Quectel Wireless Solutions 201902M66 Users Manual
M66 Hardware Design
GSM/GPRS Module Series
Rev. M66_Hardware_Design_V1.2
Date: 2016-07-08
www.quectel.com
GSM/GPRS Module Series
M66 Hardware Design
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Copyright © Quectel Wireless Solutions Co., Ltd. 2016. All rights reserved.
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About the Document
History
Revision Date Author Description
1.0 2014-08-07 Felix YIN Initial
1. Modified output power of Bluetooth
2. Modified the timing of the RFTXMON signal
3. Updated Figure 5: Reference circuit for power
supply
4. Modified description of RTC and SIM card
1.1 2014-11-24 Felix YIN
interface
5. Modified description of UART Application
6. Deleted the over-voltage automatic shutdown
function
7. Modified the antenna gain in the Table 24
8. Modified the current consumption information in
Section 5.3 & 5.4
1. Modified the configuration and timing of PCM
Interface
Added Chapter 3.11 SD Card
1.2 2016-07-08 King MA
Interface
Updated the description of
Temperature Range
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Contents
About the Document ................................................................................................................................ 2
Contents .................................................................................................................................................... 3
Table Index ............................................................................................................................................... 6
Figure Index .............................................................................................................................................. 7
1 Introduction ....................................................................................................................................... 9
1.1. Safety Information ................................................................................................................. 10
2 Product Concept ............................................................................................................................. 12
2.1. General Description .............................................................................................................. 12
2.2. Key Features ......................................................................................................................... 12
2.3. Functional Diagram ............................................................................................................... 15
2.4. Evaluation Board ................................................................................................................... 16
3 Application Interface ....................................................................................................................... 17
3.1. Pin of Module ........................................................................................................................ 18
3.1.1. Pin Assignment ............................................................................................................ 18
3.1.2. Pin Description ............................................................................................................. 19
3.2. Operating Modes .................................................................................................................. 23
3.3. Power Supply ........................................................................................................................ 24
3.3.1. Power Features of Module ........................................................................................... 24
3.3.2. Decrease Supply Voltage Drop .................................................................................... 25
3.3.3. Reference Design For Power Supply ........................................................................... 26
3.3.4. Monitor Power Supply .................................................................................................. 26
3.4. Power On and Down Scenarios ............................................................................................ 27
3.4.1. Power On ..................................................................................................................... 27
3.4.2. Power Down ................................................................................................................ 29
3.4.2.1. Power Down Module Using the PWRKEY Pin ................................................. 29
3.4.2.2. Power Down Module Using AT Command ....................................................... 30
3.4.2.3. Under-voltage Automatic Shutdown ................................................................ 30
3.4.3. Restart ......................................................................................................................... 31
3.5. Power Saving ........................................................................................................................ 31
3.5.1. Minimum Functionality Mode ....................................................................................... 31
3.5.2. SLEEP Mode ............................................................................................................... 32
3.5.3. Wake Up Module From SLEEP Mode .......................................................................... 32
3.5.4. Summary of State Transition ........................................................................................ 33
3.6. RTC Backup .......................................................................................................................... 33
3.7. Serial Interfaces .................................................................................................................... 35
3.7.1.
UART Port ................................................................................................................... 37
3.7.1.1. The Feature of UART Port ............................................................................... 37
3.7.1.2. The Connection of UART ................................................................................ 38
3.7.1.3. Firmware Upgrade ........................................................................................... 40
3.7.2. Debug Port................................................................................................................... 40
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3.7.3. Auxiliary UART Port ..................................................................................................... 41
3.7.4. UART Application ......................................................................................................... 41
3.8. Audio Interfaces .................................................................................................................... 43
3.8.1. Decrease TDD Noise and other Noise ......................................................................... 44
3.8.2. Microphone Interfaces Design ..................................................................................... 45
3.8.3. Receiver and Speaker Interface Design ...................................................................... 46
3.8.4. Earphone Interface Design .......................................................................................... 48
3.8.5. Audio Characteristics ................................................................................................... 48
3.9. PCM Interface ....................................................................................................................... 49
3.9.1. Configuration ............................................................................................................... 49
3.9.2. Timing .......................................................................................................................... 50
3.9.3. Reference Design ........................................................................................................ 51
3.9.4. AT Command ............................................................................................................... 52
3.10. SIM Card Interface ................................................................................................................ 53
3.11. SD Card Interface ................................................................................................................. 55
3.12. ADC ...................................................................................................................................... 57
3.13. Behaviors of The RI .............................................................................................................. 58
3.14. Network Status Indication ...................................................................................................... 59
3.15. RF Transmitting Signal Indication ......................................................................................... 60
4 Antenna Interface ............................................................................................................................ 63
4.1. GSM Antenna Interface ......................................................................................................... 63
4.1.1. Reference Design ........................................................................................................ 63
4.1.2. RF Output Power ......................................................................................................... 64
4.1.3. RF Receiving Sensitivity .............................................................................................. 65
4.1.4. Operating Frequencies ................................................................................................ 65
4.1.5. RF Cable Soldering ..................................................................................................... 66
4.2. Bluetooth Antenna Interface .................................................................................................. 66
5 Electrical, Reliability and Radio Characteristics .......................................................................... 69
5.1. Absolute Maximum Ratings .................................................................................................. 69
5.2. Operating Temperature ......................................................................................................... 69
5.3. Power Supply Ratings ........................................................................................................... 70
5.4. Current Consumption ............................................................................................................ 71
5.5. Electro-static Discharge ........................................................................................................ 73
6 Mechanical Dimensions..........................................................................................................
