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
|
#include "project.h"
static int check_min_ident (uint8_t *i)
{
if (i[0]) return 1;
if (!i[1]) return 1;
if (!i[2]) return 1;
if (!i[3]) return 1;
if (!i[4]) return 1;
if (!i[5]) return 1;
if (!i[6]) return 1;
if (i[7]) return 1;
return 0;
}
static void msf_set_ident (uint8_t *i)
{
i[0] = 0;
i[1] = 1;
i[2] = 1;
i[3] = 1;
i[4] = 1;
i[5] = 1;
i[6] = 1;
i[7] = 0;
}
static void msf_make_bits (UTC u, uint8_t *a, uint8_t *b)
{
bzero (a, 60);
bzero (b, 60);
a[0] = 1;
b[0] = 1;
bcd_set (a, 17, 24, u.year % 100);
bcd_set (a, 25, 29, u.month);
bcd_set (a, 30, 35, u.mday);
bcd_set (a, 36, 38, u.wday - 1);
bcd_set (a, 39, 44, u.hour);
bcd_set (a, 45, 51, u.minute);
msf_set_ident (&a[52]);
b[53] = 0; /* about to be BST */
b[54] = set_parity (a, 17, 24);
b[55] = set_parity (a, 25, 35);
b[56] = set_parity (a, 36, 38);
b[57] = set_parity (a, 39, 51);
b[58] = 0; /*BST vs GMT */
}
static void process_bits (uint8_t *bitsa, uint8_t *bitsb)
{
UTC u;
if (check_min_ident (&bitsa[52])) return;
if (check_parity (bitsa, 17, 24, bitsb[54])) return;
if (check_parity (bitsa, 25, 35, bitsb[55])) return;
if (check_parity (bitsa, 36, 38, bitsb[56])) return;
if (check_parity (bitsa, 39, 51, bitsb[57])) return;
u.jday = 0;
u.year = bcd (bitsa, 17, 24);
u.month = bcd (bitsa, 25, 29);
u.mday = bcd (bitsa, 30, 35);
u.hour = bcd (bitsa, 39, 44);
u.minute = bcd (bitsa, 45, 51);
u.second = 0;
u.nanosecond = 0;
printf ("MSF: decoded %02d-%02d-%02d %02d:%02d\r\n", u.year, u.month, u.mday, u.hour, u.minute);
}
void msf_make_stream (uint8_t *v, UTC u)
{
unsigned s;
uint8_t a[60], b[60];
uint8_t *pa, *pb;
msf_make_bits (u, a, b);
process_bits (a, b);
bzero (v, 600);
for (s = 0, pa = a, pb = b; s < 60; ++s, v += 10, ++pa, ++pb) {
if (!s)
memset (v, 1, 5);
v[0] = 1;
v[1] = *pa;
v[2] = *pb;
}
}
|
