Philips TDA9874H Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TDA9874H

Digital TV sound demodulator/decoder

Preliminary speciﬁcation File under Integrated Circuits, IC02

1998 Apr 27

Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

CONTENTS

1 FEATURES 2 GENERAL DESCRIPTION

2.1 Supported standards 3 ORDERING INFORMATION 4 BLOCK DIAGRAM 5 PINNING INFORMATION

5.1 Pinning

5.2 Pin description 6 FUNCTIONAL DESCRIPTION

6.1 Description of the demodulator and decoder section

6.2 Description of the DSP

6.3 Description of the analog audio section

7.1 Introduction

7.2 Power-up state

7.3 Slave receiver mode

7.4 Slave transmitter mode

8I 9 EXTERNAL COMPONENTS 10 LIMITING VALUES 11 THERMAL CHARACTERISTICS 12 CHARACTERISTICS 13 PACKAGE OUTLINE 14 SOLDERING

14.1 Introduction

14.2 Reflow soldering

14.3 Wave soldering

14.4 Repairing soldered joints

15 DEFINITIONS 16 LIFE SUPPORT APPLICATIONS 17 PURCHASE OF PHILIPS I2C COMPONENTS

C-BUS CONTROL

S-BUS DESCRIPTION

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Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

1 FEATURES

• SIF input switch e.g. to select between terrestrial TV SIF

and SAT SIF sources

• SIF AGC with 21 dB control range

• SIF 8-bit Analog-to-Digital Converter (ADC)

• DQPSK demodulation for different standards,

simultaneously with 1-channel FM demodulation

• NICAM decoding (B/G, I and L standard)

• Two-carrier multi-standard FM demodulation

(B/G, D/K and M standard)

• Decoding for three analog multi-channel systems

(A2, A2+ and A2*) and satellite sound

• Adaptive de-emphasis for satellite

• Programmable identification (B/G, D/K and M standard)

and different identification times

• Optional AM demodulation for system L, simultaneously

with NICAM

• Monitor selection for FM/AM demodulator outputs and

FM and NICAM signals

• Digital crossbar switch

S serial audio output with matrix, level adjust and mute

• I

• Dual audio Digital-to-Analog Converter (DAC) from

digital crossbar switch to analog crossbar switch, bandwidth 15 kHz

• Analog crossbar switch with inputs for mono and stereo

• Output selection of mono, stereo, dual, dual A or dual B

• 20 kHz bandwidth for analog path

• Standby mode.

2.1 Supported standards

The multi-standard/multi-stereo capability of the TDA9874H is mainly of interest in Europe, but also in Hong Kong/PR China and South East Asia. This includes B/G, D/K, I, M and L standard. In other application areas there exist subsets of those standard combinations or only single standards are transmitted.

Standard M is transmitted in Europe by the American Forces Network with European channel spacing (7 MHz VHF, 8 MHz UHF) and monaural sound.

The AM sound of L/L’ standard is normally demodulated in the 1st sound IF. The resulting AF signal has to be entered into the mono audio input of the TDA9874H. A second possibility is to use the internal AM demodulator stage, giving limited performance.

Korea has a stereo sound system similar to Europe and is supported by the TDA9874H. Differences include deviation, modulation contents and identification. It is based on M standard.

An overview of the supported standards and sound systems and their key parameters is given in Table 1.

The analog multi-channel systems are sometimes also named 2CS (2 carrier systems).

2 GENERAL DESCRIPTION

The TDA9874H is a single-chip Digital TV Sound Demodulator/Decoder (DTVSD1) for analog and digital multi-channel sound systems in TV/VCR sets and satellite receivers.

