cvw/soc/fifo/sync_r2w.sv
2024-03-27 10:16:31 -05:00

45 lines
1.6 KiB
Systemverilog

///////////////////////////////////////////
// sync_r2w.sv
//
// Written: Clifford E Cummings 16 June 2005
// Modified: james.stine@okstate.edu 19 February 2024
//
// Purpose: FIFO read-domain to write-domain synchronizer
//
// Documentation:
//
// A component of the CORE-V-WALLY configurable RISC-V project.
// https://github.com/openhwgroup/cvw
//
// Copyright (C) 2021-24 Harvey Mudd College & Oklahoma State University
//
// SPDX-License-Identifier: Apache-2.0 WITH SHL-2.1
//
// Licensed under the Solderpad Hardware License v 2.1 (the “License”); you may not use this file
// except in compliance with the License, or, at your option, the Apache License version 2.0. You
// may obtain a copy of the License at
//
// https://solderpad.org/licenses/SHL-2.1/
//
// Unless required by applicable law or agreed to in writing, any work distributed under the
// License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
// either express or implied. See the License for the specific language governing permissions
// and limitations under the License.
////////////////////////////////////////////////////////////////////////////////////////////////
module sync_r2w #(parameter ADDRSIZE = 4)
(wq2_rptr, rptr, wclk, wrst_n);
input logic [ADDRSIZE:0] rptr;
input logic wclk;
input logic wrst_n;
output logic [ADDRSIZE:0] wq2_rptr;
logic [ADDRSIZE:0] wq1_rptr;
always @(posedge wclk or negedge wrst_n)
if (!wrst_n) {wq2_rptr,wq1_rptr} <= 0;
else {wq2_rptr,wq1_rptr} <= {wq1_rptr,rptr};
endmodule // sync_r2w