Trimble Outdoors Part Number 45005-00-ENG manual Serial Data Communication, Port B, Port a Timing

System Operation 5

5.3Serial Data Communication

When the Acutime 2000 has acquired a set of satellites that conforms to the mask and mode settings and has collected a valid ephemeris for each satellite, it automatically commences periodic outputs of GPS data and generates a timing pulse (PPS).

5.3.1Port B

The Acutime 2000 outputs periodic TSIP health, mode, and time messages on Port B. These status messages confirm that the receiver is working. These packets are described in Appendix A, Trimble Standard Interface Protocol.

The factory default port setting is 9600 baud in/out, 8 data bits, odd parity, 1 stop bit. The serial port setting can be changed and stored in serial EEPROM using a TSIP command.

This port can also be configured to transmit timing packets, using packet 8E-A5 to determine which timing packet to output on this port.

5.3.2Port A (Timing)

The Acutime 2000 has a dedicated serial port for outputting comprehensive time packets. Messages are output after the PPS and after external events. The factory default setting is TSIP, 9600, 8-odd-1, output only.

The host system receives both the PPS and the time packet identifying each pulse. Use packet 8E-A5 to determine which timing superpacket to output on this port.

The Acutime 2000 generates a packet in response to the external event input. The event count field in packet 8F-0B (or 8F-AD) increments for each event received. This field resets after a power cycle and rolls over at 65535. The event tag messages are interleaved with the PPS messages. PPS tags are distinguished by a zero (0) in the event count field. The Acutime 2000 accepts external events up to a

5-10 Acutime 2000 Synchronization Kit User Guide