TEF6902A datasheet(21/106 Pages) NXP

21 / 106 page

TEF6902A_3

Product data sheet

Rev. 03 — 19 March 2008

21 of 106

NXP Semiconductors

TEF6902A

Integrated car radio

8.1.7 Read mode: data byte TEMP

8.2 Write mode

The device is controlled by the I2C-bus. After the Integrated Circuit (IC) address the MSA

byte contains the control of the tuning action via the bits MODE[2:0] and subaddressing

via bits SA[4:0] (see Figure 8).

All circuits are controlled by the CONTROL register. Any data change in the CONTROL

subaddress range 00h to 05h includes data that may lead to audible disturbance when

changed. Therefore the subaddress range 00h to 05h is not loaded in the CONTROL

of tuning actions and mute control, freeing the microcontroller from cumbersome controls

and timings. The subaddress range of 06h onwards does not contain such critical data.

I2C-bus information in this range will be loaded in the CONTROL register directly (at

acknowledge of each byte).

Controlled by a state machine the BUFFER data will be loaded in the CONTROL register

for new settings. However at the same time the CONTROL data is loaded in the BUFFER

previous data remains available in the BUFFER register (see Figure 10, Figure 11 and

Figure 12).

Via MODE several operational modes can be selected for the state machine. MODE offers

all standard tuning actions as well as generic control for ﬂexibility. The state machine

controls the tuner directly by controlling the I2C-bus data. Internal circuits like the IF

counter, mute and weak signal processing are controlled complementary to the tuner

action. The state machine operation starts at the end of transmission (P = STOP). In case

a previous action is still active this is overruled and the new action deﬁned by MODE is

started immediately.

When only the address byte is transmitted no action is started and no setting is changed,

this can be used to test the presence of the device on the bus. To minimize the I2C-bus

transmission time only bytes that include data changes need to be written. Following the

MSA byte the transmission can start at any given data byte deﬁned by the subaddress

(SA) bits. In case of MODE = preset, search or load the value of buffered data that is not

overwritten by the new transmission will equal the control register content, i.e. the current

tuner state. Instead in case of MODE = buffer, AF update, jump, check or end any not

overwritten BUFFER data remains to be the existing BUFFER register content, i.e. the

previous tuner state.

Table 20.

TEMP - format of data byte 6

TEMP7

TEMP6

TEMP5

TEMP4

TEMP3

TEMP2

TEMP1

TEMP0

Table 21.

TEMP - data byte 6 bit description

Bit

Symbol

Description

7 to 0

TEMP[7:0] on-chip temperature; 1 step

≈ 1 K; relative indication

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