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Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

2.1.1 ANALOG 2-CARRIER SYSTEMS

Table 1 Frequency modulation

STANDARD

SOUND

SYSTEM

CARRIER

FREQUENCY

(MHz)

FM DEVIATION (kHz) MODULATION BANDWIDTH/

DE-EMPHASIS

NOM. MAX. OVER. SC1 SC2

(kHz/µs)

M mono 4.5 15 25 50 mono − 15/75 M A2+ 4.5/4.724 15 25 50 B/G A2 5.5/5.742 27 50 80

⁄2(L + R)1⁄2(L − R) 15/75 (Korea)

⁄2(L + R) R 15/50

I mono 6.0 27 50 80 mono − 15/50 D/K A2 6.5/6.742 27 50 80 D/K A2* 6.5/6.258 27 50 80

⁄2(L + R) R 15/50

Table 2 Identiﬁcation for A2 systems

PARAMETER A2; A2* A2+ (KOREA)

Pilot frequency 54.6875 kHz = 3.5 × line frequency 55.0699 kHz = 3.5 × line frequency Stereo identiﬁcation frequency

Dual identiﬁcation frequency

117.5 Hz

274.1 Hz

line frequency

= 149.9 Hz

------------------------------------133

line frequency

= 276.0 Hz

-------------------------------------

line frequency

------------------------------------105

line frequency

-------------------------------------

AM modulation depth 50% 50%

2.1.2 2-CARRIER SYSTEMS WITH NICAM

Table 3 NICAM

SC1

STANDARD

FREQUENCY

(MHz)

TYPE

MODULATION

INDEX (%)

DEVIATION

(kHz)

SC2

(MHz)

NICAM

DE-EMPHASIS

ROLL-OFF

(%)

NICAM

CODING

NOM. MAX. NOM. MAX.

B/G 5.5 FM −−27 50 5.85 J17 40 note 1 I 6.0 FM −−27 50 6.552 J17 100 note 1 D/K 6.5 FM −−27 50 5.85 J17 40 tbf L 6.5 AM 54 100 −−5.85 J17 40 note 1

Note

1. See

“EBU specification”

or equivalent specification.

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Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

2.1.3 SATELLITE SYSTEMS An important specification for satellite TV reception is the Astra specification. The TDA9874H is suited for the reception

of Astra and other satellite signals, with sound carrier frequencies from 4 to 9.2 MHz.

Table 4 FM satellite sound

CARRIER TYPE

FREQUENCY

Main 6.50

CARRIER

(MHz)

(1)

MODULATION

INDEX

0.26 85 mono 15/50 Sub 7.02/7.20 0.15 50 m/st/d Sub 7.38/7.56 0.15 50 m/st/d Sub 7.74/7.92 0.15 50 m/st/d Sub 8.10/8.28 0.15 50 m/st/d

MAXIMUM

FM DEVIATION

(kHz)

MODULATION

(2) (2) (2) (2)

BANDWIDTH/

DE-EMPHASIS

(kHz/µs)

(1)

15/adaptive 15/adaptive 15/adaptive 15/adaptive

(3) (3) (3) (3)

Notes

1. For other satellite systems, frequencies of e.g. 5.80 MHz, 6.60 MHz or 6.65 MHz can also be received. A de-emphasis of 60 µs or in accordance with J17 is available.

2. m/st/d = mono or stereo or dual language sound.

3. Adaptive de-emphasis = compatible to transmitter specification.

3 ORDERING INFORMATION

TYPE

NUMBER

NAME DESCRIPTION VERSION

PACKAGE

TDA9874H QFP44 plastic quad ﬂat package; 44 leads (lead length 2.35 mm); body 14 × 14 × 2.2 mm SOT205-1

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Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

