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//
// Copyright 2011 Ettus Research LLC
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
module fifo_to_gpmc_async
(input clk, input reset, input clear,
input [17:0] data_i, input src_rdy_i, output dst_rdy_o,
output [15:0] EM_D, input EM_NCS, input EM_NOE,
input [15:0] frame_len);
// Synchronize the async control signals
reg [2:0] cs_del, oe_del;
reg [15:0] counter;
always @(posedge clk)
if(reset)
begin
cs_del <= 3'b11;
oe_del <= 3'b11;
end
else
begin
cs_del <= { cs_del[1:0], EM_NCS };
oe_del <= { oe_del[1:0], EM_NOE };
end
wire do_read = ( (~cs_del[1] | ~cs_del[2]) & (oe_del[1:0] == 2'b01)); // change output on trailing edge
wire first_read = (counter == 0);
wire last_read = ((counter+1) == frame_len);
assign EM_D = data_i[15:0];
assign dst_rdy_o = do_read;
endmodule // fifo_to_gpmc_async
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