• For signal source selection and formats
• For task handling and trigger conditions
• For input and output acquisition window definition
• For H-prescaler, V-scaler and H-phase scaling.
Raw VBI-data is handled as specific input format and needs its own programming page (equals own task).
In VBI pass through operation the processing of prescaler and vertical scaling has to be set to no-processing, however,
the horizontal fine scaling VPD can be activated. Upscaling (oversampling, zooming), free of frequency folding, up to a
factor of 3.5 can be achieved, as required by some software data slicing algorithms.
These raw samples are transported through the image port as valid data and can be output as Y only format. Also this
Y only lines can be framed by SAV and EAV codes.
8.3.1 ACQUISITION CONTROL AND TASK HANDLING (SUBADDRESSES 80H, 90H, 91H, 94H TO 9FH AND C4H TO CFH)
The acquisition control receives horizontal and vertical synchronization signals from the decoder section or from the
X-port. The acquisition window is generated via pixel and line counters at the appropriate places in the data path. From
X-port only qualified pixels and lines (lines with qualified pixel) are counted.
The acquisition window parameters are as follows:
• Signal source selection regarding input video stream and formats from the decoder, or from X-port (programming bits
SCSRC[1:0] 91H[5:4] and FSC[2:0] 91H[2:0])
Remark: The input of raw VBI-data from the internal decoder need to be controlled via the decoder output formatter
and the LCR registers (see Section 8.2)
• Vertical offset defined in lines of the video source, parameter YO[11:0] 99H[3:0] 98H[7:0]
• Vertical length defined in lines of the video source, parameter YS[11:0] 9BH[3:0] 9AH[7:0]
• Vertical length defined in number of target lines, as a result of vertical scaling, parameter YD[11:0] 9FH[3:0] 9EH[7:0]
• Horizontal offset defined in number of pixels of the video source, parameter XO[11:0] 95H[3:0] 94H[7:0]
• Horizontal length defined in number of pixels of the video source, parameter XS[11:0] 97H[3:0] 96H[7:0]
• Horizontal destination size, defined in target pixels after fine scaling, parameter XD[11:0] 9DH[3:0] 9CH[7:0].
The source start offset (XO11 to XO0 and YO11 to YO0) opens the acquisition window, and the target size
(XD11 to XD0, YD11 to YD0) closes the window, but the window is cut vertically, if there are less output lines than
expected. The trigger events for the pixel and line counts are the horizontal and vertical reference edges as defined in
The task handling is controlled by subaddress 80H and 90H (see Section 126.96.36.199).
To support instable non standard input signals, different operational modes are implemented (bits CMOD and FMOD).
188.8.131.52 Input ﬁeld processing
The scaler directly gets a corresponding field ID information from the SAA7115 decoder path.
If switched to the X-port, the trigger event for the field sequence detection from external signals (X-port) are defined in
subaddress 92H. From the X-port the state of the scalers H-reference signal at the time of the V-reference edge is taken
as field sequence identifier FID. For example, if the falling edge of the XRV input signal is the reference and the state of
XRH input is logic 0 at that time, the detected field ID is logic 0.
The bits XFDV[92H] and XFDH[92H] define the detection event and state of the flag from the X-port. For the default
setting of XFDV and XFDH at ‘00’ the state of the H-input at the falling edge of the V-input is taken.
Conﬁdential - NDA required
Last edited by H. Lambers