WM8775-EV1B Evaluation Board User Handbook

WM8775-EV1B
Evaluation Board User Handbook
Rev 1.2
WM8775-EV1M
TABLE OF CONTENTS
INTRODUCTION ............................................................................................. 3
GETTING STARTED ....................................................................................... 3
EVALUATION KIT CHECKLIST ............................................................................. 3
CUSTOMER REQUIREMENTS.............................................................................. 3
EVALUATION BOARD OPERATION.............................................................. 4
POWER SUPPLIES ............................................................................................... 4
BOARD FUNCTIONALITY ..................................................................................... 4
DIGITAL INPUT...................................................................................................... 5
ANALOGUE INPUT ................................................................................................ 5
DIGITAL INPUT...................................................................................................... 5
INTERFACES......................................................................................................... 6
HEADERS .............................................................................................................. 6
JUMPERS .............................................................................................................. 7
SWITCHES ............................................................................................................ 7
LINKS ..................................................................................................................... 7
SOFTWARE CONTROL.................................................................................. 8
3-WIRE MODE ....................................................................................................... 8
2-WIRE MODE ....................................................................................................... 8
REGISTER MAP .................................................................................................... 9
SERIAL INTERFACE SOFTWARE DESCRIPTION...................................... 10
SOFTWARE DOWNLOAD ................................................................................... 10
SOFTWARE INSTALLATION............................................................................... 10
SOFTWARE OPERATION ................................................................................... 11
EVALUATION BOARD CONFIGURATION .......................................................... 13
SCHEMATIC LAYOUT .................................................................................. 15
WM8775-EV1B PCB LAYOUT...................................................................... 22
WM8775-EV1B BILL OF MATERIAL............................................................ 26
APPENDIX .................................................................................................... 28
EXTERNAL DSP CONNECTION TO THE WM8775-EV1B .................................. 28
EVALUATION SUPPORT ............................................................................. 31
IMPORTANT NOTICE ................................................................................... 32
ADDRESS: ........................................................................................................... 32
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WM8775-EV1M
INTRODUCTION
The WM8775 is a high performance ADC with 4 channel input multiplexer for surround sound
AV processing applications for home hi-fi and automotive audio.
This evaluation platform and documentation should be used in conjunction with the latest
version of the WM8775 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 WM8775.
GETTING STARTED
EVALUATION KIT CHECKLIST
The following items are available from Wolfson:
•
WM8775-EV1B Evaluation Board (order from Wolfson)
•
WM8775-EV1S .exe file for control software (download from
http://www.wolfsonmicro.com/)
•
WM8775-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 +2.7V to +5.5V
•
PC and printer cable (for software control)
Minimum PC spec requirements are:
•
Win95/98/NT/2000/XP
•
486 Processor
ADC Signal Path Requires:
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•
Analogue coaxial signal source
•
Digital coaxial or optical data receiving unit
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WM8775-EV1M
EVALUATION BOARD OPERATION
POWER SUPPLIES
Using appropriate power leads with 4mm connectors, power supplies should be connected
as described in Table 1.
REF-DES
J1
SOCKET NAME
+5V
SUPPLY
+5V
J2
DGND
0V
J3
DVDD
+2.7V to +3.6V
J4
AVDD
+2.7V to +5.5V
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.
Note: Refer to WM8775 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 the required digital clocks (MCLK, BCLK, ADCLRC) to
the WM8775 evaluation board. There is a coaxial input (J8) via a standard phono connector
(the CS8427 device will then generate the clocks) or a direct digital input is available via one
side of a 2x6 pin header (H1). A further option is to input a MCLK via connector J12 and use
the CPLD (U4) to generate BCLK and ADCLRC.
The analogue input signals are applied to the evaluation board via double phono connectors
J7 (AIN_LEFT/RIGHT1), J9 (AIN_LEFT/RIGHT2), J10 (AIN_LEFT/RIGHT3), J14
(AIN_LEFT/RIGHT4).
There are two options for outputting digital data from the WM8775 evaluation board. There is
a coaxial output (J6) via a standard phono connector. The digital signals may also be
accessed via one side of a 2x8 pin header (H2).
