Ehong EH-MB05 User manual

EH
-
MB05
Bluetooth® technology
audio
module
FCCID:2ACCRMB05
• Bluetooth radio
-
-
-
-
-
Fully embedded Bluetooth® v
3.0 +EDR
Class2 module
128-bit encryption security
Range up to 15m
Multipoint capability(7 transmit data devices
connected at the same time)
• Support profiles
-
-
-
SPP (Master and slave)
iAP (ipod accessory protocol)
HFP ,A2DP,AVRCP,HID(Salve)
EH
-
MB05
• User interface
-
Send AT command over UART
- Firmware upgrade over USB
-
With SPP service active: 560kbps tr
ansmission
speed (UART)
-
PCM interface (I2S,SPDIF)
- I2C interface(Master )
• Audio codec
-
-
-
16bit internal stereo codec :95dB SNR for DAC
64MIPS Kalimba DSP coprocessor
Support Apt-X ,AAC, Apt-XLL,SBC codec
• General I/O
-
-
11 general purpose I/Os
2 analogue I/O
• FCC and Bluetooth® qualified
• Single voltage supply: 3.3V typical
• Small form factor: 23.24 x 11.93 x 2.2mm
• Operating temperature range: -40 °C to 85 °C
• The operation distance >20cm
Version 2.0
July 21 2014
Shanghai Ehong Technologies Inc

Bluetooth Audio Module
1. Contents
1.
2.
3.
4.
Description
.............................................................................................................................
................................... 4
Application................................................................................................................................................................. 4
EH-MB05 Product numbering ............................................................................................................................. 4
Electrical Characteristic ........................................................................................................................................ 5
4.1.
Recommend operation conditions
.............................
.................................................................................... 5
Absolute Maximum Rating
.............................................................................................................................. 5
Power consumptions ........................................................................................................................................ 6
Input/output Terminal Characteristics ........................................................................................................... 6
4.2.
4.3.
4.4.
4.4.1.
4.4.2.
4.4.3.
4.4.4.
Digital Terminals
.............................................................................................................................
........... 6
USB .............................................................................................................................................................. 7
Internal CODEC Analogue to Digital Converter ................................................................................. 7
Internal CODEC Digital to Analogue Converter ................................................................................. 8
5.
6.
Pinout and Terminal Description
..........................................................................
.............................................. 9
5.1.
Pin assignment
.............................................................................................................................
..................... 9
Physical Interfaces
...................
.............................................................................................................................
11
6.1.
Power Supply
.............................................................................................................
...................................... 11
Reset .................................................................................................................................................................. 12
PIO ...................................................................................................................................................................... 12
AIO
...................................................................................................................................................................... 12
UART.................................................................................................................................................................. 13
I2C Master ........................................................................................................................................................ 13
6.2.
6.3.
6.4.
6.5.
6.6.
6.6.1.
Apple iOS CP reference design
...............................................................
............................................ 14
6.7.
Digital Audio Interfaces
.............................................................................................................................
..... 15
6.7.1
6.7.2
PCM
............................
.............................................................................................................................
.. 16
Digital Audio Interface (I S) .................................................................................................................. 16
2
6.7.3
IEC 60958 Interface (SPDIF)
............................................................................................................... 19
6.8
Microphone input
.............................................................
................................................................................ 20
Analog Output stage
....................................................................................................................................... 21
USB .................................................................................................................................................................... 21
6.9
6.10
7.
8.
EH
-
MB05 Reference Design
.........................................................
...................................................................... 23
Mechanical and PCB Footprint Characteristics.......................................................................................... 24
Shanghai Ehong Technologies Inc

