
2003 Dec 19
33
Philips Semiconductors
Product specification
New In Car Entertainment car radio tuner IC with
Precision Adjacent Channel Suppression (NICE-PACS)
TEA6849H
12 I
2
C-BUS PROTOCOL
12.1
I
2
C-bus specification
InformationabouttheI
2
C-buscanbefoundinthebrochure
“The I
2
C-bus and how to use it”(order number
9398 393 40011).
The standard I
2
C-bus specification is expanded by the
following definitions.
IC addresses:
1st IC address C2H: 1100001 R/W
2nd IC address C0H: 1100000 R/W.
Structure of the I
2
C-bus logic: slave transceiver with auto
increment.
Subaddresses are not used.
A second I
2
C-bus address can be selected by connecting
pin FREF via a 68 k
resistor to GND.
Exception to the standard I
2
C-bus specification:
The data hold time t
HD;DAT
must be at least 1
μ
s.
12.1.1
D
ATA TRANSFER
Data sequence: address, byte 0, byte 1, byte 2, byte 3,
byte 4, byte 5, byte 6, and byte 7. The data transfer has to
be in this order. The LSB = 0 indicates a WRITE operation
to the TEA6849H.
Bit 7 of each byte is considered the MSB and has to be
transferred as the first bit of the byte.
The data becomes valid at the output of the internal
latches with the acknowledge of each byte. A STOP
condition after any byte can shorten transmission times.
When writing to the transceiver by using the STOP
condition before completion of the whole transfer:
The remaining bytes will contain the old information
If the transfer of a byte is not completed, this byte is lost
and the previous information is available.
12.1.2
I
2
C-
BUS PULL
-
UP RESISTORS
When the IC is used together with the TEA688x or
TEF689x and both SCL and SDA lines are connected via
the I
2
C-bus to the TEA688x or TEF689x, the pull-up
resistors of the tuner IC should be connected to the digital
supply voltage of the TEA688x or TEF689x. Otherwise an
I
2
C-bus pull-down can occur switching off the tuner IC
supply when the I
2
C-bus buffer interface of the TEA688x
or TEF689x is enabled for data transfer to the tuner IC.
12.1.3
F
REQUENCY SETTING
For new frequency setting, in both AM and FM mode, the
programmable divider is enabled by setting bit MUTE = 1.
To select an FM frequency, two I
2
C-bus transmissions are
necessary:
First: bit MUTE = 1
Second: bit MUTE = 0.
12.1.4
D
EFAULT SETTINGS
No default settings at power-on reset.
One I
2
C-bus
transmission is required to program the IC.