M85 Hardware Design
GSM/GPRS Module Series
Rev. M85_Hardware_Design_V3.0
Date: 2015-10-22
www.quectel.com
GSM/GPRS Module Series
M85 Hardware Design
Our aim is to provide customers with timely and comprehensive service. For any assistance, please contact our company headquarters:
Quectel Wireless Solutions Co., Ltd.
Office 501, Building 13, No.99, Tianzhou Road, Shanghai, China, 200233
Tel: +86 21 5108 6236
Mail: info@quectel.com
Or our local office, for more information, please visit:
http://www.quectel.com/support/salesupport.aspx
For technical support, to report documentation errors, please visit: http://www.quectel.com/support/techsupport.aspx
Or Email: Support@quectel.com
GENERAL NOTES
QUECTEL OFFERS THIS INFORMATION AS A SERVICE TO ITS CUSTOMERS. THE INFORMATION
PROVIDED IS BASED UPON CUSTOMERS’ REQUIREMENTS. QUECTEL MAKES EVERY EFFORT TO ENSURE THE QUALITY OF THE INFORMATION IT MAKES AVAILABLE. QUECTEL DOES NOT MAKE ANY WARRANTY AS TO THE INFORMATION CONTAINED HEREIN, AND DOES NOT ACCEPT ANY LIABILITY FOR ANY INJURY, LOSS OR DAMAGE OF ANY KIND INCURRED BY USE OF OR RELIANCE UPON THE INFORMATION. ALL INFORMATION SUPPLIED HEREIN IS SUBJECT TO CHANGE WITHOUT PRIOR NOTICE.
COPYRIGHT
THIS INFORMATION CONTAINED HERE IS PROPRIETARY TECHNICAL INFORMATION OF QUECTEL CO., LTD. TRANSMITTABLE, REPRODUCTION, DISSEMINATION AND EDITING OF THIS DOCUMENT AS WELL AS UTILIZATION OF THIS CONTENTS ARE FORBIDDEN WITHOUT PERMISSION. OFFENDERS WILL BE HELD LIABLE FOR PAYMENT OF DAMAGES. ALL RIGHTS ARE RESERVED IN THE EVENT OF A PATENT GRANT OR REGISTRATION OF A UTILITY MODEL OR DESIGN.
Copyright © Quectel Wireless Solutions Co., Ltd. 2015. All rights reserved.
M85_Hardware_Design |
Confidential / Released |
1 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
About the Document
History
|
Revision |
|
|
Date |
|
Author |
|
|
Description |
|
|
|
|
|
|
|
|
|
|||||
|
|
|
|
|
|
|
|||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
1.0 |
|
2012-07-15 |
|
Winter CHEN |
Initial |
||||||
|
|
|
|
|
|
||||||
1.1 |
|
2013-11-04 |
|
Felix YIN |
Optimized the parameters of VBAT ripple in Table 33 |
||||||
|
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
1. |
Updated module key features in Table 1 |
||
|
|
|
|
|
|
|
|
2. |
Modified pin assignment in Figure 2 |
||
|
|
|
|
|
|
|
|
3. |
Updated DC characteristics of module’s pins in |
||
|
|
|
|
|
|
|
|
|
|
Table 4 |
|
|
|
|
|
|
|
|
|
4. |
Updated reference circuit for power supply in |
||
3.0 |
|
2015-03-13 |
|
Stone YU/ |
|
|
Figure 5 |
||||
|
|
Hollis WANG |
5. |
Modified over-voltage or under-voltage automatic |
|||||||
|
|
|
|
|
|
||||||
|
|
|
|
|
|
|
|
|
|
shutdown in Section 3.4.2.3 |
|
|
|
|
|
|
|
|
|
6. |
Modified RTC backup in Section 3.6 |
||
|
|
|
|
|
|
|
|
7. |
Modified UART application in Section 3.7.4 |
||
|
|
|
|
|
|
|
|
8. |
Deleted the data call mode in Section 3.13 |
||
|
|
|
|
|
|
|
|
9. |
Added antenna requirement in Section 4.5 |
||
|
|
|
|
|
|
|
|
|
|
|
|
M85_Hardware_Design |
Confidential / Released |
2 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
Contents
About the Document................................................................................................................................... |
|
2 |
|||
Contents ....................................................................................................................................................... |
|
|
3 |
||
Table Index................................................................................................................................................... |
|
|
6 |
||
Figure Index ................................................................................................................................................. |
|
|
7 |
||
1 |
Introduction |
.......................................................................................................................................... |
|
9 |
|
|
1.1. |
Safety Information ................................................................................................................. |
10 |
||
2 |
Product Concept ................................................................................................................................ |
|
11 |
||
|
2.1. |
General Description............................................................................................................... |
11 |
||
|
2.2. |
Directives and Standards ...................................................................................................... |
11 |
||
|
|
2.2.1. |
FCC Statement............................................................................................................... |
11 |
|
|
|
2.2.2. |
FCC Radiation Exposure Statement.............................................................................. |
12 |
|
|
2.3. |
Key Features |
......................................................................................................................... |
12 |
|
|
2.4. |
Functional Diagram ............................................................................................................... |
14 |
||
|
2.5. |
Evaluation Board ................................................................................................................... |
15 |
||
3 |
Application Interface |
......................................................................................................................... |
16 |
||
|
3.1. |
Pin of Module......................................................................................................................... |
17 |
||
|
|
3.1.1. |
Pin Assignment .............................................................................................................. |
17 |
|
|
|
3.1.2. |
Pin Description ............................................................................................................... |
18 |
|
|
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...................................................................................... |
24 |
||
|
|
3.3.3. Reference Design For Power Supply ............................................................................ |
25 |
||
|
|
3.3.4. |
Monitor Power Supply .................................................................................................... |
26 |
|
|
3.4. |
Power On and Down Scenarios ............................................................................................ |
26 |
||
|
|
3.4.1. |
Power On ....................................................................................................................... |
26 |
|
|
|
3.4.2. |
Power Down ................................................................................................................... |
28 |
|
|
|
3.4.2.1. |
Power Down Module Using the PWRKEY Pin ................................................ |
28 |
|
|
|
3.4.2.2. |
Power Down Module Using AT Command ...................................................... |
29 |
|
|
|
3.4.2.3. |
Over-voltage or Under-voltage Automatic Shutdown...................................... |
29 |
|
|
|
3.4.2.4. |
Emergency Shutdown Using EMERG_OFF Pin ............................................. |
30 |
|
|
|
3.4.3. |
Restart ............................................................................................................................ |
|
31 |
|
3.5. |
Power Saving ........................................................................................................................ |
32 |
||
|
|
3.5.1. |
Minimum Functionality Mode ......................................................................................... |
32 |
|
|
|
3.5.2. |
SLEEP Mode.................................................................................................................. |
33 |
|
|
|
3.5.3. Wake up Module from SLEEP Mode ............................................................................. |
33 |
||
|
|
3.5.4. |
Summary of State Transition.......................................................................................... |
33 |
|
|
3.6. |
RTC Backup .......................................................................................................................... |
|
34 |
M85_Hardware_Design |
Confidential / Released |
3 / 88 |
|
|
|
|
|
|
GSM/GPRS Module Series |
|
|
|
|
|
|
M85 Hardware Design |
|
|
|
|
