WT32i Datasheet by Silicon Labs

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($9 SILIEIJN LABS
WT32i BLUETOOTH AUDIO MODULE
DATA SHEET
Monday, 18 March 2019
Version 1.3.1
Silicon Labs
VERSION HISTORY
VERSION
COMMENT
1.0
First version
1.1
Added example how to protect the battery by shutting down the regulators at
certain voltage level
1.2
Fixed PCM pin numbering
1.21
Design check list added
1.22
UART brake signal updated
1.23
Chapter 9.3.1 added
1.24
Added note to reset section
1.3
Updated order codes and added more information about iWRAP versions.
1.3.1
Fixed one wrong build number
Silicon Labs
TABLE OF CONTENTS
1 Design Check List..........................................................................................................................................6
2 WT32i Product Numbering ............................................................................................................................7
3 Block diagram ................................................................................................................................................8
4 Pinout and Terminal Description ...................................................................................................................9
5 Electrical Characteristics ............................................................................................................................ 12
5.1 Absolute Maximum Ratings ................................................................................................................ 12
5.2 Recommended Operating Conditions ................................................................................................. 12
5.3 Digital Terminals.................................................................................................................................. 12
5.4 Audio Characteristics .......................................................................................................................... 13
5.4.1 ADC .............................................................................................................................................. 13
5.4.2 DAC .............................................................................................................................................. 14
5.4.3 A2DP Codecs............................................................................................................................... 14
5.5 RF Characteristics ............................................................................................................................... 16
5.5.1 RF Transceiver ............................................................................................................................ 16
5.5.2 Antenna Characteristics ............................................................................................................... 17
5.6 Current Consumption .......................................................................................................................... 20
6 Power Control and Regulation ................................................................................................................... 21
6.1 Protecting the Battery by Configuring the Module to Turn Off at Certain Voltage .............................. 23
6.2 Reset ................................................................................................................................................... 24
6.2.1 Internal POR ................................................................................................................................ 24
7 Battery Charger .......................................................................................................................................... 26
8 GPIO and AIO Functions ............................................................................................................................ 27
8.1 iWRAP supported GPIO Functions ..................................................................................................... 27
8.2 Outputting Internal Clocks ................................................................................................................... 27
8.3 Auxiliary ADC ...................................................................................................................................... 28
8.4 Software I2C Interface ........................................................................................................................ 28
9 Serial Interfaces .......................................................................................................................................... 29
9.1 UART Interface .................................................................................................................................... 29
9.1.1 Resetting Through UART Break Signal ....................................................................................... 30
9.1.2 UART Configuration While Reset is Active .................................................................................. 30
9.1.3 UART Bypass Mode .................................................................................................................... 30
9.2 USB Interface ...................................................................................................................................... 31
9.3 Programming and Debug Interface (SPI) ............................................................................................ 32
9.3.1 Multi-slave Operation ................................................................................................................... 32
10 Audio Interfaces ...................................................................................................................................... 33
10.1 Stereo Audio Codec Interface ...................................................................................................... 33
10.1.1 ADC .............................................................................................................................................. 33
Silicon Labs
10.1.2 DAC .............................................................................................................................................. 35
10.1.3 Microphone Input ......................................................................................................................... 36
10.1.4 Line Input ..................................................................................................................................... 37
10.1.5 Output Stage ................................................................................................................................ 38
10.1.6 Mono Operation ........................................................................................................................... 40
10.1.7 Side Tone ..................................................................................................................................... 40
10.2 PCM Interface .............................................................................................................................. 40
10.3 I2S Interface ................................................................................................................................. 40
10.4 IEC 60958 Interface ..................................................................................................................... 42
11 Design Guidelines ................................................................................................................................... 44
11.1 Audio Layout Guide ..................................................................................................................... 44
11.1.1 EMC Considerations .................................................................................................................... 44
11.1.2 Choosing Capacitors and Resistors ............................................................................................ 44
11.2 RF Layout Guide .......................................................................................................................... 45
11.3 Example Application Schematics ................................................................................................. 48
12 Physical Dimensions ............................................................................................................................... 52
13 Soldering Recommendations .................................................................................................................. 54
14 Package .................................................................................................................................................. 55
15 Certification Guidance for an End Product Using WT32i ....................................................................... 57
15.1 Bluetooth End Product Listing...................................................................................................... 57
15.2 CE Approval of an End-Product ................................................................................................... 57
15.3 FCC Certification of an End Product ............................................................................................ 58
15.3.1 Co-location with Other Transmitters ............................................................................................ 59
15.4 IC Certification of an End Product ............................................................................................... 59
15.5 MIC Japan Certification of an End Product .................................................................................. 59
16 WT32i Certifications ................................................................................................................................ 59
16.1 Bluetooth ...................................................................................................................................... 59
16.2 CE ................................................................................................................................................ 59
16.3 FCC .............................................................................................................................................. 60
16.4 IC .................................................................................................................................................. 61
16.4.1 IC .................................................................................................................................................. 61
16.5 MIC Japan .................................................................................................................................... 62
16.6 KCC (South-Korea) ...................................................................................................................... 62
16.7 Qualified Antenna Types for WT32i-E ......................................................................................... 62
Silicon Labs
WT32i Bluetooth® Audio Module
DESCRIPTION
WT32i is an audio specific Bluetooth 3.0
module with excellent radio frequency
performance and enhanced audio features,
enabling a best in class Bluetooth audio
experience. In addition to a
certified Bluetooth radio and software stack,
WT32i also contains a DSP, stereo audio
codec, and battery charger making it ideal
for fixed and portable audio applications.
WT32i includes Bluegiga's
iWRAP6 Bluetooth stack software which
implements A2DP, AVRCP v.1.5 profiles
and supports aptX® and AAC audio codecs
for stereo audio applications. For hands-free
applications iWRAP6 software also
supports HFP v.1.6, HSP, MAP and
PBAP and CVC® echo cancellation software.
For data communications to Android and
iOS applications iWRAP6 also
implements Bluetooth Serial Port Profile
(SPP) and Apple iAP profiles. WT32i is an
ideal solution for developers who want to
quickly integrate the latest Bluetooth audio
technologies without the time and costs
typically involved with a Bluetooth audio
chipset design.
APPLICATIONS:
Stereo speakers and sound bars
Hi-Fi devices
Hands-free kits
Stereo headsets
Figure 1: WT32i Bluetooth Audio Module
KEY FEATURES:
Bluetooth 3.0 compliant
Excellent Radio Performance
o Transmit power: +6.5 dBm
o Receiver sensitivity: -90 dBm
o Link budget: 96.5 dB
Integrated chip antenna or U.FL
antenna connector
Audio features
o Integrated DSP
o 16-bit stereo codec
o 44.1kHz ADC, 48kHz DAC
o Analog, I2S, PCM, SPDIF, and
microphone interfaces
o Optional aptX® and AAC stereo
audio codecs
o Optional CVC® echo
cancellation
o Wide Band Speech
Built-in battery charger
UART host interface
802.11 co-existence interface
10 software programmable IO pins
Operating voltage: 1.8V to 3.6V
Temperature range: -40C to +85C
Bluetooth, CE, FCC, IC, Korea and
Japan qualified
Integrated iWRAP6 Bluetooth stack
o 13 Bluetooth profiles
o Apple iAP1 and iAP2
compatibility
Silicon Labs
1 Design Check List
LDO
(1.8V...3.6V)
EN
IN
VDD_BAT
VREG_ENA
VDD_IO
On/Off cntrl
Battery Voltage
(2.7V...4.4V)
WT32i
Reset
Host CPU
GPIO
Min 15mm Min 15mm
6mm Metal clearance
area
Board edge
GND plane indentation 2mm GND plane indentation max 5.9 mm
Make sure that VRE_ENA is connected correctly
Use iWRAP command SET CONTROL VREGEN
command to configure the VREG_ENA pin
according to the HW
Reserve test points for SPI interface for
debugging and FW updates
The internal power on reset does not work
properly if the host pulls the reset line low during
boot. To prevent this, place a diode to the reset
input.
POWERING THE MODULE
RF LAYOUT
Make sure that the layout for the antenna is done
as instrcucted.
AUDIO DESIGN AND LAYOUT
See the example schematics on pages 49 -52
Avoid using single ended audio traces. Always
use differential audio signaling when possible
Use solid GND plane and make sure that all the
GND pins are connected to it by placing a GND
via right next to any GND pins.
When routing single ended audio traces, make
sure that the return current (i.e. GND) follows the
traces all the way from start to the end
DO NOT COMPROMISE AUDIO ROUTING
Differential audio signals are traced parallel
to make sure they have perfect common mode
rejection . All the audio traces are routed on a
solid GND plane.
Differential audio tarces are routed
symmetrically and parallel
www abs.com/aboutrus/contactrsales www.5ilabs.com/aboutrus/contactrsales
Silicon Labs
2 WT32i Product Numbering
Product code
Description
WT32i-A-AI61
WT32i Bluetooth Module with internal chip antenna and iWRAP 6.1.0 (build
1022) Bluetooth software
WT32i-A-AI61-APTX
WT32i Bluetooth Module with internal chip antenna and aptX® audio codec
capable iWRAP 6.1.0 (build 1024) Bluetooth software.
WT32i-A-AI61IAP
WT32i Bluetooth Module with internal chip antenna and Apple iAP capable
iWRAP 6.1.0 (build 1055) Bluetooth software. Available only to Apple MFI
licensees. Contact www.silabs.com/about-us/contact-sales for more
information.
WT32i-E-AI61
WT32i Bluetooth Module with U.FL connector and iWRAP 6.1.0 (build
1022) Bluetooth software
WT32i-E-AI61-APTX
WT32i Bluetooth Module with U.FL connector and aptX® audio codec
capable iWRAP 6.1.0 (build 1024) Bluetooth software.
WT32i-E-AI61IAP
WT32i Bluetooth Module with U.FL connector and Apple iAP capable
iWRAP 6.1.0 (build 1055) Bluetooth software. Available only to Apple MFI
licensees. Contact www.silabs.com/about-us/contact-sales for more
information.
DKWT32i-A
WT32i development kit
333 7
Silicon Labs
3 Block diagram
RAM
Baseband
DSP
MCU
Kalimba DSP
2.4
GHz
Radio
I/O
BC05-MM
XTAL
Balanced
filtter
Antenna
Flash
UART/USB
PIO
Audio In/Out
PCM/I2S
SPI
Reset
circuitry
Figure 2: Block Diagram of WT32i
BC05-MM
The BlueCore®5-Multimedia External is a single-chip radio and baseband IC for Bluetooth 2.4GHz systems. It
provides a fully compliant Bluetooth v3.0 specification system for data and voice. BlueCore5-Multimedia
External contains the Kalimba DSP coprocessor with double the MIPS of BlueCore3-Multimedia External,
supporting enhanced audio applications.
XTAL
Ther reference clock of WT32i is generated with 26 MHz crystal. All BC05-MM internal digital clocks are
generated using a phase locked loop, which is locked to the frequency of either the 26 MHz crystal or an
internally generated watchdog clock frequency of 1kHz.
