AN4146 - STMicroelectronics

AN4146
Application note
STSmartVoice demonstration board STEVAL-MKI126Vx
Introduction
This application note describes the STSmartVoice demonstration board STEVALMKI126Vx. The connections and setup of the programming and interface boards are also
detailed as well as other versions of the main board hosting the different microphones.
The STA321MP/MPL (package option respectively VFQFPN56 and TQFP64) has been
designed to decode the pulse-density modulation (PDM) signal coming from the
microphones and convert it into the most common digital audio format: I2S. The device is
also able to provide pulse-width modulation (PWM) outputs, one per channel, suitable to
support an analog interface. The processor also includes a digital block, the hardware
accelerator, composed of a chain of biquads (see Figure 1).
The STEVAL-MKI126Vx board can connect up to six microphones using the sockets
provided or through a dedicated six-microphone array. The digital interface of the device
allows interfacing the MIC output to the most widely used audio receivers and digital
amplifiers or simply evaluating the MIC using generic audio measurement equipment. The
filtered PWM signals allow the connection of a headset to listen to the audio received
through the microphones.
The fully digital path ensures a high level of processing with sound preconditioning, filtering
and voice enhancement. The pre- and post-mixing of the signals coming from the
microphones, in combination with the frequency equalization block, allow the
implementation of acoustic algorithms such as beam forming.
Figure 1. Microphone processor
STA321MP/MPL
MEMS Digital
Microphone 1
1
PDM
Interface
MEMS Digital
Microphone 6
6
SDA
SCL
I2C
Audio
Matrix
( Muxing/
Mixing )
PLL
PWM
Scalable
Microphone
Processor TM
Serial Data
Output
Hardware
Accelerator
I2S
OUTxA
OUTxB
LRCK
BICK
SDAT 1/2/3
Clock management
March 2013
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www.st.com
Contents
AN4146
Contents
1
2
3
Demonstration board and accessories . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1
Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2
STEVAL-MKI126Vx board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3
Microphone adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4
STEVAL-MKI126Vx overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.5
STEVAL-MIKI126Vx connections and setup . . . . . . . . . . . . . . . . . . . . . . . 9
1.5.1
Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.5.2
Clock management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.5.3
MEMS microphones, PDM interface and level shifter . . . . . . . . . . . . . . 12
1.5.4
Output section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Selectors, jumpers and connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1
Selectors and jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.2
Microphone audio adapter connections . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Software settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Appendix A STEVAL-MKI126Vx schematics, layout and BOM . . . . . . . . . . . . . . 22
4
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Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
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List of tables
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
L/R channel selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Selectors and jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Jumpers and further options - summary table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
I2C writes of setup file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
STEVAL-MK126Vx bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
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List of figures
AN4146
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24.
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Microphone processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
STEVAL-CCA035V1 (APWLink). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
STEVAL-MKI138V1 (ST audio hub) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
STEVAL-MKI126Vx . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
MP34DT01 microphone adapter board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
STEVAL-MKI126Vx - block diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
STEVAL-MKI126Vx placement and serigraphy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Power supply - block diagram subsection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Clock management - block diagram subsection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Microphones and I/O interfaces - block diagram subsection . . . . . . . . . . . . . . . . . . . . . . . 13
Headphone out schematic - only one channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Female headers on STEVAL-MKI126Vx board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Microphone audio adapter board plugged into STEVAL-MKI126
(STSmartVoice demonstration board) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Interface board connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
APWorkbench launch wizard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
APWorkbench tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Multi-microphone interface panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Pre- and post-mixer of channel 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
STEVAL-MKI126Vx schematic - page 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
STEVAL-MKI126Vx schematic - page 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
STEVAL-MKI126Vx schematic - page 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
STEVAL-MKI126Vx schematic - page 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
STEVAL-MKI126Vx layout - top view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
STEVAL-MKI126Vx layout - bottom view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
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1
Demonstration board and accessories
Demonstration board and accessories
The STSmartVoice board STEVAL-MKI126Vx requires a dedicated interface board,
STEVAL-CCA035V1 (APWLink) or STEVAL-MKI138V1 (ST audio hub), for programming
the device. Additional boards hosting the microphones are compatible with the board using
suitable connectors placed onboard. These boards are listed and shown in the following
sections and figures.
1.1
Interface
The STEVAL-CCA035V1 works as a programming board since it manages writing to the
I2C. The microphone processor is a digital device set using the I2C commands. In addition,
the STEVAL-CCA035V1 also serves as an interface board since the I2S provided by the
processor is routed on its connector (referred to as the APWLink connector). Finally, this
board also provides on the connector the 12.288 MHz clock used by the processor in case
the sampling frequency of the I2S is 192 kHz or 48 kHz.
Figure 2. STEVAL-CCA035V1 (APWLink)
The STEVAL-MKI138V1 performs the functions listed above plus supports audio streaming
via the USB cable. Basically the ST audio hub, using the STM32F107RC microcontroller, is
able to program the STA321MPL device via the I2C and decodes the I2S into a USB stream
in order for the PC to manage the sound captured by the microphones.