........ 75
6.1. Mechanical Dimensions of Module ....................................................................................... 75
6.2. Recommended Footprint ....................................................................................................... 77
6.3. Top View of the Module ......................................................................................................... 78
6.4. Bottom View of the Module ................................................................................................... 78
7 Storage and Manufacturing ............................................................................................................ 79
7.1. Storage.................................................................................................................................. 79
7.2. Soldering ............................................................................................................................... 80
7.3. Packaging ............................................................................................................................. 81
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7.3.1. Tape and Reel Packaging ............................................................................................ 81
8 Appendix A References .................................................................................................................. 83
9 Appendix B GPRS Coding Schemes ............................................................................................. 88
10 Appendix C GPRS Multi-slot Classes ............................................................................................ 92
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Table Index
TABLE 1: MODULE KEY FEATURES ..................................................................................................... 13
TABLE 2: CODING SCHEMES AND MAXIMUM NET DATA RATES OVER AIR INTERFACE ............... 15
TABLE 3: IO PARAMETERS DEFINITION .............................................................................................. 19
TABLE 4: PIN DESCRIPTION ................................................................................................................. 19
TABLE 5: OVERVIEW OF OPERATING MODES ................................................................................... 23
TABLE 6: SUMMARY OF STATE TRANSITION ...................................................................................... 33
TABLE 7: LOGIC LEVELS OF THE UART INTERFACE ......................................................................... 36
TABLE 8: PIN DEFINITION OF THE UART INTERFACES ..................................................................... 36
TABLE 9: PIN DEFINITION OF AUDIO INTERFACE .............................................................................. 43
TABLE 10: TYPICAL ELECTRET MICROPHONE CHARACTERISTICS ................................................ 48
TABLE 11: TYPICAL SPEAKER CHARACTERISTICS ........................................................................... 48
TABLE 12: PIN DEFINITION OF PCM INTERFACE ............................................................................... 49
TABLE 13: CONFIGURATION ................................................................................................................ 50
TABLE 14: QPCMON COMMAND DESCRIPTION ................................................................................. 52
TABLE 15: QPCMVOL COMMAND DESCRIPTION ............................................................................... 53
TABLE 16: PIN DEFINITION OF THE SIM INTERFACE ......................................................................... 53
TABLE 17: PIN DEFINITION OF SD CARD INTERFACE ....................................................................... 55
TABLE 18: PIN NAME OF THE SD CARD AND T-FLASH (MICRO SD) CARD...................................... 56
TABLE 19: PIN DEFINITION OF THE ADC ............................................................................................. 57
TABLE 20: CHARACTERISTICS OF THE ADC ...................................................................................... 57
TABLE 21: BEHAVIORS OF THE RI ....................................................................................................... 58
TABLE 22: WORKING STATE OF THE NETLIGHT ................................................................................ 59
TABLE 23: PIN DEFINITION OF THE RFTXMON .................................................................................. 60
TABLE 24: PIN DEFINITION OF THE RF_ANT ...................................................................................... 63
TABLE 25: ANTENNA CABLE REQUIREMENTS ................................................................................... 64
TABLE 26: ANTENNA REQUIREMENTS ................................................................................................ 64
TABLE 27: THE MODULE CONDUCTED RF OUTPUT POWER ........................................................... 64
TABLE 28: THE MODULE CONDUCTED RF RECEIVING SENSITIVITY .............................................. 65
TABLE 29: THE MODULE OPERATING FREQUENCIES ...................................................................... 65
