/* $NetBSD: clk_rawdcf.c,v 1.9 2024/08/18 20:47:17 christos Exp $ */
/*
* /src/NTP/REPOSITORY/ntp4-dev/libparse/clk_rawdcf.c,v 4.18 2006/06/22 18:40:01 kardel RELEASE_20060622_A
*
* clk_rawdcf.c,v 4.18 2006/06/22 18:40:01 kardel RELEASE_20060622_A
*
* Raw DCF77 pulse clock support
*
* Copyright (c) 1995-2015 by Frank Kardel <kardel <AT> ntp.org>
* Copyright (c) 1989-1994 by Frank Kardel, Friedrich-Alexander Universitaet Erlangen-Nuernberg, Germany
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#if defined(REFCLOCK) && defined(CLOCK_PARSE) && defined(CLOCK_RAWDCF)
#include "ntp_fp.h"
#include "timevalops.h"
#include "ntp_unixtime.h"
#include "ntp_calendar.h"
#include "parse.h"
#ifdef PARSESTREAM
# include <sys/parsestreams.h>
#endif
#ifndef PARSEKERNEL
# include "ntp_stdlib.h"
#endif
/*
* DCF77 raw time code
*
* From "Zur Zeit", Physikalisch-Technische Bundesanstalt (PTB), Braunschweig
* und Berlin, Maerz 1989
*
* Timecode transmission:
* AM:
* time marks are send every second except for the second before the
* next minute mark
* time marks consist of a reduction of transmitter power to 25%
* of the nominal level
* the falling edge is the time indication (on time)
* time marks of a 100ms duration constitute a logical 0
* time marks of a 200ms duration constitute a logical 1
* FM:
* see the spec. (basically a (non-)inverted psuedo random phase shift)
*
* Encoding:
* Second Contents
* 0 - 10 AM: free, FM: 0
* 11 - 14 free
* 15 R - "call bit" used to signalize irregularities in the control facilities
* (until 2003 indicated transmission via alternate antenna)
* 16 A1 - expect zone change (1 hour before)
* 17 - 18 Z1,Z2 - time zone
* 0 0 illegal
* 0 1 MEZ (MET)
* 1 0 MESZ (MED, MET DST)
* 1 1 illegal
* 19 A2 - expect leap insertion/deletion (1 hour before)
* 20 S - start of time code (1)
* 21 - 24 M1 - BCD (lsb first) Minutes
* 25 - 27 M10 - BCD (lsb first) 10 Minutes
* 28 P1 - Minute Parity (even)
* 29 - 32 H1 - BCD (lsb first) Hours
* 33 - 34 H10 - BCD (lsb first) 10 Hours
* 35 P2 - Hour Parity (even)
* 36 - 39 D1 - BCD (lsb first) Days
* 40 - 41 D10 - BCD (lsb first) 10 Days
* 42 - 44 DW - BCD (lsb first) day of week (1: Monday -> 7: Sunday)
* 45 - 49 MO - BCD (lsb first) Month
* 50 MO0 - 10 Months
* 51 - 53 Y1 - BCD (lsb first) Years
* 54 - 57 Y10 - BCD (lsb first) 10 Years
* 58 P3 - Date Parity (even)
* 59 - usually missing (minute indication), except for leap insertion
*/
static parse_pps_fnc_t pps_rawdcf;
static parse_cvt_fnc_t cvt_rawdcf;
static parse_inp_fnc_t inp_rawdcf;
typedef struct last_tcode {
time_t tcode; /* last converted time code */
timestamp_t tminute; /* sample time for minute start */
timestamp_t timeout; /* last timeout timestamp */
} last_tcode_t;
#define BUFFER_MAX 61
clockformat_t clock_rawdcf =
{
inp_rawdcf, /* DCF77 input handling */
cvt_rawdcf, /* raw dcf input conversion */
pps_rawdcf, /* examining PPS information */
0, /* no private configuration data */
"RAW DCF77 Timecode", /* direct decoding / time synthesis */
BUFFER_MAX, /* bit buffer */