Figure 3. STEVAL-MKI138V1 (ST audio hub)
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Demonstration board and accessories
1.2
AN4146
STEVAL-MKI126Vx board
The main task of the STEVAL-MKI126Vx in Figure 4 is to convert the PDM signals provided
by the microphones both into the more common I2S and PWM. The I2S signal is routed both
on a general connector and APWLink connector. The PWM signals, properly filtered,
provide an analog interface. There are two different versions of the board depending on the
microphones soldered onboard:
•
STEVAL-MKI126V1: MP45DT02 devices have been soldered
•
STEVAL-MKI126V3: MP34DT01 devices have been soldered
Figure 4. STEVAL-MKI126Vx
1.3
Microphone adapters
Microphone adapters are small circular PCBs with a single soldered MEMS microphone.
There are three different ordering codes for each board corresponding to the different type
of mounted digital microphone (STEVAL-MKI129V1 for the MP34DT02, STEVAL-MKI129V2
for the MP34DB01, and STEVAL-MKI129V3 for the MP34DT01. Please refer to AN4184
“Microphone coupon boards STEVAL-MKI129Vx based on the MP45DT02, MP34DB01,
and MP34DT01” for further details.
Figure 5. MP34DT01 microphone adapter board
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1.4
Demonstration board and accessories
STEVAL-MKI126Vx overview
Figure 6. STEVAL-MKI126Vx - block diagram
Array connector
STEVAL-MKI126V
MIC3
Vdd
MIC4
MIC5
Vdd
Clk
Out
gnd
L/R
S6
MIC6
Vdd
Clk
Vdd
Clk
Out
gnd
L/R
L/R
S7
3.3V
Clk
Out
gnd
Out
gnd
L/R
S8
S9
J3
J4
SW1
Vdd
Clk
L/R
Out
S10
3.3V
gnd
High
3.3V
MIC1
S5
SW2
S12
S13
S14
S15
S16
Low
1.8V
S17
HP Jack
3.3V
Vdd
OpAmp
Clk
L/R
Out
gnd
PDM Interface
S4
STA321MPL
Flip-flop
CK
/2
3.3V
LRCK
BICK
I2S
(3x)
SDO12
SDO34
SDO56
/4
Regulator
3.3V
SCL
JP1
S1
Regulator
1.8V
I2C
SDA
S2
PWM
3.3V
MIC2
S3
S11
Level shifter
I 2S
connector
+3.3V
Gnd +5V
11.2896MHz
APWlink
connector
The board hosts the homonymous microphone processor STA321MP or MPL according to
the package.
It also includes two voltage regulators in order to provide the required voltages. One
regulator generates 3.3 V for supplying both the processor and the microphone and the
other one generates 1.8 V in case the user desires to supply the microphones at this
voltage.
For the reason above, there is also a voltage level shifter that must be used if the
microphones and the processor are fed with different voltages.
Another important section is represented by the clock. The board hosts an oscillator in
order to provide the clock to the processor. The device is able to generate the clock for the
microphones (default clock-out value / 4), but a flip-flop has been introduced for dividing
the STA321MP clock out for a debugging purposes; the flip-flop during normal use is
bypassed.
The input section is represented by the two soldered microphones, the four microphone
sockets and the 8x2 header connector for the microphone array. The board has been
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designed for automatically switching from the microphones onboard to the microphones on
the array thanks to two voltage-controlled switches SW1 and SW2.
The output section is represented by an I2S connector that exports the I2S bus and a
headphone amplifier, TS482, which also allows a digital-to-analog path. These two paths
allow interfacing the microphones to, respectively, a generic audio processor or
measurement equipment or to interface the MEMS to a PC.
A further component is the APWLink connector that allows the control of the processor via
I2C. This connector also provides a 3.3 V source line and I2S signals.
All selectors have their own name on the board serigraphy and are composed of two
resistors where only one is soldered according to the desired functionality.
Figure 6 depicts all the components listed and the different colored traces represent the
following sections of the board:
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•
Power supply (green trace)
•
Clock management (black trace)
•
PDM interface (rainbow traces)
•
Output sections
–
Headphone out (fuchsia trace)
–
I2S signals (fuchsia trace)
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1.5
Demonstration board and accessories
STEVAL-MIKI126Vx connections and setup
The figure below represents the placement of the component and the selectors, made up of
resistors, which manage all the possible configurations and signals paths supported by the
demonstration board.
Figure 7. STEVAL-MKI126Vx placement and serigraphy
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Demonstration board and accessories
1.5.1
AN4146
Power supply
The STA321MP processor needs 3.3 V as a supply voltage while the operative voltage
range of the microphones is 1.64 V - 3.6 V where the typical value is 1.8 V. For this reason
there are two voltage regulators onboard. One regulator is used to generate the 3.3 V from
an external 5 V supply (J20) while the other one generates the 1.8 V from the 3.3 V. The
3.3 V can also be provided from the APWLink connector on pin 11 and enabled on the board
by closing JP1. In spite of the fact that the STEVAL-CCA035V1 board is always connected
(for the I2C communication) and so 3.3 V is always provided to the STEVAL-MKI126Vx, the
demonstration board also hosts the 3.3 V regulator (scaled by an external 5 V supply) to
allow better noise immunity. The following diagram depicts the supply lines scheme: S2
(R78-R79) selects the 3.3 V source while S3 (R80-R81) selects either 1.8 V or 3.3 V as the
microphone supply voltage. These selectors are indicated on the board with the serigraphy
3V3 SEL and MIC_VCC, respectively.
