Philips FTP1.1E Service Manual page 39

Circuit Descriptions, Abbreviation List, and IC Data Sheets
Note: The SCART input (1fH) path is equal to the one
described in the EM6E manual. Therefore, it is not described in
much detail here.
9.4.2
Input detection
The RGB or YPbPr input signals (2fH/3fH) are sent to the ADC
(AD9883A) together with H and V pulses from DVI (USA) or
VGA (EUR), and the Y signal from YPbPr called Sync On
Green (green is same line as Y). The AD converter:
•
Detects via H and V sync, if RGB is present or not.
•
Detects via Sync On Green, if YPbPr is present or not.
•
Detects the selected sync.
•
Selects the sync switch via I2C.
•
Does AD conversion to 848 samples per line, 8 bits in 422
format. This means one bus for Y signal with 8 bits and one
bus for UV with 4 U and 4 V bits. Depending on the system
detected by EBILD, the sample frequency is changed. Via
I2C, the "PLL_DIV" signal is given in 11 bits (2 Bytes).
When a 1fH input is detected, the AD converter is set in tristate.
1fH input flow
1Fh selection
Figure 9-4 Flowchart 1fH detection
1. If a 1fH selection is done (except for AV4 in USA), the
sound is muted and the picture is blanked.
2. The ADC is powered down.
3. The PICNIC is not in free run.
4. Both FBX and EBILD are set in 1fH (see lookup table).
5. Sound is demuted and picture is unblanked.
START
Mute sound, Blank picture
Put ADC: power down
Put PICNIC: freerun OFF
Set FBX, see lookup table
Set EBILD, see lookup table
Demute sound, Unblank picture
1FH
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FTP1.1E 9. EN 99