RESET CIRCUITRY
The internal reset circuitry keeps BC05-MM in reset during boot in order for the supply voltages to stabilize.
This is to prevent corruption of the flash memory during booting. Please see chapter 6.1 for more detailed
description.
BALANCED FILTER
The internal balanced filter provides optimal impedance matching and band pass filtering in order to achieve
lowest possible in-band and out-of-band emissions.
ANTENNA
The antenna is a ceramic chip antenna with high efficiency. The antenna is insensitive to surrounding
dielectric materials and requires only a small clearance underneath which makes it compatible with previous
WT32I designs and well suitable for designs with high density.
FLASH
16 Mbit flash memory is used for storing the Bluetooth protocol stack and Virtual Machine applications. It can
also be used as an optional external RAM for memory-intensive applications.
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Silicon Labs
Page 9 of 63
4 Pinout and Terminal Description
AUDIO_OUT_N_LEFT
AUDIO_OUT_P_LEFT
AUDIO_OUT_P_RIGHT
AUDIO_OUT_N_RIGHT
GND
AUDIO_IN_N_LEFT
AUDIO_IN_P_LEFT
GND
AUDIO_IN_N_RIGHT
AUDIO_IN_P_RIGHT
MIC_BIAS
GND
VDD_CHG
VDD_BAT
LED0
SPI_MOSI
SPI_MISO
SPI_CLK
SPI_NCSB
PCM_CLK
PCM_SYNC
PCM_OUT
PCM_IN
PIO4
PIO5
PIO6
PIO7
PIO8
UART_NCTS
UART_NRTS
RESET
GND
VDD_IO
UART_TXD
UART_RXD
PIO10
PIO9
USB_D+
USB_D-
PIO3
PIO2
PIO1
PIO0
AIO1
AIO0
GND
GND
GND
VREG_ENA 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
GND
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
50
49
48
18
19
20
21
22
23
24
25
26
27
28
29
30
Figure 3: WT32i
Pin Number
Pin Name
Pad Type
Description
1
VREG_ENA
Input
SW configurable enable pin for the
internal regulators
2-4, 18, 31,
39, 43, 48
GND
GND
GND
17
VDD_IO
Power supply
1.7V - 3.6V power supply for the serial
interfaces and GPIOs
37
VDD_BAT
Power supply / Charger
output
2.7V - 4.4V supply voltage for the
internal regulators and output of the
battery charger
38
VDD_CHG
Power supply
Nominal 5V supply voltage for the
battery charger
Table 1: Supply Terminal Descriptions
Silicon Labs
Page 10 of 63
Pin
Number
Pin Name
Pin Type
Description
19
RESET
RESET
Active high reset. If not used, leave floating. When
connected, make sure that the reset is either pulled
high or floating (connected to high impedance)
during boot.
5
AIO0
Configurable I/O
AIO0 and AIO1 can be used to read the voltage
level through the internal ADC (refer to iWRAP
User Guide for details). AIO pins can also be
configured to be used as general digital IO pins
through PS settings. Internal clocks can be routed
out through AIO pins by setting corresponding PS
settings. Note that the AIO pins are powered from
internal 1.5V supply so the maximum voltage level
of the AIO pins is 1.5V.
6
AIO1
7
PIO0
Configurable CMOS I/O
General purpose IO's can be configured with
iWRAP for various functions. Each IO can be
configured individually as output or input with
strong or weak pull-up/-down. Using particular PS
setting GPIO pins can be used to implement WiFi
co-existence signaling between WT32i and a WiFi
radio. Software I2C interface can be implemented
for slow I2C functions such as configuring external
audio codec or display.
8
PIO1
9
PIO2
10
PIO3
13
PIO9
14
PIO10
22
PIO8
23
PIO7
24
PIO6
25
PIO5
26
PIO4
11
USB_D-
I/O
USB data minus
12
USB_D+
I/O
USB data plus with selectable internal 1.5k pull-up
resistor
15
UART_RXD
CMOS Input, weak internal
pull-down
UART data input
16
UART_TXD
CMOS output, tristate,
weak internal pull-up
UART data output
20
UART_NRTS
CMOS output, tristate,
weak internal pull-up
UART request to send, active low
21
UART_NCTS
CMOS Input, weak internal
pull-down
UART clear to send, active low
32
SPI_NCSB
CMOS Input, weak internal
pull-down
SPI chip select
33
SPI_CLK
CMOS Input, weak internal
pull-down
SPI clock
Silicon Labs
Page 11 of 63
34
SPI_MISO
CMOS Input, weak internal
pull-down
SPI data input
35
SPI_MOSI
CMOS output, tristate,
weak internal pull-down
SPI data output
36
LED0
Open drain output
LED driver
Table 2: Terminal Descriptions
Pin
Number
Pin Name
Pin Type
Description
40
MIC_BIAS
Analog
41
AUDIO_IN_P_RIGHT
Analog
42
AUDIO_IN_N_RIGHT
Analog
44
AUDIO_IN_P_LEFT
Analog
45
AUDIO_IN_N_LEFT
Analog
46
AUDIO_OUT_N_RIGHT
Analog
47
AUDIO_OUT_P_RIGHT
Analog
49
AUDIO_OUT_N_LEFT
Analog
50
AUDIO_OUT_P_LEFT
Analog
27
PCM_IN / I2S IN
CMOS input, weak
internal pull-down
PCM or I2S data input
28
PCM_OUT / I2S_OUT
CMOS outptu, tristate,
weak internal pull-down
PCM or I2S data output
29
PCM_SYNC / I2S_WS
Bidirectional, weak
internal down
PCM sync or I2S word select. WT32i can
operate as a PCM/I2S master providing the
sync or as a slave receiving the sync
30
PCM_CLK / I2S_SCK
Bidirectional, weak
internal down
PCM or I2S clock. WT32i can operate as a
PCM/I2S master providing the clock or as
a slave receiving the clock.
Table 3: Audio Terminal Descriptions
Silicon Labs
Page 12 of 63
5 Electrical Characteristics
5.1 Absolute Maximum Ratings
Min
Max
Unit
Storage temperature range
-40
+85
°C
Operating temperature range
-40
+85
°C
VDD_IO
-0.4
3.6
V
VDD_BAT
-0.4
4.4
V
VDD_CHG
-0.4
6.5
V
Digital Terminal voltages
VSS - 0.4V
VDD + 0.4V
V
AIO voltages
VSS - 0.4V
1.9V
V
Table 4: Absolute Maximum Ratings
5.2 Recommended Operating Conditions
Min
Max
Unit
Storage temperature range
-40
+85
°C
Operating temperature range
-40
+85
°C
VDD_IO
1.7
3.6
V
VDD_BAT
2.7
4.4
V
VDD_CHG
0
6.5
V
Digital Terminal voltages
0
VDD
V
AIO voltages
0
1.5V
V
Table 5: Recommended Operating Conditions
5.3 Digital Terminals
Input/Output Characteristic
Min
Max
Unit
VIL input logic level low
-0.3
0.25 x VDD
V
VIL input logic level high
0.625 x VDD
VDD + 0.3
V
VOL output logic level low, IOL = 4.0mA
0
0.125
V
VOL output logic level high, IOL = -4.0mA
0.75 x VDD
VDD
V
Strong pull-up
-100
-10
µA
Strong pull-down
10
100
µA
Weak pull-up
-5
-0.2
µA
Weak pull-down
0.2
5
µA
Table 6: Digital Terminal Characteristics
Silicon Labs
Page 13 of 63
5.4 Audio Characteristics
5.4.1 ADC
Parameter
Conditions
Min
Typ
Max
Unit
Resolution
-
-
-
16
Bits
Input Sample
Rate, Fsample
-
8
-
44.1
kHz
Signal to Noise
Ratio, SNR
Fsample
8kHz
-
79
-
dB
11.025kHz
-
77
-
dB
16kHz
-
76
-
dB
22.050kHz
-
76
-
dB
32kHz
-
75
-
dB
44.1kHz
-
75
-
dB
Input full scale at maximum gain (differential)
-
4
-
mV rms
Input full scale at minimum gain (differential)
-
800
-
mV rms
3dB Bandwidth
-
20
-
kHz
Microphone mode input impedance
-
6.0
-
kHz
THD+N @ 30mV rms input
-
0.04
-
%
Table 7: ADC characteristics
Silicon Labs
Page 14 of 63
5.4.2 DAC
Parameter
Conditions
Min
Typ
Max
Unit
Resolution
-
-
-
16
Bits
Output Sample
Rate, Fsample
-
8
-
48
kHz
Signal to Noise
Ratio, SNR
Fsample
8kHz
-
95
-
dB
11.025kHz
-
95
-
dB
16kHz
-
95
-
dB
22.050kHz
-
95
-
dB
32kHz
-
95
-
dB
44.1kHz
-
95
-
dB
Output Full Voltage Swing (differential)
-
750
-
mV rms
Allowed Load
Resistive
16
-
O.C.
Ω
Capacitive
-
-
500
pF
THD+N 16Ω Load
-
-
0.1
%
THD+N 100Ω Load
-
-
0.01
%
Table 8: DAC Characteristics
5.4.3 A2DP Codecs
5.4.3.1 SBC
SBC codec is the default codec used for Bluetooth A2DP connections. Any Bluetooth device supporting A2DP
audio profile supports SBC codec. SBC was originally design to provide reasonable good audio quality while
keeping low computational complexity. SBC does not require high bit rates. Thus it works sufficiently with
Bluetooth where the bandwidth and the processing power are limited.
5.4.3.2 aptX®
The aptX is widely used in high quality audio devices. aptX can provide dynamic range up to 120 dB and it
has the shortest coding delay (<2ms) than other coding algorithms. Using aptX® the whole system latency can
be reduced significantly because unlike SBC, it does not require buffering the audio. SBC reproduces a limited
audio band width whereas aptX® encode the entire frequency range of audio.
aptX® is more robust and resilient coding scheme than SBC and thus re-transmits does not occur as with
SBC.
Both SBC and aptX® have flat frequency response up to 14 kHz. Up to 14 kHz both algorithms produce good
quality audio with very little distortion. At frequencies higher than 14 kHz the benefit of aptX® becomes
obvious. SBC exhibits increasing attenuation with increasing frequency but aptX® retains high reproduction
quality.
aptX® requires purchasing a license for each Bluetooth address and the license agreement must be done with
CSR. The combination of aptX® license and the Bluetooth address is programmed into the module in the
module production line.
dav ,14 Ath vs. BSC Frequency Response 20 (AA\ v 25 U \ Freq (kHz) —ADLX (dBV) —sac (dBV)
Silicon Labs
Page 15 of 63
Figure 4: Frequency response of aptX and SBC codecs
5.4.3.3 AAC
AAC (Advanced Audio Coding) achieves better sound quality than MP3 and it is the default audio format for
YouTube and iPhone among others. AAC has long latency (>100ms) compared to aptX®. Because of high
processing capacity requirement for encoding, WT32i does not support AAC as A2DP source. Thus WT32i
can be used for receiving (A2DP sink) AAC (from iPhone for example) but it cannot transmit AAC coded
audio.
