/* * refclock_true - clock driver for the Kinemetrics/TrueTime receivers * Receiver Version 3.0C - tested plain, with CLKLDISC * Development work being done: * - Support TL-3 WWV TOD receiver */ #ifdef HAVE_CONFIG_H #include #endif #if defined(REFCLOCK) && defined(CLOCK_TRUETIME) #include #include #include "ntpd.h" #include "ntp_io.h" #include "ntp_refclock.h" #include "ntp_unixtime.h" #include "ntp_stdlib.h" #ifdef SYS_WINNT extern int async_write(int, const void *, unsigned int); #undef write #define write(fd, data, octets) async_write(fd, data, octets) #endif /* This should be an atom clock but those are very hard to build. * * The PCL720 from P C Labs has an Intel 8253 lookalike, as well as a bunch * of TTL input and output pins, all brought out to the back panel. If you * wire a PPS signal (such as the TTL PPS coming out of a GOES or other * Kinemetrics/Truetime clock) to the 8253's GATE0, and then also wire the * 8253's OUT0 to the PCL720's INPUT3.BIT0, then we can read CTR0 to get the * number of uSecs since the last PPS upward swing, mediated by reading OUT0 * to find out if the counter has wrapped around (this happens if more than * 65535us (65ms) elapses between the PPS event and our being called.) */ #ifdef CLOCK_PPS720 # undef min /* XXX */ # undef max /* XXX */ # include # include # include # define PCL720_IOB 0x2a0 /* XXX */ # define PCL720_CTR 0 /* XXX */ #endif /* * Support for Kinemetrics Truetime Receivers * GOES: (468-DC, usable with GPS->GOES converting antenna) * GPS/TM-TMD: * XL-DC: (a 151-602-210, reported by the driver as a GPS/TM-TMD) * GPS-800 TCU: (an 805-957 with the RS232 Talker/Listener module) * TL-3: 3 channel WWV/H receiver w/ IRIG and RS-232 outputs * OM-DC: getting stale ("OMEGA") * * Most of this code is originally from refclock_wwvb.c with thanks. * It has been so mangled that wwvb is not a recognizable ancestor. * * Timcode format: ADDD:HH:MM:SSQCL * A - control A (this is stripped before we see it) * Q - Quality indication (see below) * C - Carriage return * L - Line feed * * Quality codes indicate possible error of * 468-DC GOES Receiver: * GPS-TM/TMD Receiver: (default quality codes for XL-DC) * ? +/- 1 milliseconds # +/- 100 microseconds * * +/- 10 microseconds . +/- 1 microsecond * space less than 1 microsecond * TL-3 Receiver: (default quality codes for TL-3) * ? unknown quality (receiver is unlocked) * space +/- 5 milliseconds * OM-DC OMEGA Receiver: (default quality codes for OMEGA) * WARNING OMEGA navigation system is no longer existent * > >+- 5 seconds * ? >+/- 500 milliseconds # >+/- 50 milliseconds * * >+/- 5 milliseconds . >+/- 1 millisecond * A-H less than 1 millisecond. Character indicates which station * is being received as follows: * A = Norway, B = Liberia, C = Hawaii, D = North Dakota, * E = La Reunion, F = Argentina, G = Australia, H = Japan. * * The carriage return start bit begins on 0 seconds and extends to 1 bit time. * * Notes on 468-DC and OMEGA receiver: * * Send the clock a 'R' or 'C' and once per second a timestamp will * appear. Send a 'P' to get the satellite position once (GOES only.) * * Notes on the 468-DC receiver: * * Since the old east/west satellite locations are only historical, you can't * set your clock propagation delay settings correctly and still use * automatic mode. The manual says to use a compromise when setting the * switches. This results in significant errors. The solution; use fudge * time1 and time2 to incorporate corrections. If your clock is set for * 50 and it should be 58 for using the west and 46 for using the east, * use the line * * fudge 127.127.5.0 time1 +0.008 time2 -0.004 * * This corrects the 4 milliseconds advance