GS2961A Datasheet, PDF (64/104 Pages) Gennum Corporation – Ancillary data extraction

These calculated CRC values are compared with the received CRC values.
If a mismatch in the calculated and received CRC values is detected for Y channel data
(Data Stream 1 for 3G video), the YCRC_ERR bit in the ERROR_STAT_X register is set
HIGH.
If a mismatch in the calculated and received CRC values is detected for C channel data
(Data Stream 2 for 3G video), the CCRC_ERR bit in the ERROR_STAT_X register is set
HIGH.
Y or C CRC errors are also generated if CRC values are not embedded.
Line based CRC errors are only generated when the device is operating in HD and 3G
modes.
NOTE: By default, 8-bit to 10-bit TRS remapping is enabled. If an 8-bit input is used, the
HD CRC check is based on the 10-bit remapped value, not the 8-bit value, so the CRC
Error Flag is incorrectly asserted and should be ignored. If 8-bit to 10-bit remapping is
enabled, then CRC correction and insertion should be enabled by setting the
CRC_INS_MASK bit in the IOPROC_DISABLE register LOW. This ensures that the CRC
values are updated.
4.16.3 EDH CRC Error Detection
The GS2961A also calculates Full Field (FF) and Active Picture (AP) CRC's according to
SMPTE RP165 in support of Error Detection and Handling packets in SD signals.
These calculated CRC values are compared with the received CRC values.
Error flags for AP and FF CRC errors are provided and each error flag is a logical OR of
field 1 and field 2 error conditions.
The AP_CRC_ERR bit in the VIDEO_ERROR_STAT_X register is set HIGH when an Active
Picture CRC mismatch has been detected in field 1 or 2.
The FF_CRC_ERR bit in the VIDEO_ERROR_STAT_X register is set HIGH when a Full
Field CRC mismatch has been detected in field 1 or 2.
EDH CRC errors are only indicated when the device is operating in SD mode and when
the device has correctly received EDH packets.
4.16.4 HD & 3G Line Number Error Detection
If a mismatch in the calculated and received line numbers is detected, the LNUM_ERR
bit in the VIDEO_ERROR_STAT_X register is set HIGH.
GS2961A 3Gb/s, HD, SD SDI Integrated Receiver
Data Sheet
54385 - 2
September 2012
64 of 104