If the CS8427 (U3) is being used to generate the MASTER, BCLK and ADCLRC clocks to
the WM8775 device in slave mode then a digital input is required to the CS8427. There is a
coaxial input (J8) via a standard phono connector.
There is also the facility to generate multi-rate clocks from U4 using SW3 as the rate
selection and either the MCLK from the CS8427 (U3) or an independent MCLK input to SMB
connector J12. The CPLD is designed to provide BCLK and ADCLRC at four different sample
rates: 256fs, 384fs, 512fs and 768fs. The CS8427 (U4) device is fixed at 256fs interface.
All WM8775 device pins are accessible for easy measurement via the 1x14 pin headers (J13
and J19) running up each side of the device.
Level-shift IC (U5) is used to shift the fixed +5V digital input from the CS8427 (U3) down to
the same level as DVDD and vice-versa.
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WM8775-EV1M
DIGITAL INPUT
REF-DES
J8
SOCKET NAME
SPDIF_IN
J12
MCLK
SIGNAL
Digital (AES/EBU, UEC958,
S/PDIF, EIAJ CP340/1201)
signal.
Digital MCLK for WM8775
Table 2 Digital Inputs
ANALOGUE INPUT
REF-DES
J7
SOCKET NAME
AIN_L/R_1
SIGNAL
Analogue Input signal
J9
AIN_L/R_2
Analogue Input signal
J10
AIN_L/R_3
Analogue Input signal
J14
AIN_L/R_4
Analogue Input signal
Table 3 Analogue Inputs
Note:
Analogue signals applied to these connectors are AC coupled before being input to the
WM8775.
When used in Slave Mode with the CS8427, an SPDIF signal must still be applied to phono
connector J8. This input signal is used to allow correct operation of the CS8427 as well as
being used to generate the MCLK for the WM8775.
DIGITAL INPUT
REF-DES
J6
SOCKET NAME
SPDIF_OUT
SIGNAL
Digital (AES/EBU, UEC958,
S/PDIF, EIAJ CP340/1201)
signal.
Table 4 Digital Output
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WM8775-EV1M
INTERFACES
Figure 2 Interfaces
HEADERS
H1
SIGNAL
H2
1/2
SLAVE LRC
12/11
SIGNAL
GND
3/4
GND
10/9
ADC DOUT
5/6
SLAVE BCLK
8/7
GND
7/8
GND
6/5
BCLK OUT
9/10
MCLK
4/3
GND
11/12
GND
2/1
ADCLRC OUT
Table 5 Headers
J13
WM8775
PIN NAME
J19
WM8775
PIN NAME
1
1
AIN1L
1
15
ADCREFP
2
2
BCLK
2
16
AVDD
3
3
MCLK
3
17
AGND
4
4
DOUT
4
18
AINVGR
5
5
ADCLRC
5
19
AINOPR
6
6
DGND
6
20
AINVGL
7
7
DVDD
7
21
AINOPL
8
8
MODE
8
22
AIN4R
9
9
CE
9
23
AIN4L
10
10
DI
10
24
AIN3R
11
11
CL
11
25
AIN3L
AIN2R
12
12
NC
12
26
13
13
VMIDADC
13
27
AIN2L
14
14
ADCREFGND
14
28
AIN1R
Table 6 Headers
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WM8775-EV1M
JUMPERS
JUMPERS
JUMPER STATUS
DESCRIPTION
J15
OPEN
SHORT
AINR input gain set to 1
AINR input gain set to 0.5 [default setting]
J17
OPEN
SHORT
AINL input gain set to 1
AINL input gain set to 0.5 [default setting]
Table 6 Links
SWITCHES
SWITCHES
SWITCH STATUS
SW1
(DATA FORMAT)
DESCRIPTION
1
1
1
1
SW2
2
0
0
0
3
0
0
0
4
1
0
0
5
0
0
0
6
0
1
0
DATA FORMAT
I2S Compatible [default setting]
24-bit Right Justified
Left Justified
After an input data format change has been made using
SW1, the CS8427 will only latch the new settings after
SW2 has been pressed and released.
