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CDB6422

Evaluation Board for the CS6422

Features

z Includes analog, digital (µ-law/a-law), and

POTS (Plain Old Telephone Service)

network interfaces

z Variable gain (±20 dB) and user-defined

fixed-gain options for analog acoustic and

network inputs and outputs

z Integrated DTMF generator and keypad

provide dialing function

z Operates from +5 V or +12 V power supply,

allowing for use in car

z Operates in stand-alone or PC-based

configuration

z On-board EEPROM stores CS6422

configuration settings

z On-board speaker driver capable of driving

1 Watt into a 4 Ω load with less than 1% THD

Description

The CDB6422 provides an easy platform to evaluate the

performance of the CS6422 echo cancelling IC in a tar-

get system. To facilitate evaluation, the board provides

a wide selection of network interfacing options (analog

telephone line, µ-law/a-law PCM data, or analog RCA

jack). The analog interfaces support both fixed and vari-

able gain options to allow for level-matching with target

hardware. The board includes a keypad and a DTMF

generator to enable dialing on standard analog tele-

phone systems.

The board can operate from a single +12V power supply

and can be used in a stand-alone configuration allowing

for easy testing in car cellular hands-free applications.

ORDERING INFO

CDB6422 Evaluation Board

ACOUSTIC

INPUT/

OUTPUT

GAIN AND

FILTERING

NETWORK

INPUT/

OUTPUT

GAIN AND

FILTERING

CS6422

1 WATT

SPEAKER

DRIVER

VOLTAGE

REGULATOR

PATCH AREA

DAA

DTMF

TRANSCEIVER

µ-LAW

CODEC

MICRO-

CONTROLLER

RS-

232

DIP

SWITCH

µC

RESET

6422

RST

LOAD

VOL

LEDs

RS-232

SERIAL

PORT

DIGITAL

PCM

HEADER

ANALOG

PHONE

LINE

+5V/+12VGND

KEYPAD

AIN-MIC

AIN-RCA

AOUT-RCA

NIN-RCA

NOUT-RCA

SPKR+

SPKR-

MAR ‘06

DS295DB2

Summary of content (30 pages)

