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Filename:
SAA7115_Datasheet.fm
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page 63
Last edited by H. Lambers
Philips Semiconductors
CS-PD Hamburg
CVIP2
Datasheet
SAA7115
Date:
10/23/01
Version:
0.67
In Tables 15 and 16 PHO is a usable common phase offset.
It should be noted that the equations of Fig.30 produce an interpolated output, also for the unscaled case, as the
geometrical reference position ( R ) for all conversions is the position of the first line of the lower field (see Table 15).
If there is no need for UP-LO and LO-UP conversion and the input field ID is the reference for the back-end operation,
then it is UP-LO = UP-UP and LO-UP = LO-LO and the
1
2
line phase shift (PHO + 16) can be skipped.
This case is listed in Table 16.
The SAA7115 supports 4 phase offset registers per task and component (luminance and chrominance). The value of
20H represents a phase shift of one line.
The registers are assigned to the following events; e.g. subaddresses B8H to BBH:
B8H: 00 = input field ID 0, task status bit 0 (toggle status, see Section 8.3.1.3)
B9H: 01 = input field ID 0, task status bit 1
BAH: 10 = input field ID 1, task status bit 0
BBH: 11 = input field ID 1, task status bit 1.
Depending on the input signal (interlaced or non-interlaced) and the task processing 50 Hz or field reduced processing
with one or two tasks (see examples in Section 8.3.1.3), other combinations may also be possible, but the basic
equations are the same.
Table 15
Examples for vertical phase offset usage: global equations (referring to reference position R)
Table 16
Vertical phase offset usage; assignment of the phase offsets for OFIDC[90[6]] = 0,
scaler input field ID as output ID
Notes
1.
referring to the upper input field as reference position, a value of 16 is to be substracted from the global equations of
table 15.
INPUT FIELD UNDER
PROCESSING
OUTPUT FIELD
INTERPRETATION
USED ABBREVIATION
EQUATION FOR PHASE OFFSET
CALCULATION (DECIMAL VALUES)
Upper input lines
Upper input lines
upper output lines
lower output lines
UP-UP
UP-LO
PHO + 16
Lower input lines
Lower input lines
upper output lines
lower output lines
LO-UP
LO-LO
PHO
assumed backend interprets output field ID at “0” as upper output lines
detected input
field ID
task status bit
vertical phase
offset
equation to be used (values)
0 = upper lines
0 = upper lines
1 = lower lines
1 = lower lines
0
1
0
1
YPY(C)0
YPY(C)1
YPY(C)2
YPY(C)3
UP-UP (PHO)
UP-UP (PHO)
LO-LO (PHO + YSCY / 64 - 16)
LO-LO (PHO + YSCY / 64 - 16)
PHO
YSC64
16
+
+
PHO
YSC64
+