Neoway Neo_M680 Installation manual

Neo_M680 GPRS Module
Hardware User Guide
Version 1.4

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
i
Copyright © Neoway Technology Co., Ltd 2014.All rights reserved.
No part of this document maybe reproduced or transmitted in anyformor by any means without prior
written consent of Shenzhen Neoway Technology Co., Ltd.
is the trademark of Neoway Technology Co., Ltd.
All other trademarks and trade names mentioned in this document are the property of their respective
holders.
Notice
This document is intended for system engineers (SEs), development engineers, and test engineers.
The information in this document is subject to change without notice due to product version update or
other reasons.
Every effort has been made in preparation of this document to ensure accuracy of the contents, but all
statements, information, and recommendations in this document do not constitute a warranty of any
kind, express or implied.
Neoway provides customers complete technical support. If you have any question, please contact
your account manager or email to the following email addresses:
[e-mail]
[e-mail]
Website: http://www.neoway.com.cn

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
ii
Revision Record
Issue
Changes
Revised By
Date
V1.0
Initial draft
Qiao Naiwei
2013-10
V1.1
Modified the description of some pins
Qiao Naiwei
2014-02
V1.2
Modified the PCB encapsulation and definition of
several pins
Qiao Naiwei
2014-04
V1.3
Optimized the table structure of pin definition and
interface description.
Added chapter about electric features and
reliability.
Added RF feature description.
Qiao Naiwei
2014-05
V1.4
Optimize the pictures.
Qiao Naiwei
2014-06

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
iii
Contents
About This Document......................................................................................................... 1
1 Introduction to M680 ........................................................................................................ 1
1.1 Overview.....................................................................................................................................1
1.2 Block Diagram............................................................................................................................1
1.3 Specifications..............................................................................................................................2
2 Pin Description and PCB Foot Print .............................................................................. 4
2.1 Specifications and Encapsulation................................................................................................4
2.2 Pin Definition..............................................................................................................................5
2.3 PCB Foot Print............................................................................................................................8
3 Interface Design................................................................................................................. 9
3.1 Power Supply and Switch Interfaces...........................................................................................9
3.1.1 Design Requirements .........................................................................................................9
3.1.2 VDD_EXT .......................................................................................................................12
3.1.3 VRTC ...............................................................................................................................12
3.1.4 Power-On/Off Control and Procedure..............................................................................13
3.1.5 RESET..............................................................................................................................16
3.2 UART........................................................................................................................................16
3.3 USB Interfaces ..........................................................................................................................18
3.4 DTR and RING .........................................................................................................................19
3.4.1 DTR Pin ...........................................................................................................................19
3.4.2 RING Signal Indicator......................................................................................................20
3.5 SIM Card Interface....................................................................................................................20
3.6 Running LED Indicator.............................................................................................................22
3.7 Audio Interface..........................................................................................................................23
3.8 RF Interface...............................................................................................................................26
3.8.1 RF Design and PCB Layout.............................................................................................26
3.8.2 Recommended RF Connection.........................................................................................28
4Electric Features and Reliability ..................................................................................... 29
4.1 Electric Feature .........................................................................................................................29
4.2 Temperature...............................................................................................................................29
4.3 Current.......................................................................................................................................30
4.4 ESD Protection..........................................................................................................................30
5 RF Features ....................................................................................................................... 32
5.1 Work Band.................................................................................................................................32
5.2 Transmitting Power and Receiving Sensitivity .........................................................................32
5.2.1 Transmitting Power ..........................................................................................................32
5.2.2 Receiving Sensitivity........................................................................................................33
6 Mounting the Module onto the Application Board.................................................. 34

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
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7 Package.............................................................................................................................. 34
8 Abbreviations................................................................................................................... 35