Figure 8. Power supply - block diagram subsection
S2
S3
Regulator
1.8V
JP1
Regulator
3.3V
APWlink
connector
+3.3V
Gnd +5V
Once the 3.3 V voltage supply has been chosen, the devices that are fed with this voltage
are the STA321MP, the flip-flop, the level shifter and the opamp. Regarding the
microphones section, the selector S3 offers the possibility to choose their supply level.
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1.5.2
Demonstration board and accessories
Clock management
Clock management is an important topic since all of the devices involved have their own
clock.
Figure 9. Clock management - block diagram subsection
Microphones
Clock
S10
3.3V
S11
Level shifter
High
3.3V
Low
1.8V
3.3V
PDM Interface
3.3V
STA321MPL
Flip-flop
CK
/2
/4
S1
APWlink
connector
11.2896MHz
The processor device needs two clocks: one for its digital core and one for the PDM (a
register bit allows selecting the ratio between the two clocks). The microphones and the
PDM interface need the same clock while the processor core clock is fed with a quadruple of
such clock. The core clock can be provided to the processor through the STEVALCCA035V1, 12.288 MHz on pin 15, or thanks to an onboard 11.2896 MHz oscillator, the
selector S1 (R82-R83) is used to select one of these two clocks. The choice of the
frequency value depends on the desired output sampling frequency of the I2S:
•
12.288 MHz: Fs = 12.288/64 = 192 kHz → Fs = 48 kHz enabling I2S decimator
•
11.2896 MHz: Fs = 11.2896/64 = 176.4 kHz → Fs =44.1 kHz enabling I2S decimator
The clock for the microphones and PDM interface is generated thanks to the PLL enabling
the device microphone mode (refer to the STA321MP datasheet) and exported thanks to the
clock-out (pin 25). The PDM interface is internally clocked by enabling one bit of a dedicated
device register. If the microphone mode is not enabled, the external flip-flop is used as a
frequency divider of the clock-out; this is for a debugging purposes only. For this reason, the
I/F_CLK pin stays open by not soldering it to R32.The clock routing is managed by the two
selectors S10, S11 called MIC_CLK_SEL on the board serigraphy. In microphone mode, the
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clock-out works exactly as the microphone clock, so it must be provided to the microphone
pins. This is done by closing the resistor R43 of the selector S11 (R42-R43). In the case of
supplying the microphones at 1.8 V, the clock provided to the microphones must be reduced
from 3.3 V to 1.8 V. The level shifter provides this scaled clock, if needed. When the user
wants to feed the microphones at 1.8 V, the resistor R42 of the selector S11 must be
soldered instead of R43 (R42-R43).The selector S10 (R40-R41) is used when the
microphone mode is not enabled, thus, for debugging purposes only. For this reason, both
of its resistors are not soldered.
1.5.3
MEMS microphones, PDM interface and level shifter
Table 1. L/R channel selection
L/R
Clock low
Clock high
GND
Data valid
High impedance
VDD
High impedance
Data valid
Since the STA321MP processor manages the channels separately, there is no need to set
the microphone in stereo configuration in this demonstration board. The L/R pins can be set
to either GND or VDD through the selectors S4, S5, S6, S7, S8 and S9 (respectively the
couples R38-R39, R36-R37, R46-R47, R44-R45, R48-R49 and R50-R51). By default, all
the L/R pins are connected to GND, in other words R36, R38, R44, R46, R48 and R51 are
soldered.
The processor STA321MP samples the microphone data according to the PDM interface
clock. The sampling edge can be set to both rising and falling since, in microphone mode,
the processor provides an internal PDM interface clock shifted 90º with respect to the clockout. Refer to the STA321MP/MPL datasheet for details.
The data output is a digital signal carrying the audio information with a PDM encoding. The
processor STA321MP is able to decode these signals and convert them into the more
common I2S and PWM. The I2S signal is routed both on a general connector and APWLink
connector; the PWM signals, suitably filtered, provide an analog interface (fuchsia traces in
Figure 10 on page 13).
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Demonstration board and accessories
Figure 10. Microphones and I/O interfaces - block diagram subsection
Array connector
3.3V
MIC3
Vdd
Clk
L/R
MIC4
MIC5
Vdd
Out
gnd
Clk
L/R
S6
MIC6
Vdd
Vdd
Clk
Out
gnd
L/R
S7
Clk
Out
gnd
Out
L/R
S8
gnd
S9
J3
J4
SW1
Vdd
Clk
L/R
Out
3.3V
Level shifter
gnd
High
3.3V
MIC1
S5
SW2
S12
S13
S14
S15
S16
Low
1.8V
S17
HP Jack
3.3V
Vdd
3.3V
OpAmp
Clk
L/R
Out
MIC2
3.3V
PDM Interface
PWM
LRCK
gnd
STA321MPL
S4
BICK
I2S
(3x)
SDO12
SDO34
SDO56
I 2S
connector
APWlink
connector
The inputs of the PDM interface depend on the group of selectors S12, S13, S14, S15, S16
and S17 called Data Level SEL (respectively the couples R64-R65, R70-R71, R66-R67,
R72-R73, R68-R69 and R74-R75). These selectors are set if the PDM inputs come from the
microphones or from the level shifter.