4 BLOCK DIAGRAM

handbook, full pagewidth

P1 P2

ADDR1 ADDR2

SCL

SDA

XTALI

XTALO

SYSCLK

SDO

SCK

SIF2

37 42 13 19 29 30

15 16 34

31 32 33

C-BUS

INTERFACE

IDENTIFICATION

VCXO

CLOCK

I2S-BUS

INTERFACE

DEMODULATION

INPUT SWITCH

AGC, ADC

FM/AM

DEMATRIX

2 CHANNEL

ANALOG/

SATELLITE

DECODER

DIGITAL

SELECTOR

TDA9874H

SIF1

NICAM

DEMODULATION

NICAM

DECODER

LEVEL

ADJUST

POSTFILTER

2 DACS

ANALOG

CROSSBAR

SWITCH

SUPPLY

SIF

TIMING

DETECTION

DAC

DIGITAL SUPPLY

SUPPLY DAC

REFERENCE

SUPPLY

OPERATIONAL

AMPLIFIERS

21 20 24 18

28 27 35 36 26

43 44

39 40 38

10 12

6 5 8 7

3 4

DDA2

SSA2

ref1

ref

tune

NICAM PCLK

DDD1

SSD1

DDD2

SSD2

DDD3

SSD3

DDD4

SSD4

CRESET V

DDA1

SSA1

ref2

DDA3

SSA3

EXTIR EXTIL MONOIN

TP1 TP2

22 17 11

TEST

TEST1 TEST2

Fig.1 Block diagram.

1998 Apr 27 6

AF-OUPUT

BUFFERS

OUTR OUTL

MGL248

Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

5 PINNING INFORMATION

5.1 Pinning

handbook, full pagewidth

OUTL

OUTR

DDA1

SSA1

SSD1

DDD1

SSD2

DDD2

TP2

NICAM

TP1

DDA3

P2 42

tune

ADDR1

ref2

EXTIL

TDA9874H

XTALI

XTALO

EXTIR 39

TEST2

SSA3

1 2 3 4 5 6 7 8

9 10 11

PCLK

MONOIN 38

ref

ADDR2

SSD4

SSA2

DDD4

DDA2

SYSCLK 34

TEST1

33 32 31 30

29 28 27 26 25 24 23

MGK752

SCK WS SDO SDA SCL V

DDD3

SSD3

CRESET SIF1 V

ref1

SIF2

Fig.2 Pin configuration.

1998 Apr 27 7

Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

5.2 Pin description Table 5 SOT205-1 package

SYMBOL PIN DESCRIPTION

OUTL 1 analog output left OUTR 2 analog output right V

DDA1

SSA1

SSD1

DDD1

SSD2

DDD2

TP2 9 additional test pin 2; connected to V NICAM 10 serial NICAM data output at 728 kHz TP1 11 additional test pin 1; connected to V PCLK 12 NICAM clock output at 728 kHz ADDR1 13 ﬁrst I V

tune

XTALI 15 crystal oscillator input XTALO 16 crystal oscillator output TEST2 17 test pin 2; connected to V I

ref

ADDR2 19 second I V

SSA2

DDA2

TEST1 22 test pin 1; connected to V SIF2 23 sound IF input 2 V

ref1

SIF1 25 sound IF input 1 CRESET 26 capacitor for power-on reset V

SSD3

DDD3

SCL 29 I SDA 30 I SDO 31 I

3 analog supply voltage 1; DAC circuitry 4 analog ground supply 1; DAC circuitry 5 digital ground supply 1; DAC circuitry 6 digital supply voltage 1; DAC circuitry 7 digital ground supply 2; DSP part 8 digital supply voltage 2; DSP part

for normal operation

SSD

for normal operation

SSD

C-bus slave address modiﬁer

14 tuning voltage output for crystal oscillator

for normal operation

SSD

18 resistor for reference current generation; front end circuitry

C-bus slave address modiﬁer 20 analog ground supply 2; analog front end circuitry 21 analog supply voltage 2; analog front end circuitry

for normal operation

SSD

24 reference voltage; analog front end circuitry

27 digital ground supply 3; front end circuitry 28 digital supply voltage 3; front end circuitry

C-bus clock input

C-bus data input/output

S-bus serial data output

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Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

SYMBOL PIN DESCRIPTION

WS 32 I2S-bus word select input/output SCK 33 I SYSCLK 34 system clock output V V

DDD4 SSD4

35 digital supply voltage 4; demodulator circuitry 36 digital ground supply 4; demodulator circuitry

P1 37 ﬁrst general purpose I/O pin MONOIN 38 analog mono input EXTIR 39 external audio input right channel EXTIL 40 external audio input left channel V

ref2

41 analog reference voltage DAC and operational ampliﬁers

P2 42 second general purpose I/O pin V V

DDA3 SSA3

43 analog supply voltage 3; operational ampliﬁers 44 analog ground supply 3; operational ampliﬁers