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
v
Table of Figures
Figure 2-1 Top view of the M680 module............................................................................................... 4
Figure 2-2 PCB foot print recommended for M680 (unit: mm) .............................................................. 8
Figure 3-1 Current peaks and voltage drops............................................................................................ 9
Figure 3-2 Capacitors used for the power supply.................................................................................. 10
Figure 3-3 Reference design of power supply control........................................................................... 10
Figure 3-4 Reference design of power supply controlled by p-MOSFET..............................................11
Figure 3-5 Reference designs of separated power supply...................................................................... 12
Figure 3-6 VRTC reference design........................................................................................................ 13
Figure 3-7 Power-on procedure............................................................................................................. 13
Figure 3-8 Power-off procedure............................................................................................................. 14
Figure 3-9 Reference circuit for power-on/off control .......................................................................... 14
Figure 3-10 Reference circuit for power-on/off controlled by high level.............................................. 15
Figure 3-11 Reset circuit with triode separating.................................................................................... 16
Figure 3-12 Signal connection between DCE and DTE ........................................................................ 16
Figure 3-13 Recommended circuit for the communication between 3.3V MCU and UART................ 17
Figure 3-14 Recommended circuit for the communication between 5V MCU and UART................... 18
Figure 3-15 USB circuit ........................................................................................................................ 19
Figure 3-16 RING indicator for incoming call ...................................................................................... 20
Figure 3-17 RING indicator for SMS.................................................................................................... 20
Figure 3-18 Reference design of SIM card interface............................................................................. 21
Figure 3-19 Reference of SIM card socket............................................................................................ 21
Figure 3-20 LED indicator..................................................................................................................... 22
Figure 3-21 Reference design of single-end input MIC interface.......................................................... 23
Figure 3-22 Reference design of MIC differential connections............................................................. 24
Figure 3-23 Reference design for common audio input ........................................................................ 24
Figure 3-24 Reference design for receiver output ................................................................................. 25
Figure 3-25 Reference design for speaker output.................................................................................. 25
Figure 3-26 Reference design for earphone output................................................................................ 26
Figure 3-27 Coupling capacitor interfacing........................................................................................... 26
Figure 3-28 Reference design for antenna interface.............................................................................. 27
Figure 3-29 RF layout reference............................................................................................................ 27
Figure 3-30 Encapsulation specifications of Murata RF connector....................................................... 28
Figure 3-31 RF connections................................................................................................................... 28

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
vi
Table of Tables
Table 1-1 M680 specifications................................................................................................................. 2
Table 2-1 M680 pin definition................................................................................................................. 5
Table 3-1 Power supply and switch interface.......................................................................................... 9
Table 3-2 UART .................................................................................................................................... 16
Table 3-3 USB interface ........................................................................................................................ 18
Table 3-4 DTR and RING pins.............................................................................................................. 19
Table 3-5 SIM Card Interface................................................................................................................ 20
Table 3-6 LED indicator........................................................................................................................ 22
Table 3-7 Audio interface ...................................................................................................................... 23
Table 4-1 Electric feature of the module ............................................................................................... 29
Table 4-2 Temperature Feature.............................................................................................................. 29
Table 4-3 Current feature....................................................................................................................... 30
Table 4-4 ESD feature of the module .................................................................................................... 31
Table 5-1 Work band ............................................................................................................................. 32
Table 5-2 Transmitting power (GSM800&EGSM900) ......................................................................... 32
Table 5-3 Transmitting power (DCS1800&PCS1900) .......................................................................... 33

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
1
About This Document
This document defines the features, indicators, and test standards of the M680 module and provides
reference for the hardware design of each interface. With Neo_M680 GPRS Module AT Command Set, this
user guide can help you complete wireless communication application easily.
1 Introduction to M680
M680 is a compact wireless GSM/GPRS module that supports downlink EDGE. It can provide functions of
high-quality voice, SMS, and data services and is widely used in industrial and civil fields.
1.1 Overview
Neoway M680 module adopts 83-pin LGAencapsulation and its dimensions are 18 mm x 15 mm x 2.1 mm,
which can meet most customers' requirements. It provides customers the following hardware resources:
UART interfaces, used for data communication, firmware updating and commissioning, and
supporting hardware flow control
Audio interfaces: two lines of MIC input (one differential single input and one sing-ended signal
input); EAR/SPK/REC output
10-bitADC input, voltage ranging from 0 V to 2.8 V
Adapting to 1.8 V and 3.0 V SIM card
Supporting RING/LIGHT/DTR (sleep mode) functions
Supporting time updating and timing power-on/off
Supporting firmware updating and commissioning via USB interface
1.2 Block Diagram
The M680 module consists of baseband controller, Flash ROM, RF section, application interfaces, etc. All
sections coordinate with each other to provide such communication functions as GPRS data and voice.
The following figure shows the block diagram of M680.

