Datasheet

ADV7342/ADV7343 Data Sheet
Rev. | Page 60 of 108
To ad d a –7 IRE brightness level to a PAL signal, write 0x72 to
Subaddress 0xA1.
0 × (SD Brightness Value) =
0 × (IRE Value × 2.075631) =
0 × (7 × 2.015631) = 0x(14.109417) ≈ 0001110b
0001110b into twos complement = 1110010b = 0x72
Table 50. Sample Brightness Control Values
1
Setup Level
(NTSC) with
Pedestal
Setup Level
(NTSC) Without
Pedestal
Setup
Level
(PAL)
Brightness
Control Value
22.5 IRE 15 IRE 15 IRE 0x1E
15 IRE
7.5 IRE
7.5 IRE
0x0F
7.5 IRE 0 IRE 0 IRE 0x00
0 IRE −7.5 IRE −7.5 IRE 0x71
1
Values in the range of 0x3F to 0x44 may result in an invalid output signal.
SD INPUT STANDARD AUTODETECTION
Subaddress 0x87, Bit 5
The ADV7342/ADV7343 include an SD input standard
autodetect feature. This SD feature can be enabled by setting
Subaddress 0x87, Bits[5:1].
When enabled, the ADV7342/ADV7343 can automatically
identify an NTSC or a PAL B/D/G/H/I input stream. The
ADV7342/ADV7343 automatically update the subcarrier
frequency registers with the appropriate value for the identified
standard. The ADV7342/ADV7343 are also configured to
correctly encode the identified standard.
The SD standard bits (Subaddress 0x80, Bits[1:0]) and the
subcarrier frequency registers are not updated to reflect the
identified standard. All registers retain their default or user-
defined values.
NTSC WITHOUT PEDESTAL
NO SETUP
VALUE ADDED
POSITIVE SETUP
VALUE ADDED
100 IRE
0 IRE
NEGATIVE SETUP
VALUE ADDED
–7.5 IRE
+7.5 IRE
06399-069
Figure 65. Examples of Brightness Control Values
D