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SIM508
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SIMCOM SIM508 User Manual

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SIM508
HARDWARE SPECIFICATION
SIMCOM Ltd,.
th
Apr. 2006
10
Confidential
Document Name:
SIM508 Hardware Interface Description
Version:
Date:
Doc Id:
Status:
General Notes
Simcom offers this information as a service to its customers, to support application and
engineering efforts that use Simcom products. The information provided is based upon
requirements specifically provided to Simcom by the customers. Simcom has not undertaken any
independent search for additional relevant information, including any information that may be in
the customer’s possession. Furthermore, system validation of this Simcom product within a larger
electronic system remains the responsibility of the customer or the customer’s system integrator.
All specifications supplied herein are subject to change.
Copyright
This document contains proprietary technical information which is the property of
SIMCOM Limited., copying of this document and giving it to others and the using or
communication of the contents thereof, are forbidden without express authority.
Offenders are liable to the payment of damages. All rights reserved in the event of grant
of a patent or the registration of a utility model or design. All specification supplied
herein are subject to change without notice at any time.
Copyright © SIMCOM Limited. 2006
2.01 2006-04-10
SIM508_HD_V2.01
Released
SIM508_HD_V2.01 Page 2 of 73
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Contents

Contents .............................................................................................................................................3
Version History ..................................................................................................................................7
1 Introduction.....................................................................................................................................8
1.1 Related documents ...............................................................................................................8
1.2 Terms and abbreviations ......................................................................................................9
2 Product concept.............................................................................................................................12
2.1 SIM508 key features at a glance ........................................................................................13
3 GSM Application Interface ...........................................................................................................15
3.1 Pin description....................................................................................................................15
3.2 Operating modes ................................................................................................................17
3.3 Power supply......................................................................................................................19
3.3.1 Power supply pins on the board-to-board connector...............................................19
3.3.2 Minimizing power losses ........................................................................................19
3.3.3 Monitoring power supply........................................................................................20
3.4 Power up and down scenarios ............................................................................................20
3.4.1 Turn on the GSM part of SIM508...........................................................................20
3.4.2 Turn off the GSM part of SIM508 ..........................................................................23
3.4.3 Restart the GSM part of SIM508 using the PWRKEY pin.....................................25
3.5 Charging interface..............................................................................................................25
3.5.1 Battery pack characteristics.....................................................................................26
3.5.2 Recommended battery pack ....................................................................................27
3.5.3 Implemented charging technique ............................................................................27
3.5.4 Operating modes during charging...........................................................................28
3.5.5 Charger requirements..............................................................................................29
3.6 Power saving ......................................................................................................................29
3.6.1 Minimum functionality mode..................................................................................30
3.6.2 SLEEP mode (Slow Clocking mode)......................................................................30
3.6.3 Wake up the GSM part of SIM508 from SLEEP mode ..........................................30
3.7 Summary of state transitions (except SLEEP mode) .........................................................31
3.8 RTC backup........................................................................................................................32
3.9 GSM Serial interface..........................................................................................................35
3.9.1 Function of Serial Port supporting ..........................................................................35
3.9.2 Software upgrade and Software debug....................................................................36
3.10 Audio interfaces ...............................................................................................................37
3.10.1 Speaker interface configuration ............................................................................38
3.10.2 Microphone interfaces configuration ....................................................................39
3.10.3 Earphone interface configuration..........................................................................39
3.10.4 Referenced Electronic Characteristic....................................................................40
3.11 SIM interface....................................................................................................................40
3.11.1 SIM card application.............................................................................................40
3.11.2 Design considerations for SIM card holder...........................................................42
3.12 LCD interface...................................................................................................................44
3.13 General purpose Input/Output ports.................................................................................44
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3.14 ADC .................................................................................................................................44
3.15 Behaviors of the /RING line (Serial port1 interface only) ...............................................45
3.16 Network status indication LED lamp ...............................................................................46
3.17 Buzzer ..............................................................................................................................47
4 GPS Application Interface ............................................................................................................48
4.2 Technical data.....................................................................................................................49
4.3 Pin description....................................................................................................................50
4.4 Turn on the GPS part of SIM508 .......................................................................................51
4.5 The theory of the GPS RTC circuit ....................................................................................52
4.6 The theory of the RESET Circuit .......................................................................................53
4.7 GPS operation modes.........................................................................................................54
4.8 Serial interface of the SIM508 GPS part............................................................................54
4.9 Start-up procedure..............................................................................................................55
4.9.1 Coldstart..................................................................................................................55
4.9.2 Warmstart................................................................................................................55
4.9.3 Hotstart....................................................................................................................55
5 Antenna interface ..........................................................................................................................56
5.1 GSM Antenna.....................................................................................................................56
5.1.1 Antenna connector ..................................................................................................56
5.1.2 Antenna pad ............................................................................................................56
5.1.3 Module RF output power ........................................................................................58
5.1.4 Module RF receive sensitivity.................................................................................58
5.1.5 Module receive/transmit frequency.........................................................................58
5.2 GPS Antenna ......................................................................................................................59
5.2.1 GPS Antenna Connection........................................................................................59
5.2.2 GPS Antenna Choice Consideration .......................................................................59
6 Electrical, reliability and radio characteristics ..............................................................................61
6.1 Absolute maximum ratings ................................................................................................61
6.2 Operating temperatures ......................................................................................................61
6.3 Power supply rating............................................................................................................62
6.4 Current Consumption.........................................................................................................63
6.4.1 The current consumption of the SIM508 GSM part................................................63
6.4.2 The current consumption of the SIM508 GPS part .................................................64
6.4.2.1 Power down Mode ...............................................................................................64
6.4.2.2 Push-To-Fix mode................................................................................................64
6.5 Electrostatic discharge........................................................................................................66
7 Mechanics .....................................................................................................................................67
7.1 Mechanical dimensions of SIM508....................................................................................67
7.2 Mounting SIM508 onto the application platform...............................................................68
7.3 Board-to-board connector ..................................................................................................68
7.3.1 Mechanical dimensions of 54363-0878 ..................................................................68
7.3.2 Adapter cabling .......................................................................................................70
7.3.3 PIN assignment of board-to-board connector of SIM508 .......................................71
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Table index:
TABLE 1: RELATED DOCUMENTS ..............................................................................................8
TABLE 2: TERMS AND ABBREVIATIONS...................................................................................9
TABLE 3: SIM508 KEY FEATURES .............................................................................................13
TABLE 4: CODING SCHEMES AND MAXIMUM NET DATA RATES OVER AIR
INTERFACE............................................................................................................................14
TABLE 5: BOARD-TO-BOARD CONNECTOR PIN DESCRIPTION.........................................15
TABLE 6: OVERVIEW OF OPERATING MODES .......................................................................17
TABLE 7: AT COMMANDS USED IN ALARM MODE ..............................................................22
TABLE 8: SPEC OF RECOMMENDED BATTERY PACK ..........................................................27
TABLE 9: OPERATING MODES ...................................................................................................28
TABLE 10: AT COMMAND USUALLY USED IN GHOST MODE.............................................29
TABLE 11: SUMMARY OF STATE TRANSITIONS ....................................................................31
TABLE 12: LOGIC LEVELS OF SERIAL PORTS PINS ..............................................................35
TABLE 13: AUDIO INTERFACE SIGNAL ...................................................................................37
TABLE 14: MIC INPUT DC CHARACTERISTICS......................................................................40
TABLE 15: SPEAKER OUTPUT DC CHARACTERISTICS........................................................40
TABLE 16: BUZZER OUTPUT DC CHARACTERISTICS..........................................................40
TABLE 17: SIGNAL OF SIM INTERFACE (BOARD-TO-BOARD CONNECTOR) ..................41
TABLE 18: PIN DESCRIPTION (AMPHENOL SIM CARD HOLDER)......................................42
TABLE 19: PIN DESCRIPTION (MOLEX SIM CARD HOLDER)..............................................43
TABLE 20: PIN DEFINE OF LCD INTERFACE...........................................................................44
TABLE 21: GPIO OF THE GSM PART OF SIM508......................................................................44
TABLE 22: ADC PIN OF THE GSM PART OF SIM508 ...............................................................44
TABLE 23: BEHAVIOURS OF THE /RING LINE ........................................................................45
TABLE 24: WORKING STATE OF NETWORK STATUS INDICATION LED PIN ....................46
TABLE 25: PIN DESCRIPTION.....................................................................................................50
TABLE 26: CONSOLIDATED PIN CHARACTERISTICS ...........................................................51
TABLE 27: GPS OPERATION MODES.........................................................................................54
TABLE 28: THE GSM PART OF SIM508 RF OUTPUT POWER.................................................58
TABLE 29: THE GSM PART OF SIM508 RF CONDUCTED RECEIVE SENSITIVITY............58
TABLE 30: THE GSM PART OF SIM508 RECEIVE/TRANSMIT FREQUENCY......................58
TABLE 31: ABSOLUTE MAXIMUM RATINGS (GSM PART) ...................................................61
TABLE 32: ABSOLUTE MAXIMUM RATINGS (GPS PART).....................................................61
TABLE 33: SIM508 OPERATING TEMPERATURE ....................................................................61
TABLE 34: POWER SUPPLY RATING (GSM PART) ..................................................................62
TABLE 35: POWER SUPPLY RATING (GPS PART)....................................................................63
TABLE 36: CURRENT CONSUMPTION (GSM PART)...............................................................63
TABLE 37: THE ESD ENDURE STATUE MEASURED TABLE (TEMPERATURE: 25℃,
HUMIDITY:45% ) ...................................................................................................................66
TABLE 38: PIN ASSIGNMENT OF SIM 508 ................................................................................71
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Figure Index
FIGURE 1: VBAT INPUT ...............................................................................................................19
FIGURE 2: VBAT RIPPLE WAVE AT THE MAXIMUM POWER TRANSMIT PHASE ............19
FIGURE 3: TIMING OF TURN ON SYSTEM ..............................................................................21
FIGURE 4: TIMING OF TURN OFF SYSTEM.............................................................................23
FIGURE 5: TIMING OF RESTART SYSTEM...............................................................................25
FIGURE 6: BATTERY CHARGER AND PACK............................................................................26
FIGURE 7: RTC SUPPLY FROM NON-CHARGEABLE BATTERY...........................................32
FIGURE 8: RTC SUPPLY FROM RECHARGEABLE BATTERY................................................32
FIGURE 9: RTC SUPPLY FROM CAPACITOR............................................................................33
FIGURE 10: PANASONIC EECEMOE204A CHARGE CHARACTERISTIC.............................33
FIGURE 11: MAXELL TC614 CHARGE CHARACTERISTIC ...................................................34
FIGURE 12: SEIKO TS621 CHARGE CHARACTERISTIC ........................................................34
FIGURE 13: INTERFACE OF SERIAL PORTS ............................................................................35
FIGURE 14: INTERFACE OF SOFTWARE UPGRADE...............................................................37
FIGURE 15: SPEAKER INTERFACE CONFIGURATION...........................................................38
FIGURE 16: SPEAKER INTERFACE WITH AMPLIFIER CONFIGURATION .........................38
FIGURE 17: MICROPHONE INTERFACE CONFIGURATION ..................................................39
FIGURE 18: EARPHONE INTERFACE CONFIGURATION.......................................................39
FIGURE 19: SIM INTERFACE REFERENCE CIRCUIT WITH 8PIN SIM CARD.....................41
FIGURE 20: SIM INTERFACE REFERENCE CIRCUIT WITH 6PIN SIM CARD.....................42
FIGURE 21: AMPHENOL C707 10M006 049 2 SIM CARD HOLDER .......................................42
FIGURE 22: MOLEX 91228 SIM CARD HOLDER......................................................................43
FIGURE 23: THE GSM PART OF SIM508 SERVICES AS RECEIVER ......................................45
FIGURE 24: THE GSM PART OF SIM508 SERVICES AS CALLER ..........................................45
FIGURE 25: REFERENCE CIRCUIT FOR NETWORK STATUS LED .......................................46
FIGURE 26: REFERENCE CIRCUIT FOR BUZZER ...................................................................47
FIGURE 27: THEORY OF OPERATION .......................................................................................48
FIGURE 28: TURN ON THE GPS MODULE................................................................................52
FIGURE 29: THEORY OF THE GPS RTC CIRCUIT ....................................................................53
FIGURE 30: THEORY OF THE RESET CIRCUIT........................................................................53
FIGURE 31: RF CONNECTOR AND RF PAD ..............................................................................57
FIGURE 32: RF CONNECTOR......................................................................................................59
FIGURE 33: POWER DOWN MODE ............................................................................................64
FIGURE 34: PUSH-TO-FIX MODE...............................................................................................65
FIGURE 35: POWER CONSUMPTION IN THE PTF MODE ......................................................66
FIGURE 36: SIM508 TOP VIEW AND SIDE VIEW .....................................................................67
FIGURE 37: 54363-0878 BOARD-TO-BOARD CONNECTOR PIN SIDE..................................68
FIGURE 38: BOARD TO BOARD CONNECTOR PHYSICAL PHOTO .....................................69
FIGURE 39: MM9329-2700B.........................................................................................................70
FIGURE 40: RF CONNECTOR MXTK .........................................................................................70
FIGURE 41: PHYSICAL SIM508...................................................................................................72
FIGURE 42: REFERENCE CIRCUIT WITH EXTERNAL MCU (EXAMPLE APPLICATION) 73
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Version History