SW3
(Sample Frequency
Format)
J18
(Software Control)
1
1
0
0
0
ON
OFF
2
0
1
0
0
3
0
0
1
0
4
0
0
0
1
SAMPLE FREQUENCY
768FS
512FS
384FS
256FS [default setting]
2-wire Control Mode
3-wire (SPI) Control Mode [default setting]
Table 7 Switches
LINKS
LINKS
LINK STATUS
DESCRIPTION
LNK1
(BCLK Source
Control)
Pins 1 and 2 SHORT
Pins 2 and 3 SHORT
Centre Position
H1 Source For BCLK [default setting]
MULTI BCLK (Select using SW3)
For WM8775 MASTER MODE
LNK2
(ADCLRC Source
Control)
Pins 1 and 2 SHORT
Pins 2 and 3 SHORT
Centre Position
H1 Source For ADCLRC [default setting]
MULTI ADCLRC (Select using SW3)
For WM8775 MASTER MODE
LNK3
(5V tolerant supply
control)
Pins 1 and 2 SHORT
Pins 2 and 3 SHORT
Centre Position
DVDD Supply for S/W and mode control [default setting]
+5v Supply for S/W and mode control
No Supply for S/W and mode control
Table 8 Links
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WM8775-EV1M
SOFTWARE CONTROL
There are two possible serial software control modes that may be selected to operate the
WM8775. 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 WM8775 in SPI (3-wire) mode, jumper switch J18 must be set to the OFF
position, selection of 3 wire mode will be indicated by D1 being OFF. The 3-wire serial
interface then becomes active on pins 9(CE), 10(DI) and 11(CL). 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 WM8775. The 3-wire latch,
data and clock lines may also be connected to the board via the test points TP20 (CE), TP18
(DI) and TP19 (CL).
Please refer to the WM8775 datasheet for full details of the serial interface timing and all
register features.
latch
CE
CL
DI
B15
B14
B13
B12
B11
control register address
B10
B9
B8
B7
B6
B5
B4
B3
B2
B1
B0
control register data bits
Figure 1 3-Wire Serial Interface
2-WIRE MODE
To operate the WM8775 in 2-wire mode, jumper switch J18 must be set to the ON position,
selection of 2 wire mode will be indicated by D1 being ON. The 2-wire serial interface
becomes active on pins 10(DI) and 11(CL). The serial interface on the board can be
connected to a PC via the printer port or any other standard parallel port. Note: a bi1
directional parallel port is required for 2-wire operation . The 2-wire data and clock lines
may also be connected to the board via the test points TP18 (DI) and TP19 (CL).
When used in 2-wire mode, the WM8775 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 WM8775 evaluation
board selecting address 0011011. CSB must be pulled low or driven low through the software
writes if address 0011010 is used (as is performed in the WM8775-EV1S software provided).
Figure 2 2-Wire Serial Interface
Note: 1If the 2-wire mode is not reporting as expected then the most likely cause is that the parallel port being used is not
bi-directional. In most PC’s, the parallel port can be configured in the BIOS settings during initial power up.
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WM8775-EV1M
REGISTER MAP
REGISTER
ADDRESS
(Bit 15 – 9)
Bit[8]
R0 (00h)
0
UPDATE
LINMUTE
HPLA[6:0]
R1 (01h)
1
UPDATE
RINMUTE
HPRA[6:0]
R2 (02h)
10
UPDATEA
LO1ZC
R3 (03h)
11
UPDATED
LDA[7:0]
R4 (04h)
100
UPDATED
RDA[7:0]
R5 (05h)
101
UPDATED
R6 (06h)
110
0
R7 (07h)
111
0
R8 (08h)
1000
0
Bit[7]
Bit[6]
Bit[5]
Bit[4]
Bit[3]
Bit[2]
Bit[1]
Bit[0]
HPMASTA[6:0]
MASTDA[7:0]
0
0
0
0
PL[3:0]
0
0
0
0
R9 (09h)
1001
0
0
0
R10 (0Ah)
1010
0
0
0
0
0
0
DACWL[1:0]
ADCWL[1:0]
DZCEN
0
0
0
DMUTE
ADCLRP
0
ADCMS
DACMS
R13 (0Dh)
1101
0
0
R14 (0Eh)
1110
ZCLA
LAG[7:0]
R15 (0Fh)
1111
ZCRA
RAG[7:0]
R16 (10h)
10000
R17 (11h)
10001
LCEN
R18 (12h)
10010
FDECAY
R19 (13h)
10011
0
R20 (14h)
10100
CHGPERZC[1:0]
R21 (15h)
10101
LRBOTH
MUTELA
R22 (16h)
10110
0
0
R23 (17h)
10111
ADCOSR
0
HPPD
MAXGAIN[2:0]
ALCZC
0
0
0
ADCFMT[1:0]
ADCRATE[2:0]
DACPD
ADCPD
PDWN
HLD[3:0]
ATK[3:0]
0
NGTH[2:0]
TRANWIN[2:0]
MUTERA
DEEMPH
DACFMT[1:0]
LCT[3:0]
0
DCY[3:0]
0
DZFM[1:0]
ADCBCP
ADCHPD
1100
LCSEL[1:0]
PHASE[1:0]
DACLRP
1011
0
ATC
0
R11 (0Bh)
AINPD
0
IZD
DACBCP
R12 (0Ch)
DACRATE[2:0]
0
TOD
0
NGG
NGAT
MAXATTEN[3:0]
AMX[4:0]
0
MX[2:0]
writing 000000000 to this register resets all registers to their default state
Table 9 Mapping of Program Registers
Please refer to the WM8775 datasheet for full details of the serial interface timing and all
register features.