S-bus clock input/output

1998 Apr 27 9

Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

6 FUNCTIONAL DESCRIPTION

6.1 Description of the demodulator and decoder section

6.1.1 SIF

INPUT

Two input pins are provided. SIF1 e.g. for terrestrial TV and SIF2 e.g. for a satellite tuner. As no specific filters are integrated, both inputs have the same specification giving flexibility in application. The selected signal is passed through an AGC and then digitized by an 8-bit ADC running at 24.576 MHz.

6.1.2 AGC

The gain of the AGC amplifier is controlled from the ADC output by means of a digital control loop employing hysteresis. The AGC has a fast attack behaviour to prevent ADC overloads, and a slow decay behaviour to prevent AGC oscillations. For AM demodulation the AGC must be switched off. When switched off, the control loop is reset and fixed gain settings can be chosen from a table.

The AGC can be controlled via the I

C-bus. Details can be

found in Sections 7.3.1, 7.3.2 and 7.4.6.

6.1.3 M

IXER

The digitized input signal is passed on to the mixers, which mix one or both input sound carriers down to zero IF. A 24-bit control word for each carrier sets the required frequency. Access to the mixer control word registers is via the I2C-bus (see Sections 7.3.4 and 7.3.5). When receiving NICAM programs, a feedback signal is added to the control word of the second carrier mixer to establish a carrier-frequency loop.

6.1.4 FM

AND AM DEMODULATION

An FM or AM input signal is passed through a band-limiting filter onto a demodulator that can be used for either FM or AM demodulation. Apart from the standard (fixed) de-emphasis characteristic, an adaptive de-emphasis is available for Wegener-Panda 1 encoded satellite programs.

6.1.5 FM

DECODING

A two-carrier stereo decoder recovers the left and right signal channels from the demodulated sound carriers. Both the European and Korean stereo systems are supported.

6.1.6 FM

IDENTIFICATION

The identification of the FM sound mode is performed by AM synchronous demodulation of the pilot and narrow-band detection of the identification frequencies. The result is available via the I2C-bus interface. A selection can be made via the I2C-bus for B/G, D/K and M standard, and for three different time constants that represent different trade-offs between speed and reliability of identification.

6.1.7 NICAM

DEMODULATION

The NICAM signal is transmitted in a DQPSK code at a bit rate of 728 kbits/s. The NICAM demodulator performs DQPSK demodulation and passes the resulting bitstream and clock signal to the NICAM decoder and, for evaluation purposes, to pins.

A timing loop controls the frequency of the crystal oscillator to lock the sampling instants to the symbol timing of the NICAM data. The polarity of the control signal is selectable to support applications, in which external circuitry is used to boost the tuning voltage of the oscillator.

6.1.8 NICAM

DECODING

The device performs all decoding functions in accordance with the

“EBU NICAM 728 specification”

. After locking to the frame alignment word, the data are descrambled by application of the defined pseudo-random binary sequence, and the device synchronizes to the periodic frame flag bit C0.

The status of the NICAM decoder can be read-out from the NICAM Status Register by the user (see Section 7.4.2). The OSB bit indicates that the decoder has locked to the NICAM data. The VDSP bit indicates that the decoder has locked to the NICAM data and that the data is valid sound data. The C4 bit indicates that the sound conveyed by the FM mono channel is identical to the sound conveyed by the NICAM channel. The error byte contains the number of sound sample errors, resulting from parity checking, that occurred in the past 128 ms period. The Bit Error Rate (BER) is approximately 0.0000174 times the contents of the error byte.