Data Version Description of change Author
2005-12-08 1.00 Origin Simon
2006-02-28 1.01 1.Modify figure 3, 4, 5,add “PWRKEY”
2.Modify figure 20, add “VEXT” and pull up resistor
3.Add “supporting Multiplexing”
4.Add“3.9.2 software upgrade and software debug”
5.Modify figure 28, 29, 36
6.Modify the description of “4.4 GPS Serial interface of
the SIM508 GPS part”
2006-04-10 2.01 1.Add the reference circuit of SIM508
2.Update autobauding
3.Modify figure3,4,5
4.Add table 13,17,18,25,26,27
5.Add figure28,29,30,31,34,35,36,43
6. Add “GPS Antenna Choice Consideration”
7.Add description of the GPS current consumption
Ronald
Ronald
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1 Introduction

This document describes the hardware interface of the SIMCOM SIM508 module that connects to
the specific application and the air interface. As SIM508 can be integrated with a wide range of
applications, all functional components of SIM508 are described in great detail.
This document can help you quickly understand SIM508 interface specifications, electrical and
mechanical details. With the help of this document and other SIM508 application notes, user guide,
you can use SIM508 module to design and set-up mobile applications quickly.

1.1 Related documents

Table 1: Related documents
SN Document name Remark
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
SIM508_ATC SIM508_ATC
ITU-T Draft new
recommendation
V.25ter:
GSM 07.07: Digital cellular telecommunications (Phase 2+); AT command
GSM 07.05: Digital cellular telecommunications (Phase 2+); Use of Data
GSM 07.10: Support GSM 07.10 multiplexing protocol
GSM 11.14: Digital cellular telecommunications system (Phase 2+);
GSM 11.11: Digital cellular telecommunications system (Phase 2+);
GSM 03.38: Digital cellular telecommunications system (Phase 2+);
Serial asynchronous automatic dialing and control
set for GSM Mobile Equipment (ME)
Terminal Equipment – Data Circuit terminating Equipment
(DTE – DCE) interface for Short Message Service (SMS) and
Cell Broadcast Service (CBS)
Specification of the SIM Application Toolkit for the Subscriber
Identity Module – Mobile Equipment (SIM – ME) interface
Specification of the Subscriber Identity Module – Mobile
Equipment (SIM – ME) interface
Alphabets and language-specific information
[9]
GSM 11.10
Digital cellular telecommunications system (Phase 2) ；
Mobile Station (MS) conformance specification； Part 1:
Conformance specification
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1.2 Terms and abbreviations