|
|
|
|
|
|
|
|
||
|
3.7. |
|
Serial Interfaces..................................................................................................................... |
36 |
||
|
3.7.1. |
UART Port ...................................................................................................................... |
38 |
|||
|
|
|
3.7.1.1. |
The Features of UART Port ............................................................................. |
38 |
|
|
|
|
3.7.1.2. |
The Connection of UART Port ......................................................................... |
39 |
|
|
|
|
3.7.1.3. |
Firmware Upgrade ........................................................................................... |
40 |
|
|
3.7.2. |
Debug Port ..................................................................................................................... |
41 |
|||
|
3.7.3. |
Auxiliary UART Port ....................................................................................................... |
42 |
|||
|
3.7.4. |
UART Application ........................................................................................................... |
42 |
|||
|
3.8. |
|
Audio Interfaces..................................................................................................................... |
44 |
||
|
|
3.8.1. Decrease TDD Noise and Other Noise.......................................................................... |
45 |
|||
|
3.8.2. |
Microphone Interfaces Design ....................................................................................... |
46 |
|||
|
|
3.8.3. Receiver and Speaker Interface Design ........................................................................ |
46 |
|||
|
3.8.4. |
Earphone Interface Design ............................................................................................ |
48 |
|||
|
|
3.8.5. Loud Speaker Interface Design...................................................................................... |
49 |
|||
|
3.8.6. |
Audio Characteristics ..................................................................................................... |
49 |
|||
|
3.9. |
|
SIM Card Interfaces .............................................................................................................. |
50 |
||
|
3.10. |
SD Card Interface.................................................................................................................. |
53 |
|||
|
3.11. |
PCM Interface........................................................................................................................ |
55 |
|||
|
3.11.1. |
Configuration .................................................................................................................. |
56 |
|||
|
3.11.2. |
Timing |
............................................................................................................................. |
56 |
||
|
3.11.3. |
Reference Design .......................................................................................................... |
58 |
|||
|
3.11.4. |
AT Command ................................................................................................................. |
58 |
|||
|
3.12. |
ADC ....................................................................................................................................... |
|
59 |
||
|
3.13. |
Behaviors Of ..............................................................................................................The RI |
60 |
|||
|
3.14. |
Network Status ......................................................................................................Indication |
62 |
|||
|
3.15. |
Operating Status ...................................................................................................Indication |
62 |
|||
4 |
Antenna Interface............................................................................................................................... |
|
64 |
|||
|
4.1. |
|
Reference Design.................................................................................................................. |
64 |
||
|
4.2. |
|
RF Output Power................................................................................................................... |
65 |
||
|
4.3. |
|
RF Receiving ........................................................................................................Sensitivity |
65 |
||
|
4.4. |
|
Operating Frequencies.......................................................................................................... |
66 |
||
|
4.5. |
|
Antenna Requirement ........................................................................................................... |
66 |
||
|
4.6. |
|
RF Cable Soldering ............................................................................................................... |
67 |
||
5 Electrical, Reliability ............................................................................and Radio Characteristics |
68 |
|||||
|
5.1. |
|
Absolute Maximum ...................................................................................................Ratings |
68 |
||
|
5.2. |
|
Operating Temperature ......................................................................................................... |
69 |
||
|
5.3. |
|
Power Supply ...........................................................................................................Ratings |
69 |
||
|
5.4. |
|
Current Consumption ............................................................................................................ |
70 |
||
|
5.5. |
|
Electro-static ........................................................................................................Discharge |
72 |
||
6 |
Mechanical Dimensions .................................................................................................................... |
74 |
||||
|
6.1. |
|
Mechanical .......................................................................................Dimensions of Module |
74 |
||
|
6.2. |
|
Recommended .......................................................................................................Footprint |
76 |
||
|
6.3. |
|
Top View of .........................................................................................................the Module |
77 |
||
|
|
|
||||
M85_Hardware_Design |
Confidential / Released |
4 / 88 |
|
|
|
|
GSM/GPRS Module Series |
|
|
|
|
M85 Hardware Design |
|
|
|
|
|
|
|
|
|
|
|
6.4. |
Bottom View of the Module ................................................................................................... |
77 |
|
7 |
Storage and Manufacturing .............................................................................................................. |
78 |
||
|
7.1. |
Storage .................................................................................................................................. |
78 |
|
|
7.2. |
Soldering ............................................................................................................................... |
79 |
|
|
7.3. |
Packaging.............................................................................................................................. |
80 |
|
8 |
Appendix A Reference....................................................................................................................... |
82 |
||
9 |
Appendix B GPRS Coding Scheme ................................................................................................. |
87 |
||
10 |
Appendix C GPRS Multi-slot Class.................................................................................................. |
89 |
M85_Hardware_Design |
Confidential / Released |
5 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
Table Index |
|
TABLE 1: MODULE KEY FEATURES ............................................................................................................... |
12 |
TABLE 2: CODING SCHEMES AND MAXIMUM NET DATA RATES OVER AIR INTERFACE ........................ |
14 |
TABLE 3: PIN DESCRIPTION ........................................................................................................................... |
18 |
TABLE 4: OVERVIEW OF OPERATING MODES ............................................................................................. |
