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////////////////////////////////////////////////////////////////////////////////
//
// Filename: wbutohex.v
//
// Project: FPGA library
//
// Purpose: Supports a printable character conversion from a printable
// ASCII character to six bits of valid data. The encoding is
// as follows:
//
// 0-9 -> 0-9
// A-Z -> 10-35
// a-z -> 36-61
// @ -> 62
// % -> 63
//
// Note that decoding is stateless, yet requires one clock.
//
//
// Creator: Dan Gisselquist, Ph.D.
// Gisselquist Technology, LLC
//
////////////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2015-2017, Gisselquist Technology, LLC
//
// This program is free software (firmware): you can redistribute it and/or
// modify it under the terms of the GNU General Public License as published
// by the Free Software Foundation, either version 3 of the License, or (at
// your option) any later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program. (It's in the $(ROOT)/doc directory. Run make with no
// target there if the PDF file isn't present.) If not, see
// <http://www.gnu.org/licenses/> for a copy.
//
// License: GPL, v3, as defined and found on www.gnu.org,
// http://www.gnu.org/licenses/gpl.html
//
//
////////////////////////////////////////////////////////////////////////////////
//
//
module wbutohex(i_clk, i_stb, i_byte, o_stb, o_valid, o_hexbits);
input wire i_clk, i_stb;
input wire [7:0] i_byte;
output reg o_stb, o_valid;
output reg [5:0] o_hexbits;
always @(posedge i_clk)
o_stb <= i_stb;
always @(posedge i_clk)
begin
// These are the defaults, to be overwridden by the ifs below
o_valid <= 1'b1;
o_hexbits <= 6'h00;
if ((i_byte >= 8'h30)&&(i_byte <= 8'h39)) // A digit
o_hexbits <= { 2'b0, i_byte[3:0] };
else if ((i_byte >= 8'h41)&&(i_byte <= 8'h5a)) // Upper case
o_hexbits <= (i_byte[5:0] - 6'h01 + 6'h0a);// -'A'+10
else if ((i_byte >= 8'h61)&&(i_byte <= 8'h7a))
o_hexbits <= (i_byte[5:0] +6'h03); // -'a'+(10+26)
else if (i_byte == 8'h40) // An '@' sign
o_hexbits <= 6'h3e;
else if (i_byte == 8'h25) // A '%' sign
o_hexbits <= 6'h3f;
else
o_valid <= 1'b0;
end
endmodule