604 lines
16 KiB
C
604 lines
16 KiB
C
/*
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* refclock_hpgps - clock driver for HP 58503A GPS receiver
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*/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#if defined(REFCLOCK) && defined(CLOCK_HPGPS)
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#include "ntpd.h"
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#include "ntp_io.h"
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#include "ntp_refclock.h"
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#include "ntp_stdlib.h"
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#include <stdio.h>
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#include <ctype.h>
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/* Version 0.1 April 1, 1995
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* 0.2 April 25, 1995
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* tolerant of missing timecode response prompt and sends
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* clear status if prompt indicates error;
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* can use either local time or UTC from receiver;
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* can get receiver status screen via flag4
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*
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* WARNING!: This driver is UNDER CONSTRUCTION
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* Everything in here should be treated with suspicion.
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* If it looks wrong, it probably is.
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*
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* Comments and/or questions to: Dave Vitanye
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* Hewlett Packard Company
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* dave@scd.hp.com
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* (408) 553-2856
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*
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* Thanks to the author of the PST driver, which was the starting point for
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* this one.
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*
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* This driver supports the HP 58503A Time and Frequency Reference Receiver.
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* This receiver uses HP SmartClock (TM) to implement an Enhanced GPS receiver.
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* The receiver accuracy when locked to GPS in normal operation is better
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* than 1 usec. The accuracy when operating in holdover is typically better
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* than 10 usec. per day.
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*
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* The receiver should be operated with factory default settings.
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* Initial driver operation: expects the receiver to be already locked
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* to GPS, configured and able to output timecode format 2 messages.
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*
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* The driver uses the poll sequence :PTIME:TCODE? to get a response from
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* the receiver. The receiver responds with a timecode string of ASCII
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* printing characters, followed by a <cr><lf>, followed by a prompt string
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* issued by the receiver, in the following format:
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* T#yyyymmddhhmmssMFLRVcc<cr><lf>scpi >
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*
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* The driver processes the response at the <cr> and <lf>, so what the
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* driver sees is the prompt from the previous poll, followed by this
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* timecode. The prompt from the current poll is (usually) left unread until
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* the next poll. So (except on the very first poll) the driver sees this:
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*
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* scpi > T#yyyymmddhhmmssMFLRVcc<cr><lf>
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*
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* The T is the on-time character, at 980 msec. before the next 1PPS edge.
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* The # is the timecode format type. We look for format 2.
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* Without any of the CLK or PPS stuff, then, the receiver buffer timestamp
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* at the <cr> is 24 characters later, which is about 25 msec. at 9600 bps,
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* so the first approximation for fudge time1 is nominally -0.955 seconds.
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* This number probably needs adjusting for each machine / OS type, so far:
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* -0.955000 on an HP 9000 Model 712/80 HP-UX 9.05
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* -0.953175 on an HP 9000 Model 370 HP-UX 9.10
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*
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* This receiver also provides a 1PPS signal, but I haven't figured out
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* how to deal with any of the CLK or PPS stuff yet. Stay tuned.
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*
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*/
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/*
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* Fudge Factors
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*
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* Fudge time1 is used to accomodate the timecode serial interface adjustment.
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* Fudge flag4 can be set to request a receiver status screen summary, which
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* is recorded in the clockstats file.
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*/
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/*
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* Interface definitions
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*/
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#define DEVICE "/dev/hpgps%d" /* device name and unit */
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#define SPEED232 B9600 /* uart speed (9600 baud) */
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#define PRECISION (-10) /* precision assumed (about 1 ms) */
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#define REFID "GPS\0" /* reference ID */
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#define DESCRIPTION "HP 58503A GPS Time and Frequency Reference Receiver"
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#define SMAX 23*80+1 /* for :SYSTEM:PRINT? status screen response */
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#define MTZONE 2 /* number of fields in timezone reply */
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#define MTCODET2 12 /* number of fields in timecode format T2 */
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#define NTCODET2 21 /* number of chars to checksum in format T2 */
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/*
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* Tables to compute the day of year from yyyymmdd timecode.
