Wolfson WM8973-EV1B Instruction Manual

WM8973-EV1M
Evaluation Board User Handbook
Rev 1.0

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TABLE OF CONTENTS
TABLE OF CONTENTS .................................................................................. 2
INTRODUCTION ............................................................................................. 4
GETTING STARTED ....................................................................................... 4
EVALUATION BOARD CHECKLIST ...................................................................... 4
CUSTOMER REQUIREMENTS.............................................................................. 4
POWER SUPPLIES ............................................................................................... 5
BOARD FUNCTIONALITY ..................................................................................... 5
BOARD INPUT ....................................................................................................... 6
BOARD OUTPUT ................................................................................................... 6
INTERFACES......................................................................................................... 7
HEADERS .............................................................................................................. 7
LINKS, JUMPERS AND SWITCHES ...................................................................... 9
WM8973 OPERATION .................................................................................. 10
SOFTWARE CONTROL....................................................................................... 10
SERIAL INTERFACE SOFTWARE DESCRIPTION...................................... 12
SOFTWARE DOWNLOAD................................................................................... 12
SOFTWARE INSTALLATION............................................................................... 12
SOFTWARE OPERATION ................................................................................... 12
DOWER DOWN AND INTERFACE CONTROL ................................................... 16
DAC AND ADC CONTROL................................................................................... 17
VOLUME CONTROL ............................................................................................ 18
MIXER CONTROL................................................................................................ 19
TONE CONTROL ................................................................................................. 20
SCHEMATIC LAYOUT .................................................................................. 21
WM8973-EV1B PCB LAYOUT...................................................................... 29
WM8973-EV1B BILL OF MATERIAL............................................................ 33
APPENDIX .................................................................................................... 35
EXTERNAL DSP CONNECTION TO THE WM8973-EV1B .......................... 35
AUDIO INTERFACE CONNECTIONS.................................................................. 35
SOFTWARE INTERFACE.................................................................................... 37
CONNECTION DIAGRAMS.................................................................................. 37
ADDITIONAL WM8973-EV1B SETUP RECOMMENDATIONS.................... 39
ADC TO DAC LOOPBACK................................................................................... 39
CONNECTION OF AN 8ΩMONO SPEAKER ...................................................... 40
HEADPHONE AUTO-DETECT FUNCTION ......................................................... 43

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EVALUATION SUPPORT ............................................................................. 44
IMPORTANT NOTICE ................................................................................... 45
ADDRESS: ........................................................................................................... 45

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INTRODUCTION
The WM8973 is a stereo CODEC for portable audio applications.
This evaluation platform and documentation should be used in conjunction with the latest
version of the WM8973 datasheet. The datasheet gives device functionality information as
well as timing and data format requirements.
This evaluation platform has been designed to allow the user ease of use and give optimum
performance in device measurement as well as providing the user with the ability to listen to
the excellent audio quality offered by the WM8973.
GETTING STARTED
EVALUATION BOARD CHECKLIST
The following items are available from Wolfson:
•WM8973-EV1B Evaluation Board - 6097_QFN32_EV1_REV1
•WM8973-EV1S Control Software (download from http://www.wolfsonmicro.com)
•WM8973-EV1M User Handbook (download from http://www.wolfsonmicro.com)
CUSTOMER REQUIREMENTS
Minimum customer requirements are:
•D.C. Power supply of +5V
•D.C. Power supply of +1.8V to +3.6V
•PC and printer cable (for software control)
Minimum PC spec requirements are:
•Win95/98/NT/2000/XP
•486 Processor
•Approximately 1.5Mb of free hard disk space
DAC Signal Path Requires:
•Digital coaxial or optical data source
•One set of active stereo speakers
ADC Signal Path Requires:
•Analogue coaxial or 3.5mm jack plug signal source
•Digital coaxial or optical data receiving unit
Analogue Signal Path Requires:
•Analogue coaxial or 3.5mm jack plug signal source
•One set of active stereo speakers

