2004 Mar 16
64
Philips Semiconductors
Product specification
PC-CODEC
SAA7108E; SAA7109E
9.2
Decoder output formatter
The output interface block of the decoder part contains the
ITU 656 formatter for the expansion port data output
XPD7 to XPD0 (see Section 10.4.1) and the control circuit
for the signals needed for the internal paths to the scaler
and data slicer part. It also controls the selection of the
reference signals for the RT port (RTCO, RTS0 and
RTS1) and the expansion port (XRH, XRV and XDQ).
The generation of the decoder data type control signals
SET_RAW and SET VBI is also done within this block.
These signals are decoded from the requested data type
for the scaler input and/or the data slicer, selectable by the
control registers LCR2 to LCR24 (see Section 18.2.4.2).
For each LCR value, from 2 to 23, the data type can be
programmed individually. LCR2 to LCR23 refer to line
numbers. The selection in LCR24 values is valid for the
rest of the corresponding field. The upper nibble contains
the value for field 1 (odd), the lower nibble for field 2
(even). The relationship between LCR values and line
numbers can be adjusted via VOFF8 to VOFF0, located in
subaddresses 5BH (bit 4) and 5AH (bits 7 to 0) and FOFF
subaddress 5BH (bit 7). The recommended values are
VOFF[8:0] = 03H for 50 Hz sources (with FOFF = 0) and
VOFF[8:0] = 06H for 60 Hz sources (with FOFF = 1), to
accommodate line number conventions as used for PAL,
SECAM and NTSC standards; see Tables 34 to 37.
Table 33
Data formats at decoder output
DATA TYPE NUMBER
DATA TYPE
DECODER OUTPUT DATA FORMAT
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
teletext EuroWST, CCST
European Closed Caption
Video Programming Service (VPS)
Wide screen signalling bits
US teletext (WST)
US Closed Caption (line 21)
video component signal, VBI region
CVBS data
teletext
VITC/EBU time codes (Europe)
VITC/SMPTE time codes (USA)
reserved
US NABTS
MOJI (Japanese)
Japanese format switch (L20/22)
video component signal, active video region
raw
raw
raw
raw
raw
raw
Y-C
B
-C
R
4 : 2 : 2
raw
raw
raw
raw
raw
raw
raw
raw
Y-C
B
-C
R
4 : 2 : 2