10 Powerconral steps +L +H
Silicon Labs
Page 16 of 63
5.5 RF Characteristics
5.5.1 RF Transceiver
Transceiver characteristic
Min
Typ
Max
Unit
Maximum transmit power
5
6.5
8
dBm
Minimum transmit power
-17
dBm
Transmit power stability over the temperature range
+/- 0.5
dB
Transmit power variation within the BT band
1
dB
Sensitivity DH1
RT
-90
dBm
-40C
-91
dBm
+85C
-86
dBm
Sensitivity 3DH5
RT
-83
dBm
-40C
-84
dBm
+85C
-80
dBm
Table 9: Transceiver characteristics
Table 10: Power control of WT32i
Silicon Labs
Page 17 of 63
Standard
Band /
Frequency
Min
(AVG /
PEAK)
Typ
(AVG /
PEAK)
Max
(AVG /
PEAK)
Limit by the Standard
(AVG / PEAK)
Unit
FCC part 15
transmitter
spurious
emissions
2nd harmonic
50 / 61
54 / 74
dBuV/m
3rd harmonic
< 40 /
50
54 / 74
dBuV/m
Band edge
2390MHz
54 / 74
dBuV/m
Band edge
2483.5MHz
54 / 74
dBuV/m
Band edge
2400MHz
(conducted)
-20
dBc
Band edge
2483.5MHz
(conducted)
-20
dBc
ETSI EN 300
328 transmitter
spurious
emissions
Band edge
2400MHz
-30
dBm
2nd harmonic
-35
-30
dBm
3rd harmonic
<-40
-30
dBm
ETSI EN 300
328 receiver
spurious
emissions
(2400 - 2479)
MHz
-47
dBm
(1600 - 1653)
MHz
-47
dBm
Table 11: WT32i-A spurious emissions
Note: All the emissions tested with maximum 8 dBm TX power
5.5.2 Antenna Characteristics
Note: Antenna characteristics may vary depending on the mother board layout. Following characteristics have
been measured using DKWT32i
Antenna efficiency -3.5 dB (45%)
Peak gain 0 dBi
Silicon Labs
Page 18 of 63
0 dB
-5 dB
-10 dB
-15 dB
-20 dB
Figure 5: Top view radiation pattern of DKWT32i
-2 dB
-4 dB
-6 dB
-8 dB
-10 dB
-12 dB
-14 dB
Figure 6: Side view radiation pattern of DKWT32i
Silicon Labs
Page 19 of 63
-1 dB
-2 dB
-3 dB
-4 dB
-5 dB
-6 dB
-7 dB
-8 dB
-9 dB
-10 dB
-11 dB
-12 dB
Figure 7: Front view radiation pattern
Silicon Labs
Page 20 of 63
5.6 Current Consumption
Operation Mode
Peak
Average
Unit
Idle
SET BT PAGEMODE 0 2000 0
12
2.0
mA
SET BT PAGEMODE 0 2000 1
2.0
SET BT PAGEMODE 0 2000 2
2.0
SET BT PAGEMODE 1 2000 0
32
2.0
SET BT PAGEMODE 1 2000 1
2.1
SET BT PAGEMODE 1 2000 2
2.1
SET BT PAGEMODE 2 2000 0
23
SET BT PAGEMODE 2 2000 1
2.2
SET BT PAGEMODE 2 2000 2
2.1
SET BT PAGEMODE 3 2000 0
23
SET BT PAGEMODE 3 2000 1
2.3
SET BT PAGEMODE 3 2000 2
2.2
SET BT PAGEMODE 4 2000 0
23
SET BT PAGEMODE 4 2000 1
2.3
SET BT PAGEMODE 4 2000 2
2.2
Sleep
SET BT PAGEMODE 0 2000 0
12
0.08
mA
SET BT PAGEMODE 0 2000 1
0.08
SET BT PAGEMODE 0 2000 2
0.08
SET BT PAGEMODE 1 2000 0
32
0.18
SET BT PAGEMODE 1 2000 1
0.18
SET BT PAGEMODE 1 2000 2
0.18
SET BT PAGEMODE 2 2000 0
23.5
SET BT PAGEMODE 2 2000 1
0.31
SET BT PAGEMODE 2 2000 2
0.19
SET BT PAGEMODE 3 2000 0
23
SET BT PAGEMODE 3 2000 1
0.4
SET BT PAGEMODE 3 2000 2
0.29
SET BT PAGEMODE 4 2000 0
23
SET BT PAGEMODE 4 2000 1
0.4
SET BT PAGEMODE 4 2000 2
0.29
Connected, Sniff disabled
SET BT SNIFF 0 20 1 8
4.7
Connected + Sniff, Master
SET BT SNIFF 40 20 1 8
3.9
Connected + Sniff, Master
SET BT SNIFF 1000 20 1 8
2.5
Connected + Sniff, Slave
SET BT SNIFF 40 20 1 8
3.6
Connected + Sniff, Slave
SET BT SNIFF 1000 20 1 8
2.5
A2DP Audio Streaming
A2DP SINK, INTERNAL CODEC
75
28
mA
A2DP Audio Streaming
A2DP SOURCE, INTERNAL CODEC
70
23
Table 12: Current consumption of WT32i
Silicon Labs
Page 21 of 63
6 Power Control and Regulation
WT32i contains an internal battery charger and a switch mode regulator that is mainly used for internal blocks
of the module. The module can be powered from a single 3.3 V supply provided that VDD_CHG is floating.
Alternatively the module can be powered from a battery connected to VDD_BAT and using an external
regulator for VDD_IO. 1.8 V to 3.3 V supply voltage for VDD_IO can be used to give desired signal levels for
the digital interfaces of the module. USB, however, requires 3.3 V for proper operation and thus, when USB is
in use, 3.3 V for VDD_IO is required.
Battery Charger
In
Out
Switch mode
1.8V regulator
Linear 1.5V
regulator
AIO
RF
Core
Audio
Flash
PIO
USB
UART
PCM
VDD_CHG
VDD_BAT
VREG_ENA
VDD_IO
Figure 8: Power supply configuration of WT32i
VDD_ENA is software configurable enable pin for the internal regulators. Using iWRAP the enable pin can be
configured to
1. Latch on the internal regulators at the rising edge
2. Turn the regulators on at rising edge and turn off the regulators at falling edge
3. Latch the regulators on at the rising edge and turn off the regulators at the following rising edge
GPIO can be configured to control an external regulator.
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R1
R2
LDO
(1.8V...3.6V)
EN
IN
VDD_BAT
VREG_ENA
VDD_IO
GPIO (holds the external LDO on)
ON/OFF
Button
Battery Voltage
(2.7V...4.4V)
C1
100k
100k
4u7
Figure 9: Example of making a power on/off button using the latch feature of the internal regulators
iWRAP Example: Creating an on/off button with PIO2 holding the external regulator on
“SET CONTROL VREGEN 2 4”
(PIO is defined with a bit mask. 4 in hexadecimal is 100 in binary corresponding to PIO2)
NOTE: With the configuration shown above, when doing a SW reset for the module C1 will hold the enable pin
of the external regulator high until iWRAP has booted. This will prevent the module from turning off during
reset. When resetting through the reset pin one has to make sure that the enable pin is held high as long as
the reset pin is held active.
Figure 10 shows an example how to arrange power control when on/off button is not implemented.
VREG_ENA pin must not be connected to VDD_IO because leakage from VDD_BAT to VDD_IO will prevent
VREG_ENA to fall low enough to turn off the internal regulators.
VDD BAT IN LDO On/Off cntrl EN [1.8V...3.6V)
Silicon Labs
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LDO
(1.8V...3.6V)
EN
IN
VDD_BAT
VREG_ENA
VDD_IO
On/Off cntrl
Battery Voltage
(2.7V...4.4V)
LDO
(1.8V...3.6V)
EN
IN
VDD_BAT
VREG_ENA
VDD_IO
On/Off cntrl
Battery Voltage
(2.7V...4.4V)
Figure 10: Correct and wrong connection for the power on/off control
6.1 Protecting the Battery by Configuring the Module to Turn Off at Certain
Voltage
It is important not to let the battery be drained to voltages below 2.8V. In iWRAP it is possible to define certain
level when the module turns off the regulators.
iWRAP Example: Configure WT32i to start sending low battery warning at 3.4V, turn off at 3.3V and cease
the low battery warning at 4.0V. Set PIO0 to indicate low batter
“SET CONTROL BATTERY 3400 3300 4000 10
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Page 24 of 63
6.2 Reset
WT32i may be reset from several sources: reset pin, power on reset, a UART break character or through
software configured watchdog timer.
At reset, the digital I/O pins are set to inputs for bi-directional pins and outputs are tri-state.
The chip status after a reset is as follows:
Warm Reset: data rate and RAM data remain available
Cold Reset: data rate and RAM data are not available
Table 13 shows the pin states of WT32i on reset. Pull-up (PU) and pull-down (PD) default to weak values
unless specified otherwise.
NOTE: In order to make reset work properly VREG_ENA pin (1st pin of WT32i module) has to be driven
high for the time of reset.
Pin Name / Group
I/O Type
No Core Voltage
Reset
Full Chip Reset
USB
Digital bi-directional
N/A
N/A
UART_RX
Digital input with PD
PD
PD
UART_CTS
UART_TX
Digital output with PU
PU
PU
UART_RTS
SPI_MOSI
Digital input with PD
PD
PD
SPI_CLK
SPI_MISO
Digital tristate output with
PD
SPI_CS
Digital input with PU
PU
PU
PCM_IN
Digital input with PD
PD
PD
PCM_CLK
Digital bi-directional with PD
PCM_SYNC
PCM_OUT
Digital tri-state output with
PD
GPIO
Digital bi-directional with
PU/PD
PD
PD
Table 13: Pin states on reset
6.2.1 Internal POR
WT32i has two internal POR circuits. One is internally to the BC5 chip. In BC5 the power on reset occurs
when the core supply voltage (output of the internal 1.5V regulator) falls below typically 1.26V and is released
when VDD_CORE rises above typically 1.31V.
Another POR circuit is embedded to the module and it keeps the module in reset until supply voltages have
stabilized. This is to prevent corruption of the internal flash memory during boot. The embedded POR is
shown in the figure Figure 2Figure 11.
Because the POR is based on a simple RC time constant it will not work if the supply voltage ramps very
slowly or if the reset pin is not connected to high impedance. It is recommended that the power ramp will not
take more than 10 msec. If the reset pin is connected to a host it is good to place a diode between the host
and the module as shown in Figure 12. A diode will prevent the host from pulling the reset low before the
internal flash has its supply stabilized.