sizeof(last_tcode_t)
};
static struct dcfparam
{
const unsigned char *onebits;
const unsigned char *zerobits;
} dcfparameter =
{
(const unsigned char *)"###############RADMLS1248124P124812P1248121241248112481248P??", /* 'ONE' representation */
(const unsigned char *)"--------------------s-------p------p----------------------p__" /* 'ZERO' representation */
};
static struct rawdcfcode
{
char offset; /* start bit */
} rawdcfcode[] =
{
{ 0 }, { 15 }, { 16 }, { 17 }, { 19 }, { 20 }, { 21 }, { 25 }, { 28 }, { 29 },
{ 33 }, { 35 }, { 36 }, { 40 }, { 42 }, { 45 }, { 49 }, { 50 }, { 54 }, { 58 }, { 59 }
};
#define DCF_M 0
#define DCF_R 1
#define DCF_A1 2
#define DCF_Z 3
#define DCF_A2 4
#define DCF_S 5
#define DCF_M1 6
#define DCF_M10 7
#define DCF_P1 8
#define DCF_H1 9
#define DCF_H10 10
#define DCF_P2 11
#define DCF_D1 12
#define DCF_D10 13
#define DCF_DW 14
#define DCF_MO 15
#define DCF_MO0 16
#define DCF_Y1 17
#define DCF_Y10 18
#define DCF_P3 19
static struct partab
{
char offset; /* start bit of parity field */
} partab[] =
{
{ 21 }, { 29 }, { 36 }, { 59 }
};
#define DCF_P_P1 0
#define DCF_P_P2 1
#define DCF_P_P3 2
#define DCF_Z_MET 0x2
#define DCF_Z_MED 0x1
static u_long
ext_bf(
unsigned char *buf,
int idx,
const unsigned char *zero
)
{
u_long sum = 0;
int i, first;
first = rawdcfcode[idx].offset;
for (i = rawdcfcode[idx+1].offset - 1; i >= first; i--)
{
sum <<= 1;
sum |= (buf[i] != zero[i]);
}
return sum;
}
static unsigned
pcheck(
unsigned char *buf,
int idx,
const unsigned char *zero
)
{
int i,last;
unsigned psum = 1;
last = partab[idx+1].offset;
for (i = partab[idx].offset; i < last; i++)
psum ^= (buf[i] != zero[i]);
return psum;
}
static int/*BOOL*/
zeller_expand(
clocktime_t *clock_time,
unsigned int wd
)
{
unsigned int y = (unsigned int)clock_time->year;
unsigned int m = (unsigned int)clock_time->month - 1u;
unsigned int d = (unsigned int)clock_time->day - 1u;
unsigned int c;
/* Check basic constraints first. */
if ((y >= 100u) || (m >= 12u) || (d >= 31u) || (--wd >= 7u))
return FALSE;
/* Get weekday of date in 1st century by a variation on Zeller's
* congruence. All operands are non-negative, and the month
* formula is adjusted to use a divider of 32, so we can do a
* shift instead of a 'true' division:
*/
if ((m += 10u) >= 12u) /* shift base to 0000-03-01 */
m -= 12u;
else if (--y >= 100u)
y += 100;
d += y + (y >> 2) + 2u; /* year-related share */
d += (m * 83u + 16u) >> 5; /* month-related share */
/* The next step combines the exact division by modular inverse
* with the (mod 7) step in such way that no true division and
* only one multiplication is needed. The multiplier is
* M <- ceil((3*8)/7 * 2**29)
* and combines multiplication by invmod(5, 7) -> 3 and modulus
* by 7 transformation to (mod 8) in one step.
* Note that 252 == 0 (mod 7) and that 'd' is less than 185,
* so the number to invert and reduce is strictly positive. In
* the end, 'c' is number of centuries since start of a great
* cycle and must be in [0..3] or we had bad input.
