Spectracom TPRO-cPCI, User Manual, Page: 28 / 46

TPRO-cPCI/TSAT-cPCI Spectracom Corporation
Synchronizable Timecode Generator User Manual 4-6
4.3.9.17 Time Tag Event Counter
This is intended for diagnostic purposes only. It counts the number of time tag events that have
occurred since the time tag registers were read. If it reaches maximum count (0xf), it will remain
at maximum count.
The board latches only one time tag event. If another event occurs before the user reads the
time tag registers, the second event is lost (not latched). This counter can be used to determine
whether time tag events are being lost. Read this counter immediately prior to reading the time
tag registers. If the count is
zero , no events have occurred. If it is one , the time tag registers
contain the latest event time, and no events have been lost. If it is greater than one, some time
tag events have been lost.
The user's software must be able to read the time tag register faster than the event repetition
rate. External hardware can be used to divide the time tag signal so that only every fifth event is
tagged (for example). Such hardware is the user's responsibility.
4.3.9.18 Testpoint–Interrupt
This status bit is asserted when the board is asserting an interrupt. It is used for diagnostic
purposes only. The user should examine the Flag bits, in conjunction with the IRQ Enable
bits, only when determining which interrupt to service.
4.3.9.19 Testpoint–GPS Antenna
The board receives various messages from the GPS receiver/antenna. This bit is asserted
when the board determines that the received messages are in the proper format. This does not
indicate that it is tracking satellites; it means only that the communication between the board
and the receiver/antenna is functioning properly.
If this bit is not asserted, the most likely problem is that the antenna cable is disconnected.
This bit will not be asserted during the first few seconds after a power-on reset or forced reset
command.
The TPRO-PMC will always de-assert this bit. For this reason, do not use this bit to disqualify
the board's data. Instead,
use this bit only as a troubleshooting tool .