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* Viva la leap.
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*/
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static int day1tab[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
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static int day2tab[] = {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
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/*
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* Unit control structure
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*/
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struct hpgpsunit {
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int pollcnt; /* poll message counter */
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int tzhour; /* timezone offset, hours */
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int tzminute; /* timezone offset, minutes */
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int linecnt; /* set for expected multiple line responses */
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char *lastptr; /* pointer to receiver response data */
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char statscrn[SMAX]; /* receiver status screen buffer */
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};
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/*
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* Function prototypes
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*/
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static int hpgps_start P((int, struct peer *));
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static void hpgps_shutdown P((int, struct peer *));
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static void hpgps_receive P((struct recvbuf *));
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static void hpgps_poll P((int, struct peer *));
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/*
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* Transfer vector
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*/
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struct refclock refclock_hpgps = {
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hpgps_start, /* start up driver */
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hpgps_shutdown, /* shut down driver */
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hpgps_poll, /* transmit poll message */
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noentry, /* not used (old hpgps_control) */
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noentry, /* initialize driver */
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noentry, /* not used (old hpgps_buginfo) */
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NOFLAGS /* not used */
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};
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/*
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* hpgps_start - open the devices and initialize data for processing
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*/
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static int
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hpgps_start(
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int unit,
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struct peer *peer
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)
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{
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register struct hpgpsunit *up;
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struct refclockproc *pp;
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int fd;
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char device[20];
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/*
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* Open serial port. Use CLK line discipline, if available.
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*/
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(void)sprintf(device, DEVICE, unit);
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if (!(fd = refclock_open(device, SPEED232, LDISC_CLK)))
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return (0);
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/*
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* Allocate and initialize unit structure
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*/
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if (!(up = (struct hpgpsunit *)
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emalloc(sizeof(struct hpgpsunit)))) {
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(void) close(fd);
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return (0);
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}
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memset((char *)up, 0, sizeof(struct hpgpsunit));
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pp = peer->procptr;
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pp->io.clock_recv = hpgps_receive;
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pp->io.srcclock = (caddr_t)peer;
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pp->io.datalen = 0;
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pp->io.fd = fd;
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if (!io_addclock(&pp->io)) {
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(void) close(fd);
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free(up);
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return (0);
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}
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pp->unitptr = (caddr_t)up;
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/*
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* Initialize miscellaneous variables
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*/
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peer->precision = PRECISION;
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pp->clockdesc = DESCRIPTION;
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memcpy((char *)&pp->refid, REFID, 4);
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up->tzhour = 0;
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up->tzminute = 0;
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*up->statscrn = '\0';
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up->lastptr = up->statscrn;
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up->pollcnt = 2;
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/*
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* Get the identifier string, which is logged but otherwise ignored,
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* and get the local timezone information
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*/
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up->linecnt = 1;
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if (write(pp->io.fd, "*IDN?\r:PTIME:TZONE?\r", 20) != 20)
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refclock_report(peer, CEVNT_FAULT);
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return (1);
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}
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/*
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* hpgps_shutdown - shut down the clock
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*/
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static void
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hpgps_shutdown(