PAGE 1
CDB6422 Evaluation Board for the CS6422 Features Description z Includes The CDB6422 provides an easy platform to evaluate the performance of the CS6422 echo cancelling IC in a target system. To facilitate evaluation, the board provides a wide selection of network interfacing options (analog telephone line, µ-law/a-law PCM data, or analog RCA jack). The analog interfaces support both fixed and variable gain options to allow for level-matching with target hardware.
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CDB6422 TABLE OF CONTENTS 1. GENERAL DESCRIPTION ............................................................................................................... 4 2. HARDWARE ..................................................................................................................................... 4 2.1 Powering the Board ................................................................................................................... 4 2.2 Analog Configuration ...................................
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CDB6422 3.2.13 doff - DTMF Transmit Off ......................................................................................... 10 3.2.14 dtmf [x] - DTMF Transmit On .................................................................................... 10 3.2.15 kd [0..e] - Keypad Down Event ................................................................................. 10 3.2.16 ku [0..e] - Keypad Up Event ..................................................................................... 10 3.2.
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CDB6422 1. GENERAL DESCRIPTION The CDB6422 provides an easy interface to evaluate the performance of the CS6422 echo cancelling IC in a target system. To facilitate evaluation, the board provides a wide selection of network interfacing options (analog telephone line, µ-law/a-law PCM data, or analog RCA jack). The analog interfaces support a varitey of fixed and variable gain options to allow for easy level-matching with target hardware.
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CDB6422 +20dB". The pot labeled "AIN_GAIN" (R2) controls the variable gain. 2.2.1.5 AIN5: AIN5 selects the acoustic input source from the following options: “ACTIVE” (the previous gain sources), “PASSIVE” (the RC-network), and “DTMF” (the DTMF transceiver, used for testing purposes). 2.2.1.6 AIN6, AIN7: AIN6 and AIN7 are configured based on the state of the internal MIC preamp on the CS6422.
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CDB6422 2.2.4 2.2.4.1 Network Output NOUT1: NOUT1 selects between the “ACTIVE” drive output circuitry (op-amps) and the “PASSIVE” circuitry (simple RC-network). To take advantage of the supplied filters and gain stages, set NOUT1 to the “ACTIVE” state. 2.2.4.2 NOUT2: NOUT2 selects the order of the Butterworth filter following NO at either "1-POLE" or "3-POLES". 2.2.4.3 NOUT3, NOUT4: NOUT3 and NOUT4 select the type and amount of gain for the network output circuitry.
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CDB6422 the phone after this occurs, slide the HOOK SWITCH first to the "OFF_HOOK" position and then back to the "ON_HOOK" position. 2.6.2 KEYPAD: The default state of the keypad is to generate DTMF tones when the keys are pressed to enable dialing through the analog phone network. The keypad also allows for manual CS6422 register entry and CS6422 register configuration storage and recall in association with the LOAD pushbutton (SW5). See the description of the LOAD pushbutton for more information. 2.6.
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CDB6422 The KEYPAD and status LEDs return to their normal states after the Configuration number has been selected. Because the Configuration sets are stored in EEPROM, they will survive a power-off event. However, Configuration 0 is special for two reasons: 1) it is reset to the CS6422 default register state on power-up or on microcontroller reset, and 2) it is automatically downloaded to the CS6422 when the “6422_RST” pushbutton is pressed (or the 'r' command is sent from a terminal).
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CDB6422 3.2 3.2.1 ver - Output Code Version A. Writes current code and EEPROM versions to the UART 3.2.2 3. Polls dip switches for custom configuration Command Descriptions: 3.2.4 B. No arguments accepted A. Writes 16-bit value $xxxb to CS6422 (b/2 designates register address) C. No MSG Stack pushes B. No MSG Stack pushes C. Description: reset - Reset 8515 1. Writes register value to Current register copy in EEPROM (if write is valid) A. Resets microcontroller just as with hardware reset 2.
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CDB6422 1. Saves the current state of the CS6422 register(s) bits to be changed in eeprom 2. Configures the CS6422 register(s) according to the switch function 3.2.8 swu [1..9] - Switch Up A. Notifies microcontroller that DIP switch(es) 1..9 have been switched up (handles multiple switches) B. No MSG Stack pushes C. Description: Returns the CS6422 register(s) to the state prior to the the respective 'swd' event 3.2.9 swp - Poll Dip Switches A.
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CDB6422 write the value formed by the buttons pushed to the CS6422 (i.e. push “wr [wxyz]” onto the MSG Stack) 2nd push: next 1 'kd [x]' event will push a 'recall [x]' onto the MSG Stack 3rd push: next 1 'kd [x]' event will push a 'save [x]' onto the MSG Stack 4th push: returns Keypad Mode to default DTMF state Button 3 - VOL_DOWN - decrements the CS6422 receive volume by 3dB Button 4 - VOL_UP - increments the CS6422 receive volume by 3dB 3.2.19 pu [1..4] - Push Button Up Event A.
PAGE 12
CDB6422 Echo Canceller should be disabled by setting NECD to ‘1’. 3.2.29 ext - EXT Jumper Set A. Message indicating that the jumper EXT is installed, allowing an external source to configure the CS6422 B. No arguments needed C. No pushes to the MSG Stack 3.2.30 d {number} - Dial Phone Number A. Dials phone numbers up to 14 digits. A ‘,’ will add a small delay between numbers. B. No pushes to the MSG Stack C. Description: 3.2.31 ? - List Commands A. Prints the list of available commands to the UART B.
PAGE 13
CDB6422 acoustic coupling between AO and APO to -9dB (a design target). (Alternate) Acoustic input using AIN_RCA with no mic bias and internal mic preamp disabled: In a desktop speakerphone, the acoustic coupling is typically altered by adjusting the mic preamp gain. In a hands-free car kit, the acoustic coupling is typically altered by adjusting the speaker and mic position. For this exercise, NIN4 should be set to ‘ACTIVE’, and there should be no signal connected to NIN_RCA.
PAGE 14
CDB6422 4.4 Usage Scenario #1: Analog Phone Call with Separated Speaker and Microphone In this scenario, NIN4 is set to “POTS(DAA)” to select the analog phone line as the network input source. The analog phone line is plugged into the RJ-11 jack (J6) called "Phone Line". The CS6422 is configured from default settings with the following: reg 0: 9400 -- GB = '0.
PAGE 15
CDB6422 reg 5: 014a -- NECD = '1', ASdt = '-24dB' (disable NEC and enable acoustic sidetone) Note: if the cellular phone provides a network sidetone (coupling between NO and NI), then Taps should be set to ‘39.5ms/24ms’, and NECD should be set to ‘0’.
PAGE 16
CDB6422 7) press '2' '0' '0' '6' on the keypad To make a call: 8) press and release the "LOAD" pushbutton (once) 1) initiate or answer a call from the cell phone 9) press '0' '1' '4' 'a' on the keypad At this point, the CS6422 is loaded with the correct configuration.
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CDB6422 Figure 1. Power 5.
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Figure 2.
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Figure 3.
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Figure 4.
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Figure 5.
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Figure 6.
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Figure 7.
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Figure 8.
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Figure 9.
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Figure 10.
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Figure 11.
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Figure 12.
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CDB6422 6. REVISION HISTORY Revision Date Changes DB1 AUG 1999 Initial Release DB2 MAR 2006 Update company contact information & legal statement. Contacting Cirrus Logic Support For all product questions and inquiries contact a Cirrus Logic Sales Representative. To find the one nearest to you go to www.cirrus.com IMPORTANT NOTICE Cirrus Logic, Inc. and its subsidiaries (“Cirrus”) believe that the information contained in this document is accurate and reliable.
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CDB6422 30 DS295DB2