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
2
1.3 Specifications
Table 1-1 M680 specifications
Specifications
Description
Band
GSM850/EGSM900/DCS1800/PCS1900 MHz dual-band/quad-band
Supporting band locking
Sensitivity
< -107 dBm
Max. transmit power
GSM850/EGSM900 Class4(2W)
DCS1800/PCS1900 Class1(1W)
Protocol
Supporting GSM/GPRS Phase 2/2+
AT
GSM07.07
Extended AT commands
VBAT
VRTC
Digital Interface
USB
UART
ON/OFF
Power
Manager
RF transceiver
FLASH
Digital
Baseband
Analog
Baseband
26 MHz CrystalRF Front-end-module
SIM
ADC
SIM
PC
Audio Interface
EAR
SPK
REC
MIC

Neo_M680 GPRS Module Hardware User Guide
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3
Audio
Available audio coding:
HR
FR
EFR
AMR
Supporting echo suppression
Supporting recording and DTMF check function
SMS
TEXT/PDU
Supporting SMS message receiving and transmitting and alert for new
SMS messages
Supporting SMS message management: reading/deleting/storage/list
GPRS feature
GPRS CLASS 12
Max. theoretic uplink rate: 85.6 Kbit/s
Max. theoretic downlink rate: 85.6 Kbit/s
Built-in TCP/IP protocol, supporting multiple links
Supporting server and client modes
Circuit Switch Data
CSD data service
USSD
Supplementary service
Call forwarding (CFB, CFNA, CFU)
Call waiting
Call holding and multi-way calling
UART
Supporting hardware flow control, RTS and CTS controlled via AT
commands
Supporting multiplexing
Supporting AT sending, data transmission, and software download
Supporting baudrate from 1200 bit/s to 115200 bit/s
RTC
Supporting real-time clock and time updating
Supporting timing power-on/off
CPU
ARM7-EJ@360MHz
Antenna feature
50 Ω impedance
Operating temperature
-40℃to +85℃
Operating voltage
3.5 V to 4.3 V (3.9 V is recommended)
Peak current
Max 2.0 A
Idle current
18 mA
Current in sleep mode
< 2 mA (live network)
< 1 mA (instrument, DRX=9)

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
4
2 Pin Description and PCB Foot Print
2.1 Specifications and Encapsulation
Specifications
M680
Dimensions
18 mm x 15 mm x 2.1 mm (H x W x D)
Weight
1.2 g
Encapsulation
83-pin LGA
Figure 2-1 Top view of the M680 module
GPRS_ANT
8
7
6
5
4
3
2
16
15
14
13
12
11
10
9
18 19 20
17
ON/OFF
SPKP
SPKN
MIC0P
MIC0N
EAR_L
EAR_R
MIC1
RECN
RECP
NC
NC
NC
NC
NC
NC
GND
NC
SIM_CLK
SIM_DATA
NC NC NC NC NC NC
GND
NC
GND
NC
NC
RTS
CTS
VDD_EXT
URXD
UTXD
NC
NC
DTR
RING
LIGHT
RESET
GND
VRTC
VBAT VBAT
VBAT
ADC_IN
NC NC NC NC NC NC NC
GND
GND VBAT GND GND
GND GND
GND GND
GND USB_DM USB_DP GND
NC VBUS NC NC NC NC
NC NC NCNCNCNC
SIM_RST
VSIM
1
22 23 21 28 29 27 26 25 24
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
46
45
47
48 49
50
51 52 53 54 55 56 57 58 59
60 61 62 63
6471
65
66676869
70
72 73 74 75 76 77
83 82 81 79 78 80
USB
NC
Power GND SIM UART
Audio ADC GPRS_ANT Other