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Page 25 of 63
R1
Reset BC05
Reset
22nF
220k
WT32i
BC05
Figure 11: Embedded POR of WT32i
WT32i
Reset
Host CPU
GPIO
Figure 12: An example how to connect CPU GPIO to the reset pin of the module
Silicon Labs
Page 26 of 63
7 Battery Charger
The battery charger is a constant current / constant voltage charger circuit, and is suitable for lithium
ion/polymer batteries only. It shares a connection to the battery terminal, VDD_BAT, with the switch-mode
regulator. The charger is initially calibrated by Bluegiga Technologies to have Vfloat = 4.15V - 4.2 V.
The constant current level can be varied to allow charging of different capacity batteries. WT32i allows a
number of different currents to be used in the battery charger hardware. Values written to PS key 0x039b
CHARGER_CURRENT in the range 1..15 specify the charger current from 40..135mA in even steps. Values
outside the valid 0..15 range result in no change to the charging current. The default charging current (Key =
0) is nominally 40mA. Setting 0 is interpreted as “no-change” so it will be ignored
The charger enters various states of operation as it charges a battery. These are shown below:
Off: entered when the charger is disconnected.
Trickle Charge: entered when the battery voltage is below 2.9V.
Fast Charge - Constant Current: entered when the battery voltage is above 2.9V.
Fast Charge - Constant Voltage: entered when the battery has reached Vfloat, the charger
switches mode to maintain the cell voltage at Vfloat voltage by adjusting the constant
charge current.
Standby: this is the state when the battery is fully charged and no charging takes place.
When a voltage is applied to the charger input terminal VDD_CHG, and the battery is not fully charged, the
charger will operate and a LED connected to the terminal LED0 will illuminate. By default, until the firmware is
running, the LED will pulse at a low-duty cycle to minimize current consumption.
The battery charger circuitry auto-detects the presence of a power source, allowing the firmware to detect
when the charger is powered. Therefore, when the charger supply is not connected to VDD_CHG, the
terminal must be left open circuit. The VDD_CHG pin, when not connected, must be allowed to float and not
be pulled to a power rail. When the battery charger is not enabled, this pin may float to a low undefined
voltage. Any DC connection will increase current consumption of the device. Capacitive components such as
diodes, FETs, and ESD protection, may be connected.
The battery charger is designed to operate with a permanently connected battery. If the application permits
the charger input to be connected while the battery is disconnected, the VDD_BAT pin voltage may become
unstable. This, in turn, may cause damage to the internal switch-mode regulator. Connecting a 470μF
capacitor to VDD_BAT limits these oscillations thus preventing damage.
WARNING:
Use good consideration for battery safety. Do not charge with too much current. Do not charge when the
temperature is above 60°C or below 0°C. WT32i is initially calibrated to stop charging when battery voltage is
at 4.2 V. Do not try to charge batteries above 4.2 V. Do not short circuit the battery or discharge below 1.5 V.
Silicon Labs
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8 GPIO and AIO Functions
8.1 iWRAP supported GPIO Functions
Various GPIO functions are supported by iWRAP. These include:
Setting each GPIO state individually
Binding certain iWRAP commands to GPIO to trigger the command at either the rising or falling edge
of the GPIO
Carrier detect signal to indicate an active Bluetooth connection
Implementing RS232 modem signals
iWRAP ready indicator to signal to a host that iWRAP is ready to use
UART bypass mode to route UART signals to GPIO pins instead of iWRAP
Driving low frequency pulsed signal from a GPIO
Some of the functions are FW dependent. Refer to latest iWRAP user manual for the detailed information
about the GPIO functions.
8.2 Outputting Internal Clocks
Internal clocks can be routed to either AIO0 or AIO1 by setting PS Keys. To route internal clock to AIO0 set
PSKEY_AMUX_AIO0 to 0x00fe. Following table shows how to set the PSKEY_AMUX_CLOCK to get certain
frequency from AIO0.
AMUX_CLOCK
Freq (MHz) @ AIO0
0x0014
1
0x0004
2
0x0013
3
0x0017
4
0x0003
6
0x0016
6.5
0x0007
8
0x0011
12
0x0006
13
0x0002
16
0x0009
24
0x0005
32
Table 14: Selectable internal clock frequencies from AIO0
iWRAP does not support this feature. To use this feature either the particular PS Keys must be set to each
module separately or then ask for custom FW from Bluegiga.
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8.3 Auxiliary ADC
Simple iWRAP command can be used to read the ADC output from either of the two AIO pins. Refer to latest
iWRAP user manual for the detailed information.
8.4 Software I2C Interface
PIO6 and PIO7 can be used to form a master I²C interface. The interface is formed using software to drive
these lines. Therefore it is suited only to relatively slow functions such as driving a dot matrix LCD, keyboard
scanner or configuring external audio codec. I2C interface requires a custom FW.
PIO
I2C Signal
PIO6
SCL
PIO7
SDA
Table 15: I2C Interface of WT32i
Silicon Labs
Page 29 of 63
9 Serial Interfaces
9.1 UART Interface
WT32i has a standard UART serial interface that provides a simple mechanism for communicating with other
serial devices using the RS232 protocol. UART configuration parameters, such as baud rate, parity and stop
bits can be configured with an iWRAP command.
The hardware flow control is enabled by default. HW flow control can be disabled in HW by connecting
UART_NCTS to GND and leaving UART_NRTS floating.
Parameter
Possible Values
Baud rate
Minimum
1200 baud (≤2%Error)
9600 (≤1%Error)
Maximum
4Mbaud (≤1%Error)
Flow control
RTS/CTS or None
Parity
None, Odd, Even
Number of stop bits
1 or 2
Bits per byte
8
Table 16: Possible UART settings
iWRAP Example: Configuring local UART to 9600bps, 8 data bits, no parity and 1 stop bit
SET CONTROL BAUD 9600, 8N1
(9600 = baud rate, N = No parity, 1 = 1 stop bit)
Baud Rate
Error
1200
1.73%
2400
1.73%
4800
1.73%
9600
-0.82%
19200
0.45%
38400
-0.18%
57600
0.03%
76800
0.14%
115200
0.03%
230400
0.03%
460800
-0.02%
921600
0.00%
1382400
-0.01%
1843200
0.00%
2764800
0.00%
3686400
0.00%
Table 17: Standard Baud Rates
Silicon Labs
Page 30 of 63
9.1.1 Resetting Through UART Break Signal
The UART interface can reset WT32i on reception of a break signal. A break is identified by a continuous logic
low (0V) on the UART_RX terminal. If tBRK is longer than the value (in microseconds), defined by
PSKEY_HOSTIO_UART_RESET_TIMEOUT, (0x1a4), a reset occurs. Values below 1000 are treated as zero
and values above 255000 are truncated to 255000. This feature allows a host to initialise the system to a
known state. Also, WT32i can emit a break character that may be used to wake the host.
Default PSKEY_HOSTIO_UART_RESET_TIMEOUT setting in WT32i is zero, which means that this feature is
disabled. To use this feature, either the PS setting has to be changed for each module separately or ask for
modules with custom FW with appropriate settings.
9.1.2 UART Configuration While Reset is Active
The UART interface for WT32i is tristate while the chip is being held in reset. This allows the user to daisy
chain devices onto the physical UART bus. The constraint on this method is that any devices connected to
this bus must tristate when WT32i reset is de-asserted and the firmware begins to run.
9.1.3 UART Bypass Mode
Alternatively, for devices that do not tristate the UART bus, the UART bypass mode on WT32i can be used.
The default state of WT32i after reset is de-asserted; this is for the host UART bus to be connected to the
WT32i UART, thereby allowing communication to WT32i via the UART. All UART bypass mode connections
are implemented using CMOS technology and have signalling levels of 0V and VDD_IO.
The bypass mode is enabled with a simple iWRAP command. When in bypass mode, the module is
automatically set into deep sleep state indefinitely. Physical reset is required to return to normal operation
mode. The current consumption of a module in bypass mode is equal to a module in standby (idle) mode.
It is important for the host to ensure a clean Bluetooth disconnection of any active links before the bypass
mode is invoked. Therefore, it is not possible to have active Bluetooth links while operating the bypass mode.
WT12
Host
processor
Test
interface
RXD
CTS
RTS
TXD
Another
device
TX
RTS
CTS
RX
UART_TX
UART_RTS
UART_CTS
UART_RX
RESET
PIO5
PIO6
PIO7
PIO4
UART
WTxx
WT32i
Figure 13: UART bypass architecture
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Silicon Labs
Page 31 of 63
9.2 USB Interface
WT32i has a full-speed (12Mbps) USB interface for communicating with other compatible digital devices. The
USB interface on WT32i acts as an USB peripheral, responding to requests from a master host controller.
WT32i can be used as bus-powered or self-powered device. See the WT_USB_Design_Guide available in the
Bluegiga techforum for details about the SW and HW configuration of the USB interface.
WT32i
VDD_IO
VDD_BAT
VDD_IO
Figure 14: Bus-powered WT32i device configuration
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Silicon Labs
Page 32 of 63
VDD_IO
VDD_IO
WT32i
Figure 15: Self powered WT32i device configuration
9.3 Programming and Debug Interface (SPI)
The synchronous serial port interface (SPI) is for interfacing with other digital devices. The SPI port can be
used for system debugging. It can also be used for programming the Flash memory. SPI interface is
connected by using the MOSI, MISO, CSB and CLK pins.
SPI interface cannot be used for any application purposes.
9.3.1 Multi-slave Operation
WT32i should not be connected in a multi-slave arrangement by simple parallel connection of slave MISO
lines. When WT32i is deselected (SPI_CS# = 1), the SPI_MISO line does not float. Instead, WT32i outputs 0
if the processor is running or 1 if it is stopped.
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Silicon Labs
Page 33 of 63
10 Audio Interfaces
10.1 Stereo Audio Codec Interface
Stereo audio CODEC operates from an internal 1.5V power supply. It uses fully differential architecture in
analog signal path for the best possible common mode noise rejection while effectively doubling the signal
amplitude.
The stereo audio bus standard I2S is supported and a software I2C interface can be implemented using
GPIOs to configure an external audio CODEC.
Figure 16: Stereo CODEC input and output stages
10.1.1 ADC
The ADC consists of two second-order sigma-delta converters and gain stages. The gain stage consists of
digital and analog gain stages which are controlled by iWRAP. The optimal combination of digital and analog
gain is automatically selected by iWRAP. The analog gain stage consist selectable 24 dB preamplifier for
selecting microphone or line input levels and an amplifier which can be configured in 3 dB steps. The iWRAP
gain selection values are shown in the Table 19.