BER

bit errors

----------------------total bits

error byte 1.74× 10

5–

×≈=

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Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

6.1.9 NICAM AUTO-MUTE This function is enabled by setting bit AMUTE LOW

(see Section 7.3.11). Upper and lower error limits may be defined by writing appropriate values to two registers in the I2C-bus section (see Sections 7.3.13 and 7.3.14). When the number of errors in a 128 ms period exceeds the upper error limit, the auto-mute function will switch the output sound from NICAM to whatever sound is on the first sound carrier (FM or AM) or to the analog mono input. When the error count is smaller than the lower error limit, the NICAM sound is restored.

The auto-mute function can be disabled by setting bit AMUTE HIGH. In this case clicks become audible, when the error count increases. The user will hear a signal of degrading quality.

A decision to enable/disable the auto-muting is taken by the microprocessor based on an interpretation of the application control bits C1, C2, C3 and C4, and possibly any additional strategy implemented by the setmaker in the microcontroller software.

When the AM sound in NICAM L systems is demodulated in the 1st sound IF and the audio signal connected to the mono input of the TDA9874H, the controlling microprocessor has to take care of switching from NICAM reception to mono input, if auto-muting is desired. This could be achieved by setting the AMSEL bit HIGH additionally to AMUTE bit LOW (see also Section 7.3.11).

6.1.10 C A circuit diagram of the external components of the

voltage-controlled crystal oscillator is shown in Fig.7 in Chapter 9.

6.1.11 T All test pins are active HIGH. In normal operation of the

device they can be left open-circuit, as they have internal pull-down resistors. Test functions are for manufacturing tests only and are not available to customers.

RYSTAL OSCILLATOR

EST PINS

1998 Apr 27 11

Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

6.2 Description of the DSP

6.2.1 L

EVEL SCALING

All input channels to the digital crossbar switch are equipped with a level adjust facility to change the signal level in a range of ±15 dB. Adjusting the signal level is intended to compensate for the different modulation parameters of the various TV standards. It is recommended to scale all input channels to be 15 dB below full-scale (−15 dB (FS)) under nominal conditions. This will create sufficient headroom to cope with overmodulation and avoids changes of the volume impression when switching from FM to NICAM or vice versa.

6.2.2 NICAM

PATH

The NICAM path has a switchable J17 de-emphasis.

6.2.3 NICAM

AUTO-MUTE

If NICAM is received, the AUTO-MUTE is enabled and the signal quality becomes poor, the digital crossbar switches automatically to FM, Channel 1 or the analog mono input, as selected by bit AMSEL. This automatic switching depends on the NICAM bit error rate. The auto-mute function can be disabled via the I2C-bus.

6.2.5 FM

MONITOR

This function provides data words from the FM demodulator outputs and FM and NICAM signals for external use, like carrier search or fine tuning. Source selection and data read-out are performed via the I2C-bus.

6.2.6 D

IGITAL CROSSBAR SWITCH

Input channels come from the FM and NICAM paths, while output channels comprise I2S and the audio DACs to the analog crossbar switch. Note that there is no connection from the external analog audio inputs to the digital crossbar switch.

6.2.7 D

IGITAL AUDIO OUTPUT

The digital audio output interface comprises an I2S output port and a system clock output. The I2S port is equipped with a level adjust facility that can change the signal level in a ±15 dB range in 1 dB steps. Muting is possible, too, and outputs can be disabled to improve EMC performance.

The I2S-bus output matrix provides the functions of forced mono, stereo, channel swap, Channel 1 or Channel 2.

6.2.8 C

HANNEL TO THE ANALOG CROSSBAR PATH

6.2.4 FM (AM)

PATH

A high-pass filter suppresses DC offsets from the FM demodulator that may occur due to carrier frequency offsets and supplies the FM monitor function with DC values, e.g. for the purpose of microprocessor controlled carrier search or fine-tuning functions.

An adaptive de-emphasis is available for Wegener-Panda 1 encoded satellite programs.

The de-emphasis stage offers a choice of settings for the supported TV standards.

The 2 channel decoder performs the dematrixing of

⁄2(L + R) and R to L and R signals, of1⁄2(L + R) and

⁄2(L − R) to L and R signals or of Channel 1 and

Channel 2 to L and R signals, as demanded by the different TV standards or user preferences.