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WM8775-EV1M
SERIAL INTERFACE SOFTWARE DESCRIPTION
The following section will detail the downloading and installation of evaluation software and
also the operation of the software and the functionality of each control button.
SOFTWARE DOWNLOAD
The current evaluation board software should be downloaded from the Wolfson website
[www.wolfsonmicro.com].
From the homepage it is recommended that you do a search for ‘WM8775’ and select the
‘more’ button located under the ‘EVALUATION BOARDS’ heading. Select ‘DOWNLOAD’
from the right hand side of the screen under the ‘SOFTWARE’ heading. Once you have
accepted the licence agreement you can select the WM8775_EV1S_REVx.x.ZIP link and
download to your hard drive.
SOFTWARE INSTALLATION
Once the .zip file has been downloaded, to install the software:
•
Open the .zip file
•
Double click on the setup.exe file.
•
Follow the on-screen installation instructions and save to the desired location.
The software can then be opened by either running the extracted WM8775_EV1_REV1.exe
file from the saved location. Alternatively select: Start > Programs > WM8775-EV1S Revx.x >
WM8775-EV1S.
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WM8775-EV1M
SOFTWARE OPERATION
The WM8775 software has been constructed on one main panel which has been split into the
functional areas of the device. This makes the software easy to use and also very clear what
the register setting configuration currently is.
The main menu panel shown in Figure 3 provides full register control as well as offering a
number of pull-down menus.
Figure 3 Software Main Menu Panel
SUBMIT ALL
The ‘Submit All’ button will submit the current panel settings to every register of the WM8775.
This means changes within all the visible sections will be submitted. This is the only method
for writing to the WM8775 device.
WM8775 RESET
The ‘Reset’ button writes to the reset register (R23) but does not reset the control panel
values. If the previous values are to be resubmitted then the ‘Submit All’ button should be
pressed.
RESET SOFTWARE PANEL SETTINGS
If the user would like to start afresh then the ‘Reset Software Panel Settings’ button should
also be pressed. Pressing this button does not write to the device, it only resets the panel
settings to the WM8775 default state.
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WM8775-EV1M
WOLFSON LOGO
Left clicking on the Wolfson logo will open the PCs default web browser and go top the
Wolfson Microelectronics website (‘www.wolfsonmicro.com’).
SOFTWARE INTERFACE
This panel details the selected interface method from the pull down menu. The WM8775
device should be configured using J18 to match this selection.
Important: It must be noted that the CS8427 SPDIF decoder IC will only work at a rate
of 256fs. This will limit the sample rates that may be set using the WM8775 unless an
external source is used supplying signals directly to the relevant pins of header H1 or
taking the signals from the relevant pins of header H2.
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WM8775-EV1M
EVALUATION BOARD CONFIGURATION
The WM8775 device will power up in an operational mode. Therefore no software control is
required to obtain a digital output when a signal is applied to AIN_L/R_1. For this reason it is
recommended that the default hardware configuration is as follows.
