
GS9092A Data Sheet
34715 - 0
February 2006
29 of 59
Once the above steps are completed, the application layer may set the
ANC_PKT_INS bit of the IOPROC_DISABLE register HIGH (see
Table 3-4
in
Packet Generation and Insertion on page 35
) to enable insertion of the prepared
ancillary packets into the video data stream. Ancillary data packets will be inserted
in the following frame after the ANC_PKT_INS bit has been set HIGH.
NOTE: When inserting ancillary data into the blanking region, the total number of
words cannot exceed the size of the blanking region, and the data count value in
the packet must be correct.
3.3.3.1 Ancillary Data Insertion
Once the ANC_PKT_INS bit is set HIGH, the device will start reading the user
programmed ancillary packets out of the FIFO and insert them into the video
stream. Subsequent ancillary packets programmed by the application layer will
continue to be placed into the first half of the FIFO until the ANC_DATA_SWITCH
bit is toggled (see block A of
Figure 3-7
).
By default, the ANC_DATA_SWITCH bit of the IO_CONFIG register is set LOW.
When ANC_DATA_SWITCH is toggled from LOW to HIGH, any new ancillary data
the application layer programs will be placed in the second half of the FIFO. The
device will continue to insert ancillary data from the first half of the FIFO into the
video stream (see block B of
Figure 3-7
).
Once the ancillary data in the first half of the FIFO has been inserted into the video
stream, ANC_DATA_SWITCH may be toggled again. This will clear the first half of
the FIFO and begin insertion of ancillary data from the second half of the FIFO. The
application layer may continue programming ancillary data into the second half of
the FIFO (see block C of
Figure 3-7
).
If the ANC_DATA_SWITCH bit is toggled again, any new data the application layer
programs will be placed into the first half of the FIFO. The device will continue to
insert ancillary data from the second half of the FIFO into the video stream (see
block D of
Figure 3-7
).
Toggling ANC_DATA_SWITCH again will clear the second half of the FIFO and
restore the read and write pointers to the situation shown in block A. The switching
process (shown in blocks A to D in
Figure 3-7
) will continue with each toggle of the
ANC_DATA_SWITCH bit.
NOTE: At least 1100 PCLK cycles (41us) must pass between toggles of the
ANC_DATA_SWITCH bit.
The GS9092A will insert the ancillary data programmed in the FIFO into each video
frame at the designated line(s) programmed in ANC_LINE_A[10:0] and/or
ANC_LINE_B[10:0].
Clearing the ANC_PKT_INS bit will not automatically disable ancillary data
insertion. To disable ancillary data insertion, switch the FIFO into bypass mode by
setting FIFO_MODE[1:0] = 11b. 2200 PCLK cycles after the device re-enters
ancillary data insertion mode, data extraction will commence immediately if
ANC_PKT_INS is HIGH.