Table 2: Terms and abbreviations
GSM PART Abbreviation Description
ADC Analog-to-Digital Converter
ARP Antenna Reference Point
ASIC Application Specific Integrated Circuit
BER Bit Error Rate
BTS Base Transceiver Station
CHAP Challenge Handshake Authentication Protocol
CS Coding Scheme
CSD Circuit Switched Data
CTS Clear to Send
DAC Digital-to-Analog Converter
DRX Discontinuous Reception
DSP Digital Signal Processor
DTE Data Terminal Equipment (typically computer, terminal, printer)
DTR Data Terminal Ready
DTX Discontinuous Transmission
EFR Enhanced Full Rate
EGSM Enhanced GSM
EMC Electromagnetic Compatibility
ESD Electrostatic Discharge
ETS European Telecommunication Standard
FCC Federal Communications Commission (U.S.)
FDMA Frequency Division Multiple Access
FR Full Rate
GMSK Gaussian Minimum Shift Keying
GPRS General Packet Radio Service
GSM Global Standard for Mobile Communications
HR Half Rate
I/O Input/Output
IC Integrated Circuit
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IMEI International Mobile Equipment Identity
kbps Kilo bits per second
LED Light Emitting Diode
Li-Ion Lithium-Ion
MO Mobile Originated
MS Mobile Station (GSM engine), also referred to as TE
MT Mobile Terminated
PAP Password Authentication Protocol
PBCCH Packet Switched Broadcast Control Channel
PCB Printed Circuit Board
PCS Personal Communication System, also referred to as GSM 1900
PDU Protocol Data Unit
PPP Point-to-point protocol
RF Radio Frequency
RMS Root Mean Square (value)
RP Receive Protocol
RTC Real Time Clock
Rx Receive Direction
SA Selective Availability
SAR Specific Absorption Rate
SIM Subscriber Identification Module
SMS Short Message Service
TDMA Time Division Multiple Access
TE Terminal Equipment, also referred to as DTE
TX Transmit Direction
URC Unsolicited Result Code
USSD Unstructured Supplementary Service Data
VSWR Voltage Standing Wave Ratio
Vmax Maximum Voltage Value
Vnorm Normal Voltage Value
Vmin Minimum Voltage Value
VIHmax Maximum Input High Level Voltage Value
VIHmin Minimum Input High Level Voltage Value
VILmax Maximum Input Low Level Voltage Value
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VILmin Minimum Input Low Level Voltage Value
VImax Absolute Maximum Input Voltage Value
VImin Absolute Minimum Input Voltage Value
VOHmax Maximum Output High Level Voltage Value
VOHmin Minimum Output High Level Voltage Value
VOLmax Maximum Output Low Level Voltage Value
VOLmin Minimum Output Low Level Voltage Value
Phonebook abbreviations
FD SIM fix dialing phonebook
LD SIM last dialing phonebook (list of numbers most recently dialed)
MC Mobile Equipment list of unanswered MT calls (missed calls)
ME Mobile Equipment phonebook
RC Mobile Equipment list of received calls
SM SIM phonebook
DC ME dialed calls list(+CPBW may not be applicable or this storage)(same as LD)
LA Last Number All list (LND/LNM/LNR)
ON SIM (or ME) own numbers (MSISDNs) list
SD SIM service dial number
VM SIM voice mailbox
BN SIM barred dialed number
GPS PART Abbreviation Description
ATP
DGPS
GGA GPS Fixed Data
GPS Global Positioning System
LNA
RTCM Radio Technical Commission for Maritime Services
Adaptive Trickle Power mode.
Differential GPS
Low Noise Amplifier
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2 Product concept

Designed for global market, SIM508 is a Tri-band GSM/GPRS engine that works on frequencies
GSM 900 MHz, DCS 1800 MHz and PCS1900 MHz and supports also GPS technology for
satellite navigation.
supports the GPRS coding schemes CS-1, CS-2, CS-3 and CS-4.
With a tiny configuration of 55mm x 34mm x 3.0 mm, SIM508 can fit almost all the space
requirement in your application, such as Smart phone, PDA phone, GPS hand-held device and
other mobile device, or applications of AVL (Automated Vehicle Location), location service and
so on.
The physical interface to the mobile application is made through a 80 pins board-to-board
connector, which provides all hardware interfaces between the module and customers’ boards
except the RF antenna interface.
z The keypad and SPI LCD interface will give you the flexibility to develop customized
applications.
z One serial GSM port and two serial GPS pots can help you easily develop your
applications.
z Two audio channels include two microphones inputs and two speaker outputs. This can
be easily configured by AT command.
z Charge interface
With the charge circuit integrated inside the SIM508, it is very suitable for the battery power
application.
SIM508 provide GSM RF antenna interface with two alternatives: antenna connector and antenna
pad. The antenna connector is MURATA MM9329-2700. And customer’s antenna can be soldered
to the antenna pad.
in order to properly receive satellite data.
The SIM508 is designed with power saving technique, the current consumption of GSM part
maintains as low as about 3mA in SLEEP mode.
The SIM508 is integrated with the TCP/IP protocol，Extended TCP/IP AT commands are
developed for customers to use the TCP/IP protocol easily, which is very useful for those data
transfer applications.
SIM508 provides GPRS multi-slot class10 / class 8 (option) capabilities and
A separate GPS antenna must be connected to the GPS part of the module
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2.1 SIM508 key features at a glance

Table 3: SIM508 key features
Feature Implementation
Power supply z GSM part: Supply voltage 3.4V – 4.5V
z GPS part: Separate power supply source: 3.3V ± 5%
Power saving z GSM part: Typical power consumption in SLEEP mode to
3.5mA
z GPS part: Power Down mode / Push-to-Fix mode (configured by
especially software version)
Charging Supports charging control for Li-Ion battery
Frequency bands
GSM class Small MS
Transmit power z Class 4 (2W) at EGSM900 and GSM850
GPRS connectivity
GPS features
Temperature range
DATA GPRS:
CSD:
z SIM508 Quad-band: GSM 850, GSM 900, DCS 1800, PCS
1900. The band can be set by AT COMMAND, and default
band is EGSM 900 and DCS 1800.
z Compliant to GSM Phase 2/2+
z Class 1 (1W) at DCS1800 and PCS 1900 z GPRS multi-slot class 8(option)
z GPRS multi-slot class 10(default) z GPRS mobile station class B
z GPS receiver with SiRFstar III GSC3f chip set z Processor type ARM7/TDMI z Software version: SiRF GSW3
z Normal operation: -20°C to +55°C z Restricted operation: -25°C to -20°C and +55°C to +75°C z Storage temperature -40°C to +80°C
z GPRS data downlink transfer: max. 85.6 kbps z GPRS data uplink transfer: max. 42.8 kbps z Coding scheme: CS-1, CS-2, CS-3 and CS-4 z SIM508 supports the protocols PAP (Password Authentication
Protocol) usually used for PPP connections.
z The SIM508 integrates the TCP/IP protocol. z Support Packet Switched Broadcast Control Channel (PBCCH) z CSD transmission rates: 2.4, 4.8, 9.6, 14.4 kbps, non-transparent z Unstructured Supplementary Services Data (USSD) support
SMS z MT, MO, CB, Text and PDU mode
z SMS storage: SIM card z Support transmission of SMS alternatively over CSD or GPRS.
User can choose preferred mode.
FAX Group 3 Class 1
SIM interface Supported SIM card: 1.8V ,3V
External antenna z GSM part: Connected via 50 Ohm antenna connector or antenna
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pad
z GPS part: Separate GPS antenna connector. See Figure 33 for
details
Audio features Speech codec modes:
z Half Rate (ETS 06.20) z Full Rate (ETS 06.10) z Enhanced Full Rate (ETS 06.50 / 06.60 / 06.80) z Echo cancellation
serial GSM interfaces z Serial Port Seven lines on Serial Port Interface
z Serial Port can be used for CSD FAX, GPRS service and send
AT command of controlling module.
z Serial Port can use multiplexing function z Autobauding supports baud rate from 1200 bps to 115200bps.
Two serial GPS interfaces z Serial Port A: Two lines on Serial Port A, GPS_TXA and
GPS_RXA
z Serial Port B: Two lines on Serial Port B, GPS_TXB and
GPS_RXB
Phonebook management Supported phonebook types: SM, FD, LD, MC, RC, ON,
ME,BN,VM,LA,DC,SD
SIM Application Toolkit Supports SAT class 3, GSM 11.14 Release 98
Real time clock Implemented
Timer function Programmable via AT command
Physical characteristics Size: 55±0.15 x 34±0.15 x 3.3±0.3 mm (including application
connector)
55±0.15 x 34±0.15 x 2.9±0.3 mm (excluding application connector)
Weight: 11g
Firmware upgrade Firmware upgraded over serial interface
Table 4: 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
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3 GSM Application Interface

All hardware interfaces except RF interface that connects SIM508 to the customers’ cellular
application platform is through a 80-pin 0.5mm pitch board-to-board connector. Sub-interfaces
included in this board-to-board connector are described in detail in following chapters:
z Power supply and charging control ( z Dual serial interface (see Chapter 3.9) z Two analog audio interfaces ( z SIM interface (see Chapter 3.11)
Electrical and mechanical characteristics of the board-to-board connector are specified in Chapter
6. There we also ordering information for mating connectors.