The level shifter (enabled through the level shifter EN) is used when the microphones
supply voltage is set to 1.8 V. Under this condition the sensors are a 1.8 V section while the
decoder is still a 3.3 V section. In order to match these two board portions, a level shifter is
needed to increase the PDM data output level before providing it to the processor.
In a default configuration the PDM inputs are directly connected to the microphones data, in
other words R65, R67, R69, R71, R73 and R75 are soldered.
Microphones 1 and 2 are always connected since they are soldered on the board(a), the
other four inputs depend on the connection of the microphone adapter boards. If the user
wants to use the external microphone array, the microphone adapter boards must be
unplugged and then the user must connect the array to the array connector with the
dedicated cable. When the array is plugged in, pin 2 of the array connector is forced to
a. Regarding MIC1 and MIC2, the board can host every type of ST digital microphone since it supports all the
footprints
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ground (due to the array board schematic) and this trace is used to switch off the LED D1
and to control the voltage-controlled switches SW1 and SW2 (IC1 and IC2 on the STEVALMKI126Vx board). The LED switching off indicates that the array is connected and the
switches commutate the PDM input 1 and 2 from the data of the microphones onboard to
the data of the microphones on the array.
1.5.4
Output section
The output section is simply represented by a connector that exports the I2S bus (J17) and
an operational amplifier used as the headphone driver. The STA321MP includes a PWM
modulator so it possible to export this signal and after a suitable filtering (refer to Figure 11)
an analog signal is obtained. This dual output option allows interfacing the microphones to
both a digital processor (through the I2S interface) and to analog systems like the PC line in
(filtered output).
Figure 11. Headphone out schematic - only one channel
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Selectors, jumpers and connectors
2
Selectors, jumpers and connectors
2.1
Selectors and jumpers
Table 2. Selectors and jumpers
Name on block diagram
Serigraphy
Function
S1
MCK_Sel
Core clock selection:
R82: Coming from APWLink connector
R83: Coming from on-board oscillator
S2
3V3 SEL
3.3 V selection:
R78: External supply needed
R79: Coming from APWLink connector
S3
MIC_VCC
Microphone supply voltage:
R80: 3.3 V
R81: 1.8 V
S4
LR_H/L
Microphone 2 L/R:
R38: GND
R39: Vdd
S5
LR_H/L
Microphone 1 L/R:
R36: GND
R37: Vdd
S6
Microphone 3 L/R:
R46: GND
R47: Vdd
S7
Microphone 4 L/R:
R44: GND
R45: Vdd
S8
Microphone 5 L/R:
R48: GND
R49: Vdd
S9
Microphone 6 L/R:
R50: Vdd
R51: GND
S10
MIC CLK SEL
Microphone clock voltage level:
R42: 1.8 V
R43: 3.3 V
S11
DEBUGGING
PURPOSES ONLY
MIC CLK SEL
Microphone clock voltage level:
R40: 1.8 V
R41: 3.3 V
S12
Data Level SEL
PDM1 selection:
R64: when microphones are 1.8 V supplied
R65: when microphones are 3.3 V supplied
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Selectors, jumpers and connectors
AN4146
Table 2. Selectors and jumpers (continued)
Name on block diagram
Serigraphy
Function
S13
Data Level SEL
PDM2 selection:
R70: when microphones are 1.8 V supplied
R71: when microphones are 3.3 V supplied
S14
Data Level SEL
PDM3 selection:
R66: when microphones are 3.3 V supplied
R67: when microphones are 3.3 V supplied
S15
Data Level SEL
PDM4 selection:
R72: when microphones are 1.8 V supplied
R73: when microphones are 3.3 V supplied
S16
Data Level SEL
PDM5 selection:
R68: when microphones are 1.8 V supplied
R69: when microphones are 3.3 V supplied
Data Level SEL
PDM6 selection:
R74: when microphones are 1.8 V supplied
R75: when microphones are 3.3 V supplied
S17
Table 3. Jumpers and further options - summary table
Name on block
diagram
16/30
Serigraphy
Function
JP1
3V3 APW
3V3 from APWLink board enable:
Closed: 3V3 from APWLink
Open: line open
J3-J4
TWIN3-TWIN2
Reserved
Level shifter EN
Level shifter enable:
Pin 1: GND device is disabled
Pin 3: 1.8 V device is enabled
PLL_Bypass
PLL bypass or not:
R76: PLL is bypassed
R77: PLL not bypassed
DocID023502 Rev 2
AN4146
2.2
Selectors, jumpers and connectors
Microphone audio adapter connections
Connecting the microphone audio adapter boards is very simple. The STEVAL-MKI126Vx
board hosts four groups of three female headers like those depicted in the figure below. The
J12, J25 and J26 group can host one of the three different types of microphone audio
adapters
Figure 12. Female headers on STEVAL-MKI126Vx board
Figure 13 shows the connection of the audio adapter board for the MP34DT01. It’s also
possible to cut one of the microphones and use a single small circular PCB, allowing the
evaluation of a different type of digital microphone at the same time.