23 |
TABLE 5: SUMMARY OF STATE TRANSITION ............................................................................................... |
33 |
TABLE 6: LOGIC LEVELS OF THE UART INTERFACE .................................................................................. |
37 |
TABLE 7: PIN DEFINITION OF THE UART INTERFACES .............................................................................. |
37 |
TABLE 8: PIN DEFINITION OF AUDIO INTERFACE ....................................................................................... |
44 |
TABLE 9: AOUT3 OUTPUT CHARACTERISTICS............................................................................................ |
45 |
TABLE 10: TYPICAL ELECTRET MICROPHONE CHARACTERISTICS......................................................... |
49 |
TABLE 11: TYPICAL SPEAKER CHARACTERISTICS..................................................................................... |
49 |
TABLE 12: PIN DEFINITION OF THE SIM INTERFACE .................................................................................. |
50 |
TABLE 13: PIN DEFINITION OF THE SD CARD INTERFACE ........................................................................ |
54 |
TABLE 14: PIN DEFINITION OF THE SD CARD INTERFACE ........................................................................ |
54 |
TABLE 15: PIN DEFINITION OF PCM INTERFACE......................................................................................... |
55 |
TABLE 16: CONFIGURATION........................................................................................................................... |
56 |
TABLE 17: QPCMON COMMAND DESCRIPTION .......................................................................................... |
59 |
TABLE 18: QPCMVOL COMMAND DESCRIPTION......................................................................................... |
59 |
TABLE 19: PIN DEFINITION OF THE ADC ...................................................................................................... |
60 |
TABLE 20: CHARACTERISTICS OF THE ADC................................................................................................ |
60 |
TABLE 21: BEHAVIORS OF THE RI ................................................................................................................. |
60 |
TABLE 22: WORKING STATE OF THE NETLIGHT.......................................................................................... |
62 |
TABLE 23: PIN DEFINITION OF THE STATUS ................................................................................................ |
63 |
TABLE 24: PIN DEFINITION OF THE RF_ANT ................................................................................................ |
64 |
TABLE 25: THE MODULE CONDUCTED RF OUTPUT POWER .................................................................... |
65 |
TABLE 26: THE MODULE CONDUCTED RF RECEIVING SENSITIVITY ....................................................... |
65 |
TABLE 27: THE MODULE OPERATING FREQUENCIES................................................................................ |
66 |
TABLE 28: ANTENNA CABLE REQUIREMENTS............................................................................................. |
66 |
TABLE 29: ANTENNA REQUIREMENTS.......................................................................................................... |
66 |
TABLE 30: ABSOLUTE MAXIMUM RATINGS .................................................................................................. |
68 |
TABLE 31: OPERATING TEMPERATURE........................................................................................................ |
69 |
TABLE 32: THE MODULE POWER SUPPLY RATINGS .................................................................................. |
69 |
TABLE 33: THE MODULE CURRENT CONSUMPTION .................................................................................. |
70 |
TABLE 34: THE ESD ENDURANCE (TEMPERATURE: 25ºC, HUMIDITY: 45%) ............................................ |
73 |
TABLE 35: REEL PACKING .............................................................................................................................. |
81 |
TABLE 36: RELATED DOCUMENTS ................................................................................................................ |
82 |
TABLE 37: TERMS AND ABBREVIATIONS ...................................................................................................... |
83 |
TABLE 38: DESCRIPTION OF DIFFERENT CODING SCHEMES .................................................................. |
87 |
TABLE 39: GPRS MULTI-SLOT CLASSES ...................................................................................................... |
89 |
M85_Hardware_Design |
Confidential / Released |
6 / 88 |
|
GSM/GPRS Module Series |
|
|
M85 Hardware Design |
|
Figure Index |
|
|
FIGURE 1: MODULE FUNCTIONAL DIAGRAM............................................................................................... |
15 |
|
FIGURE 2: PIN ASSIGNMENT ......................................................................................................................... |
|
17 |
FIGURE 3: VOLTAGE RIPPLE DURING TRANSMITTING .............................................................................. |
24 |
|
FIGURE 4: REFERENCE CIRCUIT FOR THE VBAT INPUT ........................................................................... |
25 |
|
FIGURE 5: REFERENCE CIRCUIT FOR POWER SUPPLY ............................................................................ |
25 |
|
FIGURE 6: TURN ON THE MODULE WITH AN OPEN-COLLECTOR DRIVER.............................................. |
26 |
|
FIGURE 7: TURN ON THE MODULE WITH A BUTTON .................................................................................. |
27 |
|
FIGURE 8: TURN-ON TIMING .......................................................................................................................... |
|
27 |
FIGURE 9: TURN-OFF TIMING ........................................................................................................................ |
|
28 |
FIGURE 10: AN OPEN-COLLECTOR DRIVER FOR EMERG_OFF ................................................................ |
30 |
|
FIGURE 11: REFERENCE CIRCUIT FOR EMERG_OFF BY USING BUTTON .............................................. |
31 |
|
FIGURE 12: TIMING OF RESTARTING SYSTEM............................................................................................ |
31 |
|
FIGURE 13: TIMING OF RESTARTING SYSTEM AFTER EMERGENCY SHUTDOWN ................................ |
32 |
|
FIGURE 14: VRTC IS SUPPLIED BY A NON-CHARGEABLE BATTERY........................................................ |
35 |
|
FIGURE 15: VRTC IS SUPPLIED BY A RECHARGEABLE BATTERY ............................................................ |
35 |
|
FIGURE 16: VRTC IS SUPPLIED BY A CAPACITOR ...................................................................................... |
36 |
|
FIGURE 17: REFERENCE DESIGN FOR FULL-FUNCTION UART................................................................ |
39 |
|
FIGURE 18: REFERENCE DESIGN FOR UART PORT................................................................................... |
40 |
|
FIGURE 19: REFERENCE DESIGN FOR UART PORT WITH HARDWARE FLOW CONTROL .................... |
40 |
|
FIGURE 20: REFERENCE DESIGN FOR FIRMWARE UPGRADE................................................................. |
41 |
|
FIGURE 21: REFERENCE DESIGN FOR DEBUG PORT ............................................................................... |
41 |
|
FIGURE 22: REFERENCE DESIGN FOR AUXILIARY UART PORT ............................................................... |
42 |
|
FIGURE 23: LEVEL MATCH DESIGN FOR 3.3V SYSTEM.............................................................................. |
42 |
|
FIGURE 24: SKETCH MAP FOR RS-232 INTERFACE MATCH...................................................................... |
43 |
|
FIGURE 25: REFERENCE DESIGN FOR AIN1&AIN2 ..................................................................................... |
46 |
|
FIGURE 26: HANDSET INTERFACE DESIGN FOR AOUT1 ........................................................................... |
46 |
|
