Meinberg GPS167LCD-MP - Manual (Page 10)

10
Pulse Outputs
The pulse generator of GPS167 generates pulses once per second (P_SEC) and once
per minute (P_MIN). Additionally, master frequencies of 10 MHz, 1 MHz and 100
kHz are derived from the OCXO. All the pulses are available with TTL level at the
rear connector.
In the default mode of operation, pulse outputs are disabled until the receiver has
synchronized after power-up. However, the system can be configured to enable those
outputs immediately after power-up. An additional TTL output (TIME_SYN) reflects
the state of synchronization. This output switches to TTL HIGH level when synchro-
nization has been achieved and returns to TTL LOW level if not a single satellite can
be received or the receiver is forced to another mode of operation by the user.
Time Capture Inputs
Two time capture inputs called User Capture 0 and 1 are provided at the rear connector
(CAP0 and CAP1) to measure asynchronous time events. A falling TTL slope at one
of these inputs lets the microprocessor save the current real time in its capture buffer.
From the buffer, capture events are transmitted via COM0 or COM1 and displayed on
LCD. The capture buffer can hold more than 500 events, so either a burst of events
with intervals down to less than 1.5 msec can be recorded or a continuous stream of
events at a lower rate depending on the transmission speed of COM0 or COM1 can be
measured. The format of the output string is ASCII, see the technical specifications at
the end of this document for details. If the capture buffer is full a message "** capture
buffer full" is transmitted, if the interval between two captures is too short the warning
"** capture overrun" is being sent.
Asynchronous Serial Ports
Two asynchronous serial interfaces are available to the user. In the default mode of
operation, the serial outputs are disabled until the receiver has synchronized after
power-up. However, the system can be configured to enable those outputs immediate-
ly after power-up. Transmission speeds, framings and mode of operation can be
configured separately using the setup menu. COM0 is compatible with other radio
remote clocks made by Meinberg. It sends Meinberg´s standard time string either once
per second, once per minute or on request with ASCII ´?´ only. The interfaces can also
be configured to transmit capture data either automatically when available or on
request. The format of the output strings is ASCII, see the technical specifications at
the end of this document for details. A separate document with programming instruc-
tions can be requested defining a binary data format which can be used to exchange
parameters with GPS167 via COM0.