GS9092ACNE3 datasheet(33/63 Pages) GENNUM

33 / 63 page

GS9092A GenLINX® III 270Mb/s Serializer for SDI and

DVB-ASI

Data Sheet

34715 - 4

May 2010

33 of 63

When there are existing ancillary data packets present in the video data stream, the

device will append the ancillary data to the existing data only when the ANC_SAV bit is

set LOW. In this case, all existing ancillary data must be contiguous after the EAV. If data

is not contiguous, the ancillary data to be inserted will be written at the first available

space where the video is set to blanking levels. When ANC_SAV is set HIGH, any data

present after the SAV will be overwritten.

To overwrite existing ancillary data, the ANC_DATA_REPLACE bit of the

FIFO_EMPTY_OFFSET register must be set HIGH. When this bit is set HIGH, existing

ancillary data will be replaced with the data to be inserted and the remainder of the line

will be set to blanking levels. The device will replace ancillary data on the line of

insertion only. Existing ancillary data on other lines will not be replaced with blanking

levels.

NOTE: If the ANC_SAV and ANC_DATA_REPLACE bits are both set HIGH, and if

ancillary data is inserted on an active picture line, the remainder of the active line will

be set to blanking levels.

Ancillary Data Readback Mode

By default, when the FIFO is in ancillary data insertion mode, the application layer can

only write ancillary data into the FIFO. However, if ANC_DATA_RDBACK is set HIGH

(bit 13 of address 06h), the GS9092A will discontinue inserting ancillary data into the

data stream and the host interface may read the ancillary data programmed into that

half of the FIFO.

3.3.3.2 Clearing the ANC Data FIFO

When switching to ANC FIFO mode, the user must follow one of the 2 methods below to

ensure that the FIFO is fully cleared.

Clearing ANC FIFO Method 1:

1. Enable ANC FIFO mode (write 10b into the FIFO_MODE register).

2. Wait for ANC_FIFO_READY bit to be asserted.

3. Toggle (LOW-to-HIGH-to-LOW) ANC_DATA_SWITCH bit (bit 12 of IO_CONFIG

Clearing ANC FIFO Method 2:

1. Power on device.

2. Set FIFO_EN pin HIGH.

3. Enable ANC FIFO mode (write 10b into the FIFO_MODE register).

4. Set FIFO_EN pin LOW.

5. Set FIFO_EN pin HIGH.

GS9092ACNE3 Datasheet(PDF) 33 Page - Gennum Corporation