FIGURE 27: SPEAKER INTERFACE DESIGN WITH AN AMPLIFIER FOR AOUT1 ....................................... |
47 |
|
FIGURE 28: HANDSET INTERFACE DESIGN FOR AOUT2 ........................................................................... |
47 |
|
FIGURE 29: SPEAKER INTERFACE DESIGN WITH AN AMPLIFIER FOR AOUT2 ....................................... |
48 |
|
FIGURE 30: EARPHONE INTERFACE DESIGN.............................................................................................. |
48 |
|
FIGURE 31: LOUD SPEAKER INTERFACE DESIGN...................................................................................... |
49 |
|
FIGURE 32: REFERENCE CIRCUIT FOR SIM1 INTERFACE WITH 8-PIN SIM CARD HOLDER ................. |
51 |
|
FIGURE 33: REFERENCE CIRCUIT FOR SIM1 INTERFACE WITH THE 6-PIN SIM CARD HOLDER ......... |
52 |
|
FIGURE 34: REFERENCE CIRCUIT FOR SIM2 INTERFACE WITH THE 6-PIN SIM CARD HOLDER ......... |
52 |
|
FIGURE 35: REFERENCE CIRCUIT FOR SD CARD ...................................................................................... |
54 |
|
FIGURE 36: LONG SYNCHRONIZATION & SIGN EXTENSION DIAGRAM ................................................... |
57 |
|
FIGURE 37: LONG SYNCHRONIZATION & ZERO PADDING DIAGRAM....................................................... |
57 |
|
FIGURE 38: SHORT SYNCHRONIZATION & SIGN EXTENSION DIAGRAM................................................. |
57 |
|
FIGURE 39: SHORT SYNCHRONIZATION & ZERO PADDING DIAGRAM .................................................... |
58 |
|
FIGURE 40: REFERENCE DESIGN FOR PCM ............................................................................................... |
58 |
|
FIGURE 41: RI BEHAVIOR OF VOICE CALLING AS A RECEIVER ................................................................ |
61 |
|
FIGURE 42: RI BEHAVIOR AS A CALLER ....................................................................................................... |
|
61 |
M85_Hardware_Design |
Confidential / Released |
7 / 88 |
|
GSM/GPRS Module Series |
|
M85 Hardware Design |
FIGURE 43: RI BEHAVIOR OF URC OR SMS RECEIVED ............................................................................. |
61 |
FIGURE 44: REFERENCE DESIGN FOR NETLIGHT ..................................................................................... |
62 |
FIGURE 45: REFERENCE DESIGN FOR STATUS.......................................................................................... |
63 |
FIGURE 46: REFERENCE DESIGN FOR RF .................................................................................................. |
64 |
FIGURE 47: RF SOLDERING SAMPLE ........................................................................................................... |
67 |
FIGURE 48: M85 MODULE TOP AND SIDE DIMENSIONS (UNIT: MM) ......................................................... |
74 |
FIGURE 49: M85 MODULE BOTTOM DIMENSIONS (UNIT: MM)................................................................... |
75 |
FIGURE 50: THE PAD DIMENSIONS (UNIT: MM) ........................................................................................... |
75 |
FIGURE 51: RECOMMENDED FOOTPRINT (UNIT: MM)................................................................................ |
76 |
FIGURE 52: TOP VIEW OF THE MODULE ...................................................................................................... |
77 |
FIGURE 53: BOTTOM VIEW OF THE MODULE.............................................................................................. |
77 |
FIGURE 54: RAMP-SOAK-SPIKE REFLOW PROFILE.................................................................................... |
79 |
FIGURE 55: TAPE AND REEL INFORMATION ................................................................................................ |
81 |
FIGURE 56: RADIO BLOCK STRUCTURE OF CS-1, CS-2 AND CS-3........................................................... |
87 |
FIGURE 57: RADIO BLOCK STRUCTURE OF CS-4....................................................................................... |
88 |
M85_Hardware_Design |
Confidential / Released |
8 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
1 Introduction
This document defines the M85 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 notes and user guide, you can use M85 module to design and set up mobile applications easily.
M85_Hardware_Design |
Confidential / Released |
9 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
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 M85 module. Manufacturers of the cellular terminal should send the following safety information to users and operating personnel and to incorporate these guidelines into all manuals supplied with the product. If not so, Quectel does not take on any liability for customer 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 mobie while driving (even with a handsfree kit) cause distraction and can lead to an accident. You must comply with laws and regulations restrcting the use of wireless devices while driving.
Switch off the cellular terminal or mobile before boarding an aircraft. Make sure it switched off. The operation of wireless appliances in an aircraft is forbidden 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 Flight Mode which must be enabled prior to boarding an aircraft.
Switch off your wireless device when in hospitals or clinics or other health care facilities. These requests are desinged to prevent possible interference with sentitive medical equipment.
Cellular terminals or mobiles operate over radio frequency signal and cellular network and cannot be guaranteed to connect in all conditions, for example no mobile fee or 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 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 exposive atmospheres including 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.
M85_Hardware_Design |
Confidential / Released |
10 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
2 Product Concept
2.1. General Description
M85 is a Quad-band GSM/GPRS engine that works at frequencies of GSM850MHz, EGSM900MHz, DCS1800MHz and PCS1900MHz. The M85 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 24.5mm × 25.3mm × 2.6mm, 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.
M85 is an SMD type module with LCC package, which can be easily embedded into applications. It provides abundant hardware interfaces like PCM and SD Card Interface.
Designed with power saving technique, the current consumption of M85 is as low as 1.3 mA in SLEEP mode when DRX is 5.
M85 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.
The module fully complies with the RoHS directive of the European Union.
2.2. Directives and Standards
The M85 module is designed to comply with the FCC statements. FCC ID: XMR201511M85
The Host system using M85 should have label ―contains FCC ID: XMR201511M85‖.
2.2.1. FCC Statement
Changes or modifications not expressly approved by the party responsible for compliance could void the
user’s authority to operate the equipment.
M85_Hardware_Design |
Confidential / Released |
11 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
2.2.2. FCC Radiation Exposure Statement
This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. This equipment should be installed and operated with minimum distance 20cm between the radiator and your body as well as kept minimum 20cm from radio antenna depending on the Mobile status of this module usage. This module should NOT be installed and operating simultaneously with other radio. The manual of the host system, which uses M85, must include RF exposure warning statement to advice user should keep minimum 20cm from the radio antenna of M85 module depending on the Mobile status. Note: If a portable device (such as PDA) uses M85 module, the device needs to do permissive change and SAR testing.
The following list indicates the performance of antenna gain in certificate testing.
Part |
Frequency Range (MHz) |
Peak Gain |
Average |
VS |
Impedanc |
|
Number |
(XZ-V) |
Gain(XZ-V) |
WR |
e |
||
|
||||||
|
|
|
|
|
|
|
|
GSM850:824 894MHz |
|
|
|
|
|
3R007 |
EGSM900:880 960MHz |
1 dBi typ. |
1 dBi typ. |
2 max |
50Ω |
|
DCS1800:1710 1880MHz |
||||||
|
|
|
|
|
||
|
PCS1900: 1850 1990MHz |
|
|
|
|
2.3. Key Features
The following table describes the detailed features of M85 module.