3.1 Pin description

Table 5: Board-to-Board Connector pin description
see Chapters 3.3 and 3.5)
see Chapter 3.10)
Power Supply
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
VBAT
BACKUP I/O
CHG_IN I
GND Digital ground
Power on or power off
Five BAT pins of the board-to-board
connector are dedicated to connect
the supply voltage. The power supply
of the GSM part of SIM508 has to be
a single voltage source of VBAT=
3.4V...4.5V. It must be able to provide
sufficient current in a transmit burst
which typically rises to 2A.mostly,
these 5 pins are voltage input
Current input for RTC when the
battery is not supplied for the system.
Current output for backup battery
when the main battery is present and
the backup battery in low voltage
state.
Voltage input for the charge circuit;
making the system detect the charger.
Vmax= 4.5V
Vmin=3.4V
Vnorm=4.0V
Vmax=2.0V
Vmin=1.2V
Vnorm=1.8V
Inorm= 20uA
Vmax=5.25V
Vmin=1.1 * VBAT
Vnorm=5.1V
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS PWRKEY I
SIM508_HD_V2.01 Page 15 of 73
Voltage input for power on key.
PWRKEY get a low level Voltage for
user to power on or power off the
VILmax=0.3*VBAT
VIHmin=0.7*VBAT
VImax=VBAT
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system, The user should keep
pressing the key for a moment when
power on or power off the system.
Because the system need margin time
assert the software.
Audio interface
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
MIC1P MIC1N
MIC2P MIC2N
SPK1P SPK1N
SPK2P SPK2N
I Positive and negative voice-band
input
I Auxiliary positive and negative
voice-band input
O Positive and negative voice-band
output
O Auxiliary positive and negative
voice-band output
BUZZER O Buzzer Output
AGND Analog ground
Display interface
DISP_D0 I/O Display data line
DISP_CLK O Display clock output
DISP_A0 O Display data or address select
DISP_EN O Display enable output
NLCDRESET O Display reset outplay
Keypad interface
KCOL0~KCOL4 O
Keypad array interface
KROW0~KROW4 I
GERNERAL PURPOSE input/output
Audio DC Characteristics refer to chapter 3.9.4
VILmin=0V
VILmax=0.9
VIHmin=2.0
VIHmax= 3.2
VOLmin=GND
VOLmax=0.2V
VOHmin=2.7
VOHmax=2.9
VILmin=0V
VILmax=0.9
VIHmin=2.0
VIHmax= 3.2
VOLmin=GND
VOLmax=0.2V
VOHmin=2.7
VOHmax=2.9
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
NETLIGHT
STATUS O Another indication for system on/off
GPIO5 I/O General purpose Input/Output port
GPIO32 I/O General purpose Input/Output port
O GSM net indicator
VILmin=0V
VILmax=0.9
VIHmin=2.0
VIHmax= 3.2
VOLmin=GND
VOLmax=0.2V
VOHmin=2.7
VOHmax=2.9
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Serial 1 interface
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
DTR I Data Terminal Ready
RXD I Receive Data
TXD O Transmit Data
RTS I Request to Send
CTS O Clear to Send
RI O Ring Indicator
DCD
O Data Carrier detection
Serial 2 interface
DEBUG_TX O
DEBUG_RX I
Serial interface for debugging and
communication by AT command
VILmin=0V
VILmax=0.9
VIHmin=2.0
VIHmax= 3.2
VOLmin=GND
VOLmax=0.2V
VOHmin=2.7
VOHmax=2.9
SIM interface
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
VSIM O Voltage Supply for SIM card
The voltage can be select
by software either 1.8v or
2.85V
SIM_DATA I/O SIM Data Output
SIM_CLOCK O SIM Clock
VILmin=0V
VILmax=0.3* VSIM
VIHmin=0.7* VSIM
SIM_PRESENCE I SIM Card Detection
SIM_RESET O SIM Reset
VIHmax= VSIM +0.3
VOLmin=GND
VOLmax=0.2V
VOHmin= VSIM -0.2
VOHmax= VSIM
AUXADC
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
AUXADC1 I
TEMP_BAT I
General purpose analog to digital
converter.
For measure the battery temperature
Input voltage value scope
0V to 2.4V

3.2 Operating modes

The following table summarizes the various operating modes, each operating modes is referred to
in the following chapters.
Table 6: Overview of operating modes
Mode Function
Normal operation GSM/GPRS
SLEEP
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Module will automatically go into SLEEP mode if DTR is set
to high level and there is no on air or audio activity is required
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and no hardware interrupt (such as GPIO interrupt or data on
serial 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. Module has registered to the GSM network,
and the module is ready to send and receive.
GSM TALK CSD connection is going on between two subscribers. In this
case, the power consumption depends on network settings such
as DTX off/on, FR/EFR/HR, hopping sequences, antenna.
GPRS IDLE Module is ready for GPRS data transfer, but no data is
currently sent or received. In this case, power consumption
depends on network settings and GPRS configuration (e.g.
multi-slot settings).
GPRS DATA There is GPRS data in transfer (PPP or TCP or UDP). In this
case, power consumption is related with network settings (e.g.
power control level), uplink / downlink data rates and GPRS
configuration (e.g. used multi-slot settings).
POWER DOWN Normal shutdown by sending the “AT+CPOWD” command or using the
PERKEY. The power management ASIC disconnects the power supply from the
base band part of the module, only the power supply for the RTC is remained.
Software is not active. The serial interfaces are not accessible. Operating voltage
(connected to VBAT) remains applied.
Minimum
functionality
mode (without
remove power
supply)
Use the “AT+CFUN” command can set the module to a minimum functionality
mode without remove the power supply. In this case, the RF part of the module
will not work or the SIM card is not accessible, or RF part and SIM card be
closed all, the serial interfaces is still accessible. The power consumption in this
case is very low.
Alarm mode RTC alert function launches this restricted operation while the module is in
POWER DOWN mode. SIM508 will not be registered to GSM network and
only parts of AT commands can be available.
GHOST Mode
(Charge-only
mode)
GHOST mode means off and charging mode. In this mode, the module can not
be registered to GSM network and only limited AT commands can be
accessible, the following way will launch GHOST mode:
z From POWER DOWN mode: Connect charger to the module’s CHG_IN
pin and VBAT pin while SIM508 is power down.
z From Normal mode: Connect charger to the module’s CHG_IN pin and
VBAT pin, then power down the module by “AT+CPOWD＝1”
Charge mode
during normal
Start charging while the module is in normal mode including: SLEEP, IDLE,
TALK, GPRS IDLE and GPRS DATA)
operation
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3.3 Power supply

The power supply of SIM508 GSM part is from a single voltage source of VBAT=
3.4V...4.5V. In some case, the ripple in a transmit burst may cause voltage drops when current
consumption rises to typical peaks of 2A, So the power supply must be able to provide
sufficient current up to 2A.
For the VBAT input, a local bypass capacitor is recommended. A capacitor (about 100µF, low
ESR) is recommended. Multi-layer ceramic chip (MLCC) capacitors can provide the best
combination of low ESR and small size but may not be cost effective. A lower cost choice may be
a 100 µF tantalum capacitor (low ESR) with a small (1 µF to 2 µF) ceramic in parallel, which is
illustrated as figure1. And the capacitors should put as closer as possible to the SIM508 VBAT
pins.
Figure 1: VBAT input
The following figure is the VBAT voltage ripple wave at the maximum power transmit phase,
the test condition is VBAT=4.0V, VBAT maximum output current =2A, C
capacitor (ESR=0.7Ω) and C
Figure 2
: VBAT ripple wave at the maximum power transmit phase
=4.7µF. B
B
=100 µF tantalum
A

3.3.1 Power supply pins on the board-to-board connector

Five VBAT pins of the board-to-board connector are dedicated to connect the supply voltage. The
CHG_IN pin serves as control signal for charging a Li-Ion battery. BACKUP can be used to back
up the RTC.

3.3.2 Minimizing power losses

Please pay special attention to the supply power when you are designing your applications. Please
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make sure that the input voltage will never drops below 3.4V even in a transmit burst during which
the current consumption may rise up to 2A. If the power voltage drops below 3.4V, the module
may be switched off. Using the board-to-board connector will be the best way to reduce the
voltage drops. You should also take the resistance of the power supply lines on the host board or of
battery pack into account.

