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//
// Copyright 2013-2014 Ettus Research LLC
// Copyright 2018 Ettus Research, a National Instruments Company
//
// SPDX-License-Identifier: LGPL-3.0-or-later
//
module timekeeper
#(parameter SR_TIME_HI = 0,
parameter SR_TIME_LO = 1,
parameter SR_TIME_CTRL = 2,
parameter INCREMENT = 64'h1)
(input clk, input reset, input pps, input sync_in, input strobe,
input set_stb, input [7:0] set_addr, input [31:0] set_data,
output reg [63:0] vita_time, output reg [63:0] vita_time_lastpps,
output reg sync_out);
//////////////////////////////////////////////////////////////////////////
// timer settings for this module
//////////////////////////////////////////////////////////////////////////
wire [63:0] time_at_next_event;
wire set_time_pps, set_time_now, set_time_sync;
wire cmd_trigger;
setting_reg #(.my_addr(SR_TIME_HI), .width(32)) sr_time_hi
(.clk(clk), .rst(reset), .strobe(set_stb), .addr(set_addr), .in(set_data),
.out(time_at_next_event[63:32]), .changed());
setting_reg #(.my_addr(SR_TIME_LO), .width(32)) sr_time_lo
(.clk(clk), .rst(reset), .strobe(set_stb), .addr(set_addr), .in(set_data),
.out(time_at_next_event[31:0]), .changed());
setting_reg #(.my_addr(SR_TIME_CTRL), .width(3)) sr_ctrl
(.clk(clk), .rst(reset), .strobe(set_stb), .addr(set_addr), .in(set_data),
.out({set_time_sync, set_time_pps, set_time_now}), .changed(cmd_trigger));
//////////////////////////////////////////////////////////////////////////
// PPS edge detection logic
//////////////////////////////////////////////////////////////////////////
reg pps_del, pps_del2;
always @(posedge clk)
{pps_del2,pps_del} <= {pps_del, pps};
wire pps_edge = !pps_del2 & pps_del;
//////////////////////////////////////////////////////////////////////////
// arm the trigger to latch a new time when the ctrl register is written
//////////////////////////////////////////////////////////////////////////
reg armed;
wire time_event = armed && ((set_time_now) || (set_time_pps && pps_edge) || (set_time_sync && sync_in));
always @(posedge clk) begin
if (reset) armed <= 1'b0;
else if (cmd_trigger) armed <= 1'b1;
else if (time_event) armed <= 1'b0;
end
//////////////////////////////////////////////////////////////////////////
// vita time tracker - update every tick or when we get an "event"
//////////////////////////////////////////////////////////////////////////
always @(posedge clk) begin
sync_out <= 1'b0;
if(reset) begin
vita_time <= 64'h0;
end else begin
if (time_event) begin
sync_out <= 1'b1;
vita_time <= time_at_next_event;
end else if (strobe) begin
vita_time <= vita_time + INCREMENT;
end
end
end
//////////////////////////////////////////////////////////////////////////
// track the time at last pps so host can detect the pps
//////////////////////////////////////////////////////////////////////////
always @(posedge clk)
if(reset)
vita_time_lastpps <= 64'h0;
else if(pps_edge)
if(time_event)
vita_time_lastpps <= time_at_next_event;
else
vita_time_lastpps <= vita_time + INCREMENT;
endmodule // timekeeper
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