Following sample rates are supported
8kHz
11.025kHz
16kHz
22.05kHz
24kHz
32kHz
44.1kHz
Silicon Labs
Page 34 of 63
iWRAP Gain Setting
(-27...39)dB
Preamp ON = 24 dB gain (MIC input)
Preamp OFF = 0 dB gain (line input)
Table 18: ADC amplifier block diagram
Gain Setting In iWRAP
ADC Gain (dB)
Preamp OFF
(Line input mode)
ADC GAIN (dB)
Preamp ON
(MIC input mode)
0
-27
-3
1
-24
0
2
-21
3
3
-18
6
4
-15
9
5
-12
12
6
-9
15
7
-6
18
8
-3
21
9
0
24
A
3
27
B
6
30
C
9
33
D
12
36
E
15
39
F
18
42
10
21
45
11
24
48
12
27
51
13
30
54
14
33
57
15
36
60
16
39
63
Table 19: ADC Gain Selection In iWRAP
iWRAP Example: Setting line input with 0 dB gain
“SET CONTROL PREAMP 0”
”SET CONTROL GAIN 9 x (x is the DAC gain)
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Page 35 of 63
10.1.2 DAC
The DAC consists of two second-order sigma-delta converters and gain stages. The gain stage consists of
digital and analog gain stages which are controlled by iWRAP. The optimal combination of digital and analog
gain is automatically selected by iWRAP. The analog gain stage consist selectable 24 dB preamplifier for
selecting microphone or line input levels and an amplifier which can be configured in 3 dB steps. The iWRAP
gain selection values are shown in Table 20.
Following sample rates are supported
8kHz
11.025kHz
16kHz
22.05kHz
24kHz
32kHz
44.1kHz
48kHz
Gain Setting In iWRAP
DAC Gain (dB)
0
-42
1
-39
2
-36
3
-33
4
-30
5
-27
6
-24
7
-21
8
-18
9
-15
A
-12
B
-9
C
-6
D
-3
E
0
F
3
10
6
11
9
12
12
13
15
14
18
15
21
16
24
Table 20: DAC gain selection in iWRAP
iWRAP Example: Setting output with 0 dB gain
”SET CONTROL GAIN x E” (x is the ADC gain)
D
Silicon Labs
Page 36 of 63
10.1.3 Microphone Input
Figure 17 shows the recommended microphone biasing. The microphone bias, MIC_BIAS, derives its power
from the VDD_BAT and requires 1uF capacitor on its output (C1).
The input impedance at AUDIO_IN_P_LEFT and AUDIO_IN_N_LEFT is typically 6kohm and C5 and C4 are
typically 1uF. If bass roll-off is required to limit the wind noise on the microphone then C4 and C5 should be
150 nF.
R2 sets the microphone load impedance and is normally in the range of 1kΩ to 2kΩ
R1, C2 and C3 improve the supply rejection by decoupling supply noise from the microphone. Values should
be selected as required. R1 can be connected or to the MIC_BIAS output (which is ground referenced and
provides good rejection of the supply) as shown in Figure 17. MIC_BIAS is configured to provide bias only
when the microphone is required. R1 may also be connected to a convenient supply, in which case the bias
network is permanently enabled.
WT32i
MIC_BIAS
C1
C2
C3
MIC
C4
C5
AUDIO_IN_N_LEFT
AUDIO_IN_P_LEFT
R1
R2
Figure 17: Microphone connection to audio input
The MIC_BIAS is like any voltage regulator and requires a minimum load to maintain regulation. The
MIC_BIAS maintains regulation within the limits 0.200mA to 1.230mA. If the microphone sits below these
limits, then the microphone output must be pre-loaded with a large value resistor to ground.
The audio input is intended for use in the range from 1μA @ 94dB SPL to about 10μA @ 94dB SPL. With
biasing resistors R1 and R2 equal to 1kΩ, this requires microphones with sensitivity between about 40dBV
and 60dBV.
Table 21 lists the possible voltage and current setting in iWRAP for the MIC_BIAS.
Setting in iWRAP
Voltage (V)
Current (mA)
0
1.71
0.200
1
1.76
0.280
2
1.82
0.340
3
1.87
0.420
4
1.95
0.480
5
2.02
0.530
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Page 37 of 63
6
2.10
0.610
7
2.18
0.670
8
2.32
0.750
9
2.43
0.810
A
2.56
0.860
B
2.69
0.950
C
2.90
1.000
D
3.08
1.090
E
3.33
1.140
F
3.57
1.230
Table 21: MIC_BIAS settings in iWRAP
10.1.4 Line Input
Line input mode is selected by setting the ADC preamplifier off (see chapter 10.1.1). In the line input mode the
input impedance varies from 6k to 30 kohm depending on the gain setting.
Figure 18 and Figure 19 show examples of line input connection with WT32i. The maximum line level rms
voltage can vary from 0.3 up to 1.6 Vrms depending on the application, while the maximum for WT32i is
0.4Vrms (0.8Vrms differential). Thus it may be necessary to use a voltage divider (R1 and R2) at the input to
attenuate the incoming signal. C1 and C2 are typically 1uF ceramic X7R or film type capacitors.
It is a good practice to place a LC (22nH + 15pF) filter close to each input to filter out any RF noise that might
couple to the audio traces.
R1
R2
C1
C2
WT32i
AUDIO_IN_N_LEFT
AUDIO_IN_P_LEFT
Line input
Figure 18: Single ended line input example
Silicon Labs
Page 38 of 63
R1
R2
C1
C2
WT32i
AUDIO_IN_N_LEFT
AUDIO_IN_P_LEFT
Line input P
Line input N
Figure 19: Differential line input example
10.1.5 Output Stage
The output stage digital circuitry converts the signal from 16-bit per sample, linear PCM of variable sampling
frequency to bit stream, which is fed into the analogue output circuitry. The output stage circuit comprises a
DAC with gain setting and class AB output stage amplifier.
The output is available as a differential signal between AUDIO_OUT_N_LEFT and AUDIO_OUT_P_LEFT for
left channel and AUDIO_OUT_N_RIGHT and AUDIO_OUT_P_RIGHT for right channel.
The output stage is capable of driving a speaker directly when its impedance is at least 16Ω.
Figure 20 show an example of differentially connected speaker and Figure 21 show an example of speaker
connected single-ended. Differential (balanced) connection provides perfect common mode rejection ratio with
effectively 3 dB higher amplitude so it is recommended to use differential signaling always when possible.
Silicon Labs
Page 39 of 63
WT32i
AUDIO_OUT_N_LEFT
AUDIO_OUT_P_LEFT
Figure 20: Differentially connected speaker
WT32i
AUDIO_OUT_N_LEFT
AUDIO_OUT_P_LEFT C1
Figure 21: Single-ended speaker connection
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10.1.6 Mono Operation
Mono operation is a single-channel operation of the stereo codec. The left channel represents the single mono
channel for audio in and audio out. In mono operation the right channel is the auxiliary mono channel that may
be used in dual mono channel operation. Dual mono feature is FW dependent and iWRAP does not generally
support it.
10.1.7 Side Tone
In some applications it is necessary to implement side tone. This involves feeding an attenuated version of the
microphone signal to the earpiece. The WT32i codec contains side tone circuitry to do this. There is no
iWRAP support for the side tone but the side tone is configurable through PS Keys. To implement a side tone,
either the PS setting has to be programmed for each module separately or ask for modules with custom FW
with appropriate settings.
The side tone hardware is configured through the following PS Keys:
PSKEY_SIDE_TONE_ENABLE
PSKEY_SIDE_TONE_GAIN
PSKEY_SIDE_TONE_AFTER_ADC
PSKEY_SIDE_TONE_AFTER_DAC
10.2 PCM Interface
The audio PCM interface supports continuous transmission and reception of PCM encoded audio data over
Bluetooth.
PCM is a standard method used to digitise audio, particularly voice, for transmission over digital
communication channels. Through its PCM interface, WT32i has hardware support for continual transmission
and reception of PCM data, so reducing processor overhead. WT32i offers a bidirectional digital audio
interface that routes directly into the baseband layer of the on-chip firmware. It does not pass through the HCI
protocol layer.
Hardware on WT32i allows the data to be sent to and received from a SCO connection.
Using HCI FW up to 3 SCO connections can be supported by the PCM interface at any one time. However
iWRAP supports only 1 SCO connection at a time.
WT32i can operate as the PCM interface master generating PCM_SYNC and PCM_CLK or as a PCM
interface slave accepting externally generated PCM_SYNC and PCM_CLK. WT32i is compatible with various
clock formats, including Long Frame Sync, Short Frame Sync and GCI timing environments.
WT32i supports 13-bit or 16-bit linear, 8-bit μ-law or A-law companded sample formats, and can receive and
transmit on any selection of 3 of the first four slots following PCM_SYNC. The PCM configuration options are
enabled by setting the PS Key PSKEY_PCM_CONFIG32. Please contact Bluegiga technical support for
details about the PCM configuration.
10.3 I2S Interface
The digital audio interface supports the industry standard formats for I2S, left-justified or righ justified. The
interface shares the same pins as the PCM interface, which means each audio bus is mutually exclusive in its
usage. The internal representation of audio samples within WT32i is 16-bit and data on SD_OUT is limited to
16-bit per channel.
WT32i is not capable of generating the master clock for I2S, so when configured as a master, it can only be
used with a codec that is capable of producing the master clock from the SCK.
Silicon Labs
Page 41 of 63
WT32i WS
SCK
I2S_IN
I2S_OUT
MCLK Generator
ASI
I2S CODEC
Figure 22: I2S scheme for WT32i
Bit
Mask
Name
Description
D[0]
0x0001
CONFIG_JUSTIFY_FORMAT
0 for left justified, 1 for right justified.
D[1]
0x0002
CONFIG_LEFT_JUSTIFY_DELAY
For left justified formats: 0 is MSB of SD
data occurs in the first SCLK period
following WS transition. 1 is MSB of SD
data occurs in the second SCLK period.
D[2]
0x0004
CONFIG_CHANNEL_POLARITY
For 0, SD data is left channel when WS
is high. For 1 SD data is right channel.
D[3]
0x0008
CONFIG_AUDIO_ATTEN_EN
For 0, 17-bit SD data is rounded down
to 16bits. For 1, the audio attenuation
defined in CONFIG_AUDIO_ATTEN is
applied over 24bits with saturated
rounding. Requires
CONFIG_16_BIT_CROP_EN to be 0.
D[7:4]
0x00F0
CONFIG_AUDIO_ATTEN
Attenuation in 6dB steps.
D[9:8]
0x0300
CONFIG_JUSTIFY_RESOLUTION
Resolution of data on SD_IN, 00=16bit,
01=20bit, 10=24bit, 11=Reserved. This
is required for right justified format and
with left justified LSB first.
D[10]
0x0400
CONFIG_16_BIT_CROP_EN
For 0, 17-bit SD_IN data is rounded
down to 16bits. For 1 only the most
significant 16bits of data are received.
Table 22: PSKEY_DIGITAL_AUDIO_CONFIG
WS L W“ \ Rfihl Channel SJ SD'N/OUT /MSBX X3\ X LSB\\\ / MSBX m X LSBW / Left—J ustified Mod a ws J—Léficmnnel \V \ 33 ngmcnaMel / 30K mmme—W SD IN/OUT RV MSBX )Q\ X LSB\ \\ / MSBX )N LSB\ RighlJuslified Mode ws \ LékChanneI “Wm SCK mmmmw SD 'N/OUT / MSB)O\ X L$B\\\ / MSBW X LSBW I25 Mode
Silicon Labs
Page 42 of 63
Figure 23: Digital Audio Interface Modes
10.4 IEC 60958 Interface
The IEC 60958 interface is a digital audio interface that uses bi-phase coding to minimize the DC content of
the transmitted signal and allows the receiver to decode the clock information from the transmitted signal. The
IEC 60958 specification is based on the 2 industry standards:
AES/EBU
Sony and Philips interface specification SPDIF
The interface is compatible with IEC 60958-1, IEC 60958-3 and IEC 60958-4.