3.3.3 Monitoring power supply

To monitor the supply voltage, you can use the “AT+CBC” command which include three parameters: charge state, voltage percent and voltage value (in mV). It returns charge state、the
battery voltage 1-100 percent of capacity and actual value measured at VBAT and GND.
The voltage is continuously measured at intervals depending on the operating mode. The displayed
voltage (in mV) is averaged over the last measuring period before the AT+CBC command was
executed.
For details please refer to document [1]

3.4 Power up and down scenarios

3.4.1 Turn on the GSM part of SIM508

The GSM part of SIM508 can be turned on by various ways, which are described in following
chapters:
z Via PWRKEY pin: starts normal operating mode ( z Via CHG_IN pin: starts GHOST modes (see chapter 3.4.1.2); z Via RTC interrupt: starts ALARM modes (
Note: Only enter AT command through serial port after SIM508 is power on and Unsolicited Result Code “RDY” is received from serial port.
Note: If configured to a fix baud rate, SIM508 will send the result code “RDY” to in dica te that it is ready to operate. This result code does not appear when autobauding is active.You can use AT+IPR=x;&W to set a fix baud rate and save the configuration to non-volatile flash memory. See Chapter AT+IPR in document[1].
3.4.1.1 Turn on the GSM part of SIM508 using the PWRKEY pin (Power on)
You can turn on the GSM part of SIM508 by driving the PWRKEY to a low level voltage for
period time. The power on scenarios illustrate as the following figure.
see chapter 3.4.1.3)
see chapter 3.4.1.1);
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Figure 3: Timing of turn on system
When power on procedure complete, the GSM part of SIM508 will send out following result code to indicate the module is ready to operate，and STATUS pin will drive to 2.8V and keep this level
when in work mode. Only set baud rate serial port can send out “RDY”, if set auto-baud rate serial
port send nothing.
RDY
3.4.1.2 Turn on the GSM part of SIM508 using the CHG_IN signal
As described in chapter 3.5, charger can be connected to the GSM part of SIM508’s CHG_IN pin
regardless of the module’s operating mode.
If the charger is connected to the module’s CHG_IN pin while the GSM part of SIM508 is in
POWER DOWN mode, it will go into the GHOST mode (Off and charging). In this mode, the
module will not register to network, and only a few AT commands can work in this mode. For
detailed information please refers to chapter 3.5.4.
When module is powered on using the CHG_IN signal, the GSM part of SIM508 sends out result
code as following when fixed baud rate:
RDY GHOST MODE +CFUN: 0
In GHOST mode, by driving the PWRKEY to a low level voltage for period time (Please refer to
the power on scenarios in 3.4.1.1), the GSM part of SIM508 will power up and go into charge
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mode (charging in normal mode), all operation and AT commands can be available. In this case,
the GSM part of SIM508 will send out result code as following:
From GHOST MODE to NORMAL MODE
3.4.1.3 Turn on the GSM part of SIM508 using the RTC (Alarm mode)
Alarm mode is a power-on approach by using the RTC. The alert function of RTC makes the
GSM part of SIM508 wake up while the module is power off. In alarm mode, the GSM part of
SIM508 will not register to GSM network and the software protocol stack is close. Thus the parts
of AT commands related with SIM card and Protocol stack will not accessible, and the others can
be used as well as in normal mode.
Use the AT+CALARM command to set the alarm time. The RTC remains the alarm time if the
GSM part of SIM508 was power down by “AT+CPOWD=1” or by PWRKEY pin. Once the alarm
time expires and executed, the GSM part of SIM508 goes into the Alarm mode. In this case, the
GSM part of SIM508 will send out an Unsolicited Result Code (URC):
RDY ALARM MODE
During Alarm mode, using AT+CFUN command to query the status of software protocol stack; it
will return 0 which indicates that the protocol stack is closed. Then after 90S, the GSM part of
SIM508 will power down automatically. However, during Alarm mode, if the software protocol is
started by AT+CFUN=1 command, the process of automatic power down will not available. In
ALARM mode, driving the PWRKEY to a low level voltage for a period will cause the GSM part
of SIM508 to power down (Please refer to the power down scenarios in 3.4.2.1).
The table follow briefly summarizes the AT commands that are used usually during alarm mode,
for details of the instructions refer to document [1]:
Table 7: AT commands used in Alarm mode
AT command USE
AT+CALARM Set alarm time
AT+CCLK Set data and time of RTC
AT + CP O W D Power down
AT+CFUN Start or close the protocol stack
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3.4.2 Turn off the GSM part of SIM508

Following procedure can be used to turn off the GSM part of SIM508:
z Normal power down procedure: Turn off the GSM part of SIM508 using the PWRKEY pin
(
see chapter 3.4.2.1)
z Normal power down procedure: Turn off the GSM part of SIM508 using AT command (see
chapter 3.4.2.2)
z Under-voltage Automatic shutdown: Takes effect if under voltage is detected (see chapter
3.4.2.3)
z Over-temperature Automatic shutdown: Takes effect if under voltage is detected (see chapter
3.4.2.4)
3.4.2.1 Turn off the GSM part of SIM508 using the PWRKEY pin (Power down)
You can turn off the GSM part of SIM508 by driving the PWRKEY to a low level voltage for
period time. The power down scenarios illustrate as Figure4.
This procedure will let the module to log off from the network and allow the software to enter into
a secure state and save data before completely disconnect the power supply.
Before the completion of the switching off procedure the module will send out result code:
NORMAL POWER DOWN
After this moment, no any AT commands can be executed. Module enters the POWER DOWN
mode, only the RTC is still active. POWER DOWN can also be indicated by STATUS pin, which
is a low level voltage in this mode.
Figure 4: Timing of turn off system
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3.4.2.2 Turn off the GSM part of SIM508 using AT command
You can use an AT command “AT+CPOWD=1” to turn off the module. This command will let the
module to log off from the network and allow the software to enter into a secure state and safe data
before completely disconnect the power supply.
Before switching off, the module will send out result code:
NORMAL POWER DOWN
After this moment, no any AT commands can be executed. Module enters the POWER DOWN
mode, only the RTC is still active. POWER DOWN can also be indicated by STATUS pin, which
is a low level voltage in this mode.
Please refer to document [1] for detail about the AT command of “AT+CPOWD”.
3.4.2.3 Under-voltage automatic shutdown
Software will constantly monitors the voltage applied on the VBAT, if the measured battery
voltage is no more than 3.5V, the module will send out result code:
POWER LOW WARNNING
If the measured battery voltage is no more than 3.4V, the following URC will be presented:
POWER LOW DOWN
After this moment, no further more AT commands can be executed. The module will log off from
network and enters POWER DOWN mode, only the RTC is still active. POWER DOWN can also
be indicated by STATUS pin, which is a low level voltage in this mode.
3.4.2.4 Over-temperature automatic shutdown
Software will constantly monitors the temperature of the module, if the measured temperature is equal or higher than 85℃, the following URC will be presented:
+CMTE:1
If the measured temperature is equal or lower than -35℃, the following URC will be presented:
+CMTE:-1
The uncritical temperature range is -40℃ to 90℃. If the measured temperature is equal or beyond this range, the module will be automatic shutdown soon.
If the measured temperature is equal or higher than 90℃, the following URC will be presented:
+CMTE:2
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If the measured temperature is equal or lower than -40℃, the following URC will be presented:
+CMTE:-2
After this moment, no further more AT commands can be executed. The module will log off from
network and enters POWER DOWN mode, only the RTC is still active. POWER DOWN can also
be indicated by STATUS pin, which is a low level voltage in this mode.
To monitor the temperature, you can use the “AT+CMTE” command to measure the temperature
when the module power on.
For details please refer to document [1]

3.4.3 Restart the GSM part of SIM508 using the PWRKEY pin

You can restart SIM508 by driving the PWRKEY to a low level voltage for period time, same as
turn on SIM508 using the PWRKEY pin. Before restart the SIM508, you need delay at least
500mS from detecting the STATUS low level on. The restart scenarios illustrate as the following
figure.
Figure 5: Timing of restart system

3.5 Charging interface

The GSM part of SIM508 has integrated a charging circuit inside the module for Li-Ion batteries
charging control, which make it very convenient for applications to manage their battery charging.
A common connection is shown in the following figure:
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Figure 6:Battery charger and pack

3.5.1 Battery pack characteristics

The GSM part of SIM508 has optimized the charging algorithm for the Li-Ion battery that meets
the characteristics listed below. To use the GSM part of SIM508’s charging algorithm properly, it
is recommended that the battery pack you integrated into your application is compliant with these
specifications. The battery pack compliant with these specifications is also important for the AT
command “AT+CBC” to monitor the voltage of battery, or the “AT+CBC” may return incorrect
battery capacity values.
z The maximum charging voltage of the Li-Ion battery pack is 4.2V and the capacity is
580mAh. Battery packs with a capacity down to 580 mAh or more than 580 mAh are allowed,
too.
z The pack should have a protection circuit to avoid overcharging, deep discharging and
over-current. This circuit should be insensitive to pulsed current.
z On the GSM part of SIM508, the build-in circuit of the GSM part of SIM508’s power
management chipset monitors the supply voltage constantly. Once the Under-voltage is
detected, the GSM part of SIM508 will power down automatically. Under-voltage thresholds
are specific to the battery pack.
z The internal resistance of the battery and the protection circuit should be as low as possible. It
is recommended not to exceed 200mΩ.
z The battery pack must be protected from reverse pole connection.
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3.5.2 Recommended battery pack

Following is the spec of recommended battery pack:
Table 8: Spec of recommended battery pack
Product name & type BYD, Li-Ion, 3.7V, 580mAh
To obtain more information
BYD COMPANY LIMITED
Please contact :
Normal voltage 3.7V
Capacity Minimum 580mAh
Charge Voltage 4.200±0.049V
Max Charge Current 1.5C
Charge Method CC / CV (Constant Current / Constant Voltage)
Max Discharge Current 1.5C (for continuous discharging mode)
Discharge Cut-off Voltage 2.75V/ cell
Internal resistance Initial≤200mΩ
After 400cycles ≤270mΩ

