TDA4687 Philips Semiconductors, TDA4687 Datasheet - Page 6

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

Philips Semiconductors
I
Control
The I
and adjust the following functions and parameters:
I
I
The I
intercommunication between ICs in an equipment.
The microcontroller transmits data to the I
in the TDA4687 over the serial data line SDA (pin 27)
synchronized by the serial clock line SCL (pin 28). Both
lines are normally connected to a positive voltage supply
through pull-up resistors. Data is transferred when the
SCL line is LOW. When SCL is HIGH the serial data line
SDA must be stable. A HIGH-to-LOW transition of the SDA
line when SCL is HIGH is defined as a START bit.
A LOW-to-HIGH transition of the SDA line when SCL is
HIGH is defined as a STOP bit.
Each transmission must start with a START bit and end
with a STOP bit. The bus is busy after a START bit and is
only free again after a STOP bit has been transmitted.
1997 Jun 23
2
2
2
C-BUS PROTOCOL
C-bus transmitter and data transfer
C-
Brightness adjust
Saturation adjust
Contrast adjust
DC output e.g. for hue control
RGB gain adjust
Peak drive limiting level adjust
Selects either 3-level or 2-level (5 V) sandcastle pulse
Enables cut-off control; enables output clamping
(2 different modes)
Selects either PAL/SECAM or NTSC matrix
Enables/disables synchronization of the execution of
I
Enables Y/CD, RGB
Video processor with automatic cut-off control
2
C-bus commands with the vertical blanking interval
BUS SPECIFICATION
2
2
C-bus is a bidirectional, two-wire, serial data bus for
C-bus transmitter provides the data bytes to select
1
or RGB
2
input.
2
C-bus receiver
6
I
Each transmission to the I
least three bytes following the START bit. Each byte is
acknowledged by an acknowledge bit immediately
following each byte. The first byte is the Module Address
(MAD) byte, also called slave address byte. This includes
the module address, 1000100 for the TDA4687.
The TDA4687 is a slave receiver (R/W = 0), therefore the
module address byte is 10001000 (88H; see also Fig.3).
The length of a data transmission is unrestricted, but the
module address and the correct subaddress must be
transmitted before the data byte(s). The order of data
transmission is shown in Figs 4 and 5.
Without auto-increment (BREN = 0 or 1) the module
address (MAD) byte is followed by a SubAddress (SAD)
byte and one data byte only (see Fig.4).
2
C-
BUS RECEIVER
(
MICROCONTROLLER WRITE MODE
2
C-bus receiver consists of at
Product specification
TDA4687
)