The SPDIF interface signals are SPDIF_IN and SPDIF_OUT and are shared no the PCM interface pins. The
input and output stages of the SPDIF pins can interface to:
75Ω coaxial cable with an RCA connector, see Figure 24
An optical link that uses Toslink optical components
E, .J[_, J]? .lzl:
Silicon Labs
Page 43 of 63
Impedance matching to 75 ohm
DC block
Impedance matching to 75 ohm
Buffering required to drive 75 ohm load
DC bias for the comparator input
Comparator (Tpd max 10ns)
1
2
U1-A
74HC14D
3
4
U1-B
74HC14D
5
6
U1-C
74HC14D
9
8
U1-D
74HC14D
R1
560R, 50V, 0.063W
R2
560R, 50V, 0.063W
R3
560R, 50V, 0.063W
R4
120R, 50V, 0.063W
C1
0.15uF/10V/X5R
1
2
J1
RCA_RED
1
2
J2
RCA_RED
R5
150R, 50V, 0.063W
R6
150R, 50V, 0.063W
C2
10000pF/25V/X7R
R11
470K, 50V, 0.063W
R12
10K, 50V, 0.063W
R13
1.0K, 50V, 0.063W
R14
1.0K, 50V, 0.063W
R15
10K, 50V, 0.063W
C4
1uF/6.3V/X5R/10%
C5
1uF/6.3V/X5R/10%
C6
0.15uF/10V/X5R
C7
0.15uF/10V/X5R
R16
100K, 50V, 0.063W
2
13
D1
ESD _PROTECTION
2
13
D2
ESD_PROTECTION
3+
1-
5
2V- 4
V+
6
SHTDN
U3
COMPARATOR_TLV3501AIDBVT
3V3
SPDIF_IN
SPDIF_OUT
3V3
3V3
Figure 24: Example circuit for SPDIF interface (co-axial)
LCDEL T E
Silicon Labs
Page 44 of 63
11 Design Guidelines
This chapter shows briefly the most important points to consider when making a design with WT32i. Please
refer to the DKWT32i datasheet for detailed description of the development board design.
11.1 Audio Layout Guide
11.1.1 EMC Considerations
To avoid RF noise coupling top the audio traces it is extremely important to make sure that there aren’t GND
loops in the audio traces. Audio layout can not be compromised. RF noise that couples to audio signal lines
usually demodulates down to audio band causing very unpleasant whining noise.
Noise couples to signals lines either through a parasitic capacitance or by coupling to a loop. The noise that
couples to a loop is proportional to the area of the loop and to the electromagnetic field flowing through the
loop. Thus the noise can be minimized in two ways. Minimizing the field strength flowing through the loop by
placing the signal lines far from the RF source or most importantly minimize the size of the loop by keeping
the trace as short as possible and making sure that the path for the return current (usually GND) is low
impedance and follows the forward current all the way as close as possible. GND vias must be placed right
next to the any component GND pins and solid GND plane must follow the trace all the way from start to the
end. When using fully differential signals they should be routed as differential pairs, parallel and symmetrically.
Typical RF noise with Bluetooth
How the BT noise couples to audio?
-1.6kHz noise
1 Bluetooth slot = 625us
1 ÷ 625e-6 = 1.6kHz
-320Hz noise
5 slot packet (A2DP profile)
1 ÷ (5 × 625e-6) = 320Hz (5)
* RF takes an amplifier out from its linear region causing demodulation of RF
down to audio band. (6)
RL
EM field couples to a
loop
RL
Noise couples through a
parasitic capacitance
Figure 25: Noise coupling schemes
11.1.2 Choosing Capacitors and Resistors
Metal film resistors have lower noise than carbon resistors which makes them more suitable for high quality
audio.
Non-linearity of capacitors within the audio path will have an impact on the audio quality at the frequencies
where the impedance of the capacitors become dominant. At higher frequencies the amplitude is not
determined by the value of the capacitors but at the lower frequencies the impact of the capacitors will be
seen.
Ceramic capacitors should be X5R or X7R type capacitors with relative high voltage rating. The higher the
capacitance value, the lower is the frequency where the non-linearity will start to have an impact. Thus it is not
a bad idea to select the capacitors value bigger than necessary from the frequency response point of view.
For optimal audio quality the best selection is to use film capacitors. Film capacitors have excellent linearity
and they are non-polarized which makes them perfect choice for using in audio path. The drawback of film
capacitors is bigger physical size and higher cost.
Figure 26 shows a modulation distortion measurement when using different type of capacitors in the audio
paths. Modulation distortion measures the amount of distortion between two closely located sine waves. The
10 80 7110 500 1000 1500 2000 —Film type luF 766 dB Ceramic YSV luF 47 dB —ceramic XSR IUuF 764
Silicon Labs
Page 45 of 63
difference between the different capacitors is obvious at low frequencies where the impedance of the
capacitor is dominant.
Figure 26: Modulation distortion with different type of capacitors
11.2 RF Layout Guide
The chip antenna of WT32i requires only a small metal clearance area directly under the antenna. The
antenna operation is dependent on the GND planes on both sides of the antenna. Minimum 15mm of GND
plane must be placed on both sides of the module and the GND plane of the motherboard must reach under
the edges of the module as shown in the Figure 27.
Silicon Labs
Page 46 of 63
Min 15mm Min 15mm
6mm Metal clearance
area
Board edge
GND plane indentation 2mm GND plane indentation max 5.9 mm
Figure 27: Recommended layout for WT32i
Figure 28: Poor layouts for WT32i
Use good layout practices to avoid excessive noise coupling to supply voltage traces or sensitive analog
signal traces. If using overlapping ground planes use stitching vias separated by max 3 mm to avoid emission
from the edges of the PCB. Connect all the GND pins directly to a solid GND plane and make sure that there
is a low impedance path for the return current following the signal and supply traces all the way from start to
the end.
(w: >>>>> : <>>j
Silicon Labs
Page 47 of 63
A good practice is to dedicate one of the inner layers to a solid GND plane and one of the inner layers to
supply voltage planes and traces and route all the signals on top and bottom layers of the PCB. This
arrangement will make sure that any return current follows the forward current as close as possible and any
loops are minimized.
Layout
Supply voltage
If possible use solid power plane
Make sure that solid GND plane follows the traces all the way
Do not route supply voltage traces across separated GND regions so that the
path for the return current is cut
MIC input
Place LC filtering and DC coupling capacitors symmetrically as close to audio
pins as possible
Place MIC biasing resistors symmetrically as close to microhone as possible.
Make sure that the bias trace does not cross separated GND regions (DGND ->
AGND) so that the path for the return current is cut. If this is not possible the do
not separate GND regions but keep one solid GND plane.
Keep the trace as short as possible
Signals
GND
Power
Signals
Recommended PCB layer configuration
Figure 29: Typical 4-layer PCB construction
Overlapping GND layers without
GND stitching vias Overlapping GND layers with
GND stitching vias shielding the
RF energy
Figure 30: Use of stitching vias to avoid emissions from the edges of the PCB
nu uF umm a mum m: u "My mu mm an a: mum. um. ham-ya m mm: m m mm b (MM, I»: «mu m mmunmN-ulflw mimic-m mmbmh Hf" m mm: m: wII am m x mm mm: a m g! <¥ my="" mum-mumm-="" un="" no:="" main:="" aim».="" mugs="" 5="" m="" mu="" 5.="" my="" mam-m="" mm".="" x="" em".="" and="" «um:="" 3:“="" “mag="" um="" mam="" na="" 4:="" i="" no:="" “nut-ma="" al="" m="" m="" l="" t="" e-="" :91:="" iméfi="" ##hhkfl="" ‘="" wfigi,»="" i="" m="" m.="" n="" m="">< 91;":qu="" 5:4="" mm="" anw="" mira-m="" «mm="">
Silicon Labs
Page 48 of 63
11.3 Example Application Schematics
Figure 31: Example schematic with on/off button, silicon microphone and stereo speakers
Silicon Labs
Page 49 of 63
During boot the diode will prevent the host pulling reset low
before the internal flash has its supply voltage stabilised
Line level input can be as high as 4.37 Vpp.