and 8 milliseconds retard * needed. The software will ask the clock which satellite it sees. * * Notes on the TrueTime TimeLink TL-3 WWV TOD receiver: * * This clock may be polled, or send one timecode per second. * That mode may be toggled via the front panel ("C" mode), or controlled * from the RS-232 port. Send the receiver "ST1" to turn it on, and * "ST0" to turn it off. Send "QV" to get the firmware revision (useful * for identifying this model.) * * Note that it can take several polling cycles, especially if the receiver * was in the continuous timecode mode. (It can be slow to leave that mode.) * * ntp.conf parameters: * time1 - offset applied to samples when reading WEST satellite (default = 0) * time2 - offset applied to samples when reading EAST satellite (default = 0) * stratum - stratum to assign to this clock (default = 0) * refid - refid assigned to this clock (default = "TRUE", see below) * flag1 - will silence the clock side of ntpd, just reading the clock * without trying to write to it. (default = 0) * flag2 - generate a debug file /tmp/true%d. * flag3 - enable ppsclock streams module * flag4 - use the PCL-720 (BSD/OS only) */ /* * Definitions */ #define DEVICE "/dev/true%d" #define SPEED232 B9600 /* 9600 baud */ /* * Radio interface parameters */ #define PRECISION (-10) /* precision assumed (about 1 ms) */ #define REFID "TRUE" /* reference id */ #define DESCRIPTION "Kinemetrics/TrueTime Receiver" /* * Tags which station (satellite) we see */ #define GOES_WEST 0 /* Default to WEST satellite and apply time1 */ #define GOES_EAST 1 /* until you discover otherwise */ /* * used by the state machine */ enum true_event {e_Init, e_Huh, e_F18, e_F50, e_F51, e_Satellite, e_TL3, e_Poll, e_Location, e_TS, e_Max}; const char *events[] = {"Init", "Huh", "F18", "F50", "F51", "Satellite", "TL3", "Poll", "Location", "TS"}; #define eventStr(x) (((int)x<(int)e_Max) ? events[(int)x] : "?") enum true_state {s_Base, s_InqTM, s_InqTCU, s_InqOmega, s_InqGOES, s_InqTL3, s_Init, s_F18, s_F50, s_Start, s_Auto, s_Max}; const char *states[] = {"Base", "InqTM", "InqTCU", "InqOmega", "InqGOES", "InqTL3", "Init", "F18", "F50", "Start", "Auto"}; #define stateStr(x) (((int)x<(int)s_Max) ? states[(int)x] : "?") enum true_type {t_unknown, t_goes, t_tm, t_tcu, t_omega, t_tl3, t_Max}; const char *types[] = {"unknown", "goes", "tm", "tcu", "omega", "tl3"}; #define typeStr(x) (((int)x<(int)t_Max) ? types[(int)x] : "?") /* * unit control structure */ struct true_unit { unsigned int pollcnt; /* poll message counter */ unsigned int station; /* which station we are on */ unsigned int polled; /* Hand in a time sample? */ enum true_state state; /* state machine */ enum true_type type; /* what kind of clock is it? */ int unit; /* save an extra copy of this */ FILE *debug; /* debug logging file */ #ifdef CLOCK_PPS720 int pcl720init; /* init flag for PCL 720 */ #endif }; /* * Function prototypes */ static int true_start (int, struct peer *); static void true_shutdown (int, struct peer *); static void true_receive (struct recvbuf *); static void true_poll (int, struct peer *); static void true_send (struct peer *, const char *); static void true_doevent (struct peer *, enum true_event); #ifdef CLOCK_PPS720 static u_long true_sample720 (void); #endif /* * Transfer vector */ struct refclock refclock_true = { true_start, /* start up driver */ true_shutdown, /* shut down driver */ true_poll, /* transmit poll message */ noentry, /* not used (old true_control) */ noentry, /* initialize driver (not used) */ noentry, /* not used (old true_buginfo) */ NOFLAGS /* not used */ }; #if !defined(__STDC__) # define true_debug (void) #else NTP_PRINTF(2, 3) static void