TABLE 30: PIN DEFINITION OF THE BT_ANT ...................................................................................... 67
TABLE 31: ABSOLUTE MAXIMUM RATINGS ........................................................................................ 69
TABLE 32: OPERATING TEMPERATURE .............................................................................................. 70
TABLE 33: THE MODULE POWER SUPPLY RATINGS ......................................................................... 70
TABLE 34: THE MODULE CURRENT CONSUMPTION ......................................................................... 71
TABLE 35: THE ESD ENDURANCE (TEMPERATURE: 25ºC, HUMIDITY: 45%) ................................... 74
TABLE 36: RELATED DOCUMENTS ...................................................................................................... 83
TABLE 37: TERMS AND ABBREVIATIONS ............................................................................................ 84
TABLE 38: DESCRIPTION OF DIFFERENT CODING SCHEMES ......................................................... 88
TABLE 39: GPRS MULTI-SLOT CLASSES ............................................................................................. 92
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Figure Index
FIGURE 1: MODULE FUNCTIONAL DIAGRAM ..................................................................................... 16
FIGURE 2: PIN ASSIGNMENT ............................................................................................................... 18
FIGURE 3: VOLTAGE RIPPLE DURING TRANSMITTING ..................................................................... 25
FIGURE 4: REFERENCE CIRCUIT FOR THE VBAT INPUT .................................................................. 25
FIGURE 5: REFERENCE CIRCUIT FOR POWER SUPPLY .................................................................. 26
FIGURE 6: TURN ON THE MODULE WITH AN OPEN-COLLECTOR DRIVER ..................................... 27
FIGURE 7: TURN ON THE MODULE WITH A BUTTON ........................................................................ 28
FIGURE 8: TURN-ON TIMING ................................................................................................................ 28
FIGURE 9: TURN-OFF TIMING .............................................................................................................. 29
FIGURE 10: TIMING OF RESTARTING SYSTEM .................................................................................. 31
FIGURE 11: VRTC IS SUPPLIED BY A NON-CHARGEABLE BATTERY ............................................... 34
FIGURE 12: VRTC IS SUPPLIED BY A RECHARGEABLE BATTERY ................................................... 34
FIGURE 13: VRTC IS SUPPLIED BY A CAPACITOR ............................................................................. 35
FIGURE 14: REFERENCE DESIGN FOR FULL-FUNCTION UART ...................................................... 39
FIGURE 15: REFERENCE DESIGN FOR UART PORT ......................................................................... 39
FIGURE 16: REFERENCE DESIGN FOR UART PORT WITH HARDWARE FLOW CONTROL............ 40
FIGURE 17: REFERENCE DESIGN FOR FIRMWARE UPGRADE ....................................................... 40
FIGURE 18: REFERENCE DESIGN FOR DEBUG PORT ...................................................................... 41
FIGURE 19: REFERENCE DESIGN FOR AUXILIARY UART PORT ...................................................... 41
FIGURE 20: LEVEL MATCH DESIGN FOR 3.3V SYSTEM .................................................................... 42
FIGURE 21: SKETCH MAP FOR RS-232 INTERFACE MATCH ............................................................ 43
FIGURE 22: REFERENCE DESIGN FOR AIN ........................................................................................ 45
FIGURE 23: HANDSET INTERFACE DESIGN FOR AOUT1 .................................................................. 46
FIGURE 24: SPEAKER INTERFACE DESIGN WITH AN AMPLIFIER FOR AOUT1 .............................. 46
FIGURE 25: HANDSET INTERFACE DESIGN FOR AOUT2 .................................................................. 47
FIGURE 26: SPEAKER INTERFACE DESIGN WITH AN AMPLIFIER FOR AOUT2 .............................. 47
FIGURE 27: EARPHONE INTERFACE DESIGN .................................................................................... 48
FIGURE 28: LONG SYNCHRONIZATION DIAGRAM ............................................................................. 51
FIGURE 29: SHORT SYNCHRONIZATION DIAGRAM .......................................................................... 51
FIGURE 30: REFERENCE DESIGN FOR PCM...................................................................................... 52
FIGURE 31: REFERENCE CIRCUIT FOR SIM INTERFACE WITH THE 6-PIN SIM CARD HOLDER ... 54
FIGURE 32: REFERENCE CIRCUIT FOR MICRO SD CARD ................................................................ 56
FIGURE 33: RI BEHAVIOR OF VOICE CALLING AS A RECEIVER ....................................................... 58
FIGURE 34: RI BEHAVIOR AS A CALLER.............................................................................................. 59
FIGURE 35: RI BEHAVIOR OF URC OR SMS RECEIVED .................................................................... 59