3.5.3 Implemented charging technique

The GSM part of SIM508 include the function for battery charging. There are three pins in the
connector related with the battery charging function: CHG_IN, VBAT and BAT_TEMP pins. The
CHG_IN pin is driven by an external voltage, system can use this pin to detect a charger supply
and provide most charging current through the GSM part of SIM508 module to battery when
charging is in fast charge state. The VBAT give out charging current from the GSM part of
SIM508 module to external battery. BAT_TEMP pin is for user to measure the battery temperature.
Just let this pin open if battery temperature measuring is not your concern.
So it is very simple to implement charging technique, you need only connect the charger to the
CHG_IN pin and connect the battery to the VBAT pin.
The GSM part of SIM508 detect charger supply and the battery is present, battery charging will
happen. If there is no charger supply or no battery present the charging will not be enabled.
Normally, there are three main states in whole charging procedure.
z DDLO charge and UVLO charge; z Fast charge; z Trickle charge;
DDLO charge and UVLO charge:
DDLO (deep discharge lock out) is the state of battery when its voltage under 2.4V. And UVLO
(under voltage lock out) means the battery voltage less than 3.2V and more than 2.4V. The battery
is not suitable for fast charge when its condition is DDLO or UVLO. The GSM part of SIM508
provides a small constant current to the battery when the battery is between DDLO and UVLO. In
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DDLO charge, The GSM part of SIM508 gives out 5mA current to the battery. And in UVLO
charge, The GSM part of SIM508 provide about 25mA current to the battery.
DDLO charge terminated when the battery voltage reaches 2.4V. UVLO charge terminated when
the battery voltage is up to 3.2V. Both DDLO and UVLO charge are controlled by the GSM part
of SIM508 hardware only.
Fast charge:
If there is a charger supply and battery present and the battery is not in DDLO and UVLO, the
GSM part of SIM508 will enter fast charge state. Fast charge controlled by the software. Fast
charge delivers a strong and constant current (about 450mA) through VBAT pin to the battery until
battery voltage reach 4.2V.
Trickle charge:
After fast charging, the battery voltage near the whole battery capacity, trick charge begins .in this
state, the GSM part of SIM508 charge the battery under constant voltage.

3.5.4 Operating modes during charging

The battery can be charged during various operating mode. That means that when the GSM engine
is in Normal mode (SLEEP, IDLE, TALK, GPRS IDLE or GPRS DATA mode), charging can be
in progress while the GSM part of SIM508 remains operational (In this case the voltage supply
should be sufficient). Here we name Charging in Normal mode as Charge mode.
If the charger is connected to the module’s CHG_IN pin and the battery is connected to the VBAT
pin while the GSM part of SIM508 is in POWER DOWN mode, the GSM part of SIM508 will go
into the GHOST mode (Off and charging). The following table gives the difference between Charge mode and GHOST mode：
Table 9: operating modes
Connect charger to module’s CHG_IN
pin and connect battery to VBAT pin of
module while the GSM part of SIM508 is
in Normal operating mode, including:
IDLE, TALK mode; SLEEP mode etc;
How to activate mode Features
z GSM remains operational and
registered GSM network while
charging is in progress;
z The serial interfaces are available in
IDLE, TALK mode, the AT
command set can be used fully in this
case;
Charge Mode
In SLEEP mode, the serial interfaces are
not available, once the serial port is
connected and there is data in transfer.
Then the GSM part of SIM508 will exit
the SLEEP mode.
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Connect charger to module’s CHG_IN
pin while the GSM part of SIM508 is in
POWER DOWN mode.
IMPORTANT: In GHOST mode not all
GHOST Mode
the software tasks are running.
Note:
VBAT can not provide much more than 5mA current while sim508 module is during the DDLO charge state. In other words it is strongly recommended that VBAT should not be the main power supply in the application subsystem while sim508 module is during the DDLO charge state.
z Battery can be charged when GSM
engine is not registered to GSM
network;
z Only a few AT commands is
available as listed below.
Table10:ATCommandusuallyusedinGHOSTmode
AT command Function
AT+CALARM Set alarm time
AT+CCLK Set data and time of RTC
AT + CP O W D Power down
AT+CBC Indicated charge state and voltage
AT+CFUN Start or close the protocol
Set AT command“ AT+CFUN =1”,module can be transferred from GHOST mode to Charging in normal mode, In GHOST
mode , the default value is

3.5.5 Charger requirements

Following is the requirements of charger for the GSM part of SIM508.
a) Simple transformer power plug
- Output voltage: 5.0V-5.25V
- Charging current limitation: 650mA
- A 10V peak voltage is allowed for maximum 1ms when charging current is switched off.
- A 1.6A peak current is allowed for maximum 1ms when charging current is switched on.

3.6 Power saving

There are two methods to achieve the GSM part of SIM508 module extreme low power.
“AT+CFUN” is used to set module into minimum functionality mode and /DTR hardware
interface signal can be used to set system to be SLEEP mode (or Slow clocking mode).
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3.6.1 Minimum functionality mode

Minimum functionality
mode reduces the functionality of the module to a minimum and, thus,
minimizes the current consumption to the lowest level. This mode is set with the “AT+CFUN” command which provides the choice of the functionality levels <fun>=0，
1，4
z 0: minimum functionality; z 1: full functionality (Default); z 4: disable phone both transmit and receive RF circuits;
If the GSM part of SIM508 has been set to minimum functionality by “AT+CFUN=0”, then the RF
function and SIM card function will be closed, in this case, the serial ports is still accessible, but all
AT commands need RF function or SIM card function will not accessible.
If the GSM part of SIM508 has disable all RF function by “AT+CFUN=4”, then RF function will
be closed, the serial ports is still active in this case but all AT commands need RF function will not
accessible.
When the GSM part of SIM508 is in minimum functionality or has been disable all RF
functionality by “AT+CFUN=4”, it can return to full functionality by “AT+CFUN=1”.
For Detailed info about “AT+CFUN”, please refer to [1].

3.6.2 SLEEP mode (Slow Clocking mode)

You can use DTR signal to control the GSM part of SIM508 module to enter or exit the SLEEP
mode in your applications.
When DTR is in high level, at the same time there is no on air or audio activity is required and no
hardware interrupt (such as GPIO interrupt or data on serial port), the GSM part of SIM508 will
enter SLEEP mode automatically. In this mode, the GSM part of SIM508 can still receive paging
or SMS from network.
In SLEEP mode, the serial port is not accessible.
Note: For some special software versions, it requests to set AT command “AT+CSCLK=1” to enable the sleep mode; the default value is 0, that can’t make the module enter sleep mode, for more details please refer to the AT command list.

3.6.3 Wake up the GSM part of SIM508 from SLEEP mode

When the GSM part of SIM508 is SLEEP mode, the following method can wake up the module.
z Enable DTR pin to wake up the GSM part of SIM508;
If DTR Pin is pull down to a low level，this signal will wake up the GSM part of SIM508
from power saving mode. The serial port will be active after DTR change to low level about
3mS.
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z Receive a voice or data call from network to wake up the GSM part of SIM508; z Receive a SMS from network to wake up the GSM part of SIM508； z RTC alarm expired to wake up the GSM part of SIM508;

3.7 Summary of state transitions (except SLEEP mode)

Table11:Summaryofstatetransitions
Further mode
Current mode
POWER
DOWN
Normal mode AT+CPOWD or
Ghost mode
(Charge-only
mode)
Charging in
normal
POWER DOWN
Use PWRKEY Connect charger to
use PWRKEY
pin
Disconnect
charger
AT+CPOWD →
“Ghost mode”,
then disconnect
charger
Normal mode Ghost mode
(Charge-only mode)
CHG_IN and connect
battery to VBAT
Connect charger to
CHG_IN and connect
battery to VBAT,
then switch off
module by
AT+CPOWD or
using PWRKEY
No direct
transition, but via
“Charging in
normal” mode
Disconnect the
charger
Turn on the module
Switch off module by
AT+CPOWD or
using PWRKEY
Charging in normal
No direct transition,
but via “Ghost
mode” or “Normal
mode”
Connect charger to
CHG_IN pin of
module and connect
battery to VBAT pin
of module
using PWRKEY OR
SET AT
Command“AT+CF
UN=1”
No direct
Alarm mode
Switch on
from
POWER
DOWN
mode bye
RTC
Set alarm by
“AT+CALA
RM”, and
then switch
off the
module.
When the
timer expire,
the module
turn on and
enter Alarm
mode
Set alarm by
“AT+CALA
RM”, when
the timer
expire,
module will
enter Alarm
mode
transition
Alarm mode Use PWRKEY
pin or wait
module switch
off
automatically
Use AT+CFUN No transition Use AT+CFUN let
SIM508_HD_V2.01 Page 31 of 73
module enter
Normal mode, then
connect the charger
to CHG_IN pin of
module
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3.8 RTC backup