+5v
DGND
DVDD
+2.7V
to
+3.6V
J1
J2
J3
AVDD
+2.7V
to
+5.5V
J4
AGND
J5
AIN_L/R_1
SPDIF_
OUT
OPEN
0
SW1
1
1
2
3
4
5
6
AIN_L/R_2
The SPDIF input is
required to provide
clocks for the
WM8775 audio
interface.
SW2
H1
SPDIF_
IN
1
H2
2
3
SW3
OPEN
J12
1
AIN_L/R_3
0
1
J11
J13
1
LNK2
PARALLEL PORT
4
LNK1
AIN_L/R_4
J19
1
1
1
1
1
LNK3
1
J15
J17
J18
1
Figure 4 Evaluation Board Default Configuration
This configuration allows an analogue signal to be applied to AIN_L/R_1 and the digital data
to be output on the SPDIF_OUT connector. The WM8775 is configured for slave mode and
the clocks are generated from the CS8427 device.
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WM8775-EV1M
LINKS AND
JUMPERS
LINK/JUMPER
STATUS
DESCRIPTION
H1
Fit jumpers (1,2)
(5,6) (9,10)
MCLK, BCLK and ADCLRC generated from CS8427
H2
Fit jumpers (1,2)
(5,6) (9,10)
ADC BCLK, ADCLRC and data to CS8427
J15
SHORT
AINR input gain set to 0.5
J17
SHORT
AINL input gain set to 0.5
SW1
1
1
2
0
3
0
4
1
SW3
1
0
2
0
3
0
4
1
5
0
6
0
DATA FORMAT
I2S Compatible
SAMPLE FREQUENCY
256FS
J18
OFF
3-wire (SPI) Control Mode
LNK1
Pins 1 and 2
SHORT
BCLK Selection from H1
LNK2
Pins 1 and 2
SHORT
ADCLRC Selection from H1
LNK3
Pins 1 and 2
SHORT
DVDD Supply for S/W and mode control
Table 10 Default Board Configuration
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WM8775-EV1M
SCHEMATIC LAYOUT
Figure 5 Functional Diagram
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WM8775-EV1M
Figure 6 Digital Interface
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WM8775-EV1M
Figure 7 Software Control
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WM8775-EV1M
Figure 8 Level Shift
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WM8775-EV1M
Figure 9 Analogue Input
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WM8775-EV1M
Figure 10 WM8775
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WM8775-EV1M
Figure 11 Power
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WM8775-EV1M
WM8775-EV1B PCB LAYOUT
Figure 12 Top Layer Silkscreen
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WM8775-EV1M
Figure 13 Top Layer
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WM8775-EV1M
Figure 14 Bottom Layer
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WM8775-EV1M
Figure 15 Bottom Layer Silkscreen
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WM8775-EV1M
WM8775-EV1B BILL OF MATERIAL
REFERENCE DESIGNATOR
QTY
0.1uF 0805 SMD Ceramic Capacitor 50V X7R
DESCRIPTION
C1, C3, C4, C14, C19, C22, C27, C29, C39, C40,
C42, C43, C44, C45, C47, C48, C49, C50, C51
19
0.01uF 0805 SMD Ceramic Capacitor 50V X7R
C11
1
10uF 10V SMD Tantalum Capacitor case A
C16
1
0.1uF 0603 SMD Ceramic Capacitor 16V X7R
C18, C20
2
10uF 6.3 Dia 2.5 pitch Oscon Through Hole Cap. 25V 20%
C2, C5, C6, C46, C52, C53, C54
7
4.7nF 0603 SMD Ceramic Capacitor 50V X7R
C21
1
Unpop 0805 SMD Ceramic Capacitor site
C23, C25, C28, C30, C33, C34, C41
7
10uF 6.3 Dia 2.5 pitch Oscon Through Hole Cap. 16V 20%
C7, C9, C12, C15, C24, C31, C35, C37
8
220pF 0805 SMD Ceramic Capacitor 50V X7R