*/
c = (((252u + wd - d) * 0x6db6db6eU) >> 29) & 7u;
if (c >= 4)
return FALSE;
/* undo calendar base shift now */
if ((m > 9u) && (++y >= 100u)) {
y -= 100u;
c = (c + 1u) & 3u;
}
/* combine year with centuries & map to [1970..2369] */
y += (c * 100u);
clock_time->year = (int)y + ((y < 370u) ? 2000 : 1600);
return TRUE;
}
static u_long
convert_rawdcf(
unsigned char *buffer,
int size,
struct dcfparam *dcfprm,
clocktime_t *clock_time
)
{
unsigned char *s = buffer;
const unsigned char *b = dcfprm->onebits;
const unsigned char *c = dcfprm->zerobits;
int i;
parseprintf(DD_RAWDCF,("parse: convert_rawdcf: \"%.*s\"\n", size, buffer));
if (size < 57)
{
#ifndef PARSEKERNEL
msyslog(LOG_ERR, "parse: convert_rawdcf: INCOMPLETE DATA - time code only has %d bits", size);
#endif
return CVT_FAIL|CVT_BADFMT;
}
for (i = 0; i < size; i++)
{
if ((*s != *b) && (*s != *c))
{
/*
* we only have two types of bytes (ones and zeros)
*/
#ifndef PARSEKERNEL
msyslog(LOG_ERR, "parse: convert_rawdcf: BAD DATA - no conversion");
#endif
return CVT_FAIL|CVT_BADFMT;
}
if (*b) b++;
if (*c) c++;
s++;
}
/*
* check Start and Parity bits
*/
if ((ext_bf(buffer, DCF_S, dcfprm->zerobits) == 1) &&
pcheck(buffer, DCF_P_P1, dcfprm->zerobits) &&
pcheck(buffer, DCF_P_P2, dcfprm->zerobits) &&
pcheck(buffer, DCF_P_P3, dcfprm->zerobits))
{
/*
* buffer OK
*/
parseprintf(DD_RAWDCF,("parse: convert_rawdcf: parity check passed\n"));
clock_time->flags = PARSEB_S_CALLBIT|PARSEB_S_LEAP;
clock_time->utctime= 0;
clock_time->usecond= 0;
clock_time->second = 0;
clock_time->minute = ext_bf(buffer, DCF_M10, dcfprm->zerobits);
clock_time->minute = TIMES10(clock_time->minute) + ext_bf(buffer, DCF_M1, dcfprm->zerobits);
clock_time->hour = ext_bf(buffer, DCF_H10, dcfprm->zerobits);
clock_time->hour = TIMES10(clock_time->hour) + ext_bf(buffer, DCF_H1, dcfprm->zerobits);
clock_time->day = ext_bf(buffer, DCF_D10, dcfprm->zerobits);
clock_time->day = TIMES10(clock_time->day) + ext_bf(buffer, DCF_D1, dcfprm->zerobits);
clock_time->month = ext_bf(buffer, DCF_MO0, dcfprm->zerobits);
clock_time->month = TIMES10(clock_time->month) + ext_bf(buffer, DCF_MO, dcfprm->zerobits);
clock_time->year = ext_bf(buffer, DCF_Y10, dcfprm->zerobits);
clock_time->year = TIMES10(clock_time->year) + ext_bf(buffer, DCF_Y1, dcfprm->zerobits);
if (!zeller_expand(clock_time, ext_bf(buffer, DCF_DW, dcfprm->zerobits)))
return CVT_FAIL|CVT_BADFMT;
switch (ext_bf(buffer, DCF_Z, dcfprm->zerobits))
{
case DCF_Z_MET:
clock_time->utcoffset = -1*60*60;
break;
case DCF_Z_MED:
clock_time->flags |= PARSEB_DST;
clock_time->utcoffset = -2*60*60;
break;
default:
parseprintf(DD_RAWDCF,("parse: convert_rawdcf: BAD TIME ZONE\n"));
return CVT_FAIL|CVT_BADFMT;
}
if (ext_bf(buffer, DCF_A1, dcfprm->zerobits))
clock_time->flags |= PARSEB_ANNOUNCE;
if (ext_bf(buffer, DCF_A2, dcfprm->zerobits))
clock_time->flags |= PARSEB_LEAPADD; /* default: DCF77 data format deficiency */
if (ext_bf(buffer, DCF_R, dcfprm->zerobits))
clock_time->flags |= PARSEB_CALLBIT;