The RTC (Real Time Clock) power supply of module can be provided by an external battery or a
battery (rechargeable or non-chargeable) through PIN 14 on the board-to-board connector. There is
a 10K resistance has been integrated in the GSM part of SIM508 module used for restricting
current. You need only a coin-cell battery or a super-cap to PIN 14 to backup power supply for
RTC .
The following figures show various sample circuits for RTC backup.
Figure 7:
RTC supply from non-chargeable battery
Figure 8:RTC supply from rechargeable battery
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Figure 9: RTC supply from capacitor
z Li-battery backup
Rechargeable Lithium coin cells such as the TC614 from Maxell, or the TS621 from Seiko, are
also small in size, but have higher capacity than the double layer capacitors resulting in longer
backup times.
Typical charge curves for each cell type are shown in following figures. Note that the rechargeable
Lithium type coin cells generally come pre-charged from the vendor.
Figure 10: Panasonic EECEMOE204A Charge Characteristic
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Figure 11: Maxell TC614 Charge Characteristic
Figure 12: Seiko TS621 Charge Characteristic
Note: Gold-capacitance backup Some suitable coin cells are the electric double layer capacitors available from Seiko (XC621), or from Panasonic (EECEM0E204A). They have a small physical size (6.8 mm diameter) and a nominal capacity of 0.2 F to 0.3 F, giving hours of backup time.
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3.9 GSM Serial interface

The GSM part of SIM508 provides unbalanced asynchronous serial port. The GSM part is
designed as a DCE (Data Communication Equipment), following the traditional DCE-DTE (Data
Terminal Equipment) connection, the module and the client (DTE) are connected through the
following signal (as figure 13 shows).
Serial port
z Port/TXD @ Client sends data to the RXD signal line of module z Port/RXD @ Client receives data from the TXD signal line of module
All pins of two serial ports have 8mA driver, the logic levels are described in following table
Table12:Logiclevelsofserialportspins
Parameter Min Max Unit
Logic low input 0 0.9 V
Logic high input 0.9 3.3 V
Logic low output GND 0.2 V
Logic high output 2.8 3 V
Figure 13: Interface of serial ports

3.9.1 Function of Serial Port supporting

z Seven lines on Serial Port Interface z Contains Data lines /TXD and /RXD, State lines /RTS and /CTS, Control lines /DTR, /DCD
and RING;
z Serial Port can be used for CSD FAX, GPRS service and send AT command of controlling
module. Serial Port can use multiplexing function;
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z Serial Port supports the communication rate as following:
300,1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200 Default as 115200bps.
z Auto-bauding supports the communication rate as following:
1200, 2400, 4800, 9600, 19200, 38400, 57600, and 115200bps.
Autobauding allows the GSM engine to automatically detect the bitrate configured in the host
application. The serial interface of the GSM engine supports autobauding for the following bitrates:
1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200. Factory setting is autobauding enabled.
This gives you the flexibility to put the GSM engine into operation no matter what bitrate your
host application is configured to. To take advantage of autobaud mode specific attention must be
paid to the following requirements:
Synchronization between DTE and DCE.
Ensure that DTE and DCE are correctly synchronized and the bitrate used by the DTE is
detected by the DCE (= ME). To allow the bitrate to be synchronized simply issue an "AT" or "at"
string. This is necessary
z after you have activated autobauding z when you start up the GSM engine while autobauding is enabled. It is recommended to wait 3
to 5 seconds before sending the first AT character. Otherwise undefined characters might be
returned.
Restrictions on autobauding operation
z The serial interface has to be operated at 8 data bits, no parity and 1 stop bit (factory setting). z The Unsolicited Result Codes like "RDY", "+CFUN: 1" and "+CPIN: READY” are not
indicated when you start up the ME while autobauding is enabled. This is due to the fact that
the new bitrate is not detected unless DTE and DCE are correctly synchronized as described
above.

3.9.2 Software upgrade and Software debug

The TXD、RXD、GND must be connected to the IO connector when user need to upgrade
software and debug software, the TXD、RXD should be used for software upgrade . The PWRKEY
pin is recommended to connect to the IO connector. The user also can add a switch between the
PWRKEY and the GND. The PWRKEY should be connected to the GND when SIM300C is
upgrading software. Please refer to the following figure.
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Figure 14: Interface of software upgrade
Note: You should match the level of serial port between DCE and DTE.

3.10 Audio interfaces

Table13:Audiointerfacesignal
Name Pin Function
(AIN1/AOUT1)
(AIN2/AOUT2)
The module provides two Analogy input channels, AIN1 and AIN2, which may be used for both
microphone and line inputs. The AIN1 and AIN2 channels are identical. One of the two channels is
typically used with a microphone built into a handset. The other channel is typically used with an
external microphone or external line input. The Module Analogy input configuration is determined
by control register settings and established using Analogy multiplexers.
For each channels, you can use AT+CMIC to set the input gain level of microphone, use
AT+ECHO to set the parameters for echo cancellation. Also, you can use AT+SIDET to set the
side-tone level. For detail, please refer to [1].
Mic1p 54 Microphone1 input +
Mic1n 56 Microphone1 input -
Spk1p 53 Audio1 output+
Spk1n 55 Audio1 output-
Mic2p 58 Microphone2 input +
Mic2n 60 Microphone2 input -
Spk2p 57 Audio2 output+
Spk2n 59 Audio2 output-
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It is suggested that you adopt the one of following two matching circuits in order to reject common mode noise and audio noise。The difference audio signals have to be layout according to difference
signal layout rules.
Note: As show in Figure 15
、
Figure 16 、Figure 17、 Figure18 (Note : all components package
are 0603) . BEAD must have low impedance and can be removed according to their
environment such as the ground plane, shielding, power lost. The best way is to plan all the components shown in the follow figure. If you want to adopt a amplifier circuit for audio, we commend National company’s LM4890. But you can select it according to your needs.

3.10.1 Speaker interface configuration

Figure 15: Speaker interface configuration
Figure 16: Speaker interface with amplifier configuration
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3.10.2 Microphone interfaces configuration

Figure 17: Microphone interface configuration

3.10.3 Earphone interface configuration

Figure18:Earphoneinterfaceconfiguration
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3.10.4 Referenced Electronic Characteristic

Table14:MICInputDCCharacteristics
Parameter Min Typ Max Unit
Worki n g Voltage 1.25 2.5 V
Working Current 5 300 uA
External
Microphone
Load Resistance
1.2 2.2 k Ohms
Table15: SPEAKER Output DC Characteristics
Parameter Min Typ Max Unit
Worki n g Voltage 2.4 2.45 2.7 V
Output Power 10 mW
Load
Resistance
Output(SPK1)
Auxiliary
Output(SPK2)
Single
Ended
Differential ≥15
Single
Ended
Differential ≥27
≥32 Normal
Ohm
≥32
Table16: Buzzer Output DC Characteristics
Parameter Min Typ Max Unit
Worki n g Voltage 2.4 2.8 3.3 V
Working Current 8 mA
Load Resistance 1 k Ohms

3.11 SIM interface

3.11.1 SIM card application

You can use AT Command to get information in SIM card. For more information, please refer to
[1].
The SIM interface supports the functionality of the GSM Phase 1 specification and also supports
the functionality of the new GSM Phase 2+ specification for FAST 64 kbps SIM (intended for use
with a SIM application Tool-kit).
Both 1.8V and 3.0V SIM Cards are supported.
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The SIM interface is powered from an internal regulator in the module having nominal voltage
2.8V. All pins reset as outputs driving low. Logic levels are as described in table17
Table17: Signal of SIM interface (board-to-board connector)
Pin Signal Description
25 VSIM SIM Card Power supply, it can identify automatically the SIM
Card power mode，one is 2.85V±0.1V, another is 1.8V±0.1V.
Current is about 10mA.
27 SIM_RESET SIM Card Reset
29 SIM_DATA SIM Card data I/O
31 SIM_CLOCK SIM Card Clock
33 SIM_PRESENCE SIM Card Detection
Following is the reference circuit about SIM interface. We recommend an Electro-Static discharge
device ST (
www.st.com ) ESDA6V1W5 or ON SEMI (www.onsemi.com ) SMF05C for “ESD
ANTI”.
The SIM_PRESENCE pin is used for detecting the SIM card removal. You can use the AT
command “AT+CSDT” to set the SIMCARD configure. For detail of this AT command, please
refer to
document [1]:
You can select the 8 pins SIM card. The reference circuit about 8 pins SIM card illustrates as
following figure.
Figure 19: SIM interface reference circuit with 8pin SIM card
If you don’t use the SIM card detection function, you can let the SIM_PRESENCE pin NC or
connect to the GND. The reference circuit about 6 pins SIM card illustrate as following figure.
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Figure 20: SIM interface reference circuit with 6pin SIM card

