GS3470 datasheet(61/169 Pages) SEMTECH

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GS3470

Final Data Sheet

Rev.8

PDS-060500

September 2017

61 of 169

Semtech

www.semtech.com

4.17.1 Programmable Ancillary Data Detection

As described above in Section 4.17, the GS3470 detects and indicates all ancillary data

types by default.

Up to 5 different ancillary data types may be programmed for detection in the

ANC_TYPE_[5:1]_DS[2:1] register for SD, HD, and 3G Level A. When these are

programmed, the GS3470 only indicates the presence of the specified ancillary data

types, ignoring all other types. For each data type to be detected, the user must

program the DID and/or SDID of that ancillary data type. If no DID or SDID values are

programmed, the GS3470 indicates the presence of all ancillary data.

For any DID or SDID value set to zero, no comparison or match is made. For example, if

the DID is programmed and the SDID is not programmed, the GS3470 only detects a

match to the DID value.

If both DID and SDID values are non-zero, then the received ancillary data type must

match both the DID and SDID before Y/1ANC and/or C/2ANC is set HIGH.

Note 1: For 3G Level B data, the ANC_TYPE_[5:1]_DS1 registers are valid for Data

Stream 1, and a second set of ANC_TYPE_[5:1]_DS2 is provided for detection of specific

ancillary data in Data Stream 2.

Note 2: SMPTE ST 352 Payload Identifier packets and Error Detection and Handling

(EDH) Packets are always detected by the GS3470, regardless of the settings of the

ANC_TYPE_[5:1]_DS1 registers and cannot be overridden.

4.17.1.1 Programmable Ancillary Data Checksum Calculation

As described above, the GS3470 calculates and compares checksum values for all

ancillary data types by default. It is possible to program which ancillary data types are

checked as described in Section 4.17.1.

When so programmed, the GS3470 only checks ancillary data checksums for the

specified data types, ignoring all other ancillary data.

The YCS_ERR_[2:1] and/or CCS_ERR_[2:1] bits in the ERROR_STAT_[2:1] register are

only set HIGH if an error condition is detected for the programmed ancillary data types.

4.17.2 SMPTE ST 352 Payload Identifier

The SMPTE ST 352 Payload Identifier is used to confirm the video format identified by

the Automatic Video Standards Detection block.

Information contained in the packet is outlined in Table 4-13.

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