Figure 13. Microphone audio adapter board plugged into STEVAL-MKI126
(STSmartVoice demonstration board)
DocID023502 Rev 2
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Software settings
3
AN4146
Software settings
The demonstration board is programmed using the PC interface board STEVAL-CCA035V1
(APWLink) or STEVAL-MKI138Vx (ST audio hub). The figure below shows the connection
using the APWLink connector (J15).
Figure 14. Interface board connection
To program the microphone processor STA321MP/MPL, the APWorkbench tool is needed.
Follow these steps to correctly set up the device:
1.
Run the tool
2.
Click on the "MEMS Microphones Demo Kit" button
3.
Select “STSmartVoice Demo Kit” in the “Microphone Kit Selection” box
4.
Click on the "Run selected application…" button
Figure 15. APWorkbench launch wizard
18/30
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AN4146
Software settings
The selection of the application allows the user to access all supported configurations of the
STSmartVoice board. The kit will work as a microphone onboard manager by selecting the
"Multi-microphone interface" choice. Then the user must confirm by clicking on the "Apply
selected configuration" button.
Figure 16. APWorkbench tool
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19/30
Software settings
AN4146
The selection of the kit as a "Multi-microphone interface" will perform the I2C writes given in
the table below.
Table 4. I2C writes of setup file
20/30
Address
Value
Note
00
9B
PDM interface enable
02
20
20: FS = XTI/256.
Example:
44.1 kHz = 11.2896 MHz/256
48 kHz = 12.288 MHz/256
04
18
Ch4/5 Binary
07
7A
Remove Soft Volume
08
80
Bridge power-UP
0A
00
Master volume 0 dB
0B
54
Ch1: +6 dB
0C
54
Ch2: +6 dB
0E
48
Ch4: +12 dB
0F
48
Ch5: +12 dB
5D
01
Microphone mode
81
09
Output I2S interface pins set as output
DocID023502 Rev 2
AN4146
Software settings
The selection of the kit as a "Multi-microphone interface" also lets the user access the
dedicated panel given in the figure below.
Figure 17. Multi-microphone interface panel
The user can route the signal of the desired microphone on the output interfaces (I2S or HP
out) using the mapping drop-down menus on the right side of the panel. These menus act
on the pre-mixer of the respective channel. In the default configuration of the I2S output data
1 and 2 (SDO12), the pre-mixer of channel 1 takes 100% of PDMIN_1 (MIC1) and channel
2 takes 100% of PDMIN_2 (MIC2). The user can also directly edit the mixer values at will.
The post-mixer works in the same way, but takes a percentage of the outcome of the
processing block.
As an example, the figure below shows the layout of the pre- and post-mixer of channel1.
Figure 18. Pre- and post-mixer of channel 1
DocID023502 Rev 2
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STEVAL-MKI126Vx schematics, layout and BOM
AN4146
Appendix A
Figure 19. STEVAL-MKI126Vx schematic - page 1
3V3_INT
1
R7
10K
R81
R79
3V3
1V8
0R0 N.F.
0R0
2
3V3_INT
MIC_VCC
3V3_INT
PWDN
SDO_56
R80
R78
3V3_INT
3V3_EXT
3V3_INT
SDO_34
0R0
0R0 N.F.
C9
1nF
XT_ACTIVE
CSX750FBC11.2896MTR
SDO_12
C17
100nF
LRCKO
C16
100nF
BICKO
4
3V3_INT
2
R77
H3
H4
1
1
H2
C14
100pF
C5
100nF
C8
100nF
49
1
1uF
C53
C49
220pF
R31
5k
R14
3.9K
42
41
R15
3.9K
40
R16
3.9K
HPOUT1
C43
470pF
R17
3.9K
C44
150pF
0R0
1
2
R19
3.9K
3
4
39
3.9K
R21
38
37
3.9K
R20
36
470pF
C45
3.9K
R23
3.9K
R22
150pF
C46
R83
U10
R18
3.9K
3.9K
R25
OUT1
VCC
IN1-
OUT2
IN1+
IN2-
GND
IN2+
7
EN
R82
6
0R0 N.F.
R84
MCLK
0R0 N.F.
