488 lines
13 KiB
C
488 lines
13 KiB
C
/*
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* refclock_heath - clock driver for Heath GC-1000 Most Accurate Clock
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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_HEATH)
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#include <stdio.h>
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#include <ctype.h>
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#ifdef TIME_WITH_SYS_TIME
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# include <sys/time.h>
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# include <time.h>
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#else
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# ifdef TM_IN_SYS_TIME
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# include <sys/time.h>
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# else
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# include <time.h>
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# endif
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#endif
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#ifdef HAVE_SYS_IOCTL_H
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# include <sys/ioctl.h>
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#endif /* not HAVE_SYS_IOCTL_H */
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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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/*
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* This driver supports the Heath GC-1000 Most Accurate Clock, with
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* RS232C Output Accessory. This is a WWV/WWVH receiver somewhat less
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* robust than other supported receivers. Its claimed accuracy is 100 ms
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* when actually synchronized to the broadcast signal, but this doesn't
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* happen even most of the time, due to propagation conditions, ambient
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* noise sources, etc. When not synchronized, the accuracy is at the
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* whim of the internal clock oscillator, which can wander into the
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* sunset without warning. Since the indicated precision is 100 ms,
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* expect a host synchronized only to this thing to wander to and fro,
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* occasionally being rudely stepped when the offset exceeds the default
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* clock_max of 128 ms.
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*
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* The internal DIPswitches should be set to operate at 1200 baud in
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* MANUAL mode and the current year. The external DIPswitches should be
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* set to GMT and 24-hour format, or to the host local time zone (with
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* DST) and 12-hour format. It is very important that the year be
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* set correctly in the DIPswitches. Otherwise, the day of year will be
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* incorrect after 28 April[?] of a normal or leap year. In 12-hour mode
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* with DST selected the clock will be incorrect by an hour for an
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* indeterminate amount of time between 0000Z and 0200 on the day DST
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* changes.
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*
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* In MANUAL mode the clock responds to a rising edge of the request to
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* send (RTS) modem control line by sending the timecode. Therefore, it
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* is necessary that the operating system implement the TIOCMBIC and
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* TIOCMBIS ioctl system calls and TIOCM_RTS control bit. Present
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* restrictions require the use of a POSIX-compatible programming
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* interface, although other interfaces may work as well.
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*
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* A simple hardware modification to the clock can be made which
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* prevents the clock hearing the request to send (RTS) if the HI SPEC
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* lamp is out. Route the HISPEC signal to the tone decoder board pin
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* 19, from the display, pin 19. Isolate pin 19 of the decoder board
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* first, but maintain connection with pin 10. Also isolate pin 38 of
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* the CPU on the tone board, and use half an added 7400 to gate the
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* original signal to pin 38 with that from pin 19.
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*
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* The clock message consists of 23 ASCII printing characters in the
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* following format:
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*
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* hh:mm:ss.f AM dd/mm/yr<cr>
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*
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* hh:mm:ss.f = hours, minutes, seconds
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* f = deciseconds ('?' when out of spec)
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* AM/PM/bb = blank in 24-hour mode
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* dd/mm/yr = day, month, year
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*
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* The alarm condition is indicated by '?', rather than a digit, at f.
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* Note that 0?:??:??.? is displayed before synchronization is first
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* established and hh:mm:ss.? once synchronization is established and
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* then lost again for about a day.
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*
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* Fudge Factors
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*
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* A fudge time1 value of .04 s appears to center the clock offset
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* residuals. The fudge time2 parameter is the local time offset east of
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* Greenwich, which depends on DST. Sorry about that, but the clock
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* gives no hint on what the DIPswitches say.
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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/heath%d" /* device name and unit */
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#define SPEED232 B1200 /* uart speed (1200 baud) */
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#define PRECISION (-4) /* precision assumed (about 100 ms) */
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#define REFID "WWV\0" /* reference ID */
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#define DESCRIPTION "Heath GC-1000 Most Accurate Clock" /* WRU */
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#define LENHEATH 23 /* min timecode length */
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/*
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* Tables to compute the ddd of year form icky dd/mm timecode. Viva la
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* 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 heathunit {
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int pollcnt; /* poll message counter */
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l_fp tstamp; /* timestamp of last poll */
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};
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/*
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* Function prototypes
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*/
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static int heath_start P((int, struct peer *));
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static void heath_shutdown P((int, struct peer *));
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static void heath_receive P((struct recvbuf *));
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static void heath_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_heath = {
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heath_start, /* start up driver */
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heath_shutdown, /* shut down driver */
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heath_poll, /* transmit poll message */
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noentry, /* not used (old heath_control) */
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noentry, /* initialize driver */
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noentry, /* not used (old heath_buginfo) */
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NOFLAGS /* not used */
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};
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#if 0
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/*
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* Gee, Unix so thoughfully omitted code to convert from a struct tm to
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* a long, so I'll just have to ferret out the inverse myself, the hard way.