true_debug(struct peer *peer, const char *fmt, ...) { va_list ap; int want_debugging, now_debugging; struct refclockproc *pp; struct true_unit *up; va_start(ap, fmt); pp = peer->procptr; up = pp->unitptr; want_debugging = (pp->sloppyclockflag & CLK_FLAG2) != 0; now_debugging = (up->debug != NULL); if (want_debugging != now_debugging) { if (want_debugging) { char filename[40]; int fd; snprintf(filename, sizeof(filename), "/tmp/true%d.debug", up->unit); fd = open(filename, O_CREAT | O_WRONLY | O_EXCL, 0600); if (fd >= 0 && (up->debug = fdopen(fd, "w"))) { #ifdef HAVE_SETVBUF static char buf[BUFSIZ]; setvbuf(up->debug, buf, _IOLBF, BUFSIZ); #else setlinebuf(up->debug); #endif } } else { fclose(up->debug); up->debug = NULL; } } if (up->debug) { fprintf(up->debug, "true%d: ", up->unit); vfprintf(up->debug, fmt, ap); } va_end(ap); } #endif /*STDC*/ /* * true_start - open the devices and initialize data for processing */ static int true_start( int unit, struct peer *peer ) { register struct true_unit *up; struct refclockproc *pp; char device[40]; int fd; /* * Open serial port */ snprintf(device, sizeof(device), DEVICE, unit); fd = refclock_open(device, SPEED232, LDISC_CLK); if (fd <= 0) return 0; /* * Allocate and initialize unit structure */ up = emalloc_zero(sizeof(*up)); pp = peer->procptr; pp->io.clock_recv = true_receive; pp->io.srcclock = peer; pp->io.datalen = 0; pp->io.fd = fd; if (!io_addclock(&pp->io)) { close(fd); pp->io.fd = -1; free(up); return (0); } pp->unitptr = up; /* * Initialize miscellaneous variables */ peer->precision = PRECISION; pp->clockdesc = DESCRIPTION; memcpy(&pp->refid, REFID, 4); up->pollcnt = 2; up->type = t_unknown; up->state = s_Base; /* * Send a CTRL-C character at the start, * just in case the clock is already * sending timecodes */ true_send(peer, "\03\r"); true_doevent(peer, e_Init); return (1); } /* * true_shutdown - shut down the clock */ static void true_shutdown( int unit, struct peer *peer ) { register struct true_unit *up; struct refclockproc *pp; pp = peer->procptr; up = pp->unitptr; if (pp->io.fd != -1) io_closeclock(&pp->io); if (up != NULL) free(up); } /* * true_receive - receive data from the serial interface on a clock */ static void true_receive( struct recvbuf *rbufp ) { register struct true_unit *up; struct refclockproc *pp; struct peer *peer; u_short new_station; char synced; int i; int lat, lon, off; /* GOES Satellite position */ /* These variables hold data until we decide to keep it */ char rd_lastcode[BMAX]; l_fp rd_tmp; u_short rd_lencode; /* * Get the clock this applies to and pointers to the data. */ peer = rbufp->recv_peer; pp = peer->procptr; up = pp->unitptr; /* * Read clock output. Automatically handles STREAMS, CLKLDISC. */ rd_lencode = refclock_gtlin(rbufp, rd_lastcode, BMAX, &rd_tmp); rd_lastcode[rd_lencode] = '\0'; /* * There is a case where generates 2 timestamps. */ if (rd_lencode == 0) return; pp->lencode = rd_lencode; strlcpy(pp->a_lastcode, rd_lastcode, sizeof(pp->a_lastcode)); pp->lastrec = rd_tmp; true_debug(peer, "receive(%s) [%d]\n", pp->a_lastcode, pp->lencode); up->pollcnt = 2; record_clock_stats(&peer->srcadr, pp->a_lastcode); /* * We get down to business, check the timecode format and decode * its contents. This code decodes a multitude of different * clock messages. Timecodes are processed if needed. All replies * will be run through the state machine to tweak driver options * and program the clock. */ /* * Clock misunderstood our last command? */ if (pp->a_lastcode[0] == '?' || strcmp(pp->a_lastcode, "ERROR 05 NO SUCH FUNCTION") == 0) { true_doevent(peer, e_Huh); return; } /* * Timecode: "nnnnn+nnn-nnn" * (from GOES clock when asked about