Microbee Systems MBS-GPS-SS2-5HZ Instrukcja Użytkownika Pobierz pdf (Strona 7)

Rev A

In position 2-3 the data, 1 PPS inversion is based upon Jumper JP10A, not the RTS bit of the

Data Port. JP10A 2-3 un-inverts the 1PPS source and JP10A 1-2 inverts the 1PPS source.

NOTE:

Refer to the Novatel Super Star II GPS OEM Module Users Manual and Firmware Manuals for

proper operation and setup of the onboard GPS.

Status Monitoring:

Overview:

Several unusual status features are available. These are provided to monitor primarily the 1PPS

timing pulse from either the INT or EXT GPS (depending upon GPS source selection), or the AUX

1PPS source. The 1PP is primarily used for synchronization of MicroBee Systems PC/104

FreeWave data radio products in Masterless TDMA mode and Push To Talk (PTT) mode. In

addition the 1PP is very useful for timetag and system synchronization uses. For these reasons

advanced features allow an AUX PPS, primarily for development without a valid GPS signal, and

polarity inversion of the signal should a system/device require this.

Additionally the 1PPS output is available in both TTL and RS-232 Levels. Please refer to the

section on J6 for further information.

DSR0 of the Data Port monitors the GPS 1PPS input, whether INT or EXT, directly from the GPS

regardless of the 1PP inversion capabilities. In other words, this is direct from the GPS.

RI0 of the Data Port monitors the 1PPS after before the inversion circuitry. Comparison of this

BIT can be used to verify inversion is set.

RI1 of the Diff Port monitors the 1PPS after the inversion circuitry. If the 1PPS is non-inverted

then this will be identical to DSR0. If inversion of the 1PP is selected then this will be the

compliment of DSR0.

CTS0 of the Data Port is used to monitor the AUX PPS in. If the AUX PPS is unused then this

can be ignored. This is used to monitor for the presence of a AUX PPS signal. If AUX PPS is

selected then the other features will work upon the AUX signal instead of the INT/EXT GPS

sources. The AUX is primarily used for development of systems requiring a 1PPS interrupt where

no GPS signal is available. Most GPS systems will not provide a 1PPS without a valid fix.

PPS IO Connector, J6 Terminal Block

J6 is the IO for the 1PP signal. The pinouts are as follows:

J6.1:

1PPS Output. This represents the 1PPS output in RS-232 level. This signal depends upon the

source and polarity selection as described previously.

J6.2:

This is the AUX PPS input. This input accepts RS-232 level signals. It is important to remember

that if used with a TTL source you must invert the signal. This is because RS-232 level signals

are inverted relative to TTL.

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Microbee Systems MBS-GPS-SS2-5HZ Instrukcja Użytkownika Strona 7