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FUNKUHREN
Technical Information
Operating Instructions
DCF77 PC32
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Impressum
Werner Meinberg
Auf der Landwehr 22
D-31812 Bad Pyrmont
Phone: ++49 52 81 - 9309-0
Fax: ++49 52 81 - 9309-30
Internet: http://www.meinberg.de
Email: info@meinberg.de
October 21, 2002
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Table of Contents
Impressum ............................................................................................ 2
Driver Diskette for DOS/Windows...................................................... 4
General Information about DCF77 ...................................................... 5
Overview .............................................................................................. 7
Installing the PC32 in the Computer.................................................... 8
Connectors and LEDs in the Rear Panel .................................... 9
Activating the Pulse Outputs .................................................... 10
The Driver Software .......................................................................... 11
Files on the Diskette shipped with the Board ........................... 11
Copying the distributed Software to the Hard Disk ................. 11
Using PCPSINFO.EXE ............................................................ 12
The resident driver for DOS/Windows .................................... 15
Controlling the Resident Driver ............................................... 16
Technical Specifications .................................................................... 17
Replacing the Lithium Battery ................................................. 19
CE Label ................................................................................... 19
Format of the Meinberg Standard Time String ........................ 20
PC32 Component Layout ......................................................... 21
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Driver Disk ette for DOS/Windows
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General Information about DCF77
The radio remote clocks made by Meinberg receive the signal from the long wave
transmitter DCF77. This long wave transmitter installed in Mainflingen near Frankfurt/Germany transmits the reference time of the Federal Republic of Germany. This
time reference is either the Central European Time (Mitteleuropäische Zeit, MEZ) or
the Central European Summer Time (Mitteleuropäische Sommerzeit, MESZ). The
transmitter is controlled by the atomic clock plant at the Federal Physical Technical
Institute (PTB) in Braunschweig/Germany and transmits the current time of day, date
of month and day of week in coded second pulses. Once every minute the complete
time information is available.
At the beginning of every second the amplitude of the high precision 77.5 kHz
carrier frequency is lowered by 75% for a period of 0.1 or 0.2 sec. The length of these
time marks represent a binary coding scheme using the short time mark for logical
zeroes and the long time mark for logical ones. The information on the current date
and time as well as some parity and status bits can be decoded from the time marks of
the 15th up to the 58th second every minute. The absence of any time mark at the 59th
second of a minute signals that a new minute will begin with the next time mark.
Our radio remote clocks decode the highly accurate information on date and time
within a wide range around Germany. So some of our clocks are installed in Bilbao/
Spain as well as in the city of Umeå in northern Sweden - fully satisfying the
requirements of the users. The radio remote clocks automatically switch to summertime and back. The reception of the time information is free of charge and does not need
to be registered.
Generally it is important to position the antenna in an optimal way. It should be
mounted at least 30 centimeters away from the clock unit and from solid steel. The
antenna should be aligned at a right angle to the direction of the transmitter (Frankfurt).
Figure: Decoding Scheme
M Start of Minute (0.1 sec)
R RF Transmission via secondary antenna
A1 Announcement of a change in daylight saving
Z1, Z2 Time zone identification
Z1,Z2 = 0,1: Daylight saving disabled
Z1,Z2 = 1,0: Daylight saving enabled
A2 Announcement of a leap second
S Start of time code information (0.2 sec)
P1, P2, P3 Even parity bits
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Overview
Several product lines of radio remote clocks for IBM compatible computers are
available from Meinberg. While all of them are using a common software interface,
different computer architectures require different board layouts. So the board called
PC32 can be installed in every standard PC with ISA or EISA bus. PC32E is the name
of the corresponding eurocard size board for 19" modular computers with AT96 or
ISA96 bus. Microchannel architectures (e. g. IBM PS/2 Model 50 and above) are
supported by our microchannel adapter PS31.
An external ferrit antenna makes the signal from DCF77 available to the on-board
long wave receiver. The demodulated time marks are decoded by the clock´s microprocessor. If no errors are detected in the current time message an additional plausibility check against the previous time message is performed. If that plausibility check
passes, too, the battery buffered real time clock on the board is synchronized corresponding to the decoded time and date.
Software running on the computer can read out the date/time/status and some more
information. Access to the board is made via writing to/reading from two I/O ports.