parseprintf(DD_RAWDCF,("parse: convert_rawdcf: TIME CODE OK: %02d:%02d, %02d.%02d.%02d, flags 0x%lx\n",
(int)clock_time->hour, (int)clock_time->minute, (int)clock_time->day, (int)clock_time->month,(int) clock_time->year,
(u_long)clock_time->flags));
return CVT_OK;
}
else
{
/*
* bad format - not for us
*/
#ifndef PARSEKERNEL
msyslog(LOG_ERR, "parse: convert_rawdcf: start bit / parity check FAILED for \"%.*s\"", size, buffer);
#endif
return CVT_FAIL|CVT_BADFMT;
}
}
/*
* parse_cvt_fnc_t cvt_rawdcf
* raw dcf input routine - needs to fix up 50 baud
* characters for 1/0 decision
*/
static u_long
cvt_rawdcf(
unsigned char *buffer,
int size,
struct format *param,
clocktime_t *clock_time,
void *local
)
{
last_tcode_t *t = (last_tcode_t *)local;
unsigned char *s = (unsigned char *)buffer;
unsigned char *e = s + size;
const unsigned char *b = dcfparameter.onebits;
const unsigned char *c = dcfparameter.zerobits;
u_long rtc = CVT_NONE;
unsigned int i, lowmax, highmax, cutoff, span;
#define BITS 9
unsigned char histbuf[BITS];
/*
* the input buffer contains characters with runs of consecutive
* bits set. These set bits are an indication of the DCF77 pulse
* length. We assume that we receive the pulse at 50 Baud. Thus
* a 100ms pulse would generate a 4 bit train (20ms per bit and
* start bit)
* a 200ms pulse would create all zeroes (and probably a frame error)
*/
for (i = 0; i < BITS; i++)
{
histbuf[i] = 0;
}
cutoff = 0;
lowmax = 0;
while (s < e)
{
unsigned int ch = *s ^ 0xFF;
/*
* these lines are left as an excercise to the reader 8-)
*/
if (!((ch+1) & ch) || !*s)
{
for (i = 0; ch; i++)
{
ch >>= 1;
}
*s = (unsigned char) i;
histbuf[i]++;
cutoff += i;
lowmax++;
}
else
{
parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: character check for 0x%x@%d FAILED\n", *s, (int)(s - (unsigned char *)buffer)));
*s = (unsigned char)~0;
rtc = CVT_FAIL|CVT_BADFMT;
}
s++;
}
if (lowmax)
{
cutoff /= lowmax;
}
else
{
cutoff = 4; /* doesn't really matter - it'll fail anyway, but gives error output */
}
parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: average bit count: %d\n", cutoff));
lowmax = 0;
highmax = 0;
parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: histogram:"));
for (i = 0; i <= cutoff; i++)
{
lowmax+=histbuf[i] * i;
highmax += histbuf[i];
parseprintf(DD_RAWDCF,(" %d", histbuf[i]));
}
parseprintf(DD_RAWDCF, (" <M>"));
lowmax += highmax / 2;
if (highmax)
{
lowmax /= highmax;
}
else
{
lowmax = 0;
}
highmax = 0;
cutoff = 0;
for (; i < BITS; i++)
{
highmax+=histbuf[i] * i;
cutoff +=histbuf[i];
parseprintf(DD_RAWDCF,(" %d", histbuf[i]));
}
parseprintf(DD_RAWDCF,("\n"));
if (cutoff)
{
highmax /= cutoff;
}
else
{
highmax = BITS-1;
}
span = cutoff = lowmax;
for (i = lowmax; i <= highmax; i++)
{
if (histbuf[cutoff] > histbuf[i])
{
cutoff = i;
span = i;
}
else
if (histbuf[cutoff] == histbuf[i])
{
span = i;
}
}
cutoff = (cutoff + span) / 2;
parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: lower maximum %d, higher maximum %d, cutoff %d\n", lowmax, highmax, cutoff));
s = (unsigned char *)buffer;
while (s < e)
{
if (*s == (unsigned char)~0)