Table 1: Module Key Features
|
|
Feature |
|
Implementation |
|
|
|
|
|
|
|
|
|
|
|
Power Supply |
|
Single supply voltage: 3.3V~4.6V |
|
|
|
|
|
Typical supply voltage: 4.0V |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Power Saving |
|
Typical power consumption in SLEEP mode: 1.3 mA@ DRX=5 |
|
|
|
|
|
1.2 mA@ DRX=9 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
M85_Hardware_Design |
|
Confidential / Released |
12 / 88 |
|
|
|
|
|
|
GSM/GPRS Module Series |
|
|
|
|
|
|
M85 Hardware Design |
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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 |
||
|
|
|
|
Support the protocols PAP (Password Authentication Protocol) |
||
|
DATA GPRS |
|
usually used for PPP connections |
|||
|
|
|
|
|
Internet service protocols: |
|
|
|
|
|
|
TCP/UDP/FTP/PPP/HTTP/NTP/MMS/SMTP/PING |
|
|
|
|
|
Support Packet Broadcast Control Channel (PBCCH) |
||
|
|
|
|
Support Unstructured Supplementary Service Data (USSD) |
|
|
|
|
|
|
Normal operation: -35°C ~ +80°C |
||
|
Temperature Range |
Restricted operation: -40°C ~ -35°C and +80°C ~ +85°C 1) |
||||
|
|
|
|
Storage temperature: -45°C ~ +90°C |
|
|
|
SMS |
Text and PDU mode |
||||
|
SMS storage: SIM card |
|
||||
|
|
|
|
|||
|
SIM Interfaces |
Support SIM card: 1.8V, 3V |
||||
|
|
|
|
|
|
|
|
|
|
|
Speech codec modes: |
||
|
|
|
|
Half Rate (ETS 06.20) |
||
|
|
|
|
Full Rate (ETS 06.10) |
||
|
|
|
|
Enhanced Full Rate (ETS 06.50/06.60/06.80) |
||
|
Audio Features |
|
Adaptive Multi-Rate (AMR) |
|||
|
|
|
|
|
Echo Suppression |
|
|
|
|
|
|
Noise Reduction |
|
|
|
|
|
Embedded one amplifier of class AB with maximum driving power up |
||
|
|
|
|
|
to 870mW |
|
|
|
|
|
|
|
|
|
|
|
|
UART Port: |
||
|
|
|
|
Seven lines on UART port interface |
||
|
|
|
|
Used for AT command, GPRS data |
||
|
|
|
|
|
Multiplexing function |
|
|
UART Interfaces |
Support autobauding from 4800bps to 115200bps |
||||
|
Debug Port: |
|||||
|
|
|
|
|||
|
|
|
|
Two lines on debug port interface DBG_TXD and DBG_RXD |
||
|
|
|
|
Use for software debugging and log output |
||
|
|
|
|
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 |
||||
|
|
|
|
|
|
|
M85_Hardware_Design |
Confidential / Released |
13 / 88 |
|
|
|
|
GSM/GPRS Module Series |
|
|
|
|
|
M85 Hardware Design |
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
Physical Characteristics |
Size: 25.3±0.15 × 24.5±0.15 × 2.6±0.2mm |
|||
|
Weight: Approx. 3.3g |
||||
|
|
|
|
||
|
|
|
|
||
|
Firmware Upgrade |
Firmware upgrade via UART Port |
|||
|
|
|
|
||
|
Antenna Interface |
Connected to antenna pad with 50 Ohm impedance control |
|||
|
|
|
|
|
|
NOTE
1) When the module works within this temperature range, the deviations from the GSM specification may occur. For example, the frequency error or the phase error will be increased.
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 |
|||||
|
|
|
|
|
|
|
|
|
2.4. Functional Diagram
The following figure shows a block diagram of M85 and illustrates the major functional parts.
Radio frequency part
Serial Flash
Power management
The Peripheral interface
—Power supply
—Turn-on/off interface
—UART interfaces
—Audio interfaces
—SIM interfaces
—SD interface
—PCM interface
—ADC interface
—RTC interface
M85_Hardware_Design |
Confidential / Released |
14 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
—RF interface
RF_ANT |
|
|
|
|
|
|
ESD |
RF |
PAM |
|
|
|
|
|
|
||
VBAT |
|
|
|
|
|
PWRKEY |
PMU |
RF Transceiver |
26MHz |
||
|
|
|
|
|
|
EMERG_OFF |
Reset |
|
|
|
|
VRTC |
RTC |
|
|
ADC |
ADC |
|
|
|
|
||
SIM Interfaces |
SIM |
BB&RF |
PCM |
PCM |
|
|
Interface |
|
|
Interface |
|
|
|
|
|
||
GPIO& |
|
|
|
SD |
SD |
Status& |
GPIO&PWM |
|
|
||
|
|
Interface |
|
||
Netlight |
|
|
|
|
|
|
|
|
|
|
|
UART |
Serial Interface |
MEMORY |
Audio |
Audio |
|
|
|
Serial Flash |
|
|
Figure 1: Module Functional Diagram
2.5. Evaluation Board
In order to help customer to develop applications with M85, 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 [12].
M85_Hardware_Design |
Confidential / Released |
15 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
3 Application Interface
The module adopts LCC package and has 83 pins. The following chapters provide detailed descriptions about these pins below.
Power supply
Power on/down
Power saving
RTC
Serial interfaces
Audio interfaces
SIM interfaces
SD interface
PCM interface
ADC
RI
NETLIGHT
Status
M85_Hardware_Design |
Confidential / Released |
16 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
3.1. Pin of Module
3.1.1. Pin Assignment
|
|
SIM2 RST |
|
SIM2 DATA |
|
SIM2 CLK |
SIM2 VDD |
|
VBAT |
|
VBAT |
|
VBAT |
|
VBAT |
|
GND |
|
GND |
|
GND |
RF ANT |
|
GND |
GND |
|
VDD EXT |
VRTC |
|
RESERVED |
|
SIM1 PRESENCE |
|||||||||||||||||
74 |
73 |
72 |
71 |
70 |
69 |
68 |
67 |
66 65 |
64 |
63 |
62 |
61 |
60 |
59 |
58 |
57 |
|||||||||||||||||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
RESERVED 1 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
ADC0 2 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||
RESERVED 3 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Top view |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
NETLIGHT 4 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
SPK2P 5 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
AGND 6 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
GND |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||
MIC2P 7 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
RESERVED |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
MIC2N 8 |
|
|
|
|
|
|
|
|
|
|
|
|
RESERVED 75 |
|
|
82 |
|
|
|
81 GND |
|
|
|
|
|
|
|
|
|
|
|||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||||||||||||
MIC1P 9 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
MIC1N 10 |
|
|
|
|
|
|
|
|
|
|
|
|
RESERVED 76 |
|
|
83 |
|
|
|
80 GND |
|
|
|
|
|
|
|
|
|
|
|||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
SPK1N 11 |
|
|
|
|
|
|
|
|
|
|
|
|
RESERVED 77 |
|
|
78 |
|
|
|
79 GND |
|
|
|
|
|
|
|
|
|
|
|||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||
SPK1P 12 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
LOUDSPKN 13 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
RESERVED |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
LOUDSPKP 14
PWRKEY 15
STATUS 16
EMERG_OFF 17
PCM_IN 18
PCM_CLK 19
20 |
21 |
22 |
23 |
24 |
25 |
26 |
27 28 |
29 30 |
31 |
32 |
33 |
34 |
|
35 |
36 |
37 |
|||||||||||
|
PCM OUT |
PCM SYNC |
RESERVED |
RESERVED |
RESERVED |
RESERVED |
RESERVED |
RESERVED |
RESERVED |
RESERVED |
RESERVED |
RESERVED |
RESERVED |
RESERVED |
SD CMD |
SD CLK |
SD DATA0 |
GND |
|||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
VBAT |
|
SIM2 |
|
|
GND |
|
RF |
|
|
|
UART |
|
Audio |
|
ADC |
|
|
||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Power |
|
|
|
|
|
|
Other |
|
|
|
|
|
|
|
|
||||||||||||
SIM1 |
RESERVED |
SD |
|
|
|
|
PCM |
|
|
|
|
Figure 2: Pin Assignment
NOTE
56 SIM1_VDD
55 SIM1_CLK
54 SIM1_DATA
53 SIM1_RST
52 SIM_GND
51 RTS
50 RXD
49 TXD
48 CTS
47 DTR
46 RI
45 DCD
44 RESERVED
43 DBG_RXD
42 DBG_TXD
41 RXD_AUX
40 TXD_AUX
39 RESERVED
38 RESERVED
Keep all reserved pins open.
