USB_I2C_MAC_FPGA_Code.rar
源代码在线查看： eth_crc.v
`include "timescale.v"
module eth_crc (Clk, Reset, Data, Enable, Initialize, Crc, CrcError);
parameter Tp = 1;
input Clk;
input Reset;
input [3:0] Data;
input Enable;
input Initialize;
output [31:0] Crc;
output CrcError;
reg [31:0] Crc;
wire [31:0] CrcNext;
assign CrcNext[0] = Enable & (Data[0] ^ Crc[28]);
assign CrcNext[1] = Enable & (Data[1] ^ Data[0] ^ Crc[28] ^ Crc[29]);
assign CrcNext[2] = Enable & (Data[2] ^ Data[1] ^ Data[0] ^ Crc[28] ^ Crc[29] ^ Crc[30]);
assign CrcNext[3] = Enable & (Data[3] ^ Data[2] ^ Data[1] ^ Crc[29] ^ Crc[30] ^ Crc[31]);
assign CrcNext[4] = (Enable & (Data[3] ^ Data[2] ^ Data[0] ^ Crc[28] ^ Crc[30] ^ Crc[31])) ^ Crc[0];
assign CrcNext[5] = (Enable & (Data[3] ^ Data[1] ^ Data[0] ^ Crc[28] ^ Crc[29] ^ Crc[31])) ^ Crc[1];
assign CrcNext[6] = (Enable & (Data[2] ^ Data[1] ^ Crc[29] ^ Crc[30])) ^ Crc[ 2];
assign CrcNext[7] = (Enable & (Data[3] ^ Data[2] ^ Data[0] ^ Crc[28] ^ Crc[30] ^ Crc[31])) ^ Crc[3];
assign CrcNext[8] = (Enable & (Data[3] ^ Data[1] ^ Data[0] ^ Crc[28] ^ Crc[29] ^ Crc[31])) ^ Crc[4];
assign CrcNext[9] = (Enable & (Data[2] ^ Data[1] ^ Crc[29] ^ Crc[30])) ^ Crc[5];
assign CrcNext[10] = (Enable & (Data[3] ^ Data[2] ^ Data[0] ^ Crc[28] ^ Crc[30] ^ Crc[31])) ^ Crc[6];
assign CrcNext[11] = (Enable & (Data[3] ^ Data[1] ^ Data[0] ^ Crc[28] ^ Crc[29] ^ Crc[31])) ^ Crc[7];
assign CrcNext[12] = (Enable & (Data[2] ^ Data[1] ^ Data[0] ^ Crc[28] ^ Crc[29] ^ Crc[30])) ^ Crc[8];
assign CrcNext[13] = (Enable & (Data[3] ^ Data[2] ^ Data[1] ^ Crc[29] ^ Crc[30] ^ Crc[31])) ^ Crc[9];
assign CrcNext[14] = (Enable & (Data[3] ^ Data[2] ^ Crc[30] ^ Crc[31])) ^ Crc[10];
assign CrcNext[15] = (Enable & (Data[3] ^ Crc[31])) ^ Crc[11];
assign CrcNext[16] = (Enable & (Data[0] ^ Crc[28])) ^ Crc[12];
assign CrcNext[17] = (Enable & (Data[1] ^ Crc[29])) ^ Crc[13];
assign CrcNext[18] = (Enable & (Data[2] ^ Crc[30])) ^ Crc[14];
assign CrcNext[19] = (Enable & (Data[3] ^ Crc[31])) ^ Crc[15];
assign CrcNext[20] = Crc[16];
assign CrcNext[21] = Crc[17];
assign CrcNext[22] = (Enable & (Data[0] ^ Crc[28])) ^ Crc[18];
assign CrcNext[23] = (Enable & (Data[1] ^ Data[0] ^ Crc[29] ^ Crc[28])) ^ Crc[19];
assign CrcNext[24] = (Enable & (Data[2] ^ Data[1] ^ Crc[30] ^ Crc[29])) ^ Crc[20];
assign CrcNext[25] = (Enable & (Data[3] ^ Data[2] ^ Crc[31] ^ Crc[30])) ^ Crc[21];
assign CrcNext[26] = (Enable & (Data[3] ^ Data[0] ^ Crc[31] ^ Crc[28])) ^ Crc[22];
assign CrcNext[27] = (Enable & (Data[1] ^ Crc[29])) ^ Crc[23];
assign CrcNext[28] = (Enable & (Data[2] ^ Crc[30])) ^ Crc[24];
assign CrcNext[29] = (Enable & (Data[3] ^ Crc[31])) ^ Crc[25];
assign CrcNext[30] = Crc[26];
assign CrcNext[31] = Crc[27];
always @ (posedge Clk or posedge Reset)
begin
if (Reset)
Crc else
if(Initialize)
Crc else
Crc end
assign CrcError = Crc[31:0] != 32'hc704dd7b; // CRC not equal to magic number
endmodule
