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https://github.com/openhwgroup/cvw
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49 lines
1.4 KiB
Systemverilog
49 lines
1.4 KiB
Systemverilog
// ==========================================================================
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// CRC Generation Unit - Linear Feedback Shift Register implementation
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// (c) Kay Gorontzi, GHSi.de, distributed under the terms of LGPL
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// https://www.ghsi.de/CRC/index.php?
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// https://www.ghsi.de/CRC/index.php?
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// =========================================================================
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module sd_crc_16(BITVAL, Enable, CLK, RST, CRC);
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input BITVAL;// Next input bit
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input Enable;
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input CLK; // Current bit valid (Clock)
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input RST; // Init CRC value
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output reg [15:0] CRC; // Current output CRC value
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// We need output registers
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wire inv;
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assign inv = BITVAL ^ CRC[15]; // XOR required?
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always @(posedge CLK or posedge RST) begin
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if (RST) begin
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CRC = 0;
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end
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else begin
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if (Enable==1) begin
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CRC[15] = CRC[14];
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CRC[14] = CRC[13];
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CRC[13] = CRC[12];
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CRC[12] = CRC[11] ^ inv;
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CRC[11] = CRC[10];
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CRC[10] = CRC[9];
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CRC[9] = CRC[8];
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CRC[8] = CRC[7];
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CRC[7] = CRC[6];
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CRC[6] = CRC[5];
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CRC[5] = CRC[4] ^ inv;
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CRC[4] = CRC[3];
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CRC[3] = CRC[2];
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CRC[2] = CRC[1];
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CRC[1] = CRC[0];
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CRC[0] = inv;
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end
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end
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end
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endmodule
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