Bluetooth Audio Module
RF Layout Guidelines .......................................................................................................................................... 24
9.
9.1
Feed Line and Antenna
.............................................................................................................................
..... 25
Matching network in free space ................................................................................................................... 26
9.2
10.
11.
Reflow Profile
.............................................................................................................................
........................
27
Contact Information ......................................................................................................................................... 28
2. Table of Tables
T
ABLE
1: R
ECOMMENDED
O
PERATING
C
ONDITIONS
..............................
................................................................. 5
TABLE 2: ABSOLUTE MAXIMUM RATING RECOMMENDED OPERATING CONDITIONS ................................................ 5
TABLE 3: POWER CONSUMPTIONS .......................................................................................................................... 6
TABLE 4: DIGITAL TERMINAL .................................................................................................................................. 7
TABLE 5: USB TERMINAL ....................................................................................................................................... 7
TABLE 6: ANALOGUE TO DIGITAL CONVERTER ....................................................................................................... 8
TABLE 7: DIGITAL TO ANALOGUE CONVERTER ....................................................................................................... 8
T
ABLE
8
：
PIN T
ERMINAL
D
ESCRIPTION
......................................
......................................................................... 11
T
ABLE
9: P
IN
S
TATUS ON
R
ESET
.......................................................................................................................... 12
TABLE 10: POSSIBLE UART SETTINGS ................................................................................................................ 13
TABLE 11:ALTERNATIVE FUNCTIONS OF THE DIGITAL AUDIO BUS INTERFACE ON THE PCM INTERFACE .............. 16
TABLE 12 : DIGITAL AUDIO INTERFACE SLAVE TIMING .......................................................................................... 17
TABLE 13 : DIGITAL AUDIO INTERFACE MASTER TIMING ....................................................................................... 18
TABLE 14: USB INTERFACE COMPONENT VALUES ............................................................................................... 22
3. Table of Figures
F
IGURE
1
：
P
I NOUT OF
EH
-
MB05................................................................
......................................................... 9
FIGURE 2： POW ER SUPPLY PCB DESIGN .......................................................................................................... 11
F
IGURE
3
：
C
O NNECTION
T
O
H
OST DEVICE
................
........................................................................................ 13
FIGURE 4 : EXAMPLE EEPROM CONNECTION WITH I2C INTERFACE .................................................................... 14
FIGURE 5 : APPLE CO-PROCESSOR 2.0C ............................................................................................................. 14
FIGURE 6 : APPLE CO-PROCESSOR 2.0B ............................................................................................................. 15
FIGURE 7 : AUDIO INTERFACE .............................................................................................................................. 15
FIGURE 8 : DIGITAL AUDIO INTERFACE MODES ..................................................................................................... 17
FIGURE 9 : DIGITAL AUDIO INTERFACE SLAVE TIMING .......................................................................................... 18
FIGURE 10 : DIGITAL AUDIO INTERFACE MASTER TIMING ..................................................................................... 18
FIGURE 11: EXAMPLE CIRCUIT FOR SPDIF INTERFACE (CO-AXIAL ) ..................................................................... 19
FIGURE 12: EXAMPLE CIRCUIT FOR SPDIF INTERFACE (OPTICAL) ....................................................................... 20
FIGURE 13: MICROPHONE BIASING (SINGLE CHANNEL SHOWN) ........................................................................... 20
FIGURE 14: SPEAKER OUTPUT ............................................................................................................................. 21
FIGURE 15: USB CONNECTIONS .......................................................................................................................... 22
FIGURE 16: REFERENCE DESIGN ......................................................................................................................... 23
FIGURE 17: RECOMMENDED PCB MOUNTING PATTERN (UNIT: MM, DEVIATION:0.02MM)TOP VIEW ................... 24
FIGURE 18: CLEARANCE AREA OF ANTENNA ......................................................................................................... 25
FIGURE 19: ANTENNA REFERENCE DESIGN .......................................................................................................... 26
FIGURE 20: PI MATCH NETWORK EXAMPLE ........................................................................................................... 26
FIGURE 21: RECOMMENDED REFLOW PROFILE ................................................................................................... 27
Shanghai Ehong Technologies Inc

Bluetooth Audio Module
1. Description
The EH-MB05 is an easy to use Bluetooth module, compliant with Bluetooth v3.0+EDR. The
module provides complete RF platform in a small form factor.
The EH-MB05 enables electronic devices with wireless connectivity, not requiring any RF
experience or expertise for integration into the final product. The EH-MB05 module, being a
certified solution, optimizes the time to market of the final application.
The module is designed for maximum performance in a minimal space including fast speed
UART and 11general purpose I/O lines, 1 analogueI/O lines, several serial interface options, and
up to 600 kbps transmission speed with SPP service active, 200 kbps with iAP service active.
The module is , the impedance of the feed line between the RF port and the
antenna shall be 50Ω.Embedded Bluetooth AT command firmware is a friendly interface,
Supportdifferent Bluetooth profiles, such as SPP, A2DP, AVRCP, HFP, HID, iAP and etc. iAP
over Bluetooth using apple’s authentication coprocessor.
Customers using the Apple authentication IC must register as developers, to become an
Apple certified MFI member. License fees may apply, for additional information visit:
http://developer.apple.com/programs/which-program/index.html.
Certified MFI developers developing electronic accessories that connect to an iPod®,
® ®
iPhone , and iPad can gain access to technical documentation, hardware components,
technical support and certification logos.
Customized firmware for peripheral device interaction, power optimization, security, and other
proprietary features may be supported and can be ordered pre-loaded and configured.
2. Application
•
Sports and fitness
• Home entertainment
• Service diagnostics
• Office and mobile accessories
• Commercial
• Multimedia speaker
• Automotive
• Human interface devices
3. EH-MB05 Product numbering
EH
-
MB05X
Company Name(Ehong)
A. EH -------------
B. MB05 ------------ Module Name
Shanghai Ehong Technologies Inc

