GS2970A Datasheet, PDF (79/150 Pages) Gennum Corporation – Integrated audio clock generator

Internal Write
Pointer
Bank A
0
800h
Application Layer
Read Pointer
Bank B
0 ANCDATA
ANC DATA
ANC DATA
ANC DATA
ANC DATA
ANC DATA
ANC DATA
ANC DATA
ANC DATA
800h
1023
BFFh
1023
BFFh
ANC_DATA_SWITCH = HIGH
Figure 4-34:Ancillary Data Extraction - Step D
Toggling the ANC_DATA_SWITCH bit LOW returns the process to step A (Figure 4-31).
NOTE 1: Toggling the ANC_DATA_SWITCH must occur at a time when no extraction is
taking place, i.e. when the both the Y/1ANC and C/2ANC signals are LOW.
To turn extraction off, the ANC_DATA_EXT_MASK bit must be set HIGH.
In HD mode, the device can detect ancillary data packets in the Luma video data only,
Chroma video data only, or both. By default (at power-up or after a system reset) the
device extracts ancillary data packets from the luma channel only.
In 3G mode Level A, the device can detect ancillary data packets in Luma video (Data
Stream One) only, Chroma video (Data Stream Two) only, or both. By default (at
power-up or after a system reset) the device extracts ancillary data packets from Data
Stream One only.
In 3G mode Level B mode, the device can detect ancillary data packets in Luma video
only, Chroma video only, or both from either Link A or Link B. Selection of Link A or Link
B for ANC data extraction is done via the host interface. By default (at power-up or after
a system reset) the device extracts ancillary data packets from Link A Luma only.
To extract packets from the Chroma/Data Stream Two channel only, the HD_ANC_C2
bit of the host interface must be set HIGH. To extract packets from both Luma/Data
Stream One and Chroma/Data Stream Two video data, the HD_ANC_Y1_C2 bit must be
set HIGH (the setting of the HD_ANC_C2 bit is ignored).
The default setting of both the HD_ANC_C2 and HD_ANC_Y1_C2 is LOW. The setting of
these bits is ignored when the device is configured for SD video standards.
GS2970A 3Gb/s, HD, SD SDI Receiver
Data Sheet
54244 - 2
September 2012
79 of 150