Voltage divider is used to drop this down to
below 1 Vpp to avoid saturation of WT32 input
NOTE: Differential audio provides excellent common mode rejection and effectively douples the
amplitude. Thus it is strongly recomm endable to use differential instead of single ended when ever possible
2GND
3GND
4GND
5AIO0
6AIO1
7PIO0
8PIO1
9PIO2
10 PIO3
11 USB_DN
12 USB_DP
13 PIO9
14 PIO10
15 RXD
16 TXD
17 3V3
18 GND
19 RESET
20 RTS
21 CTS
22 PIO8
23 PIO7
24 PIO6
25 PIO5
26 PIO4
27 PCM_IN
28 PCM_OUT
29 PCM_SYNC
30 PCM_CLK
31
GND
32
SPI_CS
33
SPI_CLK
34
SPI_MISO
35
SPI_MOSI
36
LED0
37
VDD_BAT
38
VDD_CHG
39
GND
40
MIC_BIAS
41
AUDIO_IN_P_RIGH
42
AUDIO_IN_N_RIGHT
43
AGND
44
AUDIO_IN_P_LEFT
45
AUDIO_IN_N_LEFT
46
AUDIO_OUT_N_RIGHT
47
AUDIO_OUT_P_RIGHT
48
AGND
49
AUDIO_OUT_N_LEFT
50
AUDIO_OUT_P_LEFT
1
MOD4
WT32I
1IN
3EN
2GND
5
OUT
4
NR
U2
TPS79933
C11
2.2uF
C13
2.2uF
C18
1uF
L3 15nH
C19
15pF
C20 1uF/X7R
C21 1uF/X7R
L4 15nH
C22
15pF
1MISO
3CLK
5CSB
23V3
4MOSI
6GND
J1
1SLEEVE
3 RING
2TIP
J3
SJ-3523-SMT-TR
1SLEEVE
3 RING
2TIP
J2
SJ-3523-SMT-TR
C24 1uF/X7R
C25 1uF/X7R
C26
330uF/6.3V/20%/TAN/ESR<10mohm
C28
330uF/6.3V/20%/TAN/ESR<10mohm
12
R3
1M, 50V, 0.1W, 5%
12
R11
1M, 50V, 0.1W, 5%
12
R12
7.5K, 50V, 0.063W
12
R15
7.5K, 50V, 0.063W
12
R16
2.2K, 50V, 0.063W
12
R17
2.2K, 50V, 0.063W
D1
3V3
3V3
ON/OFF_CNTRL_FROM_HOST
5V0
RESET_FROM_HOST
Figure 32: Example schematic with single ended line input, single ended output and with on/off control from a host
mmnnumefiuumn‘mm Inmw-nmmmmlm‘ mmmmmmmuhnm Immm-mni-wn mm- .m.. M‘ywmnmm uhcmutm-uahanmmam .w-num. maniac-1mm” mumq- ”mu-o Mn-Mmlm-flm p: mumnMM-cm- “alumna "gnu-m mu...“ u 3mm mm ‘ #:WW imp” ., L H mm» mm > . ‘35.»me my.) . \ mmmeMMWnuww-m umwnm-mhwmb‘mrmwm uploasnuKu-wwwu m... wu-wdm-mwnuwum :3”. "1'“ :1} ...""aL‘lu'CL.... 0..“ gufo. m w- n... x .4.“ m... «a...» w." Wm- m u... m, .. mum-I n. , .. A u... \
Silicon Labs
Page 50 of 63
Figure 33: Example schematic for connecting external audio PA to the stereo audio output
Silicon Labs
Page 51 of 63
Debug header
15 MICBIAS
10 MIC1L/LINE1L
12 MIC2L/LINE2L
13 MIC2R/LINE2R
14 MIC3L/LINE3L
16 MIC3R/LINE3R
11 MIC1R/LINE1R
23 HPROUT
19 HPLOUT
20 HPLCOM
22 HPRCOM
29 RIGHT_LOP
30 RIGHT_LOM
27 LEFT_LOP
28 LEFT_LOM
21
DRVSS
26
AVSS_DAC
17
AVSS_ADC
6
DVSS
32
DVDD
7
IOVDD
24
DRVDD
18
DRVDD
25
AVDD_DAC
4
DIN
5
DOUT
3
WCLK
2
BCLK
1
MCLK
31
RESET
9
SDA
8
SCL
33
GND 34
GND 35
GND 36
GND
U9
TLV320AIC32
1
RST
2
VSS
3
RST
4MR
5VDD
U10
MCP1319
1
A1
2
B1
4
A2
3
B2
SW1
R37
5.1K, 50V , 0.063W, +/-5%
C21
0.1uF/10V/X5R/10%
C22
1uF/6.3V/X 5R/10%
C23
0.1uF/10V/X5R/10%
C24
1uF/6.3V/X 5R/10%
C25
0.1uF/10V/X5R/10%
C26
1uF/6.3V/X 5R/10%
C28
0.1uF/10V/X5R/10%
C29
1uF/6.3V/X 5R/10%
C30
10uF/6.3V/X5R/10%
C31
0.1uF/10V/X5R/10%
C32
1uF/6.3V/X 5R/10%
R38
4.7K, 50V, 0.063W, 5%
R40
4.7K, 50V, 0.063W, 5%
1
2
U11
RCA_RED
1
2
U12
RCA_WHITE
C33
33 0uF/6 .3V /2 0%/T A N/E S R<10 mo hm
C34
330uF/6.3V/20%/TAN/ESR<10 mohm
1
2
U15
RCA_RED
1
2
U18
RCA_WHITE
C35
1uF/16V /20%
C36
1uF/16V /20%
R64
1M, 50V, 0.1W, 5%
R65
1M, 50V, 0.1W, 5%
R66
NP
R67
NP
C53
0.1uF/10V/X5R/10%
C54
0.1uF/10V/X5R/10%
1
2
R46
1M, 50V, 0.1W , 5%
1
2
R49
1M, 50 V, 0.1W, 5% 1
IN
3GND
2OUT
U8
AP7313
C42
1uF/6.3V/X 5R/10%
C43
1uF/6.3V/X 5R/10%
2GND
3GND
4GND
5AIO0
6AIO1
7PIO0
8PIO1
9PIO2
10 PIO3
11 US B_DN
12 US B_DP
13 PIO9
14 PIO10
15 RX D
16 T X D
17 3V3
18 GND
19 RE SET
20 RTS
21 CTS
22 P IO8
23 P IO7
24 P IO6
25 P IO5
26 P IO4
27 P CM_IN
28 P CM_OUT
29 P CM_SY NC
30 P CM_CLK
31
GND
32
SP I_CS
33
SP I_CLK
34
SPI_MISO
35
SPI_MOSI
36
LED0
37
VDD_B AT
38
VDD_CHG
39
GND
40
MIC_BIAS
41
AUDIO_IN_P_RIGH
42
AUDIO_IN_N_RIGHT
43
AGND
44
AUDIO_IN_P_LE FT
45
AUDIO_IN_N_LEFT
46
AUDIO_OUT_N_RIGHT
47
AU DIO_OU T _P _RIGH T
48
AGND
49
AU DIO_OU T _N_ LE FT
50
A UDIO_OU T _P _LE FT
1
MOD1
W T 32I
1
3
5
2
4
6
J7
3V 3
3V 3
3V 3
3V 3
PIO7/I2C_SDA
PIO6/I2C_SCL
I2S _S DIN
I2S _S DOUT
I2S _W S
I2S _S CK
3V3
3V 3
Figure 34: Example schematic with an external I2S codec
2:. $211 fi m m l a V 3 3 2
Silicon Labs
Page 52 of 63
12 Physical Dimensions
23.9 (+/-0.2) mm
Ant
Model: WT32i-A
FCC ID: QOQWT32I
IC: 5123A-BGTWT32I
KCC-CRM-BGT-WT32I
R
209-JXXXXX
15.9 (+/-0.2) mm
3.8 mm 9.15 mm
5.6 (+/-0.2) mm 17.9 (+/-0.1) mm
15.0 (+/-0.1) mm
3.35 mm
23.9 (+/-0.2) mm
2.1 (+/-0.15) mm
2.4 (+/-0.15) mm
Figure 35: Physical dimensions of WT32i
1.25mm 1.00mm e— ‘-25'“"‘ IIIIIIIIIIIIIIIII1 €97 H 0.60mm 1.00mm IIIII;:lIIIIII| F1? so 135“” IIIIIIIIIIIIIIIIIIII 1.50m + $+Ak + 1.83mm LOOmm 0.60mm |<—15.90mm —="">1 [‘7 14.9mm 1.00am 23.90am (1‘0x0‘6)mm Pin cenlev vosilion: X=D.375mm. Y=1.53mm (1.75x0.6)mln 1.83m“ W ¢0.50mm 0.50mm 9 <- 1.95mm="" pin="" center="" position:="" x="t95mm," v="0£z75mm">
Silicon Labs
Page 53 of 63
Figure 36: Pin dimensions of WT32i, top view
Figure 37: Recommended PCB land pattern for WT32i
:luu 15D z: z: 150 22 Im 21 an . .mu
Silicon Labs
Page 54 of 63
13 Soldering Recommendations
WT32i is compatible with industrial standard reflow profile for Pb-free solders. The reflow profile used is
dependent on the thermal mass of the entire populated PCB, heat transfer efficiency of the oven and
particular type of solder paste used. Consult the datasheet of particular solder paste for profile configurations.
Bluegiga Technologies will give following recommendations for soldering the module to ensure reliable solder
joint and operation of the module after soldering. Since the profile used is process and layout dependent, the
optimum profile should be studied case by case. Thus following recommendation should be taken as a
starting point guide.
- Refer to technical documentations of particular solder paste for profile configurations
- Avoid using more than one flow.
- Reliability of the solder joint and self-alignment of the component are dependent on the solder volume.
Minimum of 150m stencil thickness is recommended.
- Aperture size of the stencil should be 1:1 with the pad size.
- A low residue, “no clean” solder paste should be used due to low mounted height of the component.
Figure 38: Reference reflow profile
Carrier Tape Appearance and Dimensions p1 DU oeeonaooeo eeoooeeeeooeooeeao m t: a > o o 7/ o o p2 T B E A j if A d Demil AVA B Detail 9‘9 fl ' ” ""'” 164 24,4 44 20,2 175 4.0 2,0 20 2,8 ”a...“ :01 :01 :03 :01 +01 :01 :01 :01 :01 NOTES. 1.10 sprocket hole pitch cumulative tolerance 10.2mm. 2.carrier camber not to exceed 1mm in 100mm 3 A and B measured on a plane 0 3mm above the bottom of the pocket 4.T measure form 0 plane on the inside boltom oi the pockel to the lop surface of the carrier 5.All dimensions meet ElAr481rC requirmenls. 6.material: black Anti»static Pnlysyrene 7 Tesistiv1ty105~10quuare
Silicon Labs
Page 55 of 63
14 Package
Figure 39: Carrier tape dimensions
Reel Appearance and Dimensions W1 , £37< location="" a="" e="" c="" d="" w1="" w2="" dimensions="" 830="" 20‘="" 2="" 13‘="" d="" 2‘="" 2="" 40‘="" 5="" 49‘1="" tolerance="" i0,5="" i1="" j:0‘2="" i0,5="" i0.1="" io‘z="" notes:="" 1.="" materialihips,ant-static1o~10hohm/sq.="" 2.color="" blue="">
Silicon Labs
Page 56 of 63
Figure 40: Reel dimensions
www.bluegiga.com
Silicon Labs
Page 57 of 63
15 Certification Guidance for an End Product Using WT32i
15.1 Bluetooth End Product Listing
The Bluetooth SIG requires for every commercially available product implementing Bluetooth technology to be
listed on the Bluetooth SIG End Product Listing (EPL).
For the details on how to make the end product listing, please refer to the Bluetooth End Product Listing Guide
available in www.bluegiga.com.
15.2 CE Approval of an End-Product
When placing the CE logo to an end-product the manufacturer declares that the product is in conformity with
the requirements of the R&TTE directive. The minimum requirements for placing the CE logo to an end-
product are
Declaration of Conformity signed by the manufacturer. The person who signs the DoC must be
traceable
Generation of a technical construction file including
o Technical information about the product
o Test reports for all the relevant standards required to demonstrate that the product meets the
requirements of the R&TTE directive
The end-product manufacturer is fully responsible for the compliance of the end-product. The modules test
reports can partly be used to demonstrate the compliance but typically all the radiated tests must be re-tested
with the end product. All the conducted RF tests can be inherited from the modules test reports because the
conducted RF characteristics are not dependent on the installation of the module.
Standard
Description
Tested with
the module
Test required for
the end product
Modules test
results can be
inherited to the
end product test
report
EN 300 328
RF emissions
Module fully
tested
Radiated test cases
Yes (partly)
EN 301 489-1
EN 301 489-17
EMC immunity and
emissions
Only EM field
immunity tested
All the test cases
relevant for the end
product
No
EN 62479
Human exposure to
EM fields
Not tested. The
module is
compliant
without testing
because the TX
power is less
than 20 mW
Evaluation required
in case of multiple
radios in co-
location.
No
EN 60950
Safety
Not tested
because there
aren’t any test
cases that
would concern
the module
Full evaluation with
the end product
No
Table 23: CE standards summary for WT32i
Silicon Labs
Page 58 of 63
Note: Because all the radiated emissions must be tested with the end product in any case and because the
end product manufacturer is fully responsible for the compliance of the end product, any antenna can be
selected for WT32i-E, not just the antenna type that Bluegiga has used in the CE approvals.