satellite position) */ if ((pp->a_lastcode[5] == '+' || pp->a_lastcode[5] == '-') && (pp->a_lastcode[9] == '+' || pp->a_lastcode[9] == '-') && sscanf(pp->a_lastcode, "%5d%*c%3d%*c%3d", &lon, &lat, &off) == 3 ) { const char *label = "Botch!"; /* * This is less than perfect. Call the (satellite) * either EAST or WEST and adjust slop accodingly * Perfectionists would recalculate the exact delay * and adjust accordingly... */ if (lon > 7000 && lon < 14000) { if (lon < 10000) { new_station = GOES_EAST; label = "EAST"; } else { new_station = GOES_WEST; label = "WEST"; } if (new_station != up->station) { double dtemp; dtemp = pp->fudgetime1; pp->fudgetime1 = pp->fudgetime2; pp->fudgetime2 = dtemp; up->station = new_station; } } else { /*refclock_report(peer, CEVNT_BADREPLY);*/ label = "UNKNOWN"; } true_debug(peer, "GOES: station %s\n", label); true_doevent(peer, e_Satellite); return; } /* * Timecode: "Fnn" * (from TM/TMD clock when it wants to tell us what it's up to.) */ if (sscanf(pp->a_lastcode, "F%2d", &i) == 1 && i > 0 && i < 80) { switch (i) { case 50: true_doevent(peer, e_F50); break; case 51: true_doevent(peer, e_F51); break; default: true_debug(peer, "got F%02d - ignoring\n", i); break; } return; } /* * Timecode: "VER xx.xx" * (from a TL3 when sent "QV", so id's it during initialization.) */ if (pp->a_lastcode[0] == 'V' && pp->a_lastcode[1] == 'E' && pp->a_lastcode[2] == 'R' && pp->a_lastcode[6] == '.') { true_doevent(peer, e_TL3); NLOG(NLOG_CLOCKSTATUS) { msyslog(LOG_INFO, "TL3: %s", pp->a_lastcode); } return; } /* * Timecode: " TRUETIME Mk III" or " TRUETIME XL" * (from a TM/TMD/XL clock during initialization.) */ if (strncmp(pp->a_lastcode, " TRUETIME Mk III ", 17) == 0 || strncmp(pp->a_lastcode, " TRUETIME XL", 12) == 0) { true_doevent(peer, e_F18); NLOG(NLOG_CLOCKSTATUS) { msyslog(LOG_INFO, "TM/TMD/XL: %s", pp->a_lastcode); } return; } /* * Timecode: "N03726428W12209421+000033" * 1 2 * index 0123456789012345678901234 * (from a TCU during initialization) */ if ((pp->a_lastcode[0] == 'N' || pp->a_lastcode[0] == 'S') && (pp->a_lastcode[9] == 'W' || pp->a_lastcode[9] == 'E') && pp->a_lastcode[18] == '+') { true_doevent(peer, e_Location); NLOG(NLOG_CLOCKSTATUS) { msyslog(LOG_INFO, "TCU-800: %s", pp->a_lastcode); } return; } /* * Timecode: "ddd:hh:mm:ssQ" * 1 2 * index 0123456789012345678901234 * (from all clocks supported by this driver.) */ if (pp->a_lastcode[3] == ':' && pp->a_lastcode[6] == ':' && pp->a_lastcode[9] == ':' && sscanf(pp->a_lastcode, "%3d:%2d:%2d:%2d%c", &pp->day, &pp->hour, &pp->minute, &pp->second, &synced) == 5) { /* * Adjust the synchronize indicator according to timecode * say were OK, and then say not if we really are not OK */ if (synced == '>' || synced == '#' || synced == '?' || synced == 'X') pp->leap = LEAP_NOTINSYNC; else pp->leap = LEAP_NOWARNING; true_doevent(peer, e_TS); #ifdef CLOCK_PPS720 /* If it's taken more than 65ms to get here, we'll lose. */ if ((pp->sloppyclockflag & CLK_FLAG4) && up->pcl720init) { l_fp off; #ifdef CLOCK_ATOM /* * find out what time it really is. Include * the count from the PCL720 */ if (!clocktime(pp->day, pp->hour, pp->minute, pp->second, GMT, pp->lastrec.l_ui, &pp->yearstart, &off.l_ui)) { refclock_report(peer, CEVNT_BADTIME); return; } off.l_uf = 0; #endif pp->usec = true_sample720(); #ifdef CLOCK_ATOM TVUTOTSF(pp->usec, off.l_uf); #endif /* * Stomp all over the timestamp that was pulled out * of the input stream. It's irrelevant since we've * adjusted the input time to reflect now (via pp->usec) * rather than when the data was collected. */ get_systime(&pp->lastrec); #ifdef CLOCK_ATOM /* * Create a true offset for feeding to pps_sample() */ L_SUB(&off, &pp->lastrec); pps_sample(peer, &off); #endif true_debug(peer, "true_sample720: %luus\n", pp->usec); } #endif /* * The clock will blurt a timecode every second but we only * want one when polled. If we havn't been polled, bail out. */ if (!up->polled) return; /* We only call doevent if additional things need be done * at poll interval. Currently, its only for GOES. We also * call it for clock unknown so that it gets logged. */ if (up->type == t_goes || up->type == t_unknown) true_doevent(peer, e_Poll); if (!refclock_process(pp)) { refclock_report(peer, CEVNT_BADTIME); return; } /* * If clock is good we send a NOMINAL message so that * any previous BAD messages are nullified */ pp->lastref = pp->lastrec; refclock_receive(peer); refclock_report(peer, CEVNT_NOMINAL); /* * We have succedded in answering the poll. * Turn off the flag and return */ up->polled = 0; return; } /* * No match to known timecodes, report failure and return */ refclock_report(peer, CEVNT_BADREPLY); return; } /* * true_send - time to send the clock a signal to cough up a time sample */ static void true_send( struct peer *peer, const char *cmd ) { struct refclockproc *pp; pp = peer->procptr; if (!(pp->sloppyclockflag & CLK_FLAG1)) { size_t len = strlen(cmd); true_debug(peer, "Send '%s'\n", cmd); if (write(pp->io.fd, cmd, len) != (ssize_t)len) refclock_report(peer, CEVNT_FAULT); else pp->polls++; } } /* * state machine for initializing and controlling a clock */ static void true_doevent( struct peer *peer, enum true_event event ) { struct true_unit *up; struct refclockproc *pp; pp = peer->procptr; up = pp->unitptr; if (event != e_TS) { NLOG(NLOG_CLOCKSTATUS) { msyslog(LOG_INFO, "TRUE: clock %s, state %s, event %s", typeStr(up->type), stateStr(up->state), eventStr(event)); } } true_debug(peer, "clock %s, state %s, event %s\n", typeStr(up->type), stateStr(up->state), eventStr(event)); switch (up->type) { case t_goes: switch (event) { case e_Init: /* FALLTHROUGH */ case e_Satellite: /* * Switch back to on-second time codes and return. */ true_send(peer, "C"); up->state = s_Start; break; case e_Poll: /* * After each poll, check the station (satellite). */ true_send(peer, "P"); /* No state change needed. */ break; default: break; } /* FALLTHROUGH */ case t_omega: switch (event) { case e_Init: true_send(peer, "C"); up->state = s_Start; break; case e_TS: if (up->state != s_Start && up->state != s_Auto) { true_send(peer, "\03\r"); break; } up->state = s_Auto; break; default: break; } break; case t_tm: switch (event) { case e_Init: true_send(peer, "F18\r"); up->state = s_Init; break; case e_F18: true_send(peer, "F50\r"); /* * Timecode: " TRUETIME Mk III" or " TRUETIME XL" * (from a TM/TMD/XL clock during initialization.) */ if ( strcmp(pp->a_lastcode, " TRUETIME Mk III") == 0 || strncmp(pp->a_lastcode, " TRUETIME XL", 12) == 0) { true_doevent(peer, e_F18); NLOG(NLOG_CLOCKSTATUS) { msyslog(LOG_INFO, "TM/TMD/XL: %s", pp->a_lastcode); } return; } up->state = s_F18; break; case e_F50: true_send(peer, "F51\r"); up->state = s_F50; break; case e_F51: true_send(peer, "F08\r"); up->state = s_Start; break; case e_TS: if (up->state != s_Start && up->state != s_Auto) { true_send(peer, "\03\r"); break; } up->state = s_Auto; break; default: break; } break; case t_tcu: switch (event) { case e_Init: true_send(peer, "MD3\r"); /* GPS Synch'd Gen. */ true_send(peer, "TSU\r"); /* UTC, not GPS. */ true_send(peer, "AU\r"); /* Auto Timestamps. */ up->state = s_Start; break; case e_TS: if (up->state != s_Start && up->state != s_Auto) { true_send(peer, "\03\r"); break; } up->state = s_Auto; break; default: break; } break; case t_tl3: switch (event) { case e_Init: true_send(peer, "ST1"); /* Turn