Bluetooth Audio Module
4. Electrical Characteristic
4.1. Recommend operation conditions
Operating Condition Min Typical Max Unit
Storage Temperature -40 -- +105 °C
°C
V
Operating Temperature Range
PIO Voltage
-40
+1.7
+1.42
+2.7
2400
-- +85
+3.6
+3.3
+1.5
+3.3
2441
AIO Voltage +1.57
+3.6
V
VDD Voltage V
RF frequency 24800 MHz
Table 1: Recommended Operating Conditions
4.2. Absolute Maximum Rating
Rating Min
-40
Max
+125
+85
Unit
°C
°C
V
Storage Temperature
Operating Temperature
PIO Voltage
-40
-0.4
-0.4
-0.4
-0.4
+3.6
+1.57
+3.6
+3.6
AIO Voltage V
VDD Voltage V
USB_DP/USB_DN Voltage V
VDD+0.
4
Other Terminal Voltages except RF -0.4 V
Table 2: Absolute Maximum Rating Recommended Operating Co
nditions
Shanghai Ehong Technologies Inc

Bluetooth Audio Module
4.3. Power consumptions
Operating Condition Min Typical Max Unit
Standby, without deep sleep 2.1
0.11
-
-
-
-
3.1
0.7
40
mA
mA
mA
Standby, with deep sleep
Inquiry window time
Connected (Deep sleep
disable, sniff enable )
Connected (Deep sleep on,
(b)
(a)
- 3.3 - mA
sniff enable)
(a)
- 0.4
20
- mA
mA
Connected with data transfer 18 22
Connected with audio
streaming (A2DP) 35 40 mA
Table 3: Power consumptions
Note :
Power consumption depends on the firmware used. Typical values are shown in the table.
(a)
Sniff mode
-----
In Sniff mode, the duty cycle of the slave
’
s activity in t
he piconet may be reduced. If a
slave is in active mode on an ACL logical transport, it shall listen in every ACL slot to the master traffic,
unless that link is being treated as a scatter net link or is absent due to hold mode. With sniff mode, the
time slots when a slave is listening are reduced, so the master shall only transmit to a slave in specified
time slots. The sniff anchor points are spaced regularly with an interval of Tsniff.
(b)
Radio on(Inquiry )
----
Search time is 22 seconds
4.4. Input/output Terminal Characteristics
4.4.1.Digital Terminals
Supply Voltage Levels
Input Voltage Levels
Min Typ Max Unit
VIL input logic level low -0.3 - +0.25xVDD
VDD+0.3
V
V
VIH input logic level high 0.625VDD -
Output Voltage Levels
VOL output logic level low, lOL = 4.0mA
VOH output logic level high, lOH = -4.0mA
Input and Tri-state Current
Ii input leakage current at Vin=VDD or 0V
- -
-
0.125
VDD
V
V
0.75xVDD
-100
-100
0
0
100
100
nA
nA
Ioz tri-state output leakage current at Vo=VDD
or 0V
With strong pull-up -100
10
-40
40
-10 uA
μA
With strong pull-down 100
Shanghai Ehong Technologies Inc