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
5
2.2 Pin Definition
Table 2-1 M680 pin definition
Pin
Name
I/O
Function
Reset
Status
Level Feature
(V)
Remarks
Power Supply and Switch Interfaces
57, 58,
59, 68
VBAT
P
Main power supply
input
3.5 V to 4.3 V (3.9 V
is recommended)
36
VDD_EXT
P
2.8 V power supply
output
Supply power for IO
level shifting circuit.
Load capability: less
than 50 mA
41
VRTC
P
RTC power supply
2.8 V, maximum
charging output
current 2 mA
18, 29,
31, 46,
48, 60,
63~67,
69~71
GND
P
Ground
1
ON/OFF
DI
On/Off input
0＜VIL＜0.6
2.1 ＜VIH ＜
VBAT
Low level pulse can
change the On/Off
state.
45
RESET
DI
Reset input
0＜VIL＜0.6
2.1＜VIH＜3.1
Internally pulled up
to 2.8 V
Low level reset
Audio Interface
2
SPKP
AO
Positive electrode
of speaker output
Maximum 800
mW@8Ω
3
SPKN
AO
Negative electrode
of speaker output
4
MIC0P
AI
Positive electrode
of MIC0 output
Vpp≤200 mV
5
MIC0N
AI
Negative electrode
of MIC0 output
6
EAR_L
AO
Left sound channel
of the earphone
output
16/32Ω earphone
driving output
7
EAR_R
AO
Right sound
channel of the
earphone output
9
MIC1
AI
MIC1 output

Neo_M680 GPRS Module Hardware User Guide
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10
RECN
AO
Negative electrode
of receiver output
32 Ω receiver
driving output
11
RECP
AO
Negative electrode
of receiver output
UART Interface
34
RTS
DI
Request to send
I/PD
0＜VIL＜0.6
2.1＜VIH＜3.1
0＜VOL＜0.42
2.38＜VOH＜2.8
With 47K pull-up
inside
35
CTS
DO
Clear to send
I/PD
37
URXD
DI
UART data receive
I/PU
38
UTXD
DO
UART data
transmit
SIM Card
19
SIM_CLK
DO
SIM card clock
output
0＜VIL ＜
0.25*VSIM，
0.75*VSIM ＜
VIH＜VSIM
0＜VOL ＜
0.15*VSIM
0.85*VSIM ＜
VOH＜VSIM
Compatible with
1.8/3.0 V SIM card
20
SIM_DATA
DI/O
SIM card data IO
21
SIM_RST
DO
SIM card reset
output
22
VSIM
P
SIM card power
supply output
LED Indicators
44
LIGHT
DO
Status LED
I/PD
2.8 V/4 mA output
Sleep Mode Controlling
42
DTR
DI
Signal for
controlling sleep
mode
I/PD
0＜VIL＜0.6
2.1＜VIH＜3.1
0＜VOL＜0.42
2.38＜VOH＜2.8
Low level by default
Used together with
AT commands
SMS and Incoming Call Ring
43
RING
DO
Ring output
I/PD
0＜VIL＜0.6
2.1＜VIH＜3.1
0＜VOL＜0.42
2.38＜VOH＜2.8
Detect incoming
SMS messages or
calls
ADC Detecting
56
ADC_IN
AI
10-bit ADC input
Detectable voltage
range: 0 V to 2.8 V
GPRS Antenna

Neo_M680 GPRS Module Hardware User Guide
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7
47
GPRS_ANT
AI/O
GPRS antenna
interface
50 Ω impedance
USB Interfaces
61
USB_DM
DI/O
USB interface
differential data
cable
Complying with
the USB1.1
standard
Used for firmware
download
62
USB_DP
DI/O
79
VBUS
AI
USB voltage test
Reserved Pins
8,
12-17,
23-28,
30, 32,
33, 39,
40,
49~55,
72-78,
80~83
NC
Must be left
disconnected.
Cannot connect to
power supply or
ground.
P: indicates power supply pins
NC: indicates pins that are not supported and must not be connected
DI: indicates digital signal input pins
DO: indicates digital signal output pins
I/PD: indicates digital signal input pins with pull-down
I/PU: indicates digital signal input pins with pull-up
AI: indicates analogy signal input pins
AO: indicates analogy signal output pins
The maximum input voltage at all IO ports (including peak signal current) cannot exceed 3.1 V because
the module uses a 2.8 V IO power system. In the application of the module, the IO output voltage from the
3.3 V power supply system of the external circuit might greatly overshoot 3.1 V due to the signal integrity
design. In this situation, the IO pins of the module might be damaged if the IO signals are connected to the
IO port on the 2.8-V system. To rectify this issue, take measures to match the level. For details, see the
Section 3.2 UART.