5
3.9K
R24
C50
220uF
R30
5k
3V3_INT
3V3_INT
0R0
XTI
TS482
R27
10k
C11
100nF
R85
OSC_CK
8
R26
10k
C51
220pF
HPOUT1
C47
220pF
C48
220pF
HPOUT2
HPOUT2
+
3V3_INT
+
50
EN
C12
100nF
U8
2
H1
OUT1B
51
52
3V3_INT
3V3_INT
1
R3
3.3K
1
OUT1A
EAPD
54
55
56
57
58
59
60
61
53
GND
VDD3.3
VDD2.5
BICKO
LRCKO
SDO12
SDO34
VDD3.3
GND
VDD2.5
62
XTI
R28
10k
43
CKOUT_H
SCL
C13
1nF
R29
10k
44
32
17
0R0
R76
SDA
1
45
0R0 N.F.
CKOUT/4_H
OUT8A
31 OUT7B
OUT7A
16
3V3_INT
2
SA
PLLB
R32
0R0 N.F.
63
PWDN 64
RESET
30
15
GND
3V3_INT
EAPD
35
VDD3.3
OUT6A 34
OUT6B
33
VDD2.5
VDD3.3
RESET
VDD2.5
GND
OUT8B
14
1
VDD3.3
29
13
OUT5B
GND
12
OUT5A
BICKI
28
C1
100nF
I/F_CLK
LRCKI
27
11
OUT4B
VDD2.5
10
PDMIN_1
SDI12
CKOUT
PDMIN_2
OUT4A
26
9
U1
SDI34
VDD3.3
8
PDMIN_3
OUT3B
25
PDMIN_4
SDI56
24
3V3_INT
7
OUT3A
GND_PL
PDMIN_5
SDI78
23
6
VDD_PL
PDMIN_6
VDD3.3
PLLF
5
5X2_HEADER
GND
VDD2.5
22
4
2
10K R2
48
OUT2A 47
OUT2B
46
VDD2.5
GND
XTI
2
MVO
GND
VDD3.3
21
1
3
20
SDO_56
2
C15
100nF
SDO56
4
SCL
6
3
SDO78
8
5
SDA
7
1
19
BICKO
SDO_12
SDO_34
I/F_CLK
OSC_CK
C52
220uF
HEADPHONE O/P
1
2
3
J24
22/30
STEVAL-MKI126Vx schematics, layout and BOM
DocID023502 Rev 2
10
18
3V3_INT
J17
9
1
1
Y1
3V3_INT
LRCKO
R1
100
2
3
AN4146
STEVAL-MKI126Vx schematics, layout and BOM
Figure 20. STEVAL-MKI126Vx schematic - page 2
3V3_EXT
U7
IC-LD1117V33
J20
CN-02P
1
+
VIN
VOUT
1V8
3V3_INT
2
GND
1
C25
2
10uF/6.3v
3
C26
100nF
C27
100nF
C18
100nF
C19
100nF
U6
1
3V3_INT
1V8
5
OUT
VIN
C40
+
5
BYPASS
PDMIN_4_2378
6
MIC_DATA5
C3
1uF
4
GND
2
VINH
4
MIC_DATA3
LDS3985XX
3
3
PDMIN_2_2378
U2
1
2
MIC_DATA1
C39
100nF
7
PDMIN_6_2378
+C24
8
CKOUT_L
10uF
9
CKOUT/4_H
10uF
10
C2
33nF
VL
VCC
I/O_VL1
I/O_VCC1
I/O_VCC2
I/O_VL3
I/O_VL2
I/O_VCC3
I/O_VCC4
I/O_VL5
I/O_VL4
I/O_VCC5
I/O_VCC6
I/O_VL7
I/O_VL6
I/O_VCC7
I/O_VCC8
I/O_VL8
GND
OE
20
19
PDMIN_1_2378
18
MIC_DATA2
17
PDMIN_3_2378
16
MIC_DATA4
15
PDMIN_5_2378
14
MIC_DATA6
13
CKOUT_H
12
CKOUT/4_L
11
1V8
ST23783E
1
S1
3
2
3V3_INT
3V3
VDD 14
CKOUT_H
1D
3
CK
D
Q
Q
2CLR
13
1CK
2D 12
1PR
2CK 11
1Q
2PR
+
C23
100nF
1
2
SDO_56
3
4
BICKO
5
6
7
8
9
10
11
12
2
SDO_12
2
SCL
JP1
JP
MUTE
4
5
CKOUT/2_H
6
1Q
7
CK
D
Q
Q
GND
74VHC74
MCLK
10
2Q
9
2Q
8
2
1
R5 100
1
CLR
2
C42
1
10uF/6.3v
U4
13
14
1
15
16
C4
47pF
C6
10pF
0R0 R6
J15
SDO_34
LRCKO
2
1
R4 100
SDA
FAIL
RESET
PWDN
C7
10pF
CKOUT/4_H
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STEVAL-MKI126Vx schematics, layout and BOM
AN4146
Figure 21. STEVAL-MKI126Vx schematic - page 3
On Board MIC
MIC_VCC
R37
MIC_VCC
R39
0R0 N.F.
0R0 N.F.