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POWER SUPPLIES
Using appropriate power leads with 4mm connectors, power supplies should be connected
as described in Table 1.
REF-DES SOCKET NAME SUPPLY
J8 +5V +5V
J2 DBVDD +1.8V to +3.6V
J4 AVDD +1.8V to +3.6V
J10 DCVDD +1.42V to +3.6V
J47 HPVDD +1.8V to +3.6V
J1 DGND 0V
J5 AGND 0V
Table 1 Power Supply Connections
The DGND and AGND connections may be connected to a common GND on the supply with
no reduction in performance.
To reduce the supply connections that need to be attached to the EVB, sites L1 and L8 are
populated with 0R resistors shorting AVDD, HPVDD and DBVDD. In this configuration it is
recommended that the supply only be attached to AVDD. If separate supplies are required
the 0R resistors should be removed from sites L1 and L8.
Note: Refer to WM8973 datasheet for limitations on individual supply voltages.
Important: Exceeding the recommended maximum voltage can damage EVB
components. Under voltage may cause improper operation of some or all of the EVB
components.
BOARD FUNCTIONALITY
There are three options for inputting digital data into the WM8973 evaluation board. There is
a coaxial input (J19) via a standard phono connector or an optical input (U3) via a standard
optical receiver module. A direct digital input is also available via one side of a 2x8 pin
header (H1).
The analogue input signals are applied to the evaluation board via phono connectors J7
(RLINE_IN1), J12 (LLINE_IN1), J14 (RLINE_IN2), J22 (LLINE_IN2), J26 (RLINE_IN3) and
J45 (LLINE_IN3). Analogue inputs can also be applied to the evaluation board via 3.5mm
jack sockets J9 (MIC_IN1); J16 (MIC_IN2) and J30 (MIC_IN3).
There are two options for outputting digital data from the WM8973 evaluation board. There is
a coaxial output (J29) via a standard phono connector. The digital signals may also be
accessed via one side of a 2x8 pin header (H2).
The analogue outputs of the board are via phono connectors J43 (ROUT1), J44 (LOUT1),
J41 (LOUT2), J42 (ROUT2), J39 (MONO OUT) and J40 (OUT3). There is also an analogue
output via a 3.5mm jack socket J46 (HP_OUT).
All WM8973 device pins are accessible for easy measurement via the 2x4 pin headers (J13,
J15, J17 and J21) running up each side of the device.
Level-shift IC (U4) is used to shift the fixed +5V digital input from the CS8427 (U5) down to
the same level as DBVDD and vice-versa.

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BOARD INPUT
REF-DES SOCKET NAME SIGNAL
J19 SPDIF_IN Digital (AES/EBU, UEC958,
S/PDIF, EIAJ CP340/1201)
signal.
U3 OPTICAL_IN Digital (AES/EBU, UEC958,
S/PDIF, EIAJ CP340/1201)
optical signal.
Table 2 Digital Inputs
REF-DES SOCKET NAME SIGNAL
J7 RLINE_IN1 Analogue signal
J12 LLINE_IN1 Analogue signal
J14 RLINE_IN2 Analogue signal
J22 LLINE_IN2 Analogue signal
J26 RLINE_IN3 Analogue signal
J45 LLINE_IN3 Analogue signal
J9 MIC_IN1 Analogue signal (MIC Input)
J16 MIC_IN2 Analogue signal (MIC Input)
J30 MIC_IN3 Analogue signal (MIC Input)
Analogue signals applied to these connectors are AC coupled before
being input to the WM8973.
Table 3 Analogue Inputs
Note: When used in Master Mode, an SPDIF signal must still be applied to phono connector
J19. This input signal is used to allow correct operation of the CS8427 as well as being used
to generate the MCLK for the WM8973.
BOARD OUTPUT
REF-DES SOCKET NAME SIGNAL
J29 SPDIF_OUT Digital (AES/EBU, UEC958,
S/PDIF, EIAJ CP340/1201)
signal.
Table 4 Digital Output
REF-DES SOCKET NAME SIGNAL
J43 ROUT1 Line/Headphone Output
J44 LOUT1 Line/Headphone Output
J42 ROUT2 Speaker Output
J41 LOUT2 Speaker Output
J39 MONO OUT Mono Output
J40 OUT3 ROUT1/VREF/MONO OUT
J46 HP_OUT Headphone Output
Table 5 Analogue Outputs

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INTERFACES
Figure 1 Interfaces
HEADERS
H1 SIGNAL H2 SIGNAL
1/2 MCLK
12/11 GND
3/4 GND
10/9 ADCDAT
5/6 DACDAT
8/7 GND
7/8 GND
6/5 ADCLRC
9/10 DACLRC
4/3 GND
11/12 GND 2/1 BCLK
13/14 BCLK
15/16 GND J31 SIGNAL
1 DACLRC_OUT
J24 SIGNAL 2 GND
1 ADCLRC_IN
2 GND

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J15 WM8973 PIN NAME J17 WM8973 PIN NAME
1 1 MCLK 1 17 HPVDD
2 2 DCVDD 2 18 AVDD
3 3 DBVDD 3 19 AGND
4 4 DGND 4 20 VREF
5 5 BCLK 5 21 VMID
6 6 DACDAT 6 22 MICBIAS
7 7 DACLRC 7 23 RINPUT3/HPDETECT
8 8 ADCDAT 8 24 LINPUT3
J21 WM8973 PIN NAME J13 WM8973 PIN NAME
1 9 ADCLRC 1 25 RINPUT2
2 10 MONOOUT 2 26 LINPUT2
3 11 OUT3 3 27 RINPUT1
4 12 ROUT1 4 28 LINPUT1
5 13 LOUT1 5 29 MODE
6 14 HPGND 6 30 CSB
7 15 ROUT2 7 31 SDIN
8 16 LOUT2 8 32 SCLK
Table 6 Headers