C8, C10, C13, C17, C26, C32, C36, C38
8
HSMY-C670 0805 SMD Chip LED YELLOW
D1
1
2x6 2.54mm pitch PCB Pin Header VERTICAL
H1, H2
2
4mm Non-Insulated Panel Socket 16A
J1, J2, J3, J4, J5
5
2x5 2.54mm Male PCB Header LoPro VERTICAL
J11
1
SMB Connector PCB Mount 50 Ohm VERTICAL
J12
1
1x14 2.54mm pitch PCB Pin Header VERTICAL
J13, J19
2
1x2 PCB Pin Header 0.1" VERTICAL
J15, J17
2
36-way Centronics/IEE488 PCB mountable Connector
J16
1
1x2 Jumper Switch 0.1" on-off VERTICAL
J18
1
Phono Socket PCB mount BLACK
J6
1
Phono Socket PCB mount Pair Red/White
J7, J9, J10, J14
4
Phono Socket PCB mount YELLOW
J8
1
0R 1206 Resistor on 1210 Inductor site
L1, L2, L3
3
Unpop 1210 Surface Mount Inductor site
L4
1
3.3uH 1210 Surface Mount Inductor '1210A series'
L5
1
JSK9-16-G0 PCB 1x3 Jumper Switch 0.1" Center-off
3
VERTICAL
LNK1, LNK2, LNK3
TN0200T N- Channel MOSFET SOT23
Q1, Q2, Q3
3
10K 0805 SMD chip resistor 1% 0.1W
R1, R3, R9, R11, R16, R17, R19, R22, R24, R29,
R32, R36, R44, R55,
14
75R 0805 SMD chip resistor 1% 0.125W
R10
1
620R 0805 SMD chip resistor 1% 0.1W
R12
1
100K 0805 SMD chip resistor 1% 0.1W
R13
1
1K2 0805 SMD chip resistor 1% 0.1W
R14, R40, R43, R48
4
Unpopulated 0805 resistor site
R2, R4, R15, R20, R23, R25, R27, R30, R34,
R57, R59
11
33R 0805 SMD chip resistor 1% 0.1W
R31, R33, R35, R37, R38, R39
6
4K7 0805 SMD chip resistor 1% 0.1W
R41, R46, R52
3
5k1 0805 SMD chip resistor 1% 0.125W
R47, R50, R54, R56
4
0R 0805 SMD chip resistor 1% 0.1W
R5, R18, R21, R26, R28, R42, R45, R49, R51,
10
R58
560R 0805 SMD chip resistor 1% 0.1W
R53
1
47k 1206 SMD chip 4 resistor array 5% 0.063W
R6, R7, R8
3
Slotted Panhead Screw - M3 thread; 12mm long
SC1, SC2, SC3, SC4
4
Hexagonal brass M3 size spacer 20mm length
SPR1, SPR2, SPR3, SPR4
4
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WM8775-EV1M
DESCRIPTION
QTY
REFERENCE DESIGNATOR
DIL Switch 6-Way Rocker
SW1
1
B3F1000 SPNO PCB mount switch
SW2
1
DIL Switch 4-Way Rocker
SW3
1
1.32mm PCB Test Terminal BLACK
TP1, TP3, TP6, TP7, TP9, TP11,TP12, TP15,
TP17, TP21
10
1.32mm PCB Test Terminal RED
TP2, TP4, TP5, TP8, TP10, TP13, TP14, TP16,
TP18, TP19, TP20
11
2:1 Ratio 96KHz SPDIF Digital Audio transformer SOIC
U1
1
DS1813 5V active Low Power-On-Reset chip SOT
U2
1
CS8427 96KHz Audio Transceiver
U3
1
XC9536XL-15 3.3V 36 macrocell CPLD
U4
1
74ALVC164245 16 Bit Dual Supply Bus Transceiver SSO
U5
1
WM8775 24-bit 96kHz ADC with 4 Channel I/P Mux
U6
1
Plain M3 size washer
WSH1, WSH2, WSH3, WSH4
4
Table 11 WM8775EV1B Bill Of Material
Note: 1 The audio transformer used on this board is manufactured by Scientific Conversion Inc.
(www.scientificonversion.com).
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WM8775-EV1M
APPENDIX
EXTERNAL DSP CONNECTION TO THE WM8775-EV1B
The WM8775-EV1B evaluation board has been designed to allow it to be easily connected to
an external DSP platform with error free operation.
The following information is provided to ease the connection process and ensure that all
signals sent and received by the WM8775-EV1B are reliable and at the correct voltage
levels.
