TSAT-cPCI Spectracom CompactPCI GPS Timing Module

The Safran / Orolia / Spectracom TSAT-cPCI CompactPCI GPS Timing Module provides high-accuracy timing functions on a plug-in board for the Compact PCI computer bus. The board has an on-board clock, which is kept in sync to an external timecode input. Several timing functions are derived from the on-board clock, including a programmable periodic pulse rate output (“heartbeat”), a programmable start/stop output (“match”), a selectable frequency output (“oscillator out,” 1 kHz, 1, 5, or 10 MHz), and a time-stamping input (“time-tag”).

The TSAT-cPCI can be combined with an externally-mounted GPS antenna and 100-foot of antenna cable. The GPS satellites provide Coordinated Universal Time (UTC) accurate to within 1 micro-second, and also give position in latitude, longitude, and elevation. The board automatically syncs its on-board clock to the time transmitted by the GPS satellites. The board outputs a timecode signal, in IRIG-B format, which conveys the day, hour, minute, and seconds, and also has a 1 kHz carrier referenced to the on-board oscillator.

The TSAT-cPCI can be used as a stand-alone timecode generator. The computer programs the day, hour, minute and second. The board then continues to count from that time, using the on-board oscillator as the timebase reference. This is called “freewheeling.”

The host computer communicates to the board through a set of memory-mapped registers. When the computer boots up, the board identifies itself to the Compact PCI bus by specifying the unique Subsystem Vendor ID. The host computer can then read the instantaneous time, command the board to set time, and/or to provide an interrupt at a periodic rate, at a specified time, and/or when a time-tag event occurs.