Meinberg DCF77PC32 User Manual

FUNKUHREN

Technical Information
Operating Instructions

DCF77 PC32

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: [e-mail]

October 21, 2002

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

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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