FIGURE 36: REFERENCE DESIGN FOR NETLIGHT ............................................................................ 60
FIGURE 37: RFTXMON SIGNAL DURING BURST TRANSMISSION .................................................... 61
FIGURE 38: RFTXMON SIGNAL DURING CALL ................................................................................... 62
FIGURE 39: REFERENCE DESIGN FOR GSM ANTENNA ................................................................... 64
FIGURE 40: RF SOLDERING SAMPLE ................................................................................................. 66
FIGURE 41: REFERENCE DESIGN FOR BLUETOOTH ANTENNA ...................................................... 67
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FIGURE 42: M66 MODULE TOP AND SIDE DIMENSIONS (UNIT: MM) ................................................ 75
FIGURE 43: M66 MODULE BOTTOM DIMENSIONS (UNIT: MM) ......................................................... 76
FIGURE 44: RECOMMENDED FOOTPRINT (UNIT: MM) ...................................................................... 77
FIGURE 45: TOP VIEW OF THE MODULE ............................................................................................ 78
FIGURE 46: BOTTOM VIEW OF THE MODULE .................................................................................... 78
FIGURE 47: REFLOW SOLDERING THERMAL PROFILE .................................................................... 80
FIGURE 48: TAPE AND REEL SPECIFICATION .................................................................................... 81
FIGURE 49: DIMENSIONS OF REEL ..................................................................................................... 82
FIGURE 50: RADIO BLOCK STRUCTURE OF CS-1, CS-2 AND CS-3 .................................................. 89
FIGURE 51: RADIO BLOCK STRUCTURE OF CS-4 ............................................................................. 90
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1 Introduction
This document defines the M66 module and describes its hardware interface which are connected with
the customer application and the air interface.
This document can help you quickly understand module interface specifications, electrical and
mechanical details. Associated with application note and user guide, you can use M66 module to design
and set up mobile applications easily.
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1.1. Safety Information
The following safety precautions must be observed during all phases of the operation, such as usage,
service or repair of any cellular terminal or mobile incorporating M66 module. Manufacturers of the
cellular terminal should send the following safety information to users and operating personnel, and
incorporate these guidelines into all manuals supplied with the product. If not so, Quectel assumes no
liability for the customer’s failure to comply with these precautions.
Full attention must be given to driving at all times in order to reduce the risk of an
accident. Using a mobile while driving (even with a handsfree kit) causes
distraction and can lead to an accident. You must comply with laws and regulations
restricting the use of wireless devices while driving.
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Switch off the cellular terminal or mobile before boarding an aircraft. Make sure it is
switched off. The operation of wireless appliances in an aircraft is forbidden, so as
to prevent interference with communication systems. Consult the airline staff about
the use of wireless devices on boarding the aircraft, if your device offers a Airplane
Mode which must be enabled prior to boarding an aircraft.
Switch off your wireless device when in hospitals, clinics or other health care
facilities. These requests are desinged to prevent possible interference with
sentitive medical equipment.
Cellular terminals or mobiles operating over radio frequency signal and cellular
network cannot be guaranteed to connect in all conditions, for example no mobile
fee or with an invalid SIM card. While you are in this condition and need emergent
help, please remember using emergency call. In order to make or receive a call,
the cellular terminal or mobile must be switched on and in a service area with
adequate cellular signal strength.
Your cellular terminal or mobile contains a transmitter and receiver. When it is ON ,
it receives and transmits radio frequency energy. RF interference can occur if it is
used close to TV set, radio, computer or other electric equipment.
In locations with potencially explosive atmospheres, obey all posted signs to turn
off wireless devices such as your phone or other cellular terminals. Areas with
potencially explosive atmospheres include fuelling areas, below decks on boats,
fuel or chemical transfer or storage facilities, areas where the air contains
chemicals or particles such as grain, dust or metal powders, etc.
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2 Product Concept
2.1. General Description
M66 is a Quad-band GSM/GPRS engine that works at frequencies of GSM850MHz, EGSM900MHz,
DCS1800MHz and PCS1900MHz. The M66 features GPRS multi-slot class 12 and supports the GPRS
coding schemes CS-1, CS-2, CS-3 and CS-4. For more details about GPRS multi-slot classes and coding
schemes, please refer to the Appendix B & C.
