GS2961A Datasheet, PDF (69/104 Pages) Gennum Corporation – Ancillary data extraction

in the VIDEO_ERROR_STAT_X register is set HIGH. If an error condition in the C channel
is detected, the CCS_ERR bit in the VIDEO_ERROR_STAT_X register is set HIGH.
When operating in 3G Level A mode, the device makes comparisons on both the Y (Data
Stream 1) and C (Data Stream 2) channels separately. If an error condition in the Y
channel is detected, the YCS_ERR bit in the VIDEO_ERROR_STAT_X register is set HIGH.
If an error condition in the C channel is detected, the CCS_ERR bit in the
VIDEO_ERROR_STAT_X register is set HIGH.
When operating in 3G Level B mode, the device makes comparisons on both the Y
channel and the C channel of both Link A and Link B.
When operating in SD mode, only the YCS_ERR bit is set HIGH when checksum errors
are detected.
4.17.3.1 Programmable Ancillary Data Checksum Calculation
As described above, the GS2961A 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 GS2961A only checks ancillary data checksums for the
specified data types, ignoring all other ancillary data.
The YCS_ERR and/or CCS_ERR bits in the VIDEO_ERROR_STAT_X register are only set
HIGH if an error condition is detected for the programmed ancillary data types.
4.17.4 Video Standard Error
If a mismatch between the received SMPTE 352M packets and the calculated video
standard occurs, the GS2961A indicates a video standard error by setting the
VD_STD_ERR bit of the VIDEO_ERROR_STAT_X register HIGH.
The device detects the SMPTE 352M Packet version as defined in the SMPTE 352M
standard. If the incoming packet is Version Zero, then no comparison is made with the
internally generated payload information and the VD_STD_ERR bit is not set HIGH.
NOTE 1: If the received SMPTE 352M packet indicates 25, 30 or 29.97PsF formats, the
device only indicates an error when the video format is actually progressive. The device
detects 24 and 23.98PsF video standards and perform error checking at these rates.
NOTE 2: The VD_STD_ERR bit should be ignored in all 3G modes.
NOTE 3: VD_STD_ERR_DS1 is set incorrectly for a 1920x1080/PsF/24 payload ID. To
resolve this issue, choose one of the two methods.
• Set the VD_STD_ERR_DS1 mask bit high in the ERROR_MASK_1 register to avoid
having incorrect assertion of the DATA_ERROR pin.
• Monitor the received SMPTE ST0352 packet in the VIDEO_FORMAT_352_A_1 and
VIDEO_FORMAT_352_B_1 registers and compare that to the video format
identified in the VD_STD_DS1 bits in the DATA_FORMAT_DS1 register. Then, make
the determination of whether or not there is a mismatch on their own.
GS2961A 3Gb/s, HD, SD SDI Integrated Receiver
Data Sheet
54385 - 2
September 2012
69 of 104