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int unit,
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struct peer *peer
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)
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{
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register struct hpgpsunit *up;
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struct refclockproc *pp;
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pp = peer->procptr;
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up = (struct hpgpsunit *)pp->unitptr;
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io_closeclock(&pp->io);
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free(up);
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}
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/*
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* hpgps_receive - receive data from the serial interface
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*/
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static void
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hpgps_receive(
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struct recvbuf *rbufp
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)
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{
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register struct hpgpsunit *up;
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struct refclockproc *pp;
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struct peer *peer;
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l_fp trtmp;
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char tcodechar1; /* identifies timecode format */
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char tcodechar2; /* identifies timecode format */
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char timequal; /* time figure of merit: 0-9 */
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char freqqual; /* frequency figure of merit: 0-3 */
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char leapchar; /* leapsecond: + or 0 or - */
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char servchar; /* request for service: 0 = no, 1 = yes */
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char syncchar; /* time info is invalid: 0 = no, 1 = yes */
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short expectedsm; /* expected timecode byte checksum */
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short tcodechksm; /* computed timecode byte checksum */
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int i,m,n;
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int month, day, lastday;
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char *tcp; /* timecode pointer (skips over the prompt) */
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char prompt[BMAX]; /* prompt in response from receiver */
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/*
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* Initialize pointers and read the receiver response
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*/
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peer = (struct peer *)rbufp->recv_srcclock;
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pp = peer->procptr;
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up = (struct hpgpsunit *)pp->unitptr;
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*pp->a_lastcode = '\0';
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pp->lencode = refclock_gtlin(rbufp, pp->a_lastcode, BMAX, &trtmp);
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#ifdef DEBUG
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if (debug)
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printf("hpgps: lencode: %d timecode:%s\n",
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pp->lencode, pp->a_lastcode);
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#endif
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/*
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* If there's no characters in the reply, we can quit now
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*/
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if (pp->lencode == 0)
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return;
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/*
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* If linecnt is greater than zero, we are getting information only,
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* such as the receiver identification string or the receiver status
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* screen, so put the receiver response at the end of the status
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* screen buffer. When we have the last line, write the buffer to
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* the clockstats file and return without further processing.
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*
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* If linecnt is zero, we are expecting either the timezone
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* or a timecode. At this point, also write the response
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* to the clockstats file, and go on to process the prompt (if any),
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* timezone, or timecode and timestamp.
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*/
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if (up->linecnt-- > 0) {
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if ((int)(pp->lencode + 2) <= (SMAX - (up->lastptr - up->statscrn))) {
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*up->lastptr++ = '\n';
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(void)strcpy(up->lastptr, pp->a_lastcode);
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up->lastptr += pp->lencode;
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}
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if (up->linecnt == 0)
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record_clock_stats(&peer->srcadr, up->statscrn);
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return;
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}
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record_clock_stats(&peer->srcadr, pp->a_lastcode);
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pp->lastrec = trtmp;
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up->lastptr = up->statscrn;
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*up->lastptr = '\0';
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up->pollcnt = 2;
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/*
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* We get down to business: get a prompt if one is there, issue
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* a clear status command if it contains an error indication.
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* Next, check for either the timezone reply or the timecode reply
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* and decode it. If we don't recognize the reply, or don't get the
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* proper number of decoded fields, or get an out of range timezone,
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* or if the timecode checksum is bad, then we declare bad format
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* and exit.
