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//-----------------------------------------------------
// Design Name : serial_crc_ccitt
// File Name : serial_crc.v
// Function : CCITT Serial CRC
// Coder : Deepak Kumar Tala
//-----------------------------------------------------
module serial_crc_ccitt (
clk ,
reset ,
enable ,
init ,
data_in ,
crc_out
);
//-----------Input Ports---------------
input clk ;
input reset ;
input enable ;
input init ;
input data_in ;
//-----------Output Ports---------------
output [15:0] crc_out;
//------------Internal Variables--------
reg [15:0] lfsr;
//-------------Code Start-----------------
assign crc_out = lfsr;
// Logic to CRC Calculation
always @ (posedge clk)
if (reset) begin
lfsr <= 16'hFFFF;
end else if (enable) begin
if (init) begin
lfsr <= 16'hFFFF;
end else begin
lfsr[0] <= data_in ^ lfsr[15];
lfsr[1] <= lfsr[0];
lfsr[2] <= lfsr[1];
lfsr[3] <= lfsr[2];
lfsr[4] <= lfsr[3];
lfsr[5] <= lfsr[4] ^ data_in ^ lfsr[15];
lfsr[6] <= lfsr[5];
lfsr[7] <= lfsr[6];
lfsr[8] <= lfsr[7];
lfsr[9] <= lfsr[8];
lfsr[10] <= lfsr[9];
lfsr[11] <= lfsr[10];
lfsr[12] <= lfsr[11] ^ data_in ^ lfsr[15];
lfsr[13] <= lfsr[12];
lfsr[14] <= lfsr[13];
lfsr[15] <= lfsr[14];
end
end
endmodule
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