The simple software protocol to be used is described below. Starting with EPROM
version 3.0, the on-board clock can be set via the PC interface. It is possible but not
necessary to let the board generate periodic hardware interrupts on the computer bus.
Utility programs supplied with the boards include PCPSDRV.COM, a resident
driver (TSR) for DOS/Windows that keeps the computer´s system time synchronous
to the board time and PCPSINFO.EXE, a status display which simplifies installation.
Drivers for OS/2, Windows NT, or NetWare can be ordered separately. Sample C,
pascal, and assembler programs including source show how the board can directly be
accessed from user-written applications.
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Installing the PC32 in the Computer
Programs can read data from or write data to the board using 2 I/O ports from a block
of four addresses. The base I/O address can be set up in a wide range using the DIL
switch on the board. When being shipped, the board´s address is set to 300h corresponding to the default address used by the utility software. If one of the levers 8, 9, or
10 of the DIL switch is set to the ON position, the radio remote clock PC32 can
generate cyclic hardware interrupts on the PC's corresponding interrupt line. However, if the clock is operated using the software shipped with the board, all of the
interrupt switches should remain in the OFF position because the software shipped
with the board does not use any hardware interrupt.
SW IRQ
8 3
9 4
10 7
In most cases the board can be installed without modifications. If another board uses I/
O in the range 300h to 303h the PC32´s base address must be changed. Lever 1 of the
DIL switch is assigned to the PC's address line A2, lever 7 is assigned to A8, A9 is
hard wired to logical "1". Any switch in the ON position ties the corresponding
address line to logical "0". Some common port base addresses and the corresponding
DIL switch settings are shown in the table below:
Use the table shown below to see the DIL switch settings and corresponding I/O
addresses.
Port SW1 234567 Port SW1 2 3 4567
200 xxxxxxx 32C --x -xx 204 -xxxxxx 330 xx--xx208 x-xxxxx 334 -x--xx20C --xxxxx 338 x---xx210 xx-xxxx 33C ----xx214 - x - x x x x 340 x x x x - x 218 x - - x x x x 344 - x x x - x 21C - - - x x x x 348 x - x x - x 300 xxxxxx- 34C --xx-x304 -xxxxx - 350 xx -x -x 308 x-xxxx - 354 -x-x-x30C --xxxx- 358 x - -x -x 310 xx-xxx - 35C - - -x -x 314 - x - x x x - 360 x x x - - x 318 x - - x x x - 364 - x x - - x 31C ---xxx- 368 x-x--x320 xxx-xx- 36C --x--x324 - x x - x x - 370 x x - - - x 328 x - x - x x - 374 - x - - - x -
‘x’ —> switch in pos. ON ‘-’ —> switch in pos. OFF
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The computer has to be turned off and its case must be opened. The radio remote clock
might be installed in any slot not used yet. The rear plane must be removed before the
board can be carefully plugged in. The computer´s case should be closed again and the
antenna connected to the PC32´s coaxial plug at its rear. After the computer has been
restarted, the utility PCPSINFO.EXE should be run in order to position the antenna
(see below).
Connectors and LEDs in the Rear Panel
Three status LEDs and a 9 pin sub D connector
can be found in the rear panel (see figure below). The LEDs let the user check for proper
receiver operation. The upper, red LED is on if
the clock is running on xtal. This LED can only
change when the minute changes (seconds increment from 59 to 0). The brightness of the LED
in the middle depends on the strength of the RF
signal. The lower, green LED should be blinking exactly once per second corresponding to
the time marks from DCF77. If this LED flashes
there is some electrical noise around which prevents the receiver from decoding the time marks
and synchronizing. All information given by
these LEDs can also be obtained from the screen
of the program PCPSINFO.EXE.
The 9 pin sub D connector is wired to the
PC32's serial port. Pin assignment can be seen
from the figure beside. This port can not be used
as serial port for the computer. Instead, the clock
uses the port to send out Meinberg's standard
time string in order to control an external display or some other external device. The string is
sent out once per second, once per minute or if
requested by an incoming ASCII '?'. Starting
with EPROM version 3.2 it is also possible to
change the PC32's board time by sending such a
string to the board. Transmission speed, framing, and mode of operation can be
modified using the program PCPSINFO. The string format is described in the section
'Technical Specifications' at the end of this manual.