With a tiny profile of 15.8mm × 17.7mm × 2.3mm, the module can meet almost all the requirements for
M2M applications, including Vehicles and Personal Tracking, Security System, Wireless POS, Industrial
PDA, Smart Metering, and Remote Maintenance& Control, etc.
M66 is an SMD type module with LCC package, which can be easily embedded into applications. It
provides abundant hardware interfaces like PCM Interface.
Designed with power saving technique, the current consumption of M66 is as low as 1.3 mA in SLEEP
mode when DRX is 5.
M66 is integrated with Internet service protocols, such as TCP/UDP, FTP and PPP. Extended AT
commands have been developed for you to use these Internet service protocols easily.
M66 supports Bluetooth interface, it is fully compliant with Bluetooth
specification 3.0.
The module fully complies with the RoHS directive of the European Union.
2.2. Key Features
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The following table describes the detailed features of M66 module.
Table 1: Module Key Features
Feature Implementation
Power Supply
Power Saving
Single supply voltage: 3.3V ~ 4.6V
Typical supply voltage: 4V
Typical power consumption in SLEEP mode: 1.3 mA @DRX=5
Quad-band: GSM850, EGSM900, DCS1800, PCS1900.
Frequency Bands
The module can search these frequency bands automatically
The frequency bands can be set by AT command
Compliant to GSM Phase 2/2+
GSM Class Small MS
Transmitting Power
Class 4 (2W) at GSM850 and EGSM900
Class 1 (1W) at DCS1800 and PCS1900
GPRS multi-slot class 12 (default)
GPRS Connectivity
GPRS multi-slot class 1~12 (configurable)
GPRS mobile station class B
GPRS data downlink transfer: max. 85.6kbps
GPRS data uplink transfer: max. 85.6kbps
Coding scheme: CS-1, CS-2, CS-3 and CS-4
DATA GPRS
Support the protocols PAP (Password Authentication Protocol)
usually used for PPP connections
Internet service protocols TCP/UDP, FTP, PPP, HTTP, NTP, PING
Support Packet Broadcast Control Channel (PBCCH)
Support Unstructured Supplementary Service Data (USSD)
Temperature Range
Operation temperature range: -35°C ~ +75°C
Extended temperature range: -40°C ~ +85°C
1.2 mA @DRX=9
1)
2)
Bluetooth
SMS
Support Bluetooth specification 3.0
Output Power: Class 1 (Typical 7.5dBm)
Text and PDU mode
SMS storage: SIM card
SIM Interface Support SIM card: 1.8V, 3.0V
Audio Features
Speech codec modes:
Half Rate (ETS 06.20)
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UART Interfaces
Full Rate (ETS 06.10)
Enhanced Full Rate (ETS 06.50/06.60/06.80)
Adaptive Multi-Rate (AMR)
Echo Suppression
Noise Reduction
UART Port:
Seven lines on UART port interface
Used for AT command, GPRS data
Multiplexing function
Support autobauding from 4800bps to 115200bps
Debug Port:
Two lines on debug port interface DBG_TXD and DBG_RXD
Debug Port only used for firmware debugging
Auxiliary Port:
Used for AT command
Phonebook Management Support phonebook types: SM, ME, ON, MC, RC, DC, LD, LA
SIM Application Toolkit Support SAT class 3, GSM 11.14 Release 99
Real Time Clock Supported
Physical Characteristics
Firmware Upgrade Firmware upgrade via UART Port
Antenna Interface Connected to antenna pad with 50 Ohm impedance control
Size: 15.8±0.15 × 17.7±0.15 × 2.3±0.2mm
Weight: Approx. 1.3g
NOTES
1
1.
2)
)
Within operation temperature range, the module is 3GPP compliant.
Within extended temperature range, the module remains the ability to
establish and maintain a voice, SMS, data transmission, emergency call,
etc. There is no unrecoverable malfunction; there are also no effects on
radio spectrum and no harm to radio network. Only one or more
parameters like Pout might reduce in their value and exceed the specified
tolerances. When the temperature returns to the normal operating
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temperature levels, the module will meet 3GPP compliant again.
Table 2: Coding Schemes and Maximum Net Data Rates over Air Interface
Coding Scheme 1 Timeslot 2 Timeslot 4 Timeslot
CS-1 9.05kbps 18.1kbps 36.2kbps
CS-2 13.4kbps 26.8kbps 53.6kbps
CS-3 15.6kbps 31.2kbps 62.4kbps
CS-4 21.4kbps 42.8kbps 85.6kbps
2.3. Functional Diagram
The following figure shows a block diagram of M66 and illustrates the
major functional parts.