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* (Newton's method.)
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*/
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#define timelocal(x) invert(x, localtime)
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/*
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* comparetm compares two tm structures and returns -1 if the first
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* is less than the second, 0 if they are equal, and +1 if the first
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* is greater than the second. Only the year, month, day, hour, minute
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* and second are compared. The yearday (Julian), day of week, and isdst
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* are not compared.
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*/
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static int
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comparetm(
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struct tm *a,
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struct tm *b
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)
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{
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if (a->tm_year < b->tm_year ) return -1;
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if (a->tm_year > b->tm_year ) return 1;
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if (a->tm_mon < b->tm_mon ) return -1;
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if (a->tm_mon > b->tm_mon ) return 1;
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if (a->tm_mday < b->tm_mday ) return -1;
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if (a->tm_mday > b->tm_mday ) return 1;
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if (a->tm_hour < b->tm_hour ) return -1;
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if (a->tm_hour > b->tm_hour ) return 1;
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if (a->tm_min < b->tm_min ) return -1;
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if (a->tm_min > b->tm_min ) return 1;
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if (a->tm_sec < b->tm_sec ) return -1;
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if (a->tm_sec > b->tm_sec ) return 1;
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return 0;
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}
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static long
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invert (
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struct tm *x,
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struct tm *(*func)()
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)
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{
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struct tm *y;
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int result;
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long trial;
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long lower=0L;
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long upper=(long)((unsigned long)(~lower) >> 1);
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do {
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trial = (upper + lower) / 2L;
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y = (*func)(&trial);
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result = comparetm(x, y);
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if (result < 0) upper = trial;
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if (result > 0) lower = trial;
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} while (result != 0);
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return trial;
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}
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#endif /* 0 */
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/*
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* heath_start - open the devices and initialize data for processing
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*/
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static int
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heath_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 heathunit *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
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*/
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(void)sprintf(device, DEVICE, unit);
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if (!(fd = refclock_open(device, SPEED232, 0)))
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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 heathunit *)
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emalloc(sizeof(struct heathunit)))) {
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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 heathunit));
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pp = peer->procptr;
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pp->io.clock_recv = heath_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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peer->burst = NSTAGE;
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pp->clockdesc = DESCRIPTION;
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memcpy((char *)&pp->refid, REFID, 4);
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up->pollcnt = 2;
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return (1);
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}
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/*
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* heath_shutdown - shut down the clock
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*/
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static void
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heath_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 heathunit *up;
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struct refclockproc *pp;
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pp = peer->procptr;
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up = (struct heathunit *)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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* heath_receive - receive data from the serial interface
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*/
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static void
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heath_receive(
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struct recvbuf *rbufp
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)
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{
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register struct heathunit *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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int month, day;
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int i;
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char dsec, a[5];
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/*
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* Initialize pointers and read the timecode and timestamp
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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 heathunit *)pp->unitptr;
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pp->lencode = refclock_gtlin(rbufp, pp->a_lastcode, BMAX, &trtmp);
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/*
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* We get a buffer and timestamp for each <cr>; however, we use
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* the timestamp captured at the RTS modem control line toggle
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* on the assumption that's what the radio bases the timecode
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* on. Apparently, the radio takes about a second to make up its
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* mind to send a timecode, so the receive timestamp is
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* worthless.
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*/
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pp->lastrec = up->tstamp;
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up->pollcnt = 2;
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#ifdef DEBUG
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if (debug)
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printf("heath: timecode %d %s\n", pp->lencode,
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pp->a_lastcode);
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#endif
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/*
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* We get down to business, check the timecode format and decode
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* its contents. If the timecode has invalid length or is not in
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* proper format, we declare bad format and exit.
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*/
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if (pp->lencode < LENHEATH) {
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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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* Timecode format: "hh:mm:ss.f AM mm/dd/yy"
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*/
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if (sscanf(pp->a_lastcode, "%2d:%2d:%2d.%c%5c%2d/%2d/%2d",
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&pp->hour, &pp->minute, &pp->second, &dsec, a, &month, &day,
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&pp->year) != 8) {
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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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* If AM or PM is received, assume the clock is displaying local
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* time. First, convert to 24-hour format.