Bluetooth Audio Module
mV
rms
Input full scale at maximum gain (differential)
Input full scale at minimum gain (differential)
-
-
4 -
- mV
rms
800
3dB Bandwidth -
-
20
6
-
-
kHz
kΩ
%
Microphone mode input impedance
THD+N (microphone input) @ 30mv rms input 0.04
Table 6: Analogue to Digital Converter
4.4.4.Internal CODEC Digital to Analogue Converter
Parameter Conditions Min Typ Max
16
Unit
Bits
Resolution - -
-
Output Sample Rate, Fsample
fin=1kHz
8 48 kHz
Fsample
8kHz - 95
95
95
95
95
95
95
-
-
-
-
-
-
-
B/W=20Hz->20kHz 11.025kHz
16kHz
-
Signal to Noise
Ratio, SNR
A-Weighted -
THD+N<0.01%
0dBFS signal
Load = 100kΩ
22.050kHz
32kHz
-
-
dB
44.1kHz
48kHz
-
-
Digital Gain Digital Gain Resolution = 1/32 dB
Analogue Gain Resolution = 3dB
-24
0
21.5
-21
dB
dB
Analogue Gain -
mV
rms
Output voltage full swing (differential)
Allowed Load
- 750 -
Resistive 16
-
-
-
-
OC
500
0.01
Ω
pF
%
Capacitive
THD+N 100kΩ load
THD+N 16Ω load
-
-
-
- 0.1
-
%
SNR (Load=16Ω, 0dBFS input relative to digital
silence) 95 dB
Table 7: Digital to Analogue Converter
Shanghai Ehong T
echnologies Inc

Bluetooth Audio Module
5. Pinout and Terminal Description
5.1. Pin assignment
Figure 1：
Pinout of EH
-
MB05
Pin Symbol I/O Type Description
1 GND Ground Ground
Active LOW RESETB, input debounced
so must be low for >5ms to cause a
RESETB
CMOS input with weak
internal pull-up
2 RESETB
Input with weak internal pull- Serial Peripheral interface clock for
3
4
5
SPI_CLK
SPI_MISO
SPI_MOSI
down programming only
CMOS output, tri-state, with
weak internal pull
-down
Serial Peripheral Interface output for
programming only
CMOS input, with weak
internal pull-down
Serial Peripheral Interface input for
programming only
Chip select for Synchronous Serial
Interface for programming only, active
low
Input with weak internal pull-
up
6
7
8
SPI_CSB
LED0 Open drain output LED Driver
Bi-directional with
programmable strength
PIO3 Programmable input/output line
internal pull-up/down
CMOS output, tri-state, with
weak internal pull
-down
9 PCM_OUT Synchronous Data Output
10
11
MIC_RP
MIC_RN
Analogue
Analogue
Microphone input positive, right
Microphone input negative, right
Shanghai Ehong Technologies Inc

Bluetooth Audio Module
Bi-directional with
12
13
PIO0
PIO1
programmable strength
internal pull-up/down
Programmable input/output line
Bi-directional with
programmable strength
internal pull-up/down
Programmable input/output line
CMOS Input, with weak
internal pull-down
14
15
16
PCM_IN
GND
Synchronous Data Input
Ground
Ground
Bi-directional with weak
internal pull-down
PCM_SYNC Synchronous Data Sync
17
18
19
RF_GND
RF_IN
RF Ground
RF
RF ground
RF Transceiver input/output line
RF ground
RF_GND RF Ground
Bi-directional with weak
internal pull-down
20 PCM_CLK Synchronous Data Clock
21
22
23
24
25
26
27
28
AIO0 Bi-directional
Ground
Analogue programmable input/output line
Ground
GND
MIC_LP
MIC_LN
SPK_LN
SPK_LP
SPK_RN
SPK_RP
Analogue
Analogue
Analogue
Analogue
Analogue
Analogue
Microphone input positive, left
Microphone input negative, right
Speaker output negative, left
Speaker output positive, left
Speaker output negative, right
Speaker output positive, right
Bi-directional with
29 PIO13 programmable strength
internal pull-up/down
Programmable input/output line
30
31
VDD 3V3 power input 3V3 power input
USB data plus with selectable internal
1.5K pull up resistor
USB_DP Bi-directional
32
33
USB_DN
GND
Bi-directional
Ground
USB data minus
Ground
Bi-directional with
34 PIO9 programmable strength Programmable input/output line
internal pull-up/down
Bi-directional with
35
36
PIO14
PIO4
programmable strength
internal pull-up/down
Programmable input/output line
Programmable input/output line
Bi-directional with
Shanghai Ehong Technologies Inc

Bluetooth Audio Module
programmable strength
internal pull-up/down
37
38
GND Ground Ground
Bi-directional CMOS output,
tri-state, with weak internal
pull-up
UART_TX UART data output
CMOS input with weak
internal pull-down
39
40
UART_RX
PIO8
UART data input
Bi-directional with
programmable strength Programmable input/output line
internal pull-up/down
Bi-directional with
41
42
PIO7
PIO6
programmable strength
internal pull-up/down
Programmable input/output line
Programmable input/output line
Bi-directional with
programmable strength
internal pull-up/down
Table 8：
PIN Terminal Description
6. Physical Interfaces
6.1. Power Supply
-
-
-
-
The module DC3.3V power input.
Power supply pin connection capacitor to chip and pin as far as possible close
Capacitor decouples power to the chip
Capacitor prevents noise coupling back to power plane.
.
Figure 2：
Power Supply PCB Design
Shanghai Ehong Technologies Inc

