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Diffstat (limited to 'memory/bram_1wo_1ro_readfirst.v')
| -rw-r--r-- | memory/bram_1wo_1ro_readfirst.v | 107 |
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diff --git a/memory/bram_1wo_1ro_readfirst.v b/memory/bram_1wo_1ro_readfirst.v new file mode 100644 index 0000000..6991c87 --- /dev/null +++ b/memory/bram_1wo_1ro_readfirst.v @@ -0,0 +1,107 @@ +//====================================================================== +// +// Copyright (c) 2015, 2018 NORDUnet A/S All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions +// are met: +// - Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// +// - Redistributions in binary form must reproduce the above copyright +// notice, this list of conditions and the following disclaimer in the +// documentation and/or other materials provided with the distribution. +// +// - Neither the name of the NORDUnet nor the names of its contributors may +// be used to endorse or promote products derived from this software +// without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS +// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED +// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A +// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED +// TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR +// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF +// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING +// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +// +//====================================================================== + +module bram_1wo_1ro_readfirst # +( + parameter MEM_WIDTH = 32, + parameter MEM_ADDR_BITS = 8 +) +( + input clk, + + input [MEM_ADDR_BITS-1:0] a_addr, + input a_wr, + input [MEM_WIDTH -1:0] a_in, + output [MEM_WIDTH -1:0] a_out, + + input [MEM_ADDR_BITS-1:0] b_addr, + output [MEM_WIDTH -1:0] b_out +); + + + // + // BRAM + // + (* RAM_STYLE="BLOCK" *) + reg [MEM_WIDTH-1:0] bram[0:(2**MEM_ADDR_BITS)-1]; + + + // + // Initialization for Simulation + // + /* + integer c; + initial begin + for (c=0; c<(2**MEM_ADDR_BITS); c=c+1) + bram[c] = {MEM_WIDTH{1'b0}}; + end + */ + + + + // + // Output Registers + // + reg [MEM_WIDTH-1:0] bram_reg_b; + + assign a_out = 32'hDEADCE11; + assign b_out = bram_reg_b; + + + // + // Note, that when both ports are accessing the same location, conflict can + // potentionally arise. See Xilinx UG473 (pages 19-20, "Conflict + // Avoidance") for more information. In our configuration to avoid that the + // write port must be coded to operate in READ_FIRST mode. If the write + // port is overwriting the same address the read port is accessing, the + // write port must read the previously stored data (not the data it is + // writing, as that would be WRITE_FIRST mode). + // + + + // + // Write-Only Port A + // + always @(posedge clk) + // + if (a_wr) bram[a_addr] <= a_in; + + + // + // Read-Only Port B + // + always @(posedge clk) + // + bram_reg_b <= bram[b_addr]; + + +endmodule |