AUDIO INTERFACE CONNECTIONS
It is recommended that twisted pair (signal twisted with GND) or shielded wires are used to
make the audio interface connections between the DSP and WM8775-EV1B platforms. This
is to ensure that no interference or noise is picked up by the clocks or data lines, thus
reducing performance and reliability.
When the WM8775 is set in Slave Mode, the jumpers on header H1 should be removed,
disconnecting the digital input clocks section of the evaluation board. The audio interface
timing and data signals from the DSP platform should then be connected as shown in Figure
16. The signals should be connected to H1 and not on the header strip J13 running up the
left side of the device. Connecting the signals on the output side of the level-shift IC (U5) will
cause drive contention between U5 and the DSP and could result in damage to either or both
devices. In most cases, the DSP supplies will be set around 3V for low power portable
applications. The inputs to the level-shift IC (74ALVC164245) have a TTL threshold (i.e.
Logic High = +2V(min); Logic Low = +0.8V(max)) and low input current requirements (i.e.
15uA max) allowing most DSP's to connect directly.
Figure 16 Connections from DSP Platform
The digital inputs to the WM8775 have a CMOS threshold (i.e. Logic High (min) = DVDDx0.7;
Logic Low (max) = DVDDx0.3). These are met directly by the level shift IC outputs.
The jumpers on H2 should also be removed, disconnecting the digital output section of the
WM8775 evaluation board. The ADCDAT data (DOUT) from the WM8775 should then be
connected to the DSP via pin 4 of header strip J13 and the GND connection should be taken
from pin 6 of header strip J13.
The DOUT signal should be taken direct from the WM8775 digital output (J13) as the output
side of the level-shift IC (U5) from the WM8775 is pulled up to +5V which may overdrive and
cause damage to the DSP inputs. The digital output levels of the WM8775 are Logic High
(min) = DVDDx0.9; Logic Low (max) = DVDDx0.1 which should meet the input level
requirements of most DSPs running at +3V supplies. If the DSP is running with +5V supplies
then the connections to it should be made from the output side of the level-shift IC (U5), by
connecting H2 pin9 and using pin 10 for ground.
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WM8775-EV1M
When the WM8775 is set to Master mode the jumpers on header H1 and H2 should be
removed, and LNK1 and LNK2 should be set to the centre position, this will disconnect the
digital input section of the evaluation board. If an internal MCLK from U5 is to be used then
fit a jumper link between H1 pins 9 and 10, a SPDIF signal should then be applied to J8. If an
external MCLK signal is being used (i.e. supplied by the DSP) then the DSP platform should
be connected as shown in Figure 17. The signals should be connected to H1 and not on the
header strip J13 running up the side of the device. Connecting the signals on the output side
of the level-shift IC (U5) will cause drive contention between U5 and the DSP and could
result in damage to either or both devices. In most cases, the DSP supplies will be set
around +3V for low power portable applications. The inputs to the level-shift IC
(74ALVC164245) have a TTL threshold (i.e. Logic High = +2V(min); Logic Low = +0.8V(max))
and low input current requirements (i.e. 15uA max) allowing most DSPs to connect directly.
MCLK
GND
H1
Figure 17 Timing Connections from DSP Platform
The digital inputs to the WM8775 have a CMOS threshold (i.e. Logic High (min) = DVDDx0.7;
Logic Low (max) = DVDDx0.3). These are met directly by the level shift IC outputs.
Alternatively an SMB connector (J12) is supplied to apply an external MCLK from example a
signal generator.
The jumpers on H2 should also be removed, disconnecting the digital output section of the
WM8775 evaluation board.
The DOUT, BCLK and ADCLRC signals should be taken direct from the WM8775 digital
output (DOUT J13/4, BCLK J13/2, ADCLRC J13/5) as the output side of the level-shift IC
(U5) from the WM8775 is pulled up to +5V which may overdrive and cause damage to the
DSP inputs. The digital output levels of the WM8775 are Logic High (min) = DVDDx0.9;
Logic Low (max) = DVDDx0.1 which should meet the input level requirements of most DSPs
running at +3V supplies. If the DSP is running with +5V supplies (and +5V tolerant inputs)
then the connections from the WM8775 evaluation board to the DSP should be made from
H2 on the output side of the level-shift IC from the WM8775.