Bluetooth Audio Module
6.2. Reset
The module may be reset from several sources: RESETB pin, power-on reset, a UART break
character or via software configured watchdog timer.
The RESETB pin is an active low RESETB and is internally filtered using the internal low
frequency clock oscillator. A RESETB will be performed between 1.5 and 4.0ms following
RESETB being active. It is recommended that RESETB be applied for a period greater than
5ms.
At RESETB the digital I/O pins are set to inputs for bi-directional pins and outputs are tri-state.
The pull-down state is shown below.
Pin Name / Group
USB_DP
Pin Status on RESETB
N/a
N/a
PD
PU
PD
PD
PU
PD
PU
PD
PD
PD
PD
PD
USB_DN
UART_RX
UART_TX
SPI_MOSI
SPI_CLK
SPI_CSB
SPI_MISO
RESETB
PIOs
PCM_IN
PCM_CLK
PCM_SYNC
PCM_OUT
Table 9: Pin Status on R
eset
6.3. PIO
EH-MB05 has a total of 11 digital programmable I/O terminals. They are powered from VDD
(3.3V). Their functions depend on firmware running on the device. PIO lines can be configured
through software to have either weak or strong pull-ups or pull-downs.
Note:
All PIO lines are configured as inputs with weak pull-downs at reset.
Any of the PIO lines can be configured as interrupt request lines or as wake-up lines from sleep
modes.
6.4. AIO
EH-MB05 has 2 analogue I/O terminals. Their functions depend on software. Typically ADC
functions can be configured to battery voltage measurement. They can also be used as a digital
PIO.
Shanghai Ehong Technologies Inc

Bl
uetooth Audio Module
6.5. UART
This is a standard UART interface for communicating with other serial devices. The
UART interface provides a simple mechanism for communicating with other serial
devices using the RS232 protocol.
The UART CTS and RTS signals can be used to implement RS232 hardware flow
control where both are active low indicators.
Parameter Possible Values
1200 baud (≤2%Error)
9600 baud (≤1%Error)
3M baud (≤1%Error)
RTS/CTS or None
None, Odd or Even
1 or 2
Minimum
Maximum
Baud Rate
Flow Control
Parity
Number of Stop Bits
Bits per Byte 8
Table 10: Possible UART Settings
Figure 3：
Connection To Host device
6.6. I2C Master
PIO6, PIO7 and PIO8 can be used to form a master I C interface. The interface is formed using
2
software to drive these lines. It is suited only to relatively slow functions such as driving a LCD,
keyboard scanner or EEPROM. In the case, PIO lines need to be pulled up through 2.2KΩ
resistors.
Shanghai Ehon
g Technologies Inc

Bluetooth Audio Module
Figure 4 : Example EEPROM Connection with I
2
C Interface
6.6.1.Apple iOS CP reference design
The figures below give an indicative overview of what the hardware concept looks like. A
specific MFI co-processor layout is available for licensed MFI developers from the MFI program.
Figure 5 : Apple Co
-
processor 2.0C
Shanghai Ehong Technologies Inc

Bluetooth Audio Module
Figure 6 : Apple Co
-
processor 2.0B
6.7. Digital Audio Interfaces
The audio interface circuit consists of:
■ Stereo audio codec
■ Dual audio inputs and outputs
■ A configurable PCM, I²S or SPDIF interface
Figure 2 outlines the functional blocks of the interface. The codec supports stereo playback and
recording of audio signals at multiple sample rates with a resolution of 16-bit. The ADC and
the DAC of the codec each contain 2 independent channels. Any ADC or DAC channel can be
run at its own independent sample rate.
Figure 7 : Audio Interface
The interface for the digital audio bus shares the same pins as the PCM codec interface
described in Table 11, which means each of the audio buses are mutually exclusive in their
usage. Table 11 lists these alternative functions.
Shanghai Ehong Technologies Inc