Radio frequency part
Power management
The peripheral interface
—Power supply
—Turn-on/off interface
—UART interface
—Audio interface
—PCM interface
—SIM interface
—SD interface
—ADC interface
—RF interface
—BT interface
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Figure 1: Module Functional Diagram
2.4. Evaluation Board
In order to help you to develop applications with M66, Quectel supplies an evaluation board (EVB),
RS-232 to USB cable, power adapter, earphone, antenna and other peripherals to control or test the
module. For details, please refer to the document [11].
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3 Application Interface
The module adopts LCC package and has 44 pins. The following chapters provide detailed descriptions
about these pins.
Pin of module
Operating modes
Power supply
Power on/down
Power saving
RTC
Serial interfaces
Audio interfaces
PCM interface
SIM card interface
SD card interface
ADC
Behaviors of the RI
Network status indication
RF transmitting signal indication
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3.1. Pin of Module
3.1.1. Pin Assignment
Figure 2: Pin Assignment
NOTE
Keep all reserved pins open.
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3.1.2. Pin Description
Table 3: IO Parameters Definition
Typ e Description
IO Bidirectional input/output
DI Digital input
DO Digital output
PI Power input
PO Power output
AI Analog input
AO Analog output
Table 4: Pin Description
Power Supply
PIN Name PIN No. I/O Description DC Characteristics Comment
Make sure that
supply
Main power supply of
VBAT 42,43 PI
module:
VBAT=3.3V~4.6V
Power supply for RTC when
VBAT is not supplied for the
VRTC 44 IO
system.
Charging for backup battery or
golden capacitor when the
VBAT is applied.
max=4.6V
V
I
V
min=3.3V
I
V
norm=4.0V
I
V
max=3.3V
I
V
min=1.5V
I
V
norm=2.8V
I
V
max=3V
O
V
min=2V
O
V
norm=2.8V
O
I
max=2mA
O
Iin≈10uA
sufficient
current in a
transmitting
burst typically
rises to 1.6A.
If unused, keep
this pin open.
VDD_ 24 PO Supply 2.8V voltage for VOmax=2.9V 1. If unused,
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EXT external circuit. VOmin=2.7V
VOnorm=2.8V
I
max=20mA
O
keep this pin
open.
2. Recommend
to add a
2.2~4.7uF
bypass
capacitor,
when using
this pin for
power supply.
27,34
GND
36,37
Ground
40,41
Turn on/off
PIN Name PIN No. I/O Description DC Characteristics Comment
PWRKEY 7 DI
Power on/off key. PWRKEY
should be pulled down for a
moment to turn on or turn off
the system.
V
max=
IL
0.1×VBAT
V
min=
IH
0.6×VBAT
V
max=3.1V
IH
Audio Interface
PIN Name PIN No. I/O Description DC Characteristics Comment
MICP
MICN
SPK1P
SPK1N
3,
4
5,
6
AI
AO
Positive and negative voice
input
Channel 1 positive and
negative voice output
SPK2P 2 AO Channel 2 voice output
Analog ground. Separate
AGND 1
ground connection for
external audio circuits.
Network Status Indicator
Refer to Section 3.8
If unused, keep
these pins
open.
If unused, keep
these pins
open.
Support both
voice and
ringtone
output.
If unused, keep
this pin open.
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PIN Name PIN No. I/O Description DC Characteristics Comment
V
min=
NETLIGHT 16 DO Network status indication
OH
0.85×VDD_EXT
V
max=
OL
0.15×VDD_EXT
If unused,
keep this pin
open.
UART Port
PIN Name PIN No. I/O Description DC Characteristics Comment
min=0V
V
TXD 17 DO Transmit data
RXD 18 DI Receive data
DTR 19 DI Data terminal ready
RI 20 DO Ring indication
DCD 21 DO Data carrier detection
CTS 22 DO Clear to send
RTS 23 DI Request to send
IL
V
max=
IL
0.25×VDD_EXT
V
min=
IH
0.75×VDD_EXT
V
max=
IH
VDD_EXT+0.2
V
min=
OH
0.85×VDD_EXT
V
max=
OL
0.15×VDD_EXT
If only use
TXD, RXD and
GND to
communicate,
recommended
to keep other
pins open.
Debug Port
PIN Name PIN No. I/O Description DC Characteristics Comment
DBG_
TXD
DBG_
RXD
39 DO Transmit data
38 DI Receive data
Same as above
If unused,
keep these
pins open.