15.3 FCC Certification of an End Product
In FCC there are three different levels of product authorization:
VERIFICATION
o Required for digital devices. The end product manufacturer verifies device to FCC rules by
performing the required tests and maintains the records in case of questions
DECLARATION OF CONFORMITY
o Required for computer peripherals and receivers. The product manufacturer tests the
emissions in a FCC recognized lab according to the relevant standards, maintains the records
in case of questions and creates DoC which is supplied with the device. FCC logo must be
placed on the product. The information about the DoC is shown in the user manual
CERTIFICATION
o Required for most of the radio products. The radio has its own FCC ID and gets listed in FCC
files https://apps.fcc.gov/oetcf/eas/reports/GenericSearch.cfm. The FCC ID is labeled on the
product.
When using modular certified module, re-certification with the end product is not needed provided that the
conditions shown in the modules grant are fulfilled. The end product manufacturer is still responsible for the
DoC or the Verification of the end product as required.
The limitations and restrictions related to the modular certification of WT32i are described in the FCC grant of
the module. If the conditions mentioned in the grant are met, then only labelling the end product with
“Contains: QOQWT32I” is required.
If the conditions are not met, then there are three options to remove the restriction for the end product:
Class 2 Permissive Change
o Can be done either by Bluegiga or an agent authorized by Bluegiga.
o The FCC ID of WT32i remains unchanged and the end product labelling requirements do not
change
Change of ID
o Can be done by authorization of Bluegiga
o The FCC ID of WT32i is changed.
o The end product is labelled according to the new FCC ID of the module (“Contains:
XXXYYYY”)
o NOTE: Bluegiga will not deliver modules with custom labelling.
New certification of the end product
o Done by the end product manufacturer
o Test reports of the module can be used to reduce the amount of testing
When using WT32i-E, only the antenna types approved with the module can be used. WT32i-E is certified
with a standard 2 dBi dipole. Any other type of antenna will require authorisation either through C2PC,
Change of ID or new certification.
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15.3.1 Co-location with Other Transmitters
Co-location means co-transmission, not physical co-location. The radios are not considered to be in colocation
when the physical separation is more than 20 cm or if the transmissions overlap less than 30 seconds.
When two or more radios are in co-location human exposure must be evaluated as the sum of TX powers
from all the radios transmitting simultaneously. The FCC grant of WT32i does not allow co-location so it will
require authorization through C2PC, Change of ID or a new certification.
15.4 IC Certification of an End Product
IC certification is much like FCC. In IC there are two types of product authorizations:
Verification
Certification
When using a modular certified WT32i all that is needed, provided that WT32i is the only radio in the design,
is labelling the end product with “Contains IC: 5123ABGTWT32I”. The responsibility for the radio certification
remains with Bluegiga but the end product manufacturer is still responsible for the verification of the remaining
parts of the product.
Two main differences that are good to be aware of are:
If the TX power is less than 20 mW human exposure evaluation is not required
The test reports are valid for 1 year from the certification
15.5 MIC Japan Certification of an End Product
WT32i has MIC Japan type certification and it can be used directly in the end product without need for
recertification of the end product. Currently there aren’t any labelling requirements for an end product using a
certified module but it is recommended to place some indication to the product that it contains certified radio
module.
16 WT32i Certifications
16.1 Bluetooth
WT32i is qualified as a Bluetooth 3.0 Controller Subsystem with QDID 49552. By combining with a
prequalified Host Subsystem WT32i will make a complete Bluetooth end product without any further testing.
Listing an end product will require purchasing a declaration ID from Bluetooth SIG. Declaration ID is required
only for certain combination of QDID’s and it is only needed to pay once. After receiving the declaration ID,
multiple products can be listed with the same combination of QDID’s under the same declaration ID. If one of
the QDID’s under the Declaration ID is changed, then new declaration ID will be required.
16.2 CE
WT32i is in conformity with the essential requirements and other relevant requirements of the R&TTE
Directive (1999/5/EC). The product is conformity with the following standards and/or normative documents.
EMC (immunity only) EN 301 489-17 V2.1.1
Radiated emissions EN 300 328 V1.8.1
OEM Responsi s10 comply with FCC Regulations If detachable antennas are use
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Safety EN60950-1:2006+A11:2009+A1:2010+A12:2011
16.3 FCC
WT32i complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:
(1) this device may not cause harmful interference, and
(2) this device must accept any interference received, including interference that may
cause undesired operation.
Any changes or modifications not expressly approved by Bluegiga Technologies could void the
user’s authority to operate the equipment.
FCC RF Radiation Exposure Statement:
This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. End
users must follow the specific operating instructions for satisfying RF exposure compliance. This transmitter
meets both portable and mobile limits as demonstrated in the RF Exposure Analysis. This transmitter must not
be co-located or operating in conjunction with any other antenna or transmitter except in accordance with FCC
multi-transmitter product procedures.
OEM Responsibilities to comply with FCC Regulations
The WT32i module has been certified for integration into products only by OEM integrators under the following
condition:
The transmitter module must not be co-located or operating in conjunction with any other antenna or
transmitter except in accordance with FCC multi-transmitter product procedures.
As long as the two conditions above are met, further transmitter testing will not be required. However, the
OEM integrator is still responsible for testing their end-product for any additional compliance requirements
required with this module installed (for example, digital device emissions, PC peripheral requirements, etc.).
IMPORTANT NOTE: In the event that these conditions can not be met (for certain configurations or co-
location with another transmitter), then the FCC and Industry Canada authorizations are no longer considered
valid and the FCC ID and IC Certification Number can not be used on the final product. In these
circumstances, the OEM integrator will be responsible for re-evaluating the end product (including the
transmitter) and obtaining a separate FCC and Industry Canada authorization.
If detachable antennas are used:
This radio transmitter has been approved by FCC to operate with a 2.7 dBi dipole antenna. Any antenna of the
same type and with equal or less gain can be used with WT32i-E without retesting. Antennas of a different
type or higher gain will require authorization from FCC.
End Product Labeling
The WT32i module is labeled with its own FCC ID. If the FCC ID is not visible when the module is installed
inside another device, then the outside of the device into which the module is installed must also display a
label referring to the enclosed module. In that case, the final end product must be labeled in a visible area
with the following:
It detachable antennas are used
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Contains Transmitter Module FCC ID: QOQWT32I
or
Contains FCC ID: QOQWT32I
The OEM integrator has to be aware not to provide information to the end user regarding how to install or
remove this RF module or change RF related parameters in the user manual of the end product
16.4 IC
IC Statements:
WT32i complies with Industry Canada licence-exempt RSS standard(s). Operation is subject to the following
two conditions: (1) this device may not cause interference, and (2) this device must accept any interference,
including interference that may cause undesired operation of the device.
Under Industry Canada regulations, this radio transmitter may only operate using an antenna of a type and
maximum (or lesser) gain approved for the transmitter by Industry Canada. To reduce potential radio
interference to other users, the antenna type and its gain should be so chosen that the equivalent isotropically
radiated power (e.i.r.p.) is not more than that necessary for successful communication.
End Product Labeling
The WT32i module is labeled with its own IC Certification Number. If the IC Certification Number is not visible
when the module is installed inside another device, then the outside of the device into which the module is
installed must also display a label referring to the enclosed module. In that case, the final end product must
be labeled in a visible area with the following:
Contains Transmitter Module IC: 5123A-BGTWT32I
or
Contains IC: 5123A-BGTWT32I
The OEM integrator has to be aware not to provide information to the end user regarding how to install or
remove this RF module or change RF related parameters in the user manual of the end product
If detachable antennas are used:
This radio transmitter (identify the device by certification number, or model number ifCategory II) has been
approved by Industry Canada to operate 2.7 dBi dipole antenna. Antenna types other than this, having a gain
greater than 2.7 dBi, are strictly prohibited for use with this device.
16.4.1 IC
Déclaration d’IC :
Ce dispositif est conforme aux normes RSS exemptes de licence d’Industrie Canada. Son fonctionnement est
assujetti aux deux conditions suivantes : (1) ce dispositif ne doit pas provoquer de perturbation et (2) ce
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dispositif doit accepter toute perturbation, y compris les perturbations qui peuvent entraîner un fonctionnement
non désiré du dispositif.
Selon les réglementations d’Industrie Canada, cet émetteur radio ne doit fonctionner qu’avec une antenne
d’une typologie spécifique et d’un gain maximum (ou inférieur) approuvé pour l’émetteur par Industrie
Canada. Pour réduire les éventuelles perturbations radioélectriques nuisibles à d’autres utilisateurs, le type
d’antenne et son gain doivent être choisis de manière à ce que la puissance isotrope rayonnée équivalente
(P.I.R.E.) n’excède pas les valeurs nécessaires pour obtenir une communication convenable.
Étiquetage du produit final
Le module WT32I est étiqueté avec sa propre identification FCC et son propre numéro de certification IC. Si
l’identification FCC et le numéro de certification IC ne sont pas visibles lorsque le module est installé à
l’intérieur d’un autre dispositif, la partie externe du dispositif dans lequel le module est installé devra
également présenter une étiquette faisant référence au module inclus. Dans ce cas, le produit final devra être
étiqueté sur une zone visible avec les informations suivantes :
« Contient module émetteur IC : 5123A-BGTWT32I »
ou
« Contient IC : 5123A-BGTWT32I »
Dans le guide d’utilisation du produit final, l’intégrateur OEM doit s’abstenir de fournir des informations à
l’utilisateur final portant sur les procédures à suivre pour installer ou retirer ce module RF ou pour changer les
paramètres RF.
16.5 MIC Japan
WT32i is has MIC Japan type approval with certification number 209-J00089. WT32i is certified as a module
and it can be integrated into an end product without a need for additional MIC radio certification of the end
product.
16.6 KCC (South-Korea)
WT32i has modular certification in South-Korea with certification ID MSIP-CRM-BGT-WT32i
16.7 Qualified Antenna Types for WT32i-E
This device has been designed to operate with a 2.7 dBi dipole antenna. Any antenna of the same type and
the same or less gain can be used without additional application to FCC.
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Disclaimer
Silicon Labs intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers using or
intending to use the Silicon Labs products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each specific device, and "Typical"
parameters provided can and do vary in different applications. Application examples described herein are for illustrative purposes only. Silicon Labs reserves the right to make changes
without further notice to the product information, specifications, and descriptions herein, and does not give warranties as to the accuracy or completeness of the included information.
Without prior notification, Silicon Labs may update product firmware during the manufacturing process for security or reliability reasons. Such changes will not alter the specifications or the
performance of the product. Silicon Labs shall have no liability for the consequences of use of the information supplied in this document. This document does not imply or expressly grant
any license to design or fabricate any integrated circuits. The products are not designed or authorized to be used within any FDA Class III devices, applications for which FDA premarket
approval is required or Life Support Systems without the specific written consent of Silicon Labs. A "Life Support System" is any product or system intended to support or sustain life and/or
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