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TPRO-cPCI/TSAT-cPCI Spectracom Corporation
Synchronizable Timecode Generator User Manual 4-4
4.3.9.1 Flag–Acquire
This status bit is asserted when the board detects that a time code is present (before
synchronization is established), or when the GPS receiver is connected, but is not tracking
satellites. It is not asserted if no time code is connected to the input.
This bit corresponds to the yellow ACQ panel indicator, except this bit is not asserted during the
lamp test or in response to a command while in Blink Yellow Mode.
4.3.9.2 Flag–Sync
This is the only bit to examine when determining whether or not the board has established
synchronization. It is asserted when the board is properly synchronized to the incoming time
code, or to the GPS satellites. It also indicates that the computed longitude, latitude, and
altitude are valid (TSAT-PMC).
This bit corresponds to the green SYNC panel indicator, except this bit is not asserted during
the lamp test.
4.3.9.3 Flag–Command Overflow
This bit is intended as a tool for debugging user-written software. It is asserted if the user's
software sends a command (writes to tbreg_cmd[3]) when the board is not ready to accept a
new command. It is de-asserted by writing (any value) to tbreg_clrflag_cmov.
4.3.9.4 Flag–Match
This bit is asserted when the Match Start time occurs. Reset it by writing (any value) to the
tbreg_clrflag_m register. The Match Stop time does not affect it. This bit might be set at power-
on reset; the user must clear this bit before setting the Match Start time.
4.3.9.5 Flag–Heartbeat
This flag is set by each Heartbeat pulse; the user clears it by writing (any value) to
tbreg_clrflag_hb. The user's software must be fast enough to clear each Heartbeat before the
next one occurs. This bit might be set at power-on reset; the user must clear this bit before
using it.
The next Heartbeat output pulse will happen regardless of whether the user has cleared this
flag. The user's software does not need to clear the Heartbeat Flag if the user's software does
not interrogate this flag.
4.3.9.6 Flag–Time Tag
This bit is asserted when a Time Tag event occurs. The user acknowledges the Time Tag
event, and de-asserts this bit, by reading the tbreg_ttag_date. This bit might be set at power-on
reset; the user must clear this bit before using it.
4.3.9.7 Flag–Command Complete
This bit indicates that the board is ready to accept a new command in the tbreg_cmd[3:0]
register. Writing to tbreg_cmd[0] clears this bit. The board will assert it after processing the
command. The user must always check that this bit is asserted before sending a command.
4.3.9.8 Flag–Sync Change
This bit is asserted when Flag–Sync changes state, either from not in sync to in sync , or vice
versa. Writing (any value) resets it to tbreg_clrflag_sc.