vbatts/grub
1
0
Fork 0
Code Issues Pull requests Releases Wiki Activity

New terminal outputs using serial: morse and spkmodem.

Browse source
This commit is contained in:
Vladimir 'phcoder' Serbinenko 2013-01-16 20:39:54 +01:00
parent 34f71cb866
commit b78d6c32e3
10 changed files with 512 additions and 132 deletions
Download patch file Download diff file Expand all files Collapse all files

98
util/spkmodem-recv.c Normal file
View file

@ -0,0 +1,98 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* Compilation: gcc -o spkmodem-recv spkmodem-recv */
/* Usage: parecord --channels=1 --rate=48000 --format=s16le | ./spkmodem-recv */
#define RATE 48000
#define SAMPLES_PER_TRAME 480
#define AMPLITUDE_THRESHOLD 100000
#define FREQ_SEP_MIN 15
#define FREQ_SEP_NOM 20
#define FREQ_SEP_MAX 25
#define FREQ_DATA_MIN 10
#define FREQ_DATA_THRESHOLD 60
#define FREQ_DATA_MAX 120
#define AMPLITUDE_SAMPLES 2 * SAMPLES_PER_TRAME
#define THRESHOLD 1000
#define DEBUG 0
static signed short trame[2 * SAMPLES_PER_TRAME];
static signed short pulse[2 * SAMPLES_PER_TRAME];
static int ringpos = 0;
static int pos, f1, f2;
static int amplitude = 0;
static int lp = 0;
static void
read_sample (void)
{
amplitude -= abs (trame[ringpos]);
f1 -= pulse[ringpos];
f1 += pulse[(ringpos + SAMPLES_PER_TRAME) % (2 * SAMPLES_PER_TRAME)];
f2 -= pulse[(ringpos + SAMPLES_PER_TRAME) % (2 * SAMPLES_PER_TRAME)];
fread (trame + ringpos, 1, sizeof (trame[0]), stdin);
amplitude += abs (trame[ringpos]);
if (pos ? (trame[ringpos] < -THRESHOLD)
: (trame[ringpos] > +THRESHOLD))
{
pulse[ringpos] = 1;
pos = !pos;
f2++;
}
else
pulse[ringpos] = 0;
ringpos++;
ringpos %= 2 * SAMPLES_PER_TRAME;
lp++;
}
int
main ()
{
int bitn = 7;
char c = 0;
int i;
while (!feof (stdin))
{
if (lp > 20000)
{
fflush (stdout);
bitn = 7;
c = 0;
lp = 0;
}
if (f2 > 12 && f2 < 25
&& f1 > 5 && f1 < 120)
{
#if DEBUG
printf ("%d %d %d @%d\n", f1, f2, FREQ_DATA_THRESHOLD,
ftell (stdin) - sizeof (trame));
#endif
if (f1 < 60)
c |= (1 << bitn);
bitn--;
if (bitn < 0)
{
#if DEBUG
printf ("<%c, %x>", c, c);
#else
printf ("%c", c);
#endif
bitn = 7;
c = 0;
}
lp = 0;
for (i = 0; i < SAMPLES_PER_TRAME; i++)
read_sample ();
continue;
}
read_sample ();
}
return 0;
}