Git-Mirrors/portapack-mayhem
1
0
Fork 0
mirror of https://github.com/eried/portapack-mayhem.git synced 2025-08-14 01:15:38 -04:00
Code Issues Projects Releases Packages Wiki Activity

Added De Bruijn sequence generator

Browse source 
Moved POCSAG frequency list to SD card file for FreqMan
This commit is contained in:
furrtek 2017-07-20 16:48:59 +01:00
parent 8364bfb2ce
commit 3005403b5e
11 changed files with 248 additions and 82 deletions
Download patch file Download diff file Expand all files Collapse all files

97
firmware/application/de_bruijn.cpp Normal file
View file

@ -0,0 +1,97 @@
/*
* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
* Copyright (C) 2017 Furrtek
*
* This file is part of PortaPack.
*
* This program is free software; 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 2, 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
* MERCHANTABILITY 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; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include "de_bruijn.hpp"
/*
How this works:
B(2,4): 2 states, 4 bits
Primitive poly with n=4: 1001
0001
xor 1001 = 0 ^ 1 = 1
00011
xor 1001 = 0 ^ 1 = 1
000111
xor 1001 = 0 ^ 1 = 1
0001111
xor 1001 = 1 ^ 1 = 0
00011110
xor 1001 = 1 ^ 0 = 1
000111101
xor 1001 = 1 ^ 1 = 0
0001111010
xor 1001 = 0 ^ 1 = 1
00011110101
xor 1001 = 0 ^ 1 = 1
000111101011
xor 1001 = 1 ^ 1 = 0
0001111010110
xor 1001 = 0 ^ 0 = 0
00011110101100
xor 1001 = 1 ^ 0 = 1
000111101011001
xor 1001 = 1 ^ 1 = 0
0001111010110010
xor 1001 = 0 ^ 0 = 0
*/
void de_bruijn::init(const uint32_t n) {
if ((n < 3) || (n > 16))
length = 3;
else
length = n;
// k is 2 (binary sequence)
poly = de_bruijn_polys[length - 3];
shift_register = 1;
}
uint32_t de_bruijn::compute(const uint32_t step) {
uint32_t c, bits, masked;
uint8_t new_bit;
for (c = 0; c < step; c++) {
masked = shift_register & poly;
new_bit = 0;
for (bits = 0; bits < length; bits++) {
new_bit ^= (masked & 1);
masked >>= 1;
}
shift_register <<= 1;
shift_register |= new_bit;
}
return shift_register;
}