U3
R36
C10
1
GND
2
LR
VDD
6
DOUT
5
0R0
U5
R38
C20
100nF
10uF
C21
1
GND
2
LR
3
GND
VDD
6
DOUT
5
CLK
4
C22
100nF
10uF
0R0
MIC_DATA2_BOARD
MIC_DATA1_BOARD
3
GND
R8
4
CLK
MIC_CK
MP34DB01
MP34DB01
U9
U11
VDD
CLK
1
4
DATA
5
GND
DATA
3
U12
VDD
GND
2
3
1
4
CLK
DATA
MP34DT01
2
L/R
1
VDD
MP34DT01
5
DATA
2
1
U13
L/R
5
4
CLK
L/R
CLK
5
4
L/R
2
GND
VDD
GND
3
3
C31
15pF
MP45DT01
C28
15pF
C29
15pF
MIC_CK
100R
C30
15pF
100R
MP45DT01
R9
On board Mic socket
MIC_VCC
J26
MIC_VCC
0R0 N.F.
1
J30
3
3
CON3
R11
CON3
MIC_CK
J29
1
2
2
3
100R
C34
15pF
3
CON3
C35
15pF
CON3
2
C33
15pF
CON3
1
MIC_VCC
24/30
J31
1
2
2
3
3
CON3
CON3
R13
MIC_CK 100R
DocID023502 Rev 2
C41
15pF
J34
3
CON3
J35
1
1
2
2
3
3
CON3
CON3
0R0
MIC_CK 100R
C38
MIC_DATA6 15pF
0R0
R12
R50
2
3
CON3
0R0 N.F.
R49
R48
MIC_DATA5
C37
15pF
J14
1
J36
1
2
C36
15pF
MIC_VCC
0R0 N.F.
1
R51
J32
0R0
2
0R0
2
J28
MIC_DATA4
R46
1
100R
C32
15pF
JP
JP3
3
J25
1
R44
MIC_CK
1
R10
CON3
0R0 N.F.
2
3
J12
MIC_DATA3
R45
1
R47
2
AN4146
STEVAL-MKI126Vx schematics, layout and BOM
Figure 22. STEVAL-MKI126Vx schematic - page 4
Mic Array / on board Mic switch
Mic data level selection
Default setting : 3V3
IC1
ARRAY_DET
6
MIC_DATA1_BOARD
5
MIC_DATA1
4
MIC_DATA1_ARRAY
S2
IN
D
VCC
S1
GND
1
MIC_DATA1
0R0
PDMIN_1
2
3
R65
3V3_INT
C54
100nF
R64
PDMIN_1_2378
0R0 N.F.
MIC CLOCK SELECTION
R40
IC-STG719
CKOUT/4_L
0R0 N.F.
R67
IC2
MIC_DATA3
MIC_CK
0R0
6
MIC_DATA2_BOARD
5
MIC_DATA2
4
MIC_DATA2_ARRAY
S2
IN
D
VCC
S1
GND
1
C55
100nF
CKOUT/4_H
0R0
R66
2
3
R41
PDMIN_3
PDMIN_3_2378
0R0 N.F.
R42
CKOUT_L
0R0 N.F.
R69
IC-STG719
MIC_CK
MIC_DATA5
R43
0R0
MIC_DATA3
J3-1
PDMIN_5
CKOUT_H
0R0 N.F.
R68
J3-2
MIC_DATA4
PDMIN_5_2378
MIC_DATA5
MIC_DATA2
0R0 N.F.
MIC ARRAY INTERFACE
R71
J4-1
MIC_DATA6
J4-2
2
3
4
MIC_DATA1_ARRAY
5
6
MIC_DATA2_ARRAY
7
8
MIC_DATA3
9
10
R73
MIC_DATA4
11
12
0R0
MIC_DATA5
13
14
MIC_DATA6
15
PDMIN_2_2378
0R0 N.F.
3V3_INT
ARRAY_DET
1
MIC_CK
R70
MIC Input Selection Indicator
MIC_VCC
0R0
PDMIN_2
MIC_DATA4
PDMIN_4
16
R72
ARRAY_DET
J38
0R0 N.F.
100R
75R
R33
PDMIN_4_2378
R54
R34
220R
R75
MIC_DATA6
0R0
PDMIN_6
1
R74
PDMIN_6_2378
2
D1
LED-1
0R0 N.F.
