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//
// Copyright 2015 Ettus Research
//
// Increases AXI stream bit width by concatenating inputs across multiple clock cycles.
// Note: WIDTH_IN must be a multiple of WIDTH_OUT
module axi_packer #(
parameter WIDTH_IN = 8, // Input bit width
parameter WIDTH_OUT = 32, // Output bit width
parameter REVERSE = 0) // 0: Fill LSB to MSB, 1: Fill MSB to LSB
(
input clk, input reset, input clear,
input [WIDTH_IN-1:0] i_tdata, input i_tlast, input i_tvalid, output i_tready,
output [WIDTH_OUT-1:0] o_tdata, output o_tlast, output o_tvalid, input o_tready
);
localparam M = WIDTH_OUT/WIDTH_IN;
reg packed_tlast, packed_tvalid;
reg [WIDTH_OUT-1:0] packed_tdata;
reg [$clog2(M)-1:0] cnt;
reg i_tlast_hold;
integer i;
always @(posedge clk) begin
if (reset | clear) begin
i_tlast_hold <= 1'b0;
cnt <= 'd0;
packed_tdata <= 'd0;
packed_tvalid <= 1'b0;
packed_tlast <= 1'b0;
end else begin
packed_tvalid <= 1'b0;
packed_tlast <= 1'b0;
if (i_tvalid & i_tready) begin
if (i_tlast) begin
i_tlast_hold <= 1'b1;
end
if (cnt > M-1) begin
cnt <= 'd0;
packed_tlast <= i_tlast_hold;
packed_tvalid <= 1'b1;
end else begin
cnt <= cnt + 1;
end
if (REVERSE) begin
packed_tdata[WIDTH_OUT-1:WIDTH_OUT-WIDTH_IN] <= i_tdata;
for (i = 0; i < M-1; i = i + 1) begin
packed_tdata[WIDTH_OUT-(i+1)*WIDTH_IN-1 -: WIDTH_IN] <= packed_tdata[WIDTH_OUT-i*WIDTH_IN-1 -: WIDTH_IN];
end
end else begin
packed_tdata[WIDTH_IN-1:0] <= i_tdata;
for (i = 0; i < M-1; i = i + 1) begin
packed_tdata[(i+2)*WIDTH_IN-1 -: WIDTH_IN] <= packed_tdata[(i+1)*WIDTH_IN-1 -: WIDTH_IN];
end
end
end
end
end
axi_fifo_flop #(.WIDTH(WIDTH_OUT+1)) axi_fifo_flop_pack (
.clk(clk), .reset(reset), .clear(clear),
.i_tdata({packed_tlast,packed_tdata}), .i_tvalid(packed_tvalid), .i_tready(i_tready),
.o_tdata({o_tlast,o_tdata}), .o_tvalid(o_tvalid), .o_tready(o_tready),
.space(), .occupied());
endmodule
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