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
8
2.3 PCB Foot Print
LGA packaging is adopted to package the pins of the M680 module. Figure 2-2 shows the recommended
PCB foot print.
Figure 2-2 PCB foot print recommended for M680 (unit: mm)
0.5 1.0
0.5
1.0
18.0
15.0
1.7
1.7
1.1
1.1
6.65
1.7
1.7
1.80
1.5 4.4
8.35 5.45 2.0
1.01.3 0.6 0.7
8.5

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
9
3 Interface Design
3.1 Power Supply and Switch Interfaces
Table 3-1 Power supply and switch interface
Signal
I/O
Function
Remarks
VBAT
P
Main power supply input
3.5 V to 4.3 V (3.9 V is recommended)
VDD_EXT
P
2.8 V power supply output
Loading capability < 50 mA
VRTC
P
RTC power supply input
2.8 V
ON/OFF
DI
On/Off input
Low level pulse can change the On/Off state.
RESET
DI
Module reset input
Reset at low level
Min. 50 ms
100 ms is recommended
3.1.1 Design Requirements
VBAT is the main power supply of the module. Its input voltage ranges from 3.5 V to 4.3 V and the
preferable value is 3.9V. In addition to digital signals and analog signals, it supplies power for RF power
amplifier.
The performance of the VBAT power supply is a critical path to module's performance and stability. The
peak input current at the VBAT pin can be up to 2 A when the signal is weak and the module works at the
maximum transmitting power. The voltage will encounter a drop in such a situation. The module might
restart if the voltage drops lower than 3.5 V.
Figure 3-1 Current peaks and voltage drops
Keep above 3.5 V
Keep above 3.5 V
3.5 V
3.5 V
0 ms
0 ms 3.7 ms
3.7 ms 7.4 ms 7.4 ms 10.7 ms 10.7 ms T
T
2.0 A
2.0 A
Voltage
Voltage
Input
Current
Input
Current
3.9 V
3.9 V

Neo_M680 GPRS Module Hardware User Guide
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Figure 3-2 shows a recommended power supply design for the module.
Figure 3-2 Capacitors used for the power supply
Power Supply GPRS Module
Close to the pin of the module
D1 C1 C2 C3 C4
VBAT
Current testing point
I_max
C5
In the circuit, you can use TVS at D1 to enhance the performance of the module during a burst. SMF5.0AG
(Vrwm=5V&Pppm=200W) is recommended.A large bypass tantalum capacitor (220 μF or 100 μF) or
aluminum capacitor (470 μF or 1000 μF) is expected at C1 to reduce voltage drops during bursts together
with C2 (10 μF capacitor). In addition, you need to add 0.1 μF, 100 pF, and 33 pF filter capacitorsto enhance
the stability of the power supply.
A controllable power supply is preferable if used in harsh conditions. The module might fail to reset in
remote or unattended applications, or in an environment with great electromagnetic interference (EMI). You
can use the EN pin on the LDO or DC/DC chipset to control the switch of the power supply as shown in
Figure 3-3.
MIC29302WU in the following figure is an LDO and outputs 3 A current to ensure the performance of the
module.
Figure 3-3 Reference design of power supply control
The alternative way is to use a p-MOSFET to control the module's power, as shown in Figure 3-4. When
the external MCU detects the exceptions such as no response from the module or the disconnection of
GPRS, power off/on can rectify the module exceptions. In Figure 3-4, the module is powered on when
GPRS_EN is set to high level.
VCC_IN_5V
GPRS_EN VBAT
100 uF
TAN 0.1 uF
TVS
5V 10 uF
470uF
TAN
10K
4.75K
VOUT
MIC29302WU
EN
VIN ADJ 0.1 uF 100pF 33pF

