GS2960A Datasheet, PDF (59/99 Pages) Gennum Corporation – Ancillary data extraction

Each bit of each ERROR_MASK register corresponds to a unique error type.
By default (at power up or after system reset), all bits of the ERROR_MASK registers are
zero, enabling all errors to be reported. Individual error detection may be disabled by
setting the corresponding bit HIGH in the mask registers.
Error conditions are indicated by a DATA_ERROR signal, which is also available on the
multifunction I/O pins. This signal is normally HIGH, but is set LOW by the device when
an error condition has been detected.
This signal is a logical 'NOR' of the appropriate error status flags stored in the
ERROR_STAT_X register, which are gated by the bit settings in the ERROR_MASK
registers. When an error status bit is HIGH and the corresponding error mask bit is LOW,
the corresponding DATA_ERROR signal is set LOW by the device.
The ERROR_STAT_X registers, and correspondingly the DATA_ERROR signal, are
cleared at the start of the next video field or when read via the host interface, which ever
condition occurs first.
All bits of the ERROR_STAT_X registers are also cleared under any of the following
conditions:
1. LOCKED signal = LOW.
2. SMPTE_BYPASS = LOW.
3. When a change in video standard has been detected.
4. RESET_TRST = LOW
Table 4-12 shows the ERROR_STAT_X register and ERROR_MASK_X register.
NOTE: Since the error indication registers are cleared once per field, if an external host
micro is polling the error registers periodically, an error flag may be missed if it is
intermittent, and the polling frequency is less than the field rate.
Table 4-12: Error Status Register and Error Mask Register
Video Error Status Register
SAV_ERR (02h, 03h)
EAV_ERR (02h, 03h)
YCRC_ERR (02h, 03h)
CCRC_ERR (02h, 03h)
LNUM_ERR (02h, 03h)
YCS_ERR (02h, 03h)
CCS_ERR (02h, 03h)
AP_CRC_ERR (02h)
FF_CRC_ERR (02h)
VD_STD_ERR (02h, 03h)
Video Error Mask Register
SAV_ERR_MASK (037h, 038h)
EAV_ERR_MASK (037h, 038h)
YCRC_ERR_MASK (037h, 038h)
CCRC_ERR_MASK (037h, 038h)
LNUM_ERR_MASK (037h, 038h)
YCS_ERR_MASK (037h, 038h)
CCS_ERR_MASK (037h, 038h)
AP_CRC_ERR_MASK (037h)
FF_CRC_ERR_MASK (037h)
VD_STD_ERR_MASK (037h)
GS2960A 3Gb/s, HD, SD SDI Receiver
Data Sheet
54384 - 2
September 2012
59 of 99