This will ensure that the DSP input level specifications are met.
SOFTWARE INTERFACE
When using the WM8775-EV1B evaluation board with a DSP platform, the registers may be
set using the supplied software with a PC and parallel port cable as shown in Figure 18. The
example shown is for the WM8775 set to slave mode, interface connections to the board
depends on independent configuration for master or slave.
If the DSP is being used to write to the WM8775 registers as well as supplying/receiving the
audio interface timing and data signals, then it is recommended that twisted pair or shielded
wires are used to connect the DSP platform to the WM8775-EV1B. A direct connection can
be made to pin 9 (CE), pin 10 (DI) and pin 11 (CL) of header strip J13 for 3-wire software
mode as shown in Figure 19. This is applicable to a DSP with either 3v or 5v tolerant
thresholds as the software pins have 5v thresholds.
The same connections apply for controlling the WM8775 via 2-wire software mode (i.e. only
pin 10 (DI) and pin 11 (CL) of header strip J13 are used). Pin 9 (CE) can be pulled low on the
board if device address 0011010 [0x34h] is required or pulled high address 0011011 [0x36h]
is required.
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WM8775-EV1M
CONNECTION DIAGRAMS
Software
Control
WM8775-EV1B
J13
DSP
Platform
Audio
Interface
J19
H1
Figure 18 DSP Connection with PC Control using Wolfson Software
WM8775-EV1B
DSP
Platform
Audio
Interface
H1
J13
J19
DSP
Software
Control
Figure 19 Full DSP Control
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WM8775-EV1M
EVALUATION SUPPORT
The aim of this evaluation kit is to help you to become familiar with the functionality and
performance of the WM8775 CODEC.
If you require more information or require technical support please contact Wolfson
Microelectronics Applications group through the following channels:
Email:
[email protected]
Telephone Apps:
(+44) 131 272 7070
Fax:
(+44) 131 272 7001
Mail:
Applications Department at address on last page.
or contact your local Wolfson representative.
Additional information may be made available from time to time on our web site at
http://www.wolfsonmicro.com
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WM8775-EV1M
IMPORTANT NOTICE
Wolfson Microelectronics plc (WM) reserve the right to make changes to their products or to discontinue any product or
service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing
orders, that information being relied on is current. All products are sold subject to the WM terms and conditions of sale
supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation
of liability.
WM warrants performance of its products to the specifications applicable at the time of sale in accordance with WM’s
standard warranty. Testing and other quality control techniques are utilised to the extent WM deems necessary to support
this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by
government requirements.
In order to minimise risks associated with customer applications, adequate design and operating safeguards must be used
by the customer to minimise inherent or procedural hazards. Wolfson products are not authorised for use as critical
components in life support devices or systems without the express written approval of an officer of the company. Life
support devices or systems are devices or systems that are intended for surgical implant into the body, or support or
sustain life, and whose failure to perform when properly used in accordance with instructions for use provided, can be
reasonably expected to result in a significant injury to the user. A critical component is any component of a life support
device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or
system, or to affect its safety or effectiveness.
WM assumes no liability for applications assistance or customer product design. WM does not warrant or represent that
any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual
property right of WM covering or relating to any combination, machine, or process in which such products or services might
be or are used. WM’s publication of information regarding any third party’s products or services does not constitute WM’s
approval, license, warranty or endorsement thereof.
Reproduction of information from the WM web site or datasheets is permissible only if reproduction is without alteration and
is accompanied by all associated warranties, conditions, limitations and notices. Representation or reproduction of this
information with alteration voids all warranties provided for an associated WM product or service, is an unfair and deceptive
business practice, and WM is not responsible nor liable for any such use.
Resale of WM’s products or services with statements different from or beyond the parameters stated by WM for that
product or service voids all express and any implied warranties for the associated WM product or service, is an unfair and
deceptive business practice, and WM is not responsible nor liable for any such use.
ADDRESS:
Wolfson Microelectronics plc
20 Bernard Terrace
Edinburgh
EH8 9NX
United Kingdom
Tel :: +44 (0)131 272 7000
Fax :: +44 (0)131 272 7001
Email :: [email protected]
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