1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
|
/* -*- c++ -*- */
/*
* Copyright 2009 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio 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 3, or (at your option)
* any later version.
*
* GNU Radio 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 GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <noaa_hrpt_deframer.h>
#include <gr_io_signature.h>
#include <cstring>
#include <cstdio>
#define ST_IDLE 0
#define ST_SYNCED 1
#define SYNC1 0x0284
#define SYNC2 0x016F
#define SYNC3 0x035C
#define SYNC4 0x019D
#define SYNC5 0x020F
#define SYNC6 0x0095
#define HRPT_MINOR_FRAME_SYNC 0x0A116FD719D83C95LL
static int frames_seen = 0;
noaa_hrpt_deframer_sptr
noaa_make_hrpt_deframer()
{
return gnuradio::get_initial_sptr(new noaa_hrpt_deframer());
}
noaa_hrpt_deframer::noaa_hrpt_deframer()
: gr_block("noaa_hrpt_deframer",
gr_make_io_signature(1, 1, sizeof(char)),
gr_make_io_signature(1, 1, sizeof(short)))
{
set_output_multiple(6); // room for writing full sync when received
d_mid_bit = true;
d_last_bit = 0;
enter_idle();
}
void
noaa_hrpt_deframer::enter_idle()
{
d_state = ST_IDLE;
}
void
noaa_hrpt_deframer::enter_synced()
{
d_state = ST_SYNCED;
d_bit_count = HRPT_BITS_PER_WORD;
d_word_count = HRPT_MINOR_FRAME_WORDS-HRPT_SYNC_WORDS;
d_word = 0;
}
int
noaa_hrpt_deframer::general_work(int noutput_items,
gr_vector_int &ninput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
int ninputs = ninput_items[0];
const char *in = (const char *)input_items[0];
unsigned short *out = (unsigned short *)output_items[0];
int i = 0, j = 0;
while (i < ninputs && j < noutput_items) {
char bit = in[i++];
char diff = bit^d_last_bit;
d_last_bit = bit;
// Wait for transition if not synced, otherwise, alternate bits
if (d_mid_bit && (diff | (d_state == ST_SYNCED))) {
switch (d_state) {
case ST_IDLE:
d_shifter = (d_shifter << 1) | bit; // MSB transmitted first
if ((d_shifter & 0x0FFFFFFFFFFFFFFFLL) == HRPT_MINOR_FRAME_SYNC) {
fprintf(stderr, "SYNC #%i", frames_seen++);
out[j++] = SYNC1;
out[j++] = SYNC2;
out[j++] = SYNC3;
out[j++] = SYNC4;
out[j++] = SYNC5;
out[j++] = SYNC6;
enter_synced();
}
break;
case ST_SYNCED:
d_word = (d_word << 1) | bit; // MSB transmitted first
if (--d_bit_count == 0) {
out[j++] = d_word;
d_word = 0;
d_bit_count = HRPT_BITS_PER_WORD;
if (--d_word_count == 0) {
fprintf(stderr, "...done\n");
enter_idle();
}
}
break;
default:
throw std::runtime_error("noaa_hrpt_deframer: bad state\n");
}
d_mid_bit = false;
}
else {
d_mid_bit = true;
}
}
consume_each(i);
return j;
}
|
