GS1559-CBE2 Gennum Corp., GS1559-CBE2 Datasheet - Page 59

• Manufacturer Part Number: GS1559-CBE2
• Description: HD-LINX II Multi-Rate Deserializer with Loop-Through Cable Driver
• Manufacturer: Gennum Corp.

GS1559 Preliminary Data Sheet
4.10.7 EDH Flag Detection
As described in
Section
4.10.5.2, the GS1559 can detect EDH packets in the
received data stream. The EDH flags for ancillary data, active picture and full field
areas are extracted from the detected EDH packets and placed in the EDH_FLAG
register of the device
(Table
4-15).
One set of flags is provided for both fields 1 and 2. Field 1 flag data will be
overwritten by field 2 flag data.
The EDH_FLAG register may be read by the host interface at any time during the
received frame except on the lines defined in SMPTE RP165 where these flags are
updated.
NOTE 1: By programming the ANC_TYPE1 register (005h) with the DID word for
EDH ancillary packets, the application layer may detect a high-to-low transition on
either the YANC or CANC output pin of the GS1559 to determine (a) when EDH
packets have been received by the device, and (b) when the EDH_FLAG register
can be read by the host interface. See
Section 4.10.2
for more information on
ancillary data detection and indication.
NOTE 2: The bits of the EDH_FLAG register are sticky and will not be cleared by
a read operation. If the GS1559 is decoding a source containing EDH packets,
where EDH flags may be set, and the source is replaced by one without EDH
packets, the EDH_FLAG register will not be cleared.
NOTE 3: The GS1559 will detect EDH flags, but will not update the flags if an EDH
CRC error is detected. Gennum's GS1532 Multi-Rate Serializer allows the host to
individually set EDH flags.
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