Auxiliary Port
PIN Name PIN No. I/O Description DC Characteristics Comment
TXD_
AUX
RXD_
AUX
29 DO Transmit data
28 DI Receive data
Same as above
If unused,
keep these
pins open.
SIM Interface
PIN Name PIN No. I/O Description DC Characteristics Comment
SIM_ VDD 14 PO Power supply for SIM card
SIM_ CLK 13 DO SIM clock
The voltage can be
selected by software
automatically. Either
1.8V or 3.0V.
V
max=
OL
0.15×SIM_VDD
All signals of
SIM interface
should be
protected
against ESD
with a TVS
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M66 Hardware Design
SIM_ DATA 11 IO SIM data
VOHmin=
0.85×SIM_VDD
max=
V
IL
0.25×SIM_VDD
min=
V
IH
0.75×SIM_VDD
max=
V
OL
0.15×SIM_VDD
min=
V
OH
diode array.
Maximum
trace length is
200mm from
the module
pad to SIM
card holder.
0.85×SIM_VDD
V
max=
OL
SIM_ RST 12 DO SIM reset
0.15×SIM_VDD
V
min=
OH
0.85×SIM_VDD
SIM_
GND
10 SIM ground
ADC
PIN Name PIN No. I/O Description DC Characteristics Comment
V
AVDD 8 PO
ADC0 9 AI
Reference voltage of
ADC circuit
General purpose analog to
digital converter.
max=2.9V
O
V
min=2.7V
O
V
norm=2.8V
O
Voltage range:
0V to 2.8V
If unused,
keep this pin
open.
If unused,
keep this pin
open.
PCM
PIN Name PIN No. I/O Description DC Characteristics Comment
min= 0V
V
PCM_ CLK 30 DO PCM clock
PCM_
SYNC
PCM_
IN
PCM_
OUT
31 DO
32 DI PCM data input
33 DO PCM data output
PCM frame
synchronization
IL
V
max=
IL
0.25×VDD_EXT
V
min=
IH
0.75×VDD_EXT
V
max=
IH
VDD_EXT+0.2
V
min=
OH
0.85×VDD_EXT
V
max=
OL
If unused,
keep this pin
open.
0.15×VDD_EXT
Antenna Interface
PIN Name PIN No. I/O Description DC Characteristics Comment
RF_
ANT
35 IO GSM antenna pad Impedance of 50Ω
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BT_
ANT
26 IO BT antenna pad Impedance of 50Ω
If unused,
keep this pin
open.
Transmitting Signal Indication
PIN Name PIN No. I/O Description DC Characteristics Comment
V
min=
RFTXMON 25 DO
Transmission signal
indication
OH
0.85×VDD_EXT
V
max=
OL
0.15×VDD_EXT
If unused,
keep this pin
open.
Other Interface
PIN Name PIN No. I/O Description DC Characteristics Comment
RESERVED 15
Keep these
pins open.
3.2. Operating Modes
The table below briefly summarizes the various operating modes in the
following chapters.
Table 5: Overview of Operating Modes
Mode Function
After enabling sleep mode by AT+QSCLK=1, the module will
automatically enter into Sleep Mode if DTR is set to high level
GSM/GPRS
Sleep
Normal Operation
GSM IDLE
and there is no interrupt (such as GPIO interrupt or data on
UART port). In this case, the current consumption of module
will reduce to the minimal level.
During Sleep Mode, the module can still receive paging
message and SMS from the system normally.
Software is active. The module has registered to the GSM
network, and the module is ready to send and receive GSM
data.
GSM connection is ongoing. In this mode, the power
GSM TALK
consumption is decided by the configuration of Power Control
Level (PCL), dynamic DTX control and the working RF band.
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POWER DOWN
Minimum
Functionality Mode
(without removing
power supply)
GPRS IDLE
GPRS
STANDBY
The module is not registered to GPRS network. The module is
not reachable through GPRS channel.
The module is registered to GPRS network, but no GPRS PDP
context is active. The SGSN knows the Routing Area where the
module is located at.
The PDP context is active, but no data transfer is ongoing. The
GPRS READY
module is ready to receive or send GPRS data. The SGSN
knows the cell where the module is located at.
There is GPRS data in transfer. In this mode, power
GPRS DATA
consumption is decided by the PCL, working RF band and
GPRS multi-slot configuration.
Normal shutdown by sending the AT+QPOWD=1 command or using the
PWRKEY pin. The power management ASIC disconnects the power supply from
the base band part of the module, and only the power supply for the RTC is
remained. Software is not active. The UART interfaces are not accessible.