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*/
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switch (a[1]) {
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case 'P':
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if (12 > pp->hour)
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pp->hour += 12;
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break;
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case 'A':
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if (12 == pp->hour)
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pp->hour -= 12;
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break;
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}
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/*
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* Now make a struct tm out of it, convert to UTC, and
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* repopulate pp->
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*/
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if (' ' != a[1]) {
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struct tm t, *q;
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time_t l;
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t.tm_sec = pp->second;
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t.tm_min = pp->minute;
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t.tm_hour = pp->hour;
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t.tm_mday = day; /* not converted to yday yet */
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t.tm_mon = month-1; /* ditto */
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t.tm_year = pp->year;
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if ( t.tm_year < YEAR_PIVOT ) t.tm_year += 100; /* Y2KFixes */
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t.tm_wday = -1; /* who knows? */
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t.tm_yday = -1; /* who knows? */
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t.tm_isdst = -1; /* who knows? */
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l = mktime(&t);
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if (l == -1) {
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/* HMS: do we want to do this? */
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refclock_report(peer, CEVNT_BADTIME);
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return;
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}
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q = gmtime(&l);
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pp->year = q->tm_year;
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month = q->tm_mon+1;
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day = q->tm_mday; /* still not converted */
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pp->hour = q->tm_hour;
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/* pp->minute = q->tm_min; GC-1000 cannot adjust timezone */
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/* pp->second = q->tm_sec; by other than hour increments */
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}
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/*
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* We determine the day of the year from the DIPswitches. This
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* should be fixed, since somebody might forget to set them.
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* Someday this hazard will be fixed by a fiendish scheme that
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* looks at the timecode and year the radio shows, then computes
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* the residue of the seconds mod the seconds in a leap cycle.
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* If in the third year of that cycle and the third and later
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* months of that year, add one to the day. Then, correct the
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* timecode accordingly. Icky pooh. This bit of nonsense could
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* be avoided if the engineers had been required to write a
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* device driver before finalizing the timecode format.
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*
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* Yes, I know this code incorrectly thinks that 2000 is a leap
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* year; but, the latest year that can be set by the DIPswitches
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* is 1997 anyay. Life is short.
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* Hey! Year 2000 IS a leap year! Y2KFixes
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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 (pp->year % 4) {
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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++)
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day += day1tab[i];
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} else {
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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++)
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day += day2tab[i];
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}
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pp->day = day;
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/*
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* Determine synchronization and last update
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*/
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if (!isdigit((int)dsec))
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pp->leap = LEAP_NOTINSYNC;
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else {
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pp->msec = (dsec - '0') * 100;
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pp->leap = LEAP_NOWARNING;
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}
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if (!refclock_process(pp))
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refclock_report(peer, CEVNT_BADTIME);
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}
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/*
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* heath_poll - called by the transmit procedure
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*/
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static void
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heath_poll(
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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 heathunit *up;
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struct refclockproc *pp;
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int bits = TIOCM_RTS;
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/*
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* At each poll we check for timeout and toggle the RTS modem
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* control line, then take a timestamp. Presumably, this is the
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* event the radio captures to generate the timecode.
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*/
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pp = peer->procptr;
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up = (struct heathunit *)pp->unitptr;
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pp->polls++;
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/*
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* We toggle the RTS modem control lead to kick a timecode loose
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* from the radio. This code works only for POSIX and SYSV
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* interfaces. With bsd you are on your own. We take a timestamp
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* between the up and down edges to lengthen the pulse, which
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* should be about 50 usec on a Sun IPC. With hotshot CPUs, the
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* pulse might get too short. Later.
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*/
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if (ioctl(pp->io.fd, TIOCMBIC, (char *)&bits) < 0)
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refclock_report(peer, CEVNT_FAULT);
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get_systime(&up->tstamp);
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ioctl(pp->io.fd, TIOCMBIS, (char *)&bits);
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if (peer->burst > 0)
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return;
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if (pp->coderecv == pp->codeproc) {
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refclock_report(peer, CEVNT_TIMEOUT);
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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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refclock_receive(peer);
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peer->burst = NSTAGE;
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}
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#else
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int refclock_heath_bs;
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#endif /* REFCLOCK */
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