94 lines
2.5 KiB
Coq
94 lines
2.5 KiB
Coq
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// ***************************************************************************
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// ***************************************************************************
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// Copyright 2014 - 2017 (c) Analog Devices, Inc. All rights reserved.
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//
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// Each core or library found in this collection may have its own licensing terms.
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// The user should keep this in in mind while exploring these cores.
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//
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// Redistribution and use in source and binary forms,
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// with or without modification of this file, are permitted under the terms of either
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// (at the option of the user):
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//
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// 1. The GNU General Public License version 2 as published by the
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// Free Software Foundation, which can be found in the top level directory, or at:
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// https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html
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//
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// OR
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//
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// 2. An ADI specific BSD license as noted in the top level directory, or on-line at:
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// https://github.com/analogdevicesinc/hdl/blob/dev/LICENSE
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//
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// ***************************************************************************
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// ***************************************************************************
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module sync_event #(
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parameter NUM_OF_EVENTS = 1,
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parameter ASYNC_CLK = 1
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) (
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input in_clk,
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input [NUM_OF_EVENTS-1:0] in_event,
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input out_clk,
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output reg [NUM_OF_EVENTS-1:0] out_event
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);
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generate
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if (ASYNC_CLK == 1) begin
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wire out_toggle;
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wire in_toggle;
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reg out_toggle_d1 = 1'b0;
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reg in_toggle_d1 = 1'b0;
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sync_bits i_sync_out (
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.in(in_toggle_d1),
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.out_clk(out_clk),
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.out_resetn(1'b1),
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.out(out_toggle)
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);
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sync_bits i_sync_in (
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.in(out_toggle_d1),
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.out_clk(in_clk),
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.out_resetn(1'b1),
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.out(in_toggle)
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);
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wire in_ready = in_toggle == in_toggle_d1;
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wire load_out = out_toggle ^ out_toggle_d1;
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reg [NUM_OF_EVENTS-1:0] cdc_hold = 'h00;
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reg [NUM_OF_EVENTS-1:0] in_event_sticky = 'h00;
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wire [NUM_OF_EVENTS-1:0] pending_events = in_event_sticky | in_event;
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always @(posedge in_clk) begin
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if (in_ready == 1'b1) begin
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cdc_hold <= pending_events;
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in_event_sticky <= {NUM_OF_EVENTS{1'b0}};
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if (|pending_events == 1'b1) begin
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in_toggle_d1 <= ~in_toggle_d1;
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end
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end else begin
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in_event_sticky <= pending_events;
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end
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end
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always @(posedge out_clk) begin
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if (load_out == 1'b1) begin
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// When there is only one event, we know that it is set.
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out_event <= NUM_OF_EVENTS == 1 ? 1'b1 : cdc_hold;
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end else begin
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out_event <= {NUM_OF_EVENTS{1'b0}};
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end
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out_toggle_d1 <= out_toggle;
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end
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end else begin
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always @(*) begin
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out_event <= in_event;
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end
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end
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endgenerate
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endmodule
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