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Activating the Pulse Outputs
The radio clock PC32 generates active high TTL level pulses whenever a second or
minute changes. A jumper block on the board can be used to wire the TTL outputs
(0..5V) to some of the connector pins. In this case, absolute care must be taken if
another device is connected to the port, because voltage levels of -12V through
+12V (as commonly used with RS-232 ports) at TTL outputs may damage the
radio clock.
Jumper location
The figure below shows the assignment of the output pins if all jumpers are installed:
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The Driver Software
Programs for DOS/Windows 3.1x/Windows 95 are shipped together with the radio
clock. Optional drivers can be obtained for the following operating systems:
Novell NetWare version 3.11 and above
Windows NT version 3.51 and above
OS/2 version 2.1 and above
Files on the Diskette shipped with the Board
Root directory:
DATEIEN.TXT this list of files in German language
LIESMICH.TXT last changes/modifications in German language
FILES.TXT this list of files in English
README.TXT llast changes/modifications in English
@6AAC.ADF Adapter Description File (required for PS31 only)
PCPSINFO.EXE shows continuously the board´s status
PCPSTIME.EXE adjust computer time when beeing called, not resident
PCPSCLOC.EXE Analog clock displayed with HGC/EGA/VGA graphic
PCPSDRV.COM resident driver, keeps computer time synchronized with board time
DRV.EXE temporarily disables the resident driver
DISP.EXE enables or disables the permanent date/time window
POSXY.EXE positions the permanent date/time window on the screen
COLOR.EXE sets the screen attribute of the permanent date/time window
Copying the distributed Software to the Hard Disk
When the computer has come up after power on the utility programs should be copied
from the shipped diskette to a subdirectory on the hard disk. Assume the current drive
is C: and the new subdirectory is to be created on the current drive, create that
subdirectory (e.g. called MEINBERG) using the command
MD \MEINBERG
from the DOS command line. Make the new subdirectory the current one using the
command
CD \MEINBERG
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If the utility diskette is inserted in drive A: use the following command to copy the
files and subdirectories from the diskette to the hard disk:
XCOPY A:*.* /S
Using PCPSINFO.EXE
After the board has been installed in the computer the program PCPSINFO.EXE
should be run in order to see if the board has been properly installed. This program can
display its messages in English or in German language and the date and time in
formats used in the USA, the UK, or Germany. The default language and formats used
are derived from the DOS country code at startup. If automatic language detection
does not yield the desired result, you can force a language and date/time format using
a command line parameter or by pressing a function key when the program is running.
The command syntax is shown below:
PCPSINFO [P:xxx] [C:xx] [MONO] [?]
Usage of the command line parameters is described below:
P:xxx The board is installed using addresss xxx (hex). This parameter can be omitted if the
address matches the default address (300 hex).
C:xx Country code override. The default country code to be used is derived from the COUN-
TRY=.... entry in the CONFIG.SYS file.
xx may be set to 49 (Germany, 24h clock, dd.mm.yy), 44 (U.K, 12h clock, dd/mm/yy)
or 1 (USA, 12h clock, mm-dd-yy).
MONO Force monochrome display even if color display installed. May increase the readability
on LC displays often used with laptops.
? Displays a message how to setup port address and how to use the program. Output can
be redirected to printer ( append ">LPT1" to the command line) or file (append ">file-
name").
All the command line parameters are optional. In most cases the program is started
simply by entering PCPSINFO or, if the port address has been changed, PCPSINFO
P:xxxx. If the board can be accessed via the selected port address the screen displays
information as shown below:
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The upper part of the screen shows information about the resident driver (if the driver
has been installed). These information include the ID string of the resident driver
with the driver revision number, the number of the software interrupt used to
control the resident driver and the last recent date/time the driver has read from the
board. The number of the user interrupt is determined automatically when the resident
driver is installed. It is not affected by the hardware interrupt configured by jumpers.
The BUSY flag controls the driver´s right to access the board. If the flag is set to
OFF the driver is allowed to access the board, if it is ON, access is inhibited. This flag
can be changed from the command line using the utility DRV.EXE or by pressing the
key B in PCPSINFO. The flag DISP affects the resident driver´s feature displaying
the permanent date/time window on the screen (upper right corner in the screenshot
above). It can be altered using the utility DISP.EXE from the command line or by
pressing the key D. The flag Set RTC direct enables the driver to write directly to the
computer´s real time clock. This feature is required in some special environments
only; see the description of PCPSDRV.COM below. The Tick Counter counts the
times the driver has been activated by the computer´s periodic timer tick interrupt. If
this counter is down to zero, the computer´s system time is set and the counter is
reloaded to the Tick Reload value. The tick reload is derived from the update cycle
parameter given in the command line when PCPSDRV.COM is installed. The system
timer generates 18.2 interrupt per second, so the reload value in the figure above (182)
corresponds to an update cycle of 10 seconds.
