TDA4688 Datasheet, PDF (8/24 Pages) NXP Semiconductors – Video processor with automatic cut-off control

Philips Semiconductors
Video processor with automatic cut-off control
Product specification
TDA4688
AUTO-INCREMENT
The auto-increment format enables quick slave receiver
initialization by one transmission, when the I²C-bus control
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 TDA4688 to address the
following parameters and functions (see Table 1):
• Brightness adjust
• Saturation adjust
• Contrast adjust
• Hue control voltage
• RGB gain adjust
• Peak drive limiting adjust
• Control register functions.
The data bytes D7 to D0 (see Table 1) provide the data of
the parameters and functions for video processing.
CONTROL REGISTER 1
NMEN (NTSC Matrix Enable):
0 = PAL/SECAM matrix
1 = NTSC matrix.
BREN (Buffer Register Enable):
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 I²C-bus receiver does not accept any new data until
this data is transferred into the data registers.
SC5 (SandCastle 5 V):
0 = 3-level sandcastle pulse
1 = 2-level (5 V) sandcastle pulse.
CONTROL REGISTER 2
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 FSW₂ and FSW₁:
• FSON2 has priority over FSON1
• FSW₂ has priority over FSW₁
• FSDIS1 and FSDIS2 disable FSW₁ and FSW₂
(see Table 2).
BCOF (Black level Control Off):
0 = automatic cut-off control enabled
1 = automatic cut-off control disabled; RGB outputs are
clamped to fixed DC levels.
CONTROL REGISTER 3
MOD2 (output clamp MODe2):
0 = inactive
1 = output clamping, but brightness inactive.
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.
1997 Jun 23
8