Texas Instruments TAS3002 manual Dynamic Range Compression/Expansion DRCE, AllPass Function

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4.10 Dynamic Range Compression/Expansion (DRCE)

4.10 Dynamic Range Compression/Expansion (DRCE)

The TAS3002 device provides the user with the ability to manage the dynamic range of the audio system. The DRCE receives data, and affects scaling after the volume/loudness block. As shown in Figure 4−4, the DRCE is applied after the volume/loudness control block as a DRCE scale factor. The DRCE must be adjusted such that the signal does not reach the hard limit value. However, if the signal does reach the maximum digital value, the saturation logic serves as a hard limiter that does not allow the signal to extend beyond the available range.

(Left Channel Mixer)

SDIN1_L

LEFT_SUM

SDIN2_L

ANALOGIN_L

(Parametric

Equalization)

(7)

2nd Order IIR Filters

(Tone)

Bass/ Treble

Loudness

(DRCE Scaling)

Soft

Volume/

Saturation LEFT_OUT Logic

(Analog in From ADC)

Dynamic

Range

Control

ANALOGIN_R

SDIN1_R RIGHT_SUM

SDIN2_R

(Right Channel Mixer)

(7)

2nd Order IIR Filters

(Parametric

Equalization)

Bass/	Soft	Saturation RIGHT_OUT
Treble	Volume/	Logic
(Tone)		(DRCE Scaling)
(Tone)
	Loudness

Figure 4−4. TAS3002 Digital Signal Processing Block Diagram

The DRCE instruction consists of eight bytes that must be sent each time in the order shown in the example code of NO TAG. Each instruction downloaded must be eight bytes. If only one byte is changed, all eight bytes must be transmitted. The first two bytes remain the same for every instruction, however the last six bytes can be programmed using hexadecimal values from the corresponding tables referred to in Section NO TAG.

With high compression ratios and fast attack times available, this function is suited for a commercial killer in a television set application.

4.11 AllPass Function

This function is enabled by setting terminal 27 (ALLPASS) on the TAS3002 device to 1. When asserted, the internal equalization filters are set into AllPass (flat) mode. When this terminal is reset to 0, the equalization filters are returned to the equalization that was in use before the terminal was asserted.

In AllPass mode, the bass and treble controls are still functional.

This function is frequently used for headphones. When the headphone plug is inserted into its jack, a switched contact in the jack enables the AllPass function.

The AllPass function also can be activated by writing a 1 to bit 2 of the analog control register.

4−6

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Contents Data Manual TAS3002Digital Audio Processor With Codec 2001IMPORTANT NOTICE 1.2Features 1 Introduction1.1 Description 1.3Functional Block Diagram Figure 1−1. TAS3002 Block Diagram 1.4 Terminal Assignments 1.5 Terminal FunctionsFigure 1−2. TAS3002 Terminal Assignments Table 1−1. TAS3002 Terminal FunctionsTable 1−1. TAS3002 Terminal Functions Continued Page 2 Audio Data Formats 2.1 Serial Interface FormatsTable 2−1. Serial Interface Options … … … … 2.2 Digital Output Modes… … … … … … … …2.2.2I2S Serial-InterfaceFormat Figure 2−2. I 2S Serial-InterfaceFormat… … … … … … … …2.2.3MSB-Left-Justified, Serial-InterfaceFormat … … … …… … … … … … … …2.3 Switching Characteristics PARAMETERUNIT tcSCLK SCLK LRCLK tdSDOUT SDOUT1 SDOUT2 SDOUT0Page 3 Analog Input/Output 3.1 Analog Input3.2 Analog Output 3.2.1Direct Analog Output3.2.2Analog Output With Gain Figure 3−2. VCOM Decoupling NetworkFigure 3−3. Analog Output With External Amplifier 3.2.3Reference Voltage Filter TAS3002Figure 3−4. TAS3002 Reference Voltage Filter Page 4.1 Soft Volume Update 4 Audio Control/Enhancement Functions4.2 Software Soft Mute 4.3 Input Mixer Control4.4 Mono Mixer Control 4.5 Treble ControlFigure 4−1. TAS3002 Mixer Function 4.6 Bass Control 4.7 De-EmphasisMode DMFigure 4−2. De-EmphasisMode Frequency Response 4.8 Analog Control Register 40h Table 4−1. Analog Control Register Description4.9 Dynamic Loudness Contour 4.9.1Loudness Biquads4.9.2Loudness Gain 4.9.3Loudness Contour Operation4.10 Dynamic Range Compression/Expansion DRCE 4.11 AllPass Function4.12 Main Control Register 1 01h 4.13 Main Control Register 2 43hTable 4−2. Main Control Register 1 Description Table 4−3. Main Control Register 2 DescriptionPage Figure 5−1. Biquad Cascade Configuration 5 Filter Processor5.1 Biquad Block 5.1.1Filter CoefficientsPage 6 I2C Serial Control Interface 6.1 Introduction6.2 I2C Protocol Figure 6−1. Typical I 2C Data Transfer Sequence6.3 Operation 6.3.1Write Cycle ExampleTable 6−1. I 2C Protocol Definitions Table 6−2. I 2C Address Byte Table6.3.2TAS3002 I2C Readback Example 6.3.3I2C Wait States6.4 SMBus Operation 6.4.1Block Write Protocol6.4.2Write Byte Protocol Table 6−3. I 2C Wait States6.4.3Wait States 6.4.4TAS3002 SMBus ReadbackPage 7.2 Power-Up/Power-DownReset 7.2.1Power-UpSequence7.2.2Reset 7 Microcontroller Operation7.2.3Reset Circuit Figure 7−1. TAS3002 Reset Circuit7.2.4Fast Load Mode TAS30027.3 Power-DownMode 7.2.5Codec Reset7.3.1Power-DownTiming Sequence Figure 7−2. Power-DownTiming Sequence7.4 Test Mode 7.5 Internal Interface7.6.2GPI Architecture Table 7−1. GPI Terminal ProgrammingFigure 7−3. Internal Interface Flow Chart Restore Volume and MCRStart Power Up Initialize Default EEPROM Slave Write GPI Power Down7.7 External EEPROM Memory Maps Table 7−2. 512-ByteEEPROM Memory Map 2.0 ChannelsADDRESS BYTE NUMBERFUNCTION TAS3002TAS3002 ADDRESS NUMBERFUNCTION CATEGORYTAS3002 ADDRESS NUMBERFUNCTION CATEGORY8 Electrical Characteristics Static Digital Specifications8.2 Recommended Operating Conditions Figure 8−1. ADC Digital Filter Characteristics 8.4 ADC Digital FilterFigure 8−4. ADC High-PassFilter Characteristics 8.5 Analog-to-DigitalConverter8.6 Input Multiplexer 8.7 DAC Interpolation Filter8.8 Digital-to-AnalogConverter 8.9 DAC Output Performance Data8.10 I2C Serial Port Timing Characteristics Figure 8−7. I 2C Bus Timing9 System Diagrams Figure 9−1. Stereo ApplicationTAS3002 ClockTAS3001 Figure 9−2. TAS3002 Device, 2.1 ChannelsTAS3002 10 Mechanical Information PFB S-PQFP-G48PLASTIC QUAD FLATPACK 10−2