The lower part of the screen gives information about the board installed in the
computer: The Eprom´s ID string, the type of board (PC32 or PS31) and the port
base address which has been configured. The field labeled Serial: shows transmission speed, framing and mode of operation which have been configured for the radio
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remote clock´s serial interface. The serial interface transmits the date/time/status
string known from other Meinberg radio remote clocks. The serial parameters can be
setup by menu if the key F4 is being hit.
The line Last Sync: shows the time last synchronization has been achieved. If the
clock runs synchronous with DCF77 this field is updated once every minute. The field
labeled Date/Time: displays the board´s current date and time. If the key F3 is
pressed the user can modify the board´s date and time, should the need arise.
The board´s current state is shown in the field Status:. The first line shows whether
the clock has ever been synchronized with DCF77 since the last power-up or board
reset. If there are transient distortions the clock can be temporarily running on XTAL
for some minutes which is indicated by the second line. The third line indicates
whether daylight saving is currently in effect or not.
The signal bar is useful to install the antenna. For best results the antenna should be
mounted at least 1 meter from the computer and from solid metal parts. The length of
the bar is derived from the receiver´s AGC voltage. Because this voltage is limited
with a strong signal, the best way to align the antenna is to turn it slowly until the bar
shows minimum signal, then turn it exactly by 90 degrees to yield the maximum
signal.
Exact time marks are much more important than a long signal bar, so the small field
labeled Mod: reflects the time marks demodulated from the RF signal. This indicator
should blink exactly once per second without intermediate flashes. Pressing the key F2
enables the computer´s speaker whenever the Mod: field is on.
Pressing both the keys Alt and X simultanously lets this program terminate.
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The resident driver for DOS/Windows
The resident driver PCPSDRV.COM runs with DOS version 2.11 or greater and
Windows 3.x. It uses only about 1100 bytes of memory and periodically synchronizes
the computer´s system time to the board time. Additionally, the driver is able to
display the board´s time continuously in a window on the text screen. This feature can
be enabled and controlled by some of the utility programs (see next chapter).
In order to avoid conflicts accessing the board the driver should not be installed or
be temporarily disabled using the utility DRV.EXE if user-written software accesses
the board.
If the driver has to be installed every boot time, it should be called from the
AUTOEXEC.BAT which should reside in the root directory of the boot drive. Assuming the driver file can be found in the directory MEINBERG on drive C:, a
command line like that shown below should be added to the AUTOEXEC.BAT using
any text editor:
C:\MEINBERG\PCPSDRV [port addr] [U:xxxx] [I] [R]
The parameter port addr must be given if the board has been jumpered to use an
alternate port address instead of 300 hex.
The optional parameter U:xxxx can be used to set the time span to be used for the
periodical update of the system time. Valid numbers for xxxx are 1 to 3600 (seconds).
If this parameter is omitted the time span defaults to 1800 seconds (= 30 minutes).
The parameter I must be given in the command line if the driver shall modify the
computer´s time just after being installed. In the default case the computer´s system
time will only be modified when the clock has synchronized at least once after powerup (Status: Synchronized after last Reset). If the clock has to work in an electrically
noisy environment or with very low RF signal it can´t synchronize very often and it
could be recommended that the computer´s time is synchronized with the PC32´s time
before the clock has synchronized with DCF77 (the PC32 offers a more exact time
than the computer´s system time even when running on XTAL).
The last parameter R tells the resident driver to set the real time clock in AT
compatible computers directly. This is only required if the DOS/BIOS interrupts
which modify the computer´s time are redirected by other applications as on Novell
Netware 2.xx file servers. In the default case this parameter should not be used in
order to minimize the execution time of the resident driver.
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Controlling the Resident Driver
If the resident driver PCPSDRV.COM has been installed, some of the utility programs can be used to control the way it works. The programs described below show a
few help lines when they are called without command line parameters.
DRV.EXE temporarily disables the resident driver´s access to the board.