Neo_M680 GPRS Module Hardware User Guide
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Figure 3-4 Reference design of power supply controlled by p-MOSFET
Q2 is added to eliminate the need for a high enough voltage level of the host GPIO. In case that the GPIO
can output a high voltage greater than VDD_IN_3.9V- |VGS(th)|, where VGS(th) is the Gate ThresholdVoltage,
Q2 is not needed.
Reference components:
Q1 can be IRML6401 or Rds(on) p-MOSFET which has higher withstand voltage and drain current.
Q2: a common NPN transistor, e.g. MMBT3904; or a digital NPN transistor, e.g. DTC123. If digital
transistor is used, delete R1 and R2.
C3: 470 uF tantalum capacitor rated at 6.3V; or 1000 uF aluminum capacitor. If lithium battery is
used to supply power, C3 can be 220 uF tantalum capacitor.
Protection
Place a TVS diode (VRWM=5 V) on the VBAT power supply to ground, especially in automobile
applications. For some stable power supplies, zener diodes can decrease the power supply overshoot.
MMSZ5231B1T1G from ONSEMI and PZ3D4V2 from Prisemi are options.
Trace
The trace width of primary loop lines for VBAT onPCB must be able to support the safe transmission of 2A
current and ensure no obvious loop voltage decrease. Therefore, the trace width of VBAT loop line is
required 2 mm and the ground should be as complete as possible.
Separation
As shown in Figure 3-1, the GPRS module works in burst mode that generates voltage drops on power
supply. And furthermore this results in a 217 Hz TDD noise through power (One of the way generating
noise. Another way is through RF radiation). Analog parts, especially the audio circuits, are subjected to
this noise, known as a "buzz noise" in GSM systems. To prevent other parts from being affected, it's better

Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
12
to use separated power supplies. The module shall be supplied by an independent power, like a DC/DC or
LDO. See Figure 3-5.
DC/DC or LDO should output rated peak current larger than 2 A.
The inductor used in Reference Design (b), should be a power inductor and have a very low resistance. 10
uH with average current ability greater than 1.2A and low DC resistance is recommended.
Figure 3-5 Reference designs of separated power supply
Other circuit
DC-DC/LDO
GPRS
module
DC-DC/LDO
Power
Input
Other circuitDC-DC/LDO
GPRS
module
Power
Input 10 uH
Reference Design (a) Reference Design (b)
Never use a diode to make the drop voltage between a higher input and module power. Otherwise,
Neoway will not provide warranty for product issues caused by this. In this situation, the diode will
obviously decrease the module performances, or result in unexpected restarts, due to the forward voltage
of diode will vary greatly in different temperature and current.
EMC Considerations
Place transient overvoltage protection components like TVS diode on power supply, to absorb the power
surges. SMAJ5.0A/C could be a choice.
3.1.2 VDD_EXT
It is recommended that VDD_EXT is only used for interface level transformation. VDD_EXT can output
2.8 V and 50 mA. It stops output after the module is shut down.
3.1.3 VRTC
VRTC is the external power supply pin of RTC inside the module. It can be connected to external batteryor
supercapacitor. When VBAT works properly, VRTC outputs 2.8 V and maximum 2 mA and can be
connected to current limiting resistor or supercapacitor to charge. When VBAT is disconnected, the module
can discharge the battery or capacitor to supply power for RTC in short time. Leave it disconnected if not
used.
Figure 3-6shows the reference design of the VRTC power supply.

Neo_M680 GPRS Module Hardware User Guide
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Figure 3-6 VRTC reference design
3.1.4 Power-On/Off Control and Procedure
Prior to turning on the module, power on the host MCU and finish the UART initialization. Otherwise
conflictions may occur during initialization, due to unstable conditions.
ON/OFF is a low level pulse active input, used to turn on or off the module.
Power-On Procedure
While the module is off, drive the ON/OFF pin to ground for at least 1.2 second and then release, the
module will start.An unsolicited message (+EIND: 128) will be sent to host through UART port, indicating
that the module is powered on and can respond to AT commands.
When you design your program, you can use the unsolicited message (+EIND: 128) to check whether the
module is started or reset improperly.
Figure 3-7 Power-on procedure
Backup
battery
GPRS Module
RTC
Circuit
Capacitor
VRTC
1.5K
VBAT
ON/OFF
VDD_EXT
UART
1.2s
3s
300 ms