|
|
|
|
|
|
|
|
|
|
|
M85_Hardware_Design |
Confidential / Released |
17 / 88 |
|
GSM/GPRS Module Series
M85 Hardware Design
3.1.2. Pin Description
Table 3: Pin Description
Power Supply
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
|
|
|
CHARACTERISTICS |
||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Make sure that |
|
|
|
|
|
|
Main power supply of |
Vmax=4.6V |
supply sufficient |
|
|
|
|
67, 68, 69, |
|
current in a |
|||
|
|
VBAT |
I |
module: |
Vmin=3.3V |
|||
|
|
70 |
transmitting burst |
|||||
|
|
|
|
VBAT=3.3V~4.6V |
Vnorm=4.0V |
|||
|
|
|
|
|
typically rises to |
|||
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
1.6A. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
VImax=3.3V |
|
|
|
|
|
|
|
Power supply for RTC. |
VImin=1.5V |
|
|
|
|
|
|
|
VInorm=2.8V |
|
|
|
|
|
|
|
|
Charging for backup |
|
|
|
|
|
|
|
|
VOmax=3V |
If unused, keep |
||
|
|
VRTC |
59 |
I/O |
battery or golden |
|||
|
|
VOmin=2V |
this pin open. |
|||||
|
|
|
|
|
capacitor when the |
|||
|
|
|
|
|
VOnorm=2.8V |
|
|
|
|
|
|
|
|
VBAT is applied. |
|
|
|
|
|
|
|
|
Iout(max)=2mA |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Iin≈10uA |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1. If unused, keep |
|
|
|
|
|
|
|
|
this pin open. |
|
|
|
|
|
|
|
Vmax=2.9V |
2. Recommend to |
|
|
|
VDD_EXT |
60 |
O |
Supply 2.8V voltage for |
Vmin=2.7V |
add a 2.2~4.7uF |
|
|
|
external circuit. |
Vnorm=2.8V |
bypass capacitor, |
||||
|
|
|
|
|
||||
|
|
|
|
|
|
Imax=20mA |
when using this |
|
|
|
|
|
|
|
|
pin for power |
|
|
|
|
|
|
|
|
supply. |
|
|
|
|
|
|
|
|
|
|
|
|
|
37, 61, 62, |
|
|
|
|
|
|
|
GND |
64~66, |
|
Ground |
|
|
|
|
|
|
79~82, |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Turn on/off |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
|
|
|
CHARACTERISTICS |
||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Power on/off key. |
VILmax= |
|
|
|
|
|
|
|
0.1×VBAT |
|
|
|
|
|
|
|
|
PWRKEY should be pulled |
|
|
|
|
|
PWRKEY |
15 |
I |
VIHmin= |
|
|
|
|
|
down for a moment to turn |
|
|
||||
|
|
|
|
|
0.6×VBAT |
|
|
|
|
|
|
|
|
on or turn off the system. |
|
|
|
|
|
|
|
|
VIHmax=3.1V |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Emergency Shutdown |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
M85_Hardware_Design |
|
Confidential / Released |
18 / 88 |
|
|
|
|
|
|
|
|
|
GSM/GPRS Module Series |
||
|
|
|
|
|
|
|
|
M85 Hardware Design |
||
|
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
|||
|
|
CHARACTERISTICS |
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Emergency off. Pulled |
|
Open |
|
|
|
|
|
|
|
|
down for at least 40ms, |
|
drain/collector |
|
|
|
|
|
|
|
|
which will turn off the |
VILmax=0.45V |
driver required in |
|
|
|
EMERG_ |
|
|
|
module in case of |
cellular device |
|||
|
|
17 |
I |
VIHmin=1.35V |
||||||
|
|
OFF |
emergency. Use it only |
application. |
||||||
|
|
|
|
|
Vopenmax=1.8V |
|||||
|
|
|
|
|
|
|
when shutdown via |
If unused, keep |
||
|
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
PWRKEY or AT command |
|
this pin open. |
|
|
|
|
|
|
|
|
cannot be achieved. |
|
|
|
|
|
|
|
|
|
|
|
|||
|
|
Module Indicator |
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
|||
|
|
CHARACTERISTICS |
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Indicate module’s |
|
|
|
|
|
|
|
|
|
|
operating status. Output |
VOHmin= |
|
|
|
|
STATUS |
16 |
O |
high level when module |
0.85×VDD_EXT |
If unused, keep |
|||
|
|
turns on, while output low |
VOLmax= |
this pin open. |
||||||
|
|
|
|
|
|
|
||||
|
|
|
|
|
|
|
level when module turns |
0.15×VDD_EXT |
|
|
|
|
|
|
|
|
|
off. |
|
|
|
|
|
|
|
|
|
|
|
|||
|
|
Audio Interface |
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
|||
|
|
CHARACTERISTICS |
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
MIC1P |
9, 10 |
I |
Channel 1 positive and |
|
|
|
||
|
|
MIC1N |
negative voice input |
|
If unused, keep |
|||||
|
|
|
|
|
|
|||||
|
|
|
|
|
|
|
|
these pins open. |
||
|
|
MIC2P |
7, 8 |
I |
Channel 2 positive and |
|
||||
|
|
MIC2N |
negative voice input |
|
|
|
||||
|
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
SPK1P |
12, 11 |
O |
Channel 1 positive and |
|
1. If unused, keep |
|||
|
|
SPK1N |
negative voice output |
|
these pins open. |
|||||
|
|
|
|
|
|
|||||
|
|
|
|
|
|
|
|
|
2. Support both |
|
|
|
|
|
|
|
|
|
|
||
|
|
SPK2P |
5 |
|
O |
Channel 2 voice output |
|
voice and |
||
|
|
|
|
|
|
|
|
|
ringtone output. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Analog ground. Separate |
|
If unused, keep |
|
|
|
AGND |
6 |
|
|
ground connection for |
Refer to Section 3.8 |
|||
|
|
|
|
this pin open. |
||||||
|
|
|
|
|
|
|
external audio circuits. |
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1. If unused, keep |
|
|
|
|
|
|
|
|
|
|
these pins open. |
|
|
|
|
|
|
|
|
|
|
2. Integrate a |
|
|
|
LOUDSPKN |
13, 14 |
O |
Channel 3 positive and |
|
ClassAB |
|||
|
|
LOUDSPKP |
negative voice output |
|
amplifier |
|||||
|
|
|
|
|
|
|||||
|
|
|
|
|
|
|
|
|
internally. |
|
|
|
|
|
|
|
|
|
|
3. Support both |
|
|
|
|
|
|
|
|
|
|
voice and |
|
|
|
|
|
|
|
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
M85_Hardware_Design |
|
Confidential / Released |
19 / 88 |
|
|
|
|
|
|
|
|
|
|
GSM/GPRS Module Series |
||
|
|
|
|
|
|
|
|
|
M85 Hardware Design |
||
|
|
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
ringtone output. |
|
|
|
|
|
|
|
|
|
|
|||
|
|
Network Status Indicator |
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