Command: DRV ON or DRV OFF
Default: enabled
DISP.EXE enables or disables the date/time window on the screen.
Command: DISP ON or DISP OFF
Default: disabled
COLOR.EXE sets up the screen attribute of the date/time window
Command: COLOR fg bg
with fg and bg the color numbers of the foreground/background
Default: white characters on black
POSXY.EXE sets up the screen position of the date/time window.
Command: POSXY column row
Default: upper right corner of the screen
Using these utilities, you can enable or disable the date/time window only when
special applications are run.
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Technical Specifications
RECEIVER: Synchronous receiver with automatic gain control
Bandwidth: approx. 50Hz
ANTENNA: Active external ferrite antenna in a plastic case
Length of the cable: up to more than 100m
Standard:
BNC type connector, 5m of RG174 cable
Outdoor:
N type connector, RG58 cable
RF AMPLITUDE,
MODULATION: Indicated by LED and on-screen by utility program
TIMECODE
CHECK: Parity and consistency checking over a period of two minutes
RF distortions indicated by both LED and a bit of the
status register
Without RF signal the clock runs on XTAL
with an accuracy of 10
-5
BATTERY
BACKUP: Lithium battery or Gold Cap
when the computer is turned off, the on-board RTC keeps the
time based on XTAL for more than 10 years (lithium battery)
rsp. 150 hours (gold cap)
RELIABILITY OF
OPERATION: Microprocessor supervisory circuit provides watchdog timer,
power supply monitoring and backup-battery switchover
SYSTEM BUS
INTERFACE: IBM PC/XT/AT (ISA/EISA) compatible
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SERIAL
INTERFACE: Transmission Speed: 300 through 9600 Baud
Framing: 8N1, 7E2, 8N2, or 8E1
Mode of Operation: send string per second, per minute,
after request ´?´ received
Output String: Meinberg standard time string
(described below)
With EPROM v3.2 and above, this string can also be sent towards the board in order to set the board time.
POWER
REQUIREMENT: +5V @ 80mA
PHYSICAL
DIMENSION: 8 bit short expansion board
AMBIENT
TEMPERATURE: 0 ... 70°C
HUMIDITY: max. 85 %
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Replacing the Lithium Battery
The life time of the lithium battery on the board is at least 10 years. If the need arises
to replace the battery, the following should be noted:
ATTENTION!
Danger of explosion in case of inadequate replacement of
the lithium battery. Only identical batteries or batteries
recommended by the manufacturer must be used for
replacement. The waste battery must be disposed as pro-
posed by the manufacturer of the battery.
CE Label
This device conforms to the directive 89/336/EWG on the approximation of the laws of the Member States of the European Community relating to electromagnetc compatibility.
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Format of the Meinberg Standard Time String
The Meinberg Standard Time String is a sequence of 32 ASCII characters starting
with the STX (start-of-text) character and ending with the ETX (end-of-text) character. The format is:
<STX>D:dd.mm.yy;T:w;U:hh.mm.ss;uvxy<ETX>
The letters printed in italics are replaced by ASCII numbers whereas the other
characters are part of the time string. The groups of characters as defined below:
<STX> Start-Of-Text (ASCII code 02h)
dd.mm.yy the current date:
dd day of month (01..31)
mm month (01..12)
yy year of the century (00..99)
w the day of the week (1..7, 1 = Monday)
hh.mm.ss the current time:
hh hours (00..23)
mm minutes (00..59)
ss seconds (00..59, or 60 while leap second)
uv clock status characters:
u: ‘#’ clock has not synchronized after reset
‘ ‘ (space, 20h) clock has synchronized after reset
v: different for DCF77 or GPS receivers:
‘*’ DCF77 clock currently runs on XTAL
GPS receiver has not checked its position
‘ ‘ (space, 20h) DCF77 clock is sync'd with transmitter
GPS receiver has determined its position
x time zone indicator:
‘U’ UTC Universal Time Coordinated, formerly GMT
‘ ‘ MEZ European Standard Time, daylight saving disabled
‘S’ MESZ European Summertime, daylight saving enabled
y anouncement of discontinuity of time, enabled during last hour
before discontinuity comes in effect:
‘!’ announcement of start or end of daylight saving time
‘A’ announcement of leap second insertion
‘ ‘ (space, 20h) nothing announced
<ETX> End-Of-Text (ASCII code 03h)
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PC32 Component Lay out
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