{
*s = '?';
}
else
{
*s = (*s >= cutoff) ? *b : *c;
}
s++;
if (*b) b++;
if (*c) c++;
}
*s = '\0';
if (rtc == CVT_NONE)
{
rtc = convert_rawdcf(buffer, size, &dcfparameter, clock_time);
if (rtc == CVT_OK)
{
time_t newtime;
newtime = parse_to_unixtime(clock_time, &rtc);
if ((rtc == CVT_OK) && t)
{
if ((newtime - t->tcode) <= 600) /* require a successful telegram within last 10 minutes */
{
parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: recent timestamp check OK\n"));
clock_time->utctime = newtime;
}
else
{
parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: recent timestamp check FAIL - ignore timestamp\n"));
rtc = CVT_SKIP;
}
t->tcode = newtime;
}
}
}
return rtc;
}
/*
* parse_pps_fnc_t pps_rawdcf
*
* currently a very stupid version - should be extended to decode
* also ones and zeros (which is easy)
*/
/*ARGSUSED*/
static u_long
pps_rawdcf(
parse_t *parseio,
int status,
timestamp_t *ptime
)
{
if (!status) /* negative edge for simpler wiring (Rx->DCD) */
{
parseio->parse_dtime.parse_ptime = *ptime;
parseio->parse_dtime.parse_state |= PARSEB_PPS|PARSEB_S_PPS;
}
return CVT_NONE;
}
static long
calc_usecdiff(
timestamp_t *ref,
timestamp_t *base,
long offset
)
{
struct timeval delta;
long delta_usec = 0;
#ifdef PARSEKERNEL
delta.tv_sec = ref->tv.tv_sec - offset - base->tv.tv_sec;
delta.tv_usec = ref->tv.tv_usec - base->tv.tv_usec;
if (delta.tv_usec < 0)
{
delta.tv_sec -= 1;
delta.tv_usec += 1000000;
}
#else
l_fp delt;
delt = ref->fp;
delt.l_i -= offset;
L_SUB(&delt, &base->fp);
TSTOTV(&delt, &delta);
#endif
delta_usec = 1000000 * (int32_t)delta.tv_sec + delta.tv_usec;
return delta_usec;
}
static u_long
snt_rawdcf(
parse_t *parseio,
timestamp_t *ptime
)
{
/*
* only synthesize if all of following conditions are met:
* - CVT_OK parse_status (we have a time stamp base)
* - ABS(ptime - tminute - (parse_index - 1) sec) < 500ms (spaced by 1 sec +- 500ms)
* - minute marker is available (confirms minute raster as base)
*/
last_tcode_t *t = (last_tcode_t *)parseio->parse_pdata;
long delta_usec = -1;
if (t != NULL && t->tminute.tv.tv_sec != 0) {
delta_usec = calc_usecdiff(ptime, &t->tminute, parseio->parse_index - 1);
if (delta_usec < 0)
delta_usec = -delta_usec;
}
parseprintf(DD_RAWDCF,("parse: snt_rawdcf: synth for offset %d seconds - absolute usec error %ld\n",
parseio->parse_index - 1, delta_usec));
if (((parseio->parse_dtime.parse_status & CVT_MASK) == CVT_OK) &&
(delta_usec < 500000 && delta_usec >= 0)) /* only if minute marker is available */
{
parseio->parse_dtime.parse_stime = *ptime;
#ifdef PARSEKERNEL
parseio->parse_dtime.parse_time.tv.tv_sec++;
#else
parseio->parse_dtime.parse_time.fp.l_ui++;
#endif
parseprintf(DD_RAWDCF,("parse: snt_rawdcf: time stamp synthesized offset %d seconds\n", parseio->parse_index - 1));
return updatetimeinfo(parseio, parseio->parse_lstate);
}
return CVT_NONE;
}
/*
* parse_inp_fnc_t inp_rawdcf
*
* grab DCF77 data from input stream
*/
static u_long
inp_rawdcf(
parse_t *parseio,
char ch,
timestamp_t *tstamp
)
{