A level adjust function is provided with control positions 0 dB, +3 dB, +6 dB and +9 dB in combination with the audio DACs.

6.2.9 G

ENERAL

The level adjust functions can provide signal gain at multiple locations. Great care has to be taken when using gain with large input signals, e.g., due to overmodulation, in order not to exceed the maximum possible signal swing, which would cause severe signal distortion. The nominal signal level of the various signal sources to the digital crossbar switch should be 15 dB below digital full-scale, i.e., −15 dB (FS).

1998 Apr 27 12

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1998 Apr 27 13

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Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

NICAM

DC FILTER

FIXED

DE-EMPHASIS

ADAPTIVE

DE-EMPHASIS

FIXED

DE-EMPHASIS

2 CHANNEL

DECODER

LEVEL

ADJUST

LEVEL

ADJUST

DIGITAL

CROSSBAR

SELECT

MATRIX

FM MONITOR

LEVEL

ADJUST

LEVEL

ADJUST

DAC

MGK755

Fig.3 DSP data flow diagram.

Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

6.3 Description of the analog audio section

6.3.1 A

NALOG CROSSBAR SWITCH AND ANALOG MATRIX

The TDA9874H has one external analog stereo input, one mono input and one two-channel output port. Analog source selector switches are employed to provide the desired analog signal routing capability, which is done by the analog crossbar switch section.

The basic signal routing philosophy of the TDA9874H is that each switch handles two signal channels at the same time, e.g. Left and Right, language A and B, directly at the source. For an overview of the signal flow see Fig.5.

Each source selector switch is followed by an analog matrix to perform further selection tasks, like putting a signal from one input channel, say, language A, to both output channels or for swapping left and right channel. The analog matrix provides the functions given in Table 6.

All switches and matrices are controlled via the I2C-bus.

Table 6 Analog matrix functions

MATRIX OUTPUT

MODE

L OUTPUT R OUTPUT

1 L input R input 2 R input L input 3 L input L input 4 R input R input

6.3.2 EXTERNAL AND MONO INPUTS The external and mono inputs accept signal levels of up to

1.4 V (RMS). By adding external series resistors to provide a suitable attenuation, the external input could be used as a SCART input. Whenever the external or mono input is selected, the output of the DAC is muted to improve the crosstalk performance.

6.3.3 D

UAL AUDIO DAC

The TDA9874H comprises a two-channel audio DAC for feeding signals from the DSP section to the analog crossbar switch. These DACs have a resolution of 15 bits and employ four-fold oversampling and noise shaping.

6.3.4 A

UDIO OUTPUT BUFFERS

The output buffers provide 0 dB of gain and offer a muting possibility. The post filter capacitors of the audio DACs are connected to the buffer outputs.

6.3.5 S

TANDBY MODE

The Standby mode (see Section 7.3.2) disables most functions and reduces power dissipation of the TDA9874H, but provides no other functionality.

Internal registers may lose their information in Standby mode. Therefore, the device needs to be initialized on returning to normal operation. This can be accomplished in the same way as after a power-on reset.

handbook, full pagewidth

mono (AM)

EXTIL

EXTIR

DACL

DACR

source select

Fig.4 Switch diagram for the audio section.

1998 Apr 27 14

matrix

OUTL

OUTR

MGK754

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1998 Apr 27 15

mono

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Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

external

NICAM

FM/AM

NICAM

DEMODULATOR

FM/AM

DEMODULATOR

NICAM

DECODER

ADAPTIVE

DE-EMPHASIS

FIXED

DE-EMPHASIS

LEVEL

ADJUST

2 CHANNEL

DECODER

LEVEL

ADJUST

Fig.5 Audio signal flow.

DIGITAL

CROSSBAR

SELECT

LEVEL

ADJUST

DAC

ANALOG

CROSSBAR

SWITCH

MATRIX

BUFFER

LEVEL

ADJUST

OUT

MGK756

Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

7I2C-BUS CONTROL

7.1 Introduction

The TDA9874H is controlled only via the I

C-bus. Control is exercised by writing data to one or more internal registers. Status information can be read from an array of registers to let the controlling microprocessor determine whether any action is required.