||||
|
|
CHARACTERISTICS |
|||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
VOHmin= |
|
|
|
|
NETLIGHT |
4 |
|
O |
Network status |
0.85×VDD_EXT |
If unused, keep |
|||
|
|
|
indication |
VOLmax= |
this pin open. |
||||||
|
|
|
|
|
|
|
|||||
|
|
|
|
|
|
|
|
|
0.15×VDD_EXT |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
UART Port |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
||||
|
|
CHARACTERISTICS |
|||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
DTR |
47 |
I |
Data terminal ready |
VILmin=0V |
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
VILmax= |
If only use TXD, |
|
|
|
RXD |
50 |
I |
Receive data |
||||||
|
|
0.25×VDD_EXT |
RXD and GND to |
||||||||
|
|
|
|
|
|
|
|
|
|||
|
|
TXD |
49 |
O |
Transmit data |
VIHmin= |
communicate, |
||||
|
|
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
0.75×VDD_EXT |
recommended |
|
|
|
|
|
|
|
|
|
|
|||
|
|
RTS |
51 |
I |
Request to send |
VIHmax= |
connecting RTS |
||||
|
|
|
|
|
|
|
|
|
VDD_EXT+0.2 |
to GND via 0R |
|
|
|
CTS |
48 |
O |
Clear to send |
||||||
|
|
VOHmin= |
resistor and |
||||||||
|
|
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
0.85×VDD_EXT |
keeping other |
|
|
|
RI |
46 |
O |
Ring indication |
||||||
|
|
VOLmax= |
pins open. |
||||||||
|
|
|
|
|
|
|
|
|
|||
|
|
DCD |
45 |
O |
Data carrier detection |
0.15×VDD_EXT |
|
|
|||
|
|
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Debug Port |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
||||
|
|
CHARACTERISTICS |
|||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
DBG_TXD |
42 |
O |
Transmit data |
|
If unused, keep |
||||
|
|
|
|
|
|
|
|
|
Same as above |
||
|
|
|
|
|
|
|
|
|
these pins open. |
||
|
|
DBG_RXD |
43 |
I |
Receive data |
||||||
|
|
|
|||||||||
|
|
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Auxiliary Port |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
||||
|
|
CHARACTERISTICS |
|||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
TXD_AUX |
40 |
O |
Transmit data |
|
If unused, keep |
||||
|
|
|
|
|
|
|
|
|
Same as above |
||
|
|
|
|
|
|
|
|
|
these pins open. |
||
|
|
RXD_AUX |
41 |
I |
Receive data |
||||||
|
|
|
|||||||||
|
|
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
SIM Interface |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
||||
|
|
CHARACTERISTICS |
|||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
M85_Hardware_Design |
Confidential / Released |
20 / 88 |
|
|
|
|
|
|
|
|
GSM/GPRS Module Series |
||
|
|
|
|
|
|
|
|
M85 Hardware Design |
||
|
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
SIM1_VDD |
56 |
|
|
The voltage can be |
|
|
||
|
|
|
Power supply for SIM |
selected by software |
|
|
||||
|
|
|
|
|
|
O |
|
|
||
|
|
|
|
|
|
card |
automatically. Either |
|
|
|
|
|
SIM2_VDD |
71 |
|
|
|
||||
|
|
|
|
1.8V or 3V. |
|
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
SIM1_CLK |
55 |
|
|
VOLmax= |
All signals of SIM |
|||
|
|
|
|
|
|
|
|
0.15×SIM_VDD |
||
|
|
|
|
|
|
O |
SIM clock |
interface should be |
||
|
|
|
|
|
|
VOHmin= |
||||
|
|
|
|
|
|
|
|
protected against |
||
|
|
SIM2_CLK |
72 |
|
|
0.85×SIM_VDD |
||||
|
|
|
|
|
|
|
|
ESD with a TVS |
||
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
VILmax= |
diode array. |
|
|
|
|
|
|
|
|
|
0.25×SIM_VDD |
Maximum trace |
|
|
|
SIM1_ DATA |
54 |
|
|
VIHmin= |
||||
|
|
|
|
length is 200mm |
||||||
|
|
|
|
|
|
|
|
0.75×SIM_VDD |
||
|
|
|
|
|
|
I/O |
SIM data |
from the module |
||
|
|
|
|
|
|
VOLmax= |
||||
|
|
|
|
|
|
|
|
0.15×SIM_VDD |
pad to SIM card |
|
|
|
SIM2_DATA |
73 |
|
|
VOHmin= |
holder. |
|||
|
|
|
|
|
|
|
|
0.85×SIM_VDD |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
SIM1_RST |
53 |
|
|
VOLmax= |
|
|
||
|
|
|
|
|
|
|
||||
|
|
|
|
|
|
O |
SIM reset |
0.15×SIM_VDD |
|
|
|
|
|
|
|
|
|
|
|||
|
|
|
|
|
|
VOHmin= |
|
|
||
|
|
SIM2_RST |
74 |
|
|
|
|
|||
|
|
|
|
0.85×SIM_VDD |
|
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
VILmin=0V |
|
|
|
|
|
|
|
|
|
|
VILmax= |
|
|
|
|
SIM1_ |
|
|
|
|
0.25×VDD_EXT |
If unused, keep |
||
|
|
57 |
I |
SIM card detection |
VIHmin= |
|||||
|
|
PRESENCE |
these pins open. |
|||||||
|
|
|
|
|
|
0.75×VDD_EXT |
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
VIHmax= |
|
|
|
|
|
|
|
|
|
|
VDD_EXT+0.2 |
|
|
|
|
|
|
|
|
|
|
|
||
|
|
SIM_GND |
52 |
|
SIM ground |
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
ADC |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
|||
|
|
CHARACTERISTICS |
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
General purpose |
Voltage range: |
If unused, keep |
|
|
|
ADC0 |
2 |
|
I |
analog to digital |
||||
|
|
|
0V to 2.8V |
this pin open. |
||||||
|
|
|
|
|
|
|
converter. |
|||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
PCM |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
|||
|
|
CHARACTERISTICS |
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
PCM_CLK |
19 |
O |
PCM clock |
|
|
|
||
|
|
|
|
|
|
|
|
VILmin= 0V |
If unused, keep |
|
|
|
|
|
|
|
|
|
|||
|
|
PCM_IN |
18 |
I |
PCM data input |
VILmax= |
these pins open. |
|||
|
|
|
|
|
0.25×VDD_EXT
M85_Hardware_Design |
Confidential / Released |
21 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
|
|
|
|
|
VIHmin= |
|
|
PCM_OUT |
20 |
O |
PCM data output |
0.75×VDD_EXT |
|
|
|
|
|
|
|
|
|
|
|
|
|
VIHmax= |
|
|
|
|
|
|
VDD_EXT+0.2 |
If unused, keep |
|
|
|
|
PCM frame |
VOHmin= |
these pins open. |
|
PCM_SYNC |
21 |
O |
0.85×VDD_EXT |
|
|
|
synchronization |
|
||||
|
|
|
|
VOLmax= |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
