vpx3224d ETC-unknow, vpx3224d Datasheet - Page 33

• Manufacturer Part Number: vpx3224d
• Description: Video Pixel Decoders
• Manufacturer: ETC-unknow

Micronas
PRELIMINARY DATA SHEET
2.13. VBI Data Acquisition
The VPX supports two different data acquisition modes
for the vertical blanking interval: a bypass mode for raw
data of the vertical blanking interval and a data slicer
mode in which dedicated hardware provides constant
packets of already decoded VBI-data. The data slicer
mode is only available on VPX 3225D.
For both services, the start and end line of a vertical
blanking interval (VBI) window can be defined for each
field with FP-RAM 0x134–137. Teletext data can occur
between lines 6 and 23 of each field. However, the VBI-
window is freely programmable. It is possible to select
the whole field (beginning with line #3). If video windows
are enabled, the VBI-window should end two lines be-
fore the first valid line of the next video window. The VBI-
window can be activated via bit[0] in FP-RAM 0x138.
The identification of valid VBI-lines is possible with the
VACT-signal (or the ‘active line’-flags in the modes with
embedded syncs) or a special ‘data active’ signal on the
TDO pin. Bit[10] of FP-RAM 0x154 selects between
these two cases. In the default mode, VACT is used. The
output of both signals can be suppressed optionally with
bit[2] of FP-RAM 0x138. In this case, the graphic control-
ler has to use only the HREF signal to mask the active
video data.
In the ITU-R656 mode, VBI-data can be transmitted as
vertical ancillary data (with 7 bit resolution + odd parity).
The selections for the VBI-window will be updated by
setting bit[11] in FP-RAM 0x138.
Luminance
(Port A)
Chrominance
(Port B)
VACT or TDO*
PIXCLK
LLC
* depending on bit[10] of FP-RAM 0x154
Fig. 2–36: Timing during lines with raw VBI-data (single clock mode)
D
D
2
1
2.13.1. Raw VBI Data
The raw data mode is enabled with bit[1] of FP-RAM
0x138 (vbimode). This mode bypasses the luminance
processing of the video front-end and delivers unmodi-
fied video samples from the ADC to the output ports.
During lines within the VBI-window, specified by the
user settings in the corresponding Load-Table, the VPX
internally acquires 1140 raw data bytes of the luminance
input at a rate of 20.25 MHz corresponding to 56.296 s
of the analog video (see Fig. 2–37). Chrominance data
is not valid. The raw data samples are multiplexed inter-
nally to 570x16 bit on the luminance and chrominance
port. The external timing corresponds to the video mode
with 570 output samples for an uncropped window.
Figure 2–36 shows the timing of both data ports and the
necessary reference signals in this mode.
Fig. 2–37: Horizontal dimensions of the window
for raw VBI-data
64 ms
VPX 3225D, VPX 3224D
D
D
1138
1137
1140 samples (56.296 ms)
active video
53.33 ms
D
D
1140
1139
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