Operating voltage (connected to VBAT) remains applied.
AT+CFUN command can set the module to a minimum functionality mode
without removing the power supply. In this case, the RF part of the module will not
work or the SIM card will not be accessible, or both RF part and SIM card will be
disabled, but the UART port is still accessible. The power consumption in this
case is very low.
3.3. Power Supply
3.3.1. Power Features of Module
The power supply is one of the key issues in designing GSM terminals. Because of the 577us radio burst
in GSM every 4.615ms, power supply must be able to deliver high current peaks in a burst period. During
these peaks, drops on the supply voltage must not exceed minimum working voltage of module.
For the M66 module, the max current consumption could reach to 1.6A during a burst transmission. It will
cause a large voltage drop on the VBAT. In order to ensure stable operation of the module, it is
recommended that the max voltage drop during the burst transmission does not exceed 400mV.
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Figure 3: Voltage Ripple during Transmitting
3.3.2. Decrease Supply Voltage Drop
The power supply range of the module is 3.3V to 4.6V. Make sure that the input voltage will never drop
below 3.3V even in a burst transmission. If the power voltage drops below 3.3V, the module could turn off
automatically. For better power performance, it is recommended to place a 100uF tantalum capacitor with
low ESR (ESR=0.7Ω) and ceramic capacitor 100nF, 33pF and 10pF near the VBAT pin. The reference
circuit is illustrated in Figure 4.
The VBAT route should be wide enough to ensure that there is not too much voltage drop during burst
transmission. The width of trace should be no less than 2mm and the principle of the VBAT route is the
longer route, the wider trace.
Figure 4: Reference Circuit for the VBAT Input
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3.3.3. Reference Design For Power Supply
The power design for the module is very important, since the performance of power supply for the module
largely depends on the power source. The power supply is capable of providing the sufficient current up to
2A at least. If the voltage drop between the input and output is not too high, it is suggested to use a LDO
as module’s power supply. If there is a big voltage difference between the input source and the desired
output (VBAT), a switcher power converter is recommended to use as a power supply.
The following figure shows a reference design for +5V input power source. The designed output for the
power supply is 4.0V and the maximum load current is 3A. In addition, in order to get a stable output
voltage, a zener diode is placed close to the pins of VBAT. As to the zener diode, it is suggested to use a
zener diode whose reverse zener voltage is 5.1V and dissipation power is more than 1 Watt.
Figure 5: Reference Circuit for Power Supply
NOTE
It is suggested to control the module’s main power supply (VBAT) via LDO enable pin to restart the
module when the module has become abnormal. Power switch circuit like P-channel MOSFET switch
circuit can also be used to control VBAT.
3.3.4. Monitor Power Supply
The command “AT+CBC” can be used to monitor the supply voltage of the module. The unit of the
displayed voltage is mV.
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For details, please refer to the document [1].
3.4. Power On and Down Scenarios
3.4.1. Power On
The module can be turned on by driving the pin PWRKEY to a low level
voltage. An open collector driver circuit is suggested to control the
PWRKEY. A simple reference circuit is illustrated as below.
Figure 6: Turn on the Module with an Open-collector Driver
NOTES
1. M66 module is set to autobauding mode (AT+IPR=0) by default. In the autobauding mode, URC “RDY”
is not reported to the host controller after module is powered on. When the module is powered on after
a delay of 4 or 5 seconds, it can receive AT command. Host controller should first send an AT string in
order that the module can detect baud rate of host controller, and it should continue to send the next AT
string until receiving OK string from the module. Then enter AT+IPR=x;&W to set a fixed baud rate for
the module and save the configuration to flash memory of the module. After these configurations, the
URC RDY would be received from the UART Port of the module every time when the module is
powered on. For more details, refer to the section AT+IPR in document [1].
2. When AT command is responded, indicates module is turned on successfully, or else the module fails
to be turned on.
The other way to control the PWRKEY is through a button directly. A TVS component is indispensable to
be placed nearby the button for ESD protection. For the best performance, the TVS component must be
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M66 Hardware Design
placed nearby the button. When pressing the key, electrostatic strike may generate from finger. A
reference circuit is shown in the following figure.
Figure 7: Turn on the Module with a Button
The turn-on timing is illustrated as the following figure.
Figure 8: Turn-on Timing
NOTE
Make sure that VBAT is stable before pulling down PWRKEY pin. The time of T1 is recommended to be
100ms.
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