LED On: On board Mic
LED Off: Mic Array
DocID023502 Rev 2
25/30
STEVAL-MKI126Vx schematics, layout and BOM
Figure 23. STEVAL-MKI126Vx layout - top view
Figure 24. STEVAL-MKI126Vx layout - bottom view
26/30
DocID023502 Rev 2
AN4146
AN4146
STEVAL-MKI126Vx schematics, layout and BOM
Table 5. STEVAL-MK126Vx bill of material
Type
Package
Description
Qty
Reference
Manufacturer
CCAP
CC0603
100 nF +/-10% X7R 50 V
18
C1 C5 C8 C11 C12
C15 C16 C17 C18
C19 C20 C22 C26
C27 C54 C55 C23
C39
CCAP
CC0805
10 uF +/-10% X7R 10 V
2
C10 C21
Murata
CCAP
CC0603
15 pF +/-10% NPO 50 V
12
C28 C29 C30 C31
C32 C33 C34 C35
C36 C37 C38 C41
Murata
CCAP
CC0603
220 pF +/-10% NPO 50 V
4
C47-49 C51
Murata
CCAP
CC1206
10 uF +/-10% X7R 10 V
4
C24 C25 C40 C42
Murata
CCAP
CC0603
1 nF +/-5% X7R 50 V
2
C9 C13
Murata
CCAP
CC0603
1 uF +/-10% X7R 10 V
2
C3 C53
Murata
CCAP
CC0603
100 pF +/-10% NPO 50 V
1
C14
Murata
CCAP
CC0603
10 pF +/-10% NPO 50 V
2
C6 C7
Murata
CCAP
CC0603
47 pF +/-10% NPO 50 V
1
C4
Murata
CCAP
CC0603
470 pF +/-10% NPO 50 V
2
C43 C45
Murata
CCAP
CC0603
150 pF +/-10% NPO 50 V
2
C44 C46
Murata
CCAP
CC0603
33nF +/-5% X7R 50V
1
C2
Murata
TCAP
C7343
220 uf 10 V +/-10% 125°C
tanatalum
2
C50 C52
19
R6 R36 R38 R43
R44 R46 R48 R51
R65 R67 R69 R71
R73 R75 R76 R79
R80 R82 R84
Murata
Murata
RES
R0603
0 ohm +/-10% 1/8W
AVX
RES
R0603
0 ohm +/-10% 1/8W
20
R32 R37 R39 R40
R41 R42 R45 R47
R49 R50 R64 R66
R68 R70 R72 R74
R77 R78 R81 R83
R85
RES
R0603
100 ohm +/-10% 1/8W
10
R1 R4 R5 R8 R9 R10
R11 R12 R13 R33
Murata
RES
R0603
220 ohm +/-10% 1/8W
1
R34
Murata
RES
R0603
75 ohm +/-10% 1/8W
1
R54
Murata
RES
R0603
10K ohm +/-10% 1/8W
6
R2 R7 R26 R27 R28
R29
Murata
RES
R0603
3.3 k ohm +/-10% 1/8W
1
R3
Murata
DocID023502 Rev 2
Remark
Do not
solder
27/30
STEVAL-MKI126Vx schematics, layout and BOM
AN4146
Table 5. STEVAL-MK126Vx bill of material (continued)
Type
Package
Description
Qty
RES
R0603
3.9 k ohm +/-1% 1/8W
12
R14 R15 R16 R17
R18 R19 R20 R21
R22 R23 R24 R25
Murata
RES
R0603
5K ohm +/-1% 1/8W
2
R30 R31
Murata
Diode
D1206
SMD LED diode, red,1.8 V
1
D1
any source
OSC
SMD5X7
CSX750FBC11.2896MTR
1
Y1
Citizen
Connector
Throughhole
1x3 2.54 mm pitch female
connector
12
J12 J14 J25 J26 J28
J29 J30 J31 J32 J34
J35 J36
any source
Connector
Throughhole
1x3 2.54 mm pitch male
connector
1
S1
any source
Connector
Throughhole
2x8 2.54 mm pitch male
Connector
2
J15 J38
any source
Connector
Throughhole
2x5 2.54 mm pitch male
connector
1
J17
any source
Connector
Throughhole
1x2 2.54 mm pitch male
connector
5
J3 J4 JP1 JP3 J20
any source
Phonejack
Throughhole
SONGCHEN CKX-3.5-06
1
J24
Plastic
supportor
Throughhole
female 8 mm
4
any source
Plastic
supportor
Throughhole
male 3 mm
4
any source
IC
TQFP64
STA321MPL
1
U1
STMicroelectronics
IC
VQFN56
STA321MP
1
U8
STMicroelectronics
IC
SOT23-5
LDS3985M18R 1.8 V
regulator
1
U2
STMicroelectronics
IC
TSOP20
ST2378ETTR
1
U6
STMicroelectronics
IC
MINISO8
TS482IST
1
U10
STMicroelectronics
IC
SO14
74VHC74MTR
1
U4
STMicroelectronics
IC
SOT223
LD1117S33
1
U7
STMicroelectronics
IC
SOT236L
STG719STR
2
IC1 IC2
STMicroelectronics
MEMS
mic
MP34DT01
2
U12 U13
STMicroelectronics
Solder
for V3
MEMS
mic
MP34DB01
2
U9 U11
STMicroelectronics
Solder
for V2
MEMS
mic
MP45DT02
2
U3 U5
STMicroelectronics
Solder
for V1
28/30
Reference
DocID023502 Rev 2
Manufacturer
Remark
Song Cheng
Do not
solder
AN4146
4
Revision history
Revision history
Table 6. Document revision history
Date
Revision
02-Oct-2012
1
Initial release.
2
Added audio hub demonstration board (STEVAL-MKI138V1) to application note
Updated Section 1: Demonstration board and accessories, added Figure 3
Updated Section 1.3: Microphone adapters, updated Figure 5
Updated Section 2.2: Microphone audio adapter connections, added Figure 12, updated
Figure 13
Updated Section 3: Software settings, added Figure 14, updated Figure 15, 16, 17
22-Mar-2013
Changes
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