2004 Jun 29
74
Philips Semiconductors
Product specification
HD-CODEC
SAA7108AE; SAA7109AE
9.5.5
D
ATA STREAM CODING AND REFERENCE SIGNAL
GENERATION
(
SUBADDRESSES
84H, 85H
AND
93H)
As horizontal and vertical reference signals are logic 1,
activegatesignalsaregenerated,whichframethetransfer
of the valid output data. Alternatively, the horizontal and
vertical trigger pulses can be generated on the rising
edges of the gates.
Due to the dynamic FIFO behaviour of the complete scaler
path, the output signal timing has no fixed timing
relationship to the real-time input video stream. Thus fixed
propagation delays, in terms of clock cycles, related to the
analog input can not be defined.
The data stream is accompanied by a data qualifier.
Additionally invalid data cycles are marked with code 00H.
If ITU 656 like codes are not required, they can be
suppressed in the output stream.
As a further option, it is possible to provide the scaler with
an external gating signal on pin ITRDY. It is therefore
possible to hold the data output for a certain time and to
get valid output data in bursts of a guaranteed length.
The sketched reference signals and events can be
mapped to the I port output pins IDQ, IGPH, IGPV, IGP0
and IGP1. The polarities of all the outputs can be modified
to enable flexible use. The default polarity for the qualifier
and reference signals is logic 1 (active).
Table 32 shows the relevant and supported SAV and EAV
coding.
Table 32
SAV/EAV codes on the I port
Notes
1.
2.
The leading byte sequence is: FFH-00H-00H.
The MSB of the SAV/EAV code byte is controlled by:
a) Scaler output data: task A
MSB = CONLH[90H[7]]; task B
MSB = CONLH[C0H[7]].
b) VBI data slicer output data: DID[5:0] 5DH[5:0] = 3EH
MSB = 1; DID[5:0] 5DH[5:0] = 3FH
MSB = 0.
EVENT DESCRIPTION
SAV/EAV CODES ON I PORT
(1)
(HEX)
COMMENT
MSB
(2)
OF SAV/EAV BYTE = 0 MSB
(2)
OF SAV/EAV BYTE = 1
FIELD ID = 0
FIELD ID = 1
FIELD ID = 0
FIELD ID = 1
Next pixel is FIRST pixel of any
active line
Previous pixel was LAST pixel
of any active line, but not the
last
Next pixel is FIRST pixel of any
V-blanking line
Previous pixel was LAST pixel
of the last active line or of any
V-blanking line
No valid data, do not capture
and do not increment pointer
0E
49
80
C7
HREF = active;
VREF = active
HREF = inactive;
VREF = active
13
54
9D
DA
25
62
AB
EC
HREF = active;
VREF = inactive
HREF = inactive;
VREF = inactive
38
7F
B6
F1
00
IDQ pin inactive