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LINKS, JUMPERS AND SWITCHES
LINKS AND JUMPERS LINK/JUMPER STATUS DESCRIPTION
J18 (BCLK) OPEN
SHORT
Master mode
Slave mode [default setting]
J20 (ADCLRC) OPEN
SHORT
Master mode
Slave mode [default setting]
J25 (DACLRC) OPEN
SHORT
Master mode
Slave mode [default setting]
J23 OPEN
SHORT
Master mode
Slave mode (Ties ADCLRC to DACLRC) [default setting]
J32, J33, J34 and J35 OPEN
SHORT
OUT signals are AC coupled [default setting]
OUT signals are not AC coupled
J37 (external speaker connection) Pin 1 – AGND
Pin 2 – +ve speaker connection
J38 (external speaker connection) Pin 1 – AGND
Pin 2 – -ve speaker connection
J6 (DC input connection) Pin 1 – DC signal input
Pin 2 – AGND
J11 (DC input connection) Pin 1 – DC signal input
Pin 2 – AGND
Table 7 Links
SWITCHES SWITCH STATUS DESCRIPTION
SW6 After an input data format change has been made using
SW3, the CS8427 will only latch the new settings after
SW6 has been pressed and released.
SW3
(DATA FORMAT)
12 3 4 5 6 DATA FORMAT
1 0 0 1 0 0 I2S Compatible [default setting]
1 0 0 0 0 1 24-bit Right Justified
1 0 0 0 0 0 Left Justified
SW4
(Software Control)
Pins 1 and 2 SHORT
Pins 2 and 3 SHORT
3-wire (SPI) Control Mode [default setting]
2-wire Control Mode
SW1, SW2
(R/Line Input 1 Select)
Pins 1 and 2 SHORT
Pins 2 and 3 SHORT
MIC Input Select (3.5mm Jack Socket)
Line Input Select (Phono Socket) [default setting]
SW5, SW7
(R/Line Input 2 Select)
Pins 1 and 2 SHORT
Pins 2 and 3 SHORT
MIC Input Select (3.5mm Jack Socket)
Line Input Select (Phono Socket) [default setting]
SW8, SW9
(R/Line Input 3 Select)
Pins 1 and 2 SHORT
Pins 2 and 3 SHORT
MIC Input Select (3.5mm Jack Socket)
Line Input Select (Phono Socket) [default setting]
SW27, SW28
(R/LOUT 1 Select)
Pins 1 and 2 SHORT
Pins 2 and 3 SHORT
HP Output Select (3.5mm Jack Socket)
Line Output Select (Phono Socket) [default setting]
SW36 Pins 1 and 2 SHORT
Pins 2 and 3 SHORT
Connects to OUT3 for HP output DC reference
Connects to GND for HP output reference [default setting]
Table 8 Switches

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WM8973 OPERATION
SOFTWARE CONTROL
There are two possible serial software control modes that may be selected to operate the
WM8973. The standard SPI user interface is a 3-wire solution with the second option being
a 2-wire solution.
3-WIRE MODE
To operate the WM8973 in SPI (3-wire) mode, jumper switch SW4 must be set so that pins
1 and 2 are SHORT. The 3-wire serial interface then becomes active on pins 30(CSB),
31(SDIN) and 32(SCLK). The serial interface on the board can be connected to a PC via the
printer port or any other standard parallel port. The port used can be selected through the
software provided. The software supplied with this kit gives the user access to all the
possible features provided by the WM8973. The 3-wire latch, data and clock lines may also
be connected to the board via the test points TP2 (CSB), TP4 (SDIN) and TP3 (SCLK).
Please refer to the WM8973 datasheet for full details of the serial interface timing and all
register features.
CSB
SCLK
SDIN B15 B6B7B8B9B10B11B12B13B14 B1B2B3B4B5 B0
Figure 2 3-Wire Serial Interface
2-WIRE MODE
To operate the WM8973 in 2-wire mode, jumper switch SW4 must be set so that pins 2 and
3 are SHORT. The 2-wire serial interface becomes active on pins 31(SDIN) and 32(SCLK).
The serial interface on the board can be connected to a PC via the printer port or any other
standard parallel port. Note: a bi-directional parallel port is required for 2-wire
operation1. The 2-wire data and clock lines may also be connected to the board via the test
points TP4 (SDIN) and TP3 (SCLK).
When used in 2-wire mode, the WM8973 has two possible addresses (0011010 [0x34h] or
0011011 [0x36h]) that are selectable by pulling CSB low or high. If connecting a probe to the
Test Points it must be noted that the CSB line is pulled high on the WM8973 evaluation
board selecting address 0011011. CSB must be pulled low or driven low through the software
writes if address 0011010 is used (as is done in the WM8973-EV1S software provided).
SDIN
SCLK
ACK
R ADDR ACK
DATA B15-8
STOPSTART
DATA B7-0R/W ACK
Figure 3 2-Wire Serial Interface
Note: 1If the 2-wire mode does not operate as expected, the likely cause is the configuration
of the parallel port interface mode. Check that the port is configured for bi-directional
communication. Most PCs allow the parallel port to be configured in the BIOS settings during
initial PC power up.