Meinberg PTP270PEX, Manual

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2.4 Pulse and frequency outputs Page 3
2.4 Pulse and frequency outputs
The pulse generator of PTP270PEX contains three independent channels (PPO0, PPO1, PPO2). These TTL
outputs can be mapped to pins at the 9-pin connector at the rear slot cover by using a DIL switch. The pulse
outputs are able to provide a pulse per second (PPS) or a 10MHz standard frequency. They are congured by
the monitor program.
2.5 Time capture inputs
The board provides two time capture inputs called User Capture 0 and 1 (CAP0 and CAP1) which can be mapped
to pins at the 9 pin connector at the rear panel. These inputs can be used 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 buer.
From the buer, an ASCII string per capture event can be transmitted via COM1 or displayed using the monitoring
program. The capture buer 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 COM1 can be measured. The format of the output string is described in the technical specications at
the end of this document. If the capture buer is full a message "** capture buer full" is transmitted, if the
interval between two captures is too short the warning "** capture overrun" is being sent via COM1.
2.6 Asynchronous serial port
An asynchronous serial interface (RS232) COM0 is available to the user via a submin-D connector in the rear
panel slot cover. In the default mode of operation, the serial output is disabled until the module has synchronized
it`s internal time base to a PTP Grandmaster. However, it can be congured to be enabled immediately after
power-up. The monitoring program can be used to setup transmission speed, framing and mode of operation of
the serial interface. It can be congured to transmit either time strings (once per second, once per minute, or on
request with ASCII ? only), or to transmit capture strings (automatically when available, or on request). The
format of the output strings is ASCII, see the technical specications at the end of this document for details.
PTP270PEX Date: 22nd November 2012 3