TEA6845AH Просмотр технического описания (PDF) - Philips Electronics

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TEA6845AH

New In Car Entertainment (NICE) car radio

Philips Electronics 

Philips Semiconductors

New In Car Entertainment (NICE) car radio

Product specification

TEA6845AH; TEA6845H

12 I2C-BUS PROTOCOL

12.1 I2C-bus specification

Information about the I2C-bus can be found in the brochure

“The I2C-bus and how to use it” (order number

9398 393 40011).

The standard I2C-bus specification is expanded by the

following definitions.

IC addresses:

• 1st IC address C2: 1100001

• 2nd IC address C0: 1100000.

Structure of the I2C-bus logic: slave transceiver with auto

increment.

Subaddresses are not used.

12.1.1 TEST MODE

Connecting pin fref to VDDA1 via a 100 kΩ resistor or

feeding 50 µA into that pin switches the IC into the test

mode.

During test mode the digital-to-analog converters of the

level and antenna DAA functions can be sequenced by the

I2C-bus SCL line.

During test mode either the TEA6880H or TEF6890H

reference frequency, the PLL reference frequency divider

or the programmable divider output can be switched to

pin fref.

12.1.3 I2C-bus pULL-UP RESISTORS

When the IC is used together with the TEA6880H or

TEF6890H and both SCL and SDA lines are connected via

the I2C-bus to the TEA6880H or TEF6890H, the pull-up

resistors of the tuner IC should be connected to the digital

supply voltage of the TEA6880H or TEF6890H. Otherwise

an I2C-bus pull-down can occur switching off the tuner IC

supply when the I2C-bus buffer interface of the TEA6880H

or TEF6890H is enabled for data transfer to the tuner IC.

12.1.4 FREQUENCY 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 I2C-bus transmissions are

necessary:

• First: bit MUTE = 1

• Second: bit MUTE = 0.

12.1.2 DATA TRANSFER FOR THE TEA6845

Data sequence: address, byte 1, byte 2, byte 3, byte 4,

byte 5, and byte 6. The data transfer has to be in this

order. The LSB = 0 indicates a WRITE operation to the

TEA6845.

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.

In byte 5, 4 bits are reserved for test mode purposes.

Those can only be used when the test mode is activated

by the select pin fref.

2001 Apr 12

28

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