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dgisselq |
////////////////////////////////////////////////////////////////////////////////
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//
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// Filename: wbutohex.v
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//
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// Project: FPGA library
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//
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// Purpose: Supports a printable character conversion from a printable
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// ASCII character to six bits of valid data. The encoding is
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// as follows:
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//
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// 0-9 -> 0-9
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// A-Z -> 10-35
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// a-z -> 36-61
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// @ -> 62
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// % -> 63
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//
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// Note that decoding is stateless, yet requires one clock.
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//
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//
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// Creator: Dan Gisselquist, Ph.D.
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// Gisselquist Technology, LLC
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//
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////////////////////////////////////////////////////////////////////////////////
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//
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// Copyright (C) 2015-2016, Gisselquist Technology, LLC
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//
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// This program is free software (firmware): you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as published
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// by the Free Software Foundation, either version 3 of the License, or (at
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// your option) any later version.
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//
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// This program is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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// for more details.
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//
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// You should have received a copy of the GNU General Public License along
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// with this program. (It's in the $(ROOT)/doc directory, run make with no
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// target there if the PDF file isn't present.) If not, see
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// <http://www.gnu.org/licenses/> for a copy.
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//
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// License: GPL, v3, as defined and found on www.gnu.org,
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// http://www.gnu.org/licenses/gpl.html
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//
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//
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////////////////////////////////////////////////////////////////////////////////
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//
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//
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module wbutohex(i_clk, i_stb, i_byte, o_stb, o_valid, o_hexbits);
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input i_clk, i_stb;
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input [7:0] i_byte;
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output reg o_stb, o_valid;
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output reg [5:0] o_hexbits;
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always @(posedge i_clk)
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o_stb <= i_stb;
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always @(posedge i_clk)
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begin
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// These are the defaults, to be overwridden by the ifs below
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o_valid <= 1'b1;
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o_hexbits <= 6'h00;
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if ((i_byte >= 8'h30)&&(i_byte <= 8'h39)) // A digit
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o_hexbits <= { 2'b0, i_byte[3:0] };
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else if ((i_byte >= 8'h41)&&(i_byte <= 8'h5a)) // Upper case
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o_hexbits <= (i_byte[5:0] - 6'h01 + 6'h0a);// -'A'+10
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else if ((i_byte >= 8'h61)&&(i_byte <= 8'h7a))
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o_hexbits <= (i_byte[5:0] +6'h03); // -'a'+(10+26)
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else if (i_byte == 8'h40) // An '@' sign
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o_hexbits <= 6'h3e;
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else if (i_byte == 8'h25) // A '%' sign
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o_hexbits <= 6'h3f;
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else
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o_valid <= 1'b0;
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end
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endmodule
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