422 lines
12 KiB
C
422 lines
12 KiB
C
/*
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* refclock_heath - clock driver for Heath GC-1000 and and GC-1000 II
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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 "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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#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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/*
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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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* There are two GC-1000 versions supported by this driver. The original
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* GC-1000 with RS-232 output first appeared in 1983, but dissapeared
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* from the market a few years later. The GC-1000 II with RS-232 output
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* first appeared circa 1990, but apparently is no longer manufactured.
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* The two models differ considerably, both in interface and commands.
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* The GC-1000 has a pseudo-bipolar timecode output triggered by a RTS
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* transition. The timecode includes both the day of year and time of
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* day. The GC-1000 II has a true bipolar output and a complement of
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* single character commands. The timecode includes only the time of
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* day.
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*
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* GC-1000
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*
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* The internal DIPswitches should be set to operate in MANUAL mode. The
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* external DIPswitches should be set to GMT and 24-hour format.
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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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* GC-1000 II
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*
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* Commands consist of a single letter and are case sensitive. When
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* enterred in lower case, a description of the action performed is
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* displayed. When enterred in upper case the action is performed.
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* Following is a summary of descriptions as displayed by the clock:
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*
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* The clock responds with a command The 'A' command returns an ASCII
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* local time string: HH:MM:SS.T xx<CR>, where
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*
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* HH = hours
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* MM = minutes
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* SS = seconds
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* T = tenths-of-seconds
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* xx = 'AM', 'PM', or ' '
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* <CR> = carriage return
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*
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* The 'D' command returns 24 pairs of bytes containing the variable
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* divisor value at the end of each of the previous 24 hours. This
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* allows the timebase trimming process to be observed. UTC hour 00 is
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* always returned first. The first byte of each pair is the high byte
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* of (variable divisor * 16); the second byte is the low byte of
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* (variable divisor * 16). For example, the byte pair 3C 10 would be
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* returned for a divisor of 03C1 hex (961 decimal).
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*
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* The 'I' command returns: | TH | TL | ER | DH | DL | U1 | I1 | I2 | ,
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* where
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*
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* TH = minutes since timebase last trimmed (high byte)
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* TL = minutes since timebase last trimmed (low byte)
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* ER = last accumulated error in 1.25 ms increments
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* DH = high byte of (current variable divisor * 16)
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* DL = low byte of (current variable divisor * 16)
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* U1 = UT1 offset (/.1 s): | + | 4 | 2 | 1 | 0 | 0 | 0 | 0 |
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* I1 = information byte 1: | W | C | D | I | U | T | Z | 1 | ,
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* where
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*
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* W = set by WWV(H)
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* C = CAPTURE LED on
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* D = TRIM DN LED on
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* I = HI SPEC LED on
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* U = TRIM UP LED on
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* T = DST switch on
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* Z = UTC switch on
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* 1 = UT1 switch on
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*
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* I2 = information byte 2: | 8 | 8 | 4 | 2 | 1 | D | d | S | ,
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* where
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*
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* 8, 8, 4, 2, 1 = TIME ZONE switch settings
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* D = DST bit (#55) in last-received frame
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* d = DST bit (#2) in last-received frame
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* S = clock is in simulation mode
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*
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* The 'P' command returns 24 bytes containing the number of frames
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* received without error during UTC hours 00 through 23, providing an
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* indication of hourly propagation. These bytes are updated each hour
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* to reflect the previous 24 hour period. UTC hour 00 is always
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* returned first.
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*
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* The 'T' command returns the UTC time: | HH | MM | SS | T0 | , where
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* HH = tens-of-hours and hours (packed BCD)
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* MM = tens-of-minutes and minutes (packed BCD)
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* SS = tens-of-seconds and seconds (packed BCD)
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* T = tenths-of-seconds (BCD)
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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 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 LENHEATH1 23 /* min timecode length */
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#define LENHEATH2 13 /* 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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* Baud rate table. The GC-1000 supports 1200, 2400 and 4800; the
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* GC-1000 II supports only 9600.
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*/
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static int speed[] = {B1200, B2400, B4800, B9600};
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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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/*
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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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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, speed[peer->ttl & 0x3], 0)))
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return (0);
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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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return (0);
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}
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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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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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struct refclockproc *pp;
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pp = peer->procptr;
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io_closeclock(&pp->io);
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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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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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pp->lencode = refclock_gtlin(rbufp, pp->a_lastcode, BMAX,
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&trtmp);
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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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switch (pp->lencode) {
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/*
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* GC-1000 timecode format: "hh:mm:ss.f AM mm/dd/yy"
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* GC-1000 II timecode format: "hh:mm:ss.f "
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*/
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case LENHEATH1:
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if (sscanf(pp->a_lastcode,
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"%2d:%2d:%2d.%c%5c%2d/%2d/%2d", &pp->hour,
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&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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break;
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/*
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* GC-1000 II timecode format: "hh:mm:ss.f "
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*/
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case LENHEATH2:
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if (sscanf(pp->a_lastcode, "%2d:%2d:%2d.%c", &pp->hour,
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&pp->minute, &pp->second, &dsec) != 4) {
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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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refclock_report(peer, CEVNT_BADREPLY);
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return;
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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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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->nsec = (dsec - '0') * 100000000;
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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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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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* 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 = peer->procptr;
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/*
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* We toggle the RTS modem control lead (GC-1000) and sent a T
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* (GC-1000 II) to kick a timecode loose from the radio. This
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* code works only for POSIX and SYSV interfaces. With bsd you
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* are on your own. We take a timestamp between the up and down
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* edges to lengthen the pulse, which should be about 50 usec on
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* a Sun IPC. With hotshot CPUs, the pulse might get too short.
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* 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(&pp->lastrec);
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if (write(pp->io.fd, "T", 1) != 1)
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refclock_report(peer, CEVNT_FAULT);
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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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pp->lastref = pp->lastrec;
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refclock_receive(peer);
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record_clock_stats(&peer->srcadr, pp->a_lastcode);
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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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peer->burst = MAXSTAGE;
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pp->polls++;
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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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