0.15×VDD_EXT |
|
|
|
|
|
|
|
|
|
SD Card |
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
|
CHARACTERISTICS |
|||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
VILmin=0V |
|
|
SD_CMD |
34 |
O |
SD command |
VILmax= |
|
|
|
|
||||
|
|
|
|
|
0.25×VDD_EXT |
|
|
|
|
|
|
VIHmin= |
|
|
|
|
|
|
|
|
|
|
|
|
|
0.75×VDD_EXT |
If unused, keep |
|
SD_CLK |
35 |
O |
SD clock |
VIHmax= |
|
|
these pins open. |
|||||
|
|
|
|
|
VDD_EXT+0.2 |
|
|
|
|
|
|
|
|
|
|
|
|
|
VOHmin= |
|
|
|
|
|
|
|
|
|
|
|
|
|
0.85×VDD_EXT |
|
|
SD_DATA0 |
36 |
I/O |
SD data |
VOLmax= |
|
|
|
|
|
|
|
|
|
|
|
|
|
0.15×VDD_EXT |
|
|
|
|
|
|
|
|
|
Antenna Interface |
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
|
CHARACTERISTICS |
|||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
RF_ANT |
63 |
I/O |
RF antenna pad |
Impedance of 50Ω |
|
|
|
|
|
|
|
|
|
Other Interface |
|
|
|
|
|
|
|
|
|
|
|
|
|
PIN NAME |
PIN NO. |
I/O |
DESCRIPTION |
DC |
COMMENT |
|
CHARACTERISTICS |
|||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1, 3, |
|
|
|
|
|
|
22~33, |
|
|
|
|
|
RESERVD |
38, 39, |
|
|
|
Keep these pins |
|
44, 58, |
|
|
|
open. |
|
|
|
|
|
|
||
|
|
75~78, |
|
|
|
|
|
|
83 |
|
|
|
|
|
|
|
|
|
|
|
M85_Hardware_Design |
Confidential / Released |
22 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
3.2. Operating Modes
The table below briefly summarizes the various operating modes in the following chapters.
Table 4: Overview of Operating Modes
Mode |
|
Function |
|
|
|
|
|
|
|
|
After enabling sleep mode by AT+QSCLK=1, the module will |
|
|
|
automatically go into Sleep Mode if DTR is set to high level and |
|
|
GSM/GPRS |
there is no interrupt (such as GPIO interrupt or data on UART |
|
|
Sleep |
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. |
|
|
|
|
|
|
GSM IDLE |
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 |
Normal |
|
|
Level (PCL), dynamic DTX control and the working RF band. |
Operation |
|
GPRS IDLE |
The module is not registered to GPRS network. The module is |
|
|
not reachable through GPRS channel. |
|
|
|
|
|
|
|
|
|
|
|
GPRS |
The module is registered to GPRS network, but no GPRS PDP |
|
|
context is active. The SGSN knows the Routing Area where the |
|
|
|
STANDBY |
|
|
|
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 consumption |
|
|
GPRS DATA |
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 |
|
|
|
or the EMERG_OFF1) pin. The power management ASIC disconnects the power |
|
POWER DOWN |
|
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. |
|
|
|
|
|
Minimum |
|
AT+CFUN command can set the module to a minimum functionality mode without |
|
Functionality |
|
removing the power supply. In this case, the RF part of the module will not work or |
|
Mode (without |
|
the SIM card will not be accessible, or both RF part and SIM card will be disabled, |
|
removing power |
|
but the UART port is still accessible. The power consumption in this case is very |
|
supply) |
|
low. |
|
|
|
|
|
M85_Hardware_Design |
Confidential / Released |
23 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
NOTE
Use the EMERG_OFF pin only when failing to turn off the module by the command AT+QPOWD=1 and the PWRKEY pin. For more details, please refer to the Section 3.4.2.4.
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 M85 module, the max current consumption could reach to 1.6A during a transmit burst. 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 transmit burst does not exceed 400mV.
4.615ms
577us
Burst:1.6A
IBAT
VBAT
Vdrop
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 transmitting burst. 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 transmit burst. The width of trace should be no less than 2mm and the principle of the VBAT route is the longer route, the wider trace.
M85_Hardware_Design |
Confidential / Released |
24 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
VBAT
+ |
|
|
|
|
|
|
|
|
|
|
|
C1 |
|
C2 |
|
C3 |
|
C4 |
|||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
100uF 100nF 10pF 33pF
0603 0603
GND
Figure 4: Reference Circuit for the VBAT Input
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.
Figure 5 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.
MIC29302WU U1
DC_IN
2 IN
C1 |
|
|
C2 |
1 |
|
|
|||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
R1 |
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||
470uF |
|
|
100nF |
|
|
|
|
|
51K |
|
|||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
R5 |
|
|||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
4.7K |
|
||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
MCU_POWER_ON/OFF |
|
|
|
||||||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
R6 |
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
47K |
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
VBAT |
|
|
OUT 4 |
|
|
|
|
|
|
|
|
R2 |
|
|
|
|
EN |
3 GND |
5 ADJ |
124K |
|
C3 |
C4 |
|
|
R4 |
D1 |
|||||
|
|
|
|
||||
|
|
|
R3 |
470R |
470uF |
100nF |
5.1V |
|
|
|
56K |
||||
|
|
|
|
|
|
|
Figure 5: Reference Circuit for Power Supply
M85_Hardware_Design |
Confidential / Released |
25 / 88 |
GSM/GPRS Module Series
M85 Hardware Design
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.
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.
PWRKEY
4.7K
Turn on pulse
47K
Figure 6: Turn on the Module with an Open-collector Driver
NOTES
1.M85 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
M85_Hardware_Design |
Confidential / Released |
26 / 88 |