static struct timeval timeout = { 1, 500000 }; /* 1.5 secongs denote second #60 */
parseprintf(DD_PARSE, ("inp_rawdcf(0x%p, 0x%x, ...)\n", (void*)parseio, ch));
parseio->parse_dtime.parse_stime = *tstamp; /* collect timestamp */
if (parse_timedout(parseio, tstamp, &timeout))
{
last_tcode_t *t = (last_tcode_t *)parseio->parse_pdata;
long delta_usec;
parseprintf(DD_RAWDCF, ("inp_rawdcf: time out seen\n"));
/* finish collection */
(void) parse_end(parseio);
if (t != NULL)
{
/* remember minute start sample time if timeouts occur in minute raster */
if (t->timeout.tv.tv_sec != 0)
{
delta_usec = calc_usecdiff(tstamp, &t->timeout, 60);
if (delta_usec < 0)
delta_usec = -delta_usec;
}
else
{
delta_usec = -1;
}
if (delta_usec < 500000 && delta_usec >= 0)
{
parseprintf(DD_RAWDCF, ("inp_rawdcf: timeout time difference %ld usec - minute marker set\n", delta_usec));
/* collect minute markers only if spaced by 60 seconds */
t->tminute = *tstamp;
}
else
{
parseprintf(DD_RAWDCF, ("inp_rawdcf: timeout time difference %ld usec - minute marker cleared\n", delta_usec));
memset((char *)&t->tminute, 0, sizeof(t->tminute));
}
t->timeout = *tstamp;
}
(void) parse_addchar(parseio, ch);
/* pass up to higher layers */
return PARSE_INP_TIME;
}
else
{
unsigned int rtc;
rtc = parse_addchar(parseio, ch);
if (rtc == PARSE_INP_SKIP)
{
if (snt_rawdcf(parseio, tstamp) == CVT_OK)
return PARSE_INP_SYNTH;
}
return rtc;
}
}
#else /* not (REFCLOCK && CLOCK_PARSE && CLOCK_RAWDCF) */
NONEMPTY_TRANSLATION_UNIT
#endif /* not (REFCLOCK && CLOCK_PARSE && CLOCK_RAWDCF) */
/*
* History:
*
* clk_rawdcf.c,v
* Revision 4.18 2006/06/22 18:40:01 kardel
* clean up signedness (gcc 4)
*
* Revision 4.17 2006/01/22 16:01:55 kardel
* update version information
*
* Revision 4.16 2006/01/22 15:51:22 kardel
* generate reasonable timecode output on invalid input
*
* Revision 4.15 2005/08/06 19:17:06 kardel
* clean log output
*
* Revision 4.14 2005/08/06 17:39:40 kardel
* cleanup size handling wrt/ to buffer boundaries
*
* Revision 4.13 2005/04/16 17:32:10 kardel
* update copyright
*
* Revision 4.12 2004/11/14 15:29:41 kardel
* support PPSAPI, upgrade Copyright to Berkeley style
*
* Revision 4.9 1999/12/06 13:42:23 kardel
* transfer correctly converted time codes always into tcode
*
* Revision 4.8 1999/11/28 09:13:50 kardel
* RECON_4_0_98F
*
* Revision 4.7 1999/04/01 20:07:20 kardel
* added checking for minutie increment of timestamps in clk_rawdcf.c
*
* Revision 4.6 1998/06/14 21:09:37 kardel
* Sun acc cleanup
*
* Revision 4.5 1998/06/13 12:04:16 kardel
* fix SYSV clock name clash
*
* Revision 4.4 1998/06/12 15:22:28 kardel
* fix prototypes
*
* Revision 4.3 1998/06/06 18:33:36 kardel
* simplified condidional compile expression
*
* Revision 4.2 1998/05/24 11:04:18 kardel
* triggering PPS on negative edge for simpler wiring (Rx->DCD)
*
* Revision 4.1 1998/05/24 09:39:53 kardel
* implementation of the new IO handling model
*
* Revision 4.0 1998/04/10 19:45:30 kardel
* Start 4.0 release version numbering
*
* from V3 3.24 log info deleted 1998/04/11 kardel
*
*/