Bluetooth
Audio Module
PCM Interface
PCM_OUT
SPDIF Interface
SPDIF_OUT
I²S Interface
SD_OUT
PCM_IN
SPDIF_IN
SD_IN
WS
PCM_SYNC
PCM_CLK
-
-
SCK
Table 11: Alternative Functions of the Digital Audio Bus Interface on the PCM Interf
ace
The audio input circuitry consists of a dual audio input that can be configured to be either
single-ended or fully differential and programmed for either microphone or line input. It has an
analogue and digital programmable gain stage for optimization of different microphones.
The audio output circuitry consists of a dual differential class A
-
B output stage.
6.7.1 PCM
The audio pulse code modulation (PCM) interface supports continuous transmission and
reception of PCM encoded audio
data over Bluetooth.
Hardware on EH
-
MB05 allows the data to be sent to and received from a SCO connection. Up
to three SCO connections can be supported by the PCM interface at any one time.
EH-MB05 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.
EH-MB05 is compatible with a variety of clock formats, including Long Frame Sync, Short
Frame Sync and GCI timing environments.
It supports 13-bit or 16-bit linear, 8-bit u-law or A-law companded sample formats and can
receive and transmit on any selection of three of the first four slots following PCM_SYNC.
EH-MB05 interfaces directly to PCM audio devices including the following:
■ Qualcomm MSM 3000 series and MSM 5000 series CDMA baseband devices
■
OKI MSM7705 four channel A
-
law and μ
-
law CODEC
■
Motorola MC145481 8
-
bit A
-
law and μ
-
law CODEC
■ Motorola MC145483 13-bit linear CODEC
■ STW 5093 and 5094 14-bit linear CODECs(8)
■
EH
-
MB05 is also compatible with the Motorola SSI interface
6.7.2 Digital Audio Interface (I
2
S)
The digital audio interface supports the industry standard formats for I2S, left
-
justified or right
-
justified. The interface shares the same pi
ns of the PCM interface as Table 11.
The I2S interface can be enabled by using AT+ commands. The module is an I2S slave device
with the default firmware. Contact with EHong for special firmware when use the module as an
I2S master. The I2S suppo
rt following formats:
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Bluetooth Audio Module
Figure 8 : Digital Audio Interface Modes
Symbol
Parameter
Min
-
Typical
M
ax
Unit
MHz
kHz
ns
-
SCK Frequency
-
-
-
-
-
-
-
-
-
6.2
-
WS Frequency
-
96
-
t
ch
tcl
SCK high time
80
80
-
SCK low time
-
ns
t
opd
tssu
tsh
tisu
tih
SCK to SD_OUT delay
WS to SCK set up time
WS to SCK hold time
SD_IN to SCK set-up time
SD_IN to SCK hold time
20
-
ns
20
20
20
20
ns
-
ns
-
ns
-
ns
Table 12 : Digital Audio Interface Slave Timing
Shanghai Ehong Technologies Inc

Bluetooth Audio Module
Figure
9 : Digital Audio Interface Slave Timing
Symbol
Parameter
Min
Typical
Max
6.2
96
20
20
-
Unit
MHz
kHz
ns
-
SCK Frequency
-
-
-
-
-
-
-
-
-
WS Frequency
t
opd
tspd
tisu
tih
SCK to SD_OUT delay
SCK to WS delay
-
-
ns
SD_IN to SCK set
-
up time
SD_IN to SCK hold time
20
10
ns
-
ns
Table 13 : Digital Audio Interface Master Timing
Figure 10 : Digital Audio Interface Master Timing
Shanghai Ehong Technologies Inc

Bluetooth Audio Module
6.7.3 IEC 60958 Interface (SPDIF)
Through AT+ command to switch if SPDIF is used.The IEC 60958 interface is a digital audio
interface that uses bi-phase coding to minimise 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 609
58
-
3 and IEC 60958
-
4.
The SPDIF interface signals are SPDIF_IN and SPDIF_OUT and are shared on the PCM
interface pins. The input and output stages of the SPDIF pins can interface to:
■
A
75Ω
coaxial cable with an RCA connector, see Figure 11.
■
An optical link that uses Toslink optical components, see Figure 12.
Figure 11: Example Circuit for SPDIF Interface (Co
-
Axial)
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Bluetooth Audio Module
Figure 12: Example Circuit for SPDIF Interface (Optical)
6.8 Microphone input
Figure 13: Microphone Biasing (Single Channel
Shown)
The audio input is intended for use in the range from 1μA @ 94dB SPL to about 10μA @ 9
4dB
SPL. With biasing resistors R1 and R2 equal to 1kΩ, this requires microphones with sensitivity
between about –40dBV and –60dBV. The microphone for each channel should be biased as
shown in Figure 14.
Shanghai Ehong Technologies Inc