on continuous stream */ break; case e_TS: up->state = s_Auto; break; default: break; } break; case t_unknown: if (event == e_Poll) break; switch (up->state) { case s_Base: if (event != e_Init) abort(); true_send(peer, "P\r"); up->state = s_InqGOES; break; case s_InqGOES: switch (event) { case e_Satellite: up->type = t_goes; true_doevent(peer, e_Init); break; case e_Init: /*FALLTHROUGH*/ case e_Huh: case e_TS: true_send(peer, "ST0"); /* turn off TL3 auto */ sleep(1); /* wait for it */ up->state = s_InqTL3; true_send(peer, "QV"); /* see if its a TL3 */ break; default: abort(); } break; case s_InqTL3: switch (event) { case e_TL3: up->type = t_tl3; up->state = s_Auto; /* Inq side-effect. */ true_send(peer, "ST1"); /* Turn on 1/sec data */ break; case e_Init: /*FALLTHROUGH*/ case e_Huh: up->state = s_InqOmega; true_send(peer, "C\r"); break; case e_TS: up->type = t_tl3; /* Already sending data */ up->state = s_Auto; break; default: msyslog(LOG_INFO, "TRUE: TL3 init fellthrough! (%d)", event); break; } break; case s_InqOmega: switch (event) { case e_TS: up->type = t_omega; up->state = s_Auto; /* Inq side-effect. */ break; case e_Init: /*FALLTHROUGH*/ case e_Huh: up->state = s_InqTM; true_send(peer, "F18\r"); break; default: abort(); } break; case s_InqTM: switch (event) { case e_F18: up->type = t_tm; true_doevent(peer, e_Init); break; case e_Init: /*FALLTHROUGH*/ case e_Huh: true_send(peer, "PO\r"); up->state = s_InqTCU; break; default: msyslog(LOG_INFO, "TRUE: TM/TMD init fellthrough!"); break; } break; case s_InqTCU: switch (event) { case e_Location: up->type = t_tcu; true_doevent(peer, e_Init); break; case e_Init: /*FALLTHROUGH*/ case e_Huh: up->state = s_Base; sleep(1); /* XXX */ break; default: msyslog(LOG_INFO, "TRUE: TCU init fellthrough!"); break; } break; /* * An expedient hack to prevent lint complaints, * these don't actually need to be used here... */ case s_Init: case s_F18: case s_F50: case s_Start: case s_Auto: case s_Max: msyslog(LOG_INFO, "TRUE: state %s is unexpected!", stateStr(up->state)); } break; default: msyslog(LOG_INFO, "TRUE: cannot identify refclock!"); abort(); /* NOTREACHED */ } #ifdef CLOCK_PPS720 if ((pp->sloppyclockflag & CLK_FLAG4) && !up->pcl720init) { /* Make counter trigger on gate0, count down from 65535. */ pcl720_load(PCL720_IOB, PCL720_CTR, i8253_oneshot, 65535); /* * (These constants are OK since * they represent hardware maximums.) */ NLOG(NLOG_CLOCKINFO) { msyslog(LOG_NOTICE, "PCL-720 initialized"); } up->pcl720init++; } #endif } /* * true_poll - called by the transmit procedure */ static void true_poll( int unit, struct peer *peer ) { struct true_unit *up; struct refclockproc *pp; /* * You don't need to poll this clock. It puts out timecodes * once per second. If asked for a timestamp, take note. * The next time a timecode comes in, it will be fed back. */ pp = peer->procptr; up = pp->unitptr; if (up->pollcnt > 0) { up->pollcnt--; } else { true_doevent(peer, e_Init); refclock_report(peer, CEVNT_TIMEOUT); } /* * polled every 64 seconds. Ask true_receive to hand in a * timestamp. */ up->polled = 1; pp->polls++; } #ifdef CLOCK_PPS720 /* * true_sample720 - sample the PCL-720 */ static u_long true_sample720(void) { unsigned long f; /* We wire the PCL-720's 8253.OUT0 to bit 0 of connector 3. * If it is not being held low now, we did not get called * within 65535us. */ if (inb(pcl720_data_16_23(PCL720_IOB)) & 0x01) { NLOG(NLOG_CLOCKINFO) { msyslog(LOG_NOTICE, "PCL-720 out of synch"); } return (0); } f = (65536 - pcl720_read(PCL720_IOB, PCL720_CTR)); #ifdef PPS720_DEBUG msyslog(LOG_DEBUG, "PCL-720: %luus", f); #endif return (f); } #endif #else int refclock_true_bs; #endif /* REFCLOCK */