GS1560A/GS1561 Data Sheet
3.10.2 Ancillary Data Detection and Indication
The GS1560A/GS1561 will detect all types of ancillary data in either the vertical or
horizontal blanking spaces and indicate via the status signal output pins YANC and
CANC the position of ancillary data in the output data stream. These status signal
outputs are synchronous with PCLK and can be used as clock enables to external
logic, or as write enables to an external FIFO or other memory device.
When operating in HD mode, (SD/HD = LOW), the YANC signal will be HIGH
whenever ancillary data is detected in the luma data stream, and the CANC signal
will be HIGH whenever ancillary data is detected in the chroma data stream.
In SD mode, (SD/HD = HIGH), the YANC and CANC signal operation will depend
on the output data format. For 20-bit demultiplexed data, (see Parallel Data
Outputs on page 65), the YANC and CANC signals will operate independently.
However, for 10-bit multiplexed data, the YANC and CANC signals will both be
HIGH whenever ancillary data is detected.
The signals will be HIGH from the start of the ancillary data preamble and will
remain HIGH until after the ancillary data checksum.
The operation of the YANC and CANC signals is shown in Figure 3-6.
27360 - 8 September 2005
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