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*
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* Timezone format (including nominal prompt):
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* scpi > -H,-M<cr><lf>
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*
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* Timecode format (including nominal prompt):
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* scpi > T2yyyymmddhhmmssMFLRVcc<cr><lf>
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*
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*/
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(void)strcpy(prompt,pp->a_lastcode);
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tcp = strrchr(pp->a_lastcode,'>');
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if (tcp == NULL)
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tcp = pp->a_lastcode;
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else
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tcp++;
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prompt[tcp - pp->a_lastcode] = '\0';
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while ((*tcp == ' ') || (*tcp == '\t')) tcp++;
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/*
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* deal with an error indication in the prompt here
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*/
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if (strrchr(prompt,'E') > strrchr(prompt,'s')){
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#ifdef DEBUG
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if (debug)
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printf("hpgps: error indicated in prompt: %s\n", prompt);
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#endif
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if (write(pp->io.fd, "*CLS\r\r", 6) != 6)
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refclock_report(peer, CEVNT_FAULT);
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}
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/*
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* make sure we got a timezone or timecode format and
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* then process accordingly
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*/
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m = sscanf(tcp,"%c%c", &tcodechar1, &tcodechar2);
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if (m != 2){
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#ifdef DEBUG
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if (debug)
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printf("hpgps: no format indicator\n");
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#endif
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refclock_report(peer, CEVNT_BADREPLY);
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return;
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}
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switch (tcodechar1) {
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case '+':
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case '-':
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m = sscanf(tcp,"%d,%d", &up->tzhour, &up->tzminute);
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if (m != MTZONE) {
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#ifdef DEBUG
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if (debug)
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printf("hpgps: only %d fields recognized in timezone\n", m);
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#endif
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refclock_report(peer, CEVNT_BADREPLY);
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return;
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}
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if ((up->tzhour < -12) || (up->tzhour > 13) ||
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(up->tzminute < -59) || (up->tzminute > 59)){
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#ifdef DEBUG
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if (debug)
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printf("hpgps: timezone %d, %d out of range\n",
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up->tzhour, up->tzminute);
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#endif
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refclock_report(peer, CEVNT_BADREPLY);
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return;
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}
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return;
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case 'T':
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break;
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default:
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#ifdef DEBUG
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if (debug)
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printf("hpgps: unrecognized reply format %c%c\n",
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tcodechar1, tcodechar2);
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#endif
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refclock_report(peer, CEVNT_BADREPLY);
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return;
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} /* end of tcodechar1 switch */
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switch (tcodechar2) {
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case '2':
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m = sscanf(tcp,"%*c%*c%4d%2d%2d%2d%2d%2d%c%c%c%c%c%2hx",
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&pp->year, &month, &day, &pp->hour, &pp->minute, &pp->second,
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&timequal, &freqqual, &leapchar, &servchar, &syncchar,
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&expectedsm);
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n = NTCODET2;
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if (m != MTCODET2){
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#ifdef DEBUG
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if (debug)
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printf("hpgps: only %d fields recognized in timecode\n", m);
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#endif
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refclock_report(peer, CEVNT_BADREPLY);
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return;
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}
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break;
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default:
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#ifdef DEBUG
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if (debug)
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printf("hpgps: unrecognized timecode format %c%c\n",
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tcodechar1, tcodechar2);
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#endif
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refclock_report(peer, CEVNT_BADREPLY);
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return;
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} /* end of tcodechar2 format switch */
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/*
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* Compute and verify the checksum.
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* Characters are summed starting at tcodechar1, ending at just
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* before the expected checksum. Bail out if incorrect.
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*/
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tcodechksm = 0;
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while (n-- > 0) tcodechksm += *tcp++;
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tcodechksm &= 0x00ff;
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if (tcodechksm != expectedsm) {
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#ifdef DEBUG
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if (debug)
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printf("hpgps: checksum %2hX doesn't match %2hX expected\n",
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tcodechksm, expectedsm);
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#endif
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refclock_report(peer, CEVNT_BADREPLY);
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return;
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}
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/*
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* Compute the day of year from the yyyymmdd format.
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*/
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if (month < 1 || month > 12 || day < 1) {
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refclock_report(peer, CEVNT_BADTIME);
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return;
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}
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if ( ! isleap_4(pp->year) ) { /* Y2KFixes */
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/* not a leap year */
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if (day > day1tab[month - 1]) {
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refclock_report(peer, CEVNT_BADTIME);
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return;
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}
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for (i = 0; i < month - 1; i++) day += day1tab[i];
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lastday = 365;
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} else {
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/* a leap year */
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if (day > day2tab[month - 1]) {
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refclock_report(peer, CEVNT_BADTIME);
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return;
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}
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for (i = 0; i < month - 1; i++) day += day2tab[i];
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lastday = 366;
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}
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/*
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* Deal with the timezone offset here. The receiver timecode is in
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* local time = UTC + :PTIME:TZONE, so SUBTRACT the timezone values.
