////////////////////////////////////////////////////
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// PPS edge detection logic
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//////////////////////////////////////////////////////////////////////////
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reg pps_del, pps_del2;
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always @(posedge clk)
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{pps_del2,pps_del} <= {pps_del, pps};
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wire pps_edge = !pps_del2 & pps_del;
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//////////////////////////////////////////////////////////////////////////
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// track the time at last pps so host can detect the pps
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//////////////////////////////////////////////////////////////////////////
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always @(posedge clk)
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if(pps_edge) vita_time_lastpps <= vita_time;
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//////////////////////////////////////////////////////////////////////////
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// arm the trigger to latch a new time when the ctrl register is written
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//////////////////////////////////////////////////////////////////////////
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reg armed;
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wire time_event = armed && ((set_time_now) || (set_time_pps && pps_edge));
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always @(posedge clk) begin
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if (reset) armed <= 1'b0;
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else if (cmd_trigger) armed <= 1'b1;
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else if (time_event) armed <= 1'b0;
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end
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//////////////////////////////////////////////////////////////////////////
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// vita time tracker - update every tick or when we get an "event"
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//////////////////////////////////////////////////////////////////////////
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always @(posedge clk)
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if(reset)
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vita_time <= 64'h0;
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else if (time_event)
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vita_time <= time_at_next_event;
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else
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vita_time <= vita_time + 64'h1;
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endmodule // timekeeper
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