TDA4687 Philips Semiconductors, TDA4687 Datasheet - Page 8

• Manufacturer Part Number: TDA4687
• Description: Video processor with automatic cut-off control
• Manufacturer: Philips Semiconductors

Philips Semiconductors
A
The auto-increment format enables quick slave receiver
initialization by one transmission, when the I
bit BREN = 0 (see control register bits of Table 1).
If BREN = 1 auto-increment is not possible.
If the auto-increment format is selected, the MAD byte is
followed by a SAD byte and by the data bytes of
consecutive subaddresses (see Fig.5).
All subaddresses from 00H to 0FH are automatically
incremented, the subaddress counter wraps round from
0FH to 00H. Reserved subaddresses 07H, 08H, 09H,
0BH and 0FH are treated as legal but have no effect.
Subaddresses outside the range 00H and 0FH are not
acknowledged by the device.
Subaddresses are stored in the TDA4687 to address the
following parameters and functions (see Table 1):
The data bytes D7 to D0 (see Table 1) provide the data of
the parameters and functions for video processing.
C
NMEN (NTSC Matrix Enable):
BREN (Buffer Register Enable):
SC5 (SandCastle 5 V):
1997 Jun 23
UTO
ONTROL REGISTER
Brightness adjust
Saturation adjust
Contrast adjust
Hue control voltage
RGB gain adjust
Peak drive limiting adjust
Control register functions.
0 = PAL/SECAM matrix
1 = NTSC matrix.
0 = new data is executed as soon as it is received
1 = data is stored in buffer registers and is transferred to
the data registers during the next vertical blanking
interval.
The I
this data is transferred into the data registers.
0 = 3-level sandcastle pulse
1 = 2-level (5 V) sandcastle pulse.
Video processor with automatic cut-off control
-
INCREMENT
2
C-bus receiver does not accept any new data until
1
2
C-bus control
8
C
FSON2 (Fast Switch 2 ON).
FSDIS2 (Fast Switch 2 Disable).
FSON1 (Fast Switch 1 ON).
FSDIS1 (Fast Switch 1 Disable).
The RGB input signals are selected by FSON2 and
FSON1 or FSW
BCOF (Black level Control Off):
C
MOD2 (output clamp MODe2)
When MOD2 = 1 and BCOF = 1 output clamp is enabled
and brightness adjust is disabled (for clamping purposes
of following RGB receivers).
(BCOF = 0) AND (MOD2 = 1); from the description given
above the influence on the clamping stage is contradictory.
Consequently, there is no purpose to this combination and
it makes no sense to switch this combination.
When the supply voltage has dropped below
approximately 6.0 V (usually occurs when the TV receiver
is switched on or the supply voltage is interrupted) all data
and function bits are set to 01H.
ONTROL REGISTER
ONTROL REGISTER
FSON2 has priority over FSON1
FSW
FSDIS1 and FSDIS2 disable FSW
(see Table 2).
0 = automatic cut-off control enabled
1 = automatic cut-off control disabled; RGB outputs are
clamped to fixed DC levels.
0 = inactive
1 = output clamping, but brightness inactive.
2
has priority over FSW
2
and FSW
2
3
1
:
1
1
Product specification
and FSW
TDA4687
2