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* For example, Pacific Standard Time is -8 hours , 0 minutes.
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* Deal with the underflows and overflows.
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*/
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pp->minute -= up->tzminute;
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pp->hour -= up->tzhour;
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if (pp->minute < 0) {
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pp->minute += 60;
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pp->hour--;
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}
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if (pp->minute > 59) {
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pp->minute -= 60;
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pp->hour++;
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}
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if (pp->hour < 0) {
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pp->hour += 24;
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day--;
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if (day < 1) {
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pp->year--;
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if ( isleap_4(pp->year) ) /* Y2KFixes */
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day = 366;
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else
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day = 365;
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}
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}
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if (pp->hour > 23) {
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pp->hour -= 24;
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day++;
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if (day > lastday) {
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pp->year++;
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day = 1;
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}
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}
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pp->day = day;
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/*
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* Decode the MFLRV indicators.
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* NEED TO FIGURE OUT how to deal with the request for service,
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* time quality, and frequency quality indicators some day.
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*/
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if (syncchar != '0') {
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pp->leap = LEAP_NOTINSYNC;
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}
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else {
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switch (leapchar) {
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case '+':
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pp->leap = LEAP_ADDSECOND;
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break;
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case '0':
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pp->leap = LEAP_NOWARNING;
|
|
break;
|
|
|
|
case '-':
|
|
pp->leap = LEAP_DELSECOND;
|
|
break;
|
|
|
|
default:
|
|
#ifdef DEBUG
|
|
if (debug)
|
|
printf("hpgps: unrecognized leap indicator: %c\n",
|
|
leapchar);
|
|
#endif
|
|
refclock_report(peer, CEVNT_BADTIME);
|
|
return;
|
|
} /* end of leapchar switch */
|
|
}
|
|
|
|
/*
|
|
* Process the new sample in the median filter and determine the
|
|
* reference clock offset and dispersion. We use lastrec as both
|
|
* the reference time and receive time in order to avoid being
|
|
* cute, like setting the reference time later than the receive
|
|
* time, which may cause a paranoid protocol module to chuck out
|
|
* the data.
|
|
*/
|
|
if (!refclock_process(pp)) {
|
|
refclock_report(peer, CEVNT_BADTIME);
|
|
return;
|
|
}
|
|
refclock_receive(peer);
|
|
|
|
/*
|
|
* If CLK_FLAG4 is set, ask for the status screen response.
|
|
*/
|
|
if (pp->sloppyclockflag & CLK_FLAG4){
|
|
up->linecnt = 22;
|
|
if (write(pp->io.fd, ":SYSTEM:PRINT?\r", 15) != 15)
|
|
refclock_report(peer, CEVNT_FAULT);
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* hpgps_poll - called by the transmit procedure
|
|
*/
|
|
static void
|
|
hpgps_poll(
|
|
int unit,
|
|
struct peer *peer
|
|
)
|
|
{
|
|
register struct hpgpsunit *up;
|
|
struct refclockproc *pp;
|
|
|
|
/*
|
|
* Time to poll the clock. The HP 58503A responds to a
|
|
* ":PTIME:TCODE?" by returning a timecode in the format specified
|
|
* above. If nothing is heard from the clock for two polls,
|
|
* declare a timeout and keep going.
|
|
*/
|
|
pp = peer->procptr;
|
|
up = (struct hpgpsunit *)pp->unitptr;
|
|
if (up->pollcnt == 0)
|
|
refclock_report(peer, CEVNT_TIMEOUT);
|
|
else
|
|
up->pollcnt--;
|
|
if (write(pp->io.fd, ":PTIME:TCODE?\r", 14) != 14) {
|
|
refclock_report(peer, CEVNT_FAULT);
|
|
}
|
|
else
|
|
pp->polls++;
|
|
}
|
|
|
|
#else
|
|
int refclock_hpgps_bs;
|
|
#endif /* REFCLOCK */
|