The device has an I2C-bus slave transceiver in accordance with the fast-mode specification with a maximum speed of 400 kbits/s. Information about the I2C-bus can be found in brochure

it”

(order number 9398 393 40011). To avoid conflicts in a

“I2C-bus and how to use

real application with other ICs providing similar or complementing functions, there are four possible slave addresses available, which can be selected by pins ADDR1 and ADDR2 (see Table 7).

Table 7 Possible slave addresses

SLAVE ADDRESS

ADDR2 ADDR1

A6 A5 A4 A3 A2 A1 A0

0 0 1011000 0 1 1011001 1 0 1011010 1 1 1011011

The I

C-bus interface remains operational in the Standby mode of the TDA9874H to allow the device to be reactivated via the I2C-bus.

7.2 Power-up state

At power-up the device is in the following state:

• All outputs muted

• No sound carrier frequency loaded

• General purpose I/O pins ready for input (HIGH)

• Input SIF1 selected with:

– AGC on – Small hysteresis.

• Demodulators for both sound carriers set to FM with: – Identification for B/G, D/K, identification mode ‘slow’ – Level adjust set to 0 dB – De-emphasis 50 µs – Dematrix set to mono – Adaptive de-emphasis on.

• OUTL and OUTR set to mono and connected to DAC

• Digital audio interface all outputs off

• Monitor set to carrier 1 DC output.

After power-up a device initialization has to be performed

via the I

C-bus to put the TDA9874H into the proper mode of operation, in accordance with the desired TV standard, etc. This can be done by writing to all registers with a single I2C-bus transmission (like a refresh operation) or by writing selectively only to those registers, the contents of which need to be changed with regard to the power-up state.

The device will not respond to a ‘general call’ on the I2C-bus, i.e. when a slave address of 0000000 is sent by a master.

1998 Apr 27 16

Philips Semiconductors Preliminary speciﬁcation

Digital TV sound demodulator/decoder TDA9874H

7.3 Slave receiver mode

As a slave receiver, the TDA9874H provides 24 registers for storing commands and data. Each register is accessed via a so-called subaddress. A subaddress can be thought of as a pointer to an internal memory location.

Detailed descriptions of the slave receiver registers are given in Sections 7.3.1 to 7.3.20.

Table 8 I

S SLAVE ADDRESS 0 A SUBADDRESS A DATA A/NA P

Table 9 Explanation of Table 8

S START condition SLAVE ADDRESS 0 data direction bit (write to device) A SUBADDRESS DATA data byte to be written into register A/NA acknowledge or not acknowledge P STOP condition

C-bus; SLAVE ADDRESS/SUBADDRESS/DATA format

BIT FUNCTION

7-bit device address

acknowledge address of register to write to

It is allowed to send more than one data byte per transmission to the TDA9874H. In that case, the subaddress is automatically incremented after each data byte, resulting in storing the sequence of data bytes at successive register locations, starting at SUBADDRESS. A transmission can start at any valid subaddress. Each byte that is properly stored, is acknowledged with A (acknowledge). If an attempt is made to write data to a non-existing subaddress, the device acknowledges with NA (not acknowledge), therefore telling the I ‘wrap-around’ of subaddresses.

Commands and data will be processed as soon as they have been received completely. Functions requiring more than one byte will, thus, be executed only after all bytes for that function have been received. If the transmission is terminated (STOP condition) before all bytes have been received, the incomplete data for that function are ignored.

Table 10 Format for a transmission employing auto-increment of subaddresses

S SLAVE ADDRESS 0 A SUBADDRESS A DATA BYTE A

Data patterns sent to the various subaddresses are not checked for being illegal or not at that address, except for the level adjust functions.

Detection of a STOP condition without a preceding acknowledge bit is regarded as a bus error. In this case, the last operation will not be executed.

C-bus master to abort the transmission. There is no

DATA A/NA P

n data bytes with auto-increment of

subaddresses

1998 Apr 27 17

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