3.11.2 Design considerations for SIM card holder

For 6 pin SIM card, we recommend to use Amphenol C707 10M006 049 2 .You can visit
http://www.amphenol.com for more information about the holder.
Figure 21: Amphenol C707 10M006 049 2 SIM card holder
Table18: Pin description (Amphenol SIM card holder)
Pin Signal Description
SIM Card Power supply, it can identify automatically the SIM
C1 VSIM
C2 SIM_RESET SIM Card Reset.
C3 SIM_CLOCK SIM Card Clock.
C5 GND Connect to GND.
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Card power mode，one is 3.0V±10%, another is 1.8V±10%.
Current is about 10mA.
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C6 VPP Not connect.
C7 SIM_DATA SIM Card data I/O.
For 8 pin SIM card, we recommend to use Molex 91228.You can visit
for more information about the holder.
http://www.molex.com
Figure 22: Molex 91228 SIM card holder
Table19: Pin description (Molex SIM card holder)
Pin Signal Description
SIM Card Power supply, it can identify automatically
C1
VSIM
the SIM Card power mode，one is 3.0V±10%,
another is 1.8V±10%. Current is about 10mA.
C2 C3 C4 C5 C6 C7 C8
SIM_RESET SIM Card Reset.
SIM_CLOCK SIM Card Clock.
GND Connect to GND.
GND Connect to GND.
VPP Not connect.
SIM_DATA SIM Card data I/O.
SIM_PRESENCE Detect SIM Card Presence
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3.12 LCD interface

The GSM part of SIM508 provides a serial LCD display interface that supports serial
communication with LCD device. These are composite pins that can be used as GPIO ports or
LCD display interface according to your application. When use as LCD interface, the following
table is the pin define. LCD interface timing should be united with the LCD device.
Table20: PIN define of LCD interface
Pin (On board-to-board connector) Name Function
38 DISP_EN Display enable
40 DISP_CLK Display clock for LCD
42 DISP_D0 Display data output
44 DISP_A0 Display data or address select
46 NLCDRESET LCD reset

3.13 General purpose Input/Output ports

Table21: GPIO of the GSM part of SIM508
Pin Name Function 19 STATUS
21 GPIO5 General Purpose Input/Output Port
35 GPIO32 General Purpose Input/Output Port
The GSM part of SIM508 supports 2 general purpose input/output signal pins and output signal
pins. Both pins can be configured through AT command “AT+CGPIO” in users’ application to
high voltage level or low voltage level. For detail of this AT command, please refer to [1].
The Status indication of the module，General Purpose Output Port

3.14 ADC

The GSM part of SIM508 provide two auxiliary ADC (General purpose analog to digital converter.)
as voltage input pin, which can be used to detect the values of some external items such as voltage、temperature etc. User can use AT command “AT+RADC” to read the voltage value added
on ADC pin. For detail of this AT command, please refer to [1].
Table 22: ADC pin of the GSM part of SIM508
Name Pin (On board-to-board connector) Input voltage scope( V )
AUXADC1 12 0 – 2.4
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3.15 Behaviors of the /RING line (Serial port1 interface only)

Table23: Behaviours of the /RING line
State RI respond
Standby
Voice calling
Data calling
SMS
If the module is used as caller, signal ring will maintain high. But when it is used as receiver,
following is timing of ring.
High
Change low，then：
（1）Change to high when establish calling.
（2）Use AT command ATH the RING hold low.
（3）Sender hang up, change to high
Change low，then：
（1）Change to high when establish calling.
（2）Use AT command ATH the RING hold low.
When receive SMS, The ring will change to LOW and hold LOW level at
about 100mS, then change to HIGH.
Figure 23: The GSM part of SIM508 Services as Receiver
Figure 24: The GSM part of SIM508 Services as caller
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3.16 Network status indication LED lamp

The PIN 16 on the board-to-board connector can be used to drive a network status indication LED
lamp. The working state of this pin is listed in table24:
\
Table24:
State The GSM part of SIM508 function
Off The GSM part of SIM508 is not running
64ms On/ 800ms Off The GSM part of SIM508 does not find the network
64ms On/ 3000ms Off The GSM part of SIM508 find the network
64ms On/ 300ms Off GPRS communication
We provide a reference circuitry for you, shown as the following figure:
Working state of network status indication LED pin
Figure 25: Reference circuit for Network status LED
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3.17 Buzzer

The PIN 23 on the board-to-board connector can be used to drive a buzzer to indicate incoming
call. The output volume of buzzer can be set by “AT+CRSL”. The reference circuit for buzzer as
shown as the following figure:
Figure 26: Reference circuit for Buzzer
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4 GPS Application Interface

A GPS receiver with high performance has been integrated to offer GPS full function, it
continuously tracks all satellites in view and provides accurate satellite position data. Otherwise,
the GPS part can run separately even while the GSM part of SIM508 has been deregistered form
the GSM network.
4.1 Theory of operation
The theory of operation is shown in the following figure:
Figure27: Theory of operation
The SIM508 GPS part is designed to use L1 Frequency (C/A Code) GPS receiver and performs the
entire GPS signal processing, from antenna input to serial position data output.
The processing steps involved are:
RF section
In the RF section the GPS signal detected by the antenna is amplified, filtered andconverted to an
intermediate frequency (IF). An A/D converter transforms the analogue
GPS channels
The received digital IF signal bit stream is passed to the baseband section, where it is fed into the
correlators. The function of the correlators is to acquire and track the satellite signals. There are 12
channels used in parallel, with each correlator looking for a characteristic PRN code sequence in
the bit stream. Once the correlator has found a valid signal, pseudo range, carrier phase and orbit
information can be extracted from the
GPS CORE
The on-board processor is running an algorithm that calculates the position, velocity and time. This
calculation is called navigation solution. Once the navigation solution is calculated, it can be
transformed into the desired coordinate system, e.g. Latitude
DATA OUT
The data of the navigation solution are available at the serial RS-232 interface.
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4.2 Technical data

Power consumption
210 mW with active antenna (continuous mode),
180mw with Passive antenna (continuous mode)
Push-to-Fix reduces power by as much as 98%
Note: This function need more software supporting form SIMCOM Ltd, please contact us for more detail.
Protocols
SiRF binary/NMEA-0183
AI3/F (SIRF Interface) for A-GPS
RTCM (for DGPS)
Position accuracy
Autonomous: < 10m SBAS（WASS，EGNOS: < 5m
Beacon DGPS: < 3m
Receiver
Tracking: L1, C/A code
Channels: 20
Update rate: Default 1 Hz
Tracking Sensitivity: -157 ± 2 dBm (see note)
Max. Altitude: <60.000 ft (18,000 m)
Max. velocity: <1.000 knots (515 m/s )
Protocol support: NMEA-0183, SiRF binary
Acquisition rate Standalone
Hotstart: < 1 seconds, open sky
Warmstart: < 38 seconds, open sky Coldstart: < 42 seconds, open sky
A-GPS
GSM or 3G: <1s, open sky
GSM or 3G: <24s, indoor
CDMA: <1s, open sky
CDMA: <18s, indoor
Note:
1) The receiver sensitivity above-mentioned is mostly related to antenna reference point, such as the antenna type, the antenna amplifier, the customer application or the placement and the applied reference setup and so on.
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2) A-GPS: This function needs more supporting form the mobile telecommunication network. A-GPS support, based on the A-GPS firmware. Now the standard version of the firmware in
SIM508 does not support A-GPS.

4.3 Pin description

Table25:Pin description
Power Supply
PIN NAME I/O DESCRIPTION
GPS_VCC I Two GPS_VCC pins of the
board-to-board connector are
dedicated to connect the supply
voltage. The power supply for GPS
whole part has to be a single voltage
source It must be able to provide
sufficient current of >150mA in the
procedure of tracking satellites
GPS_VRTC I Apply 3V dc for backup RTC &
SRAM. If unused, leave it open.
GPS_VANT I The external DC power supply for an
active GPS antenna. It’s input voltage
depends on the type of chosen active
antenna, for the 5V type, it has to be
connected to 5V external power
supply; for the 3V type, it can be
connected to the GPS_VCC_RF pin
directly which provides 2.85V DC.
Vmax= 5.0V
Vmin=3V
Vnorm=3.3V
Vmax= 3.3V
Vmin=2.7V
Vnorm=3.0V
Imax=25mA
Vmax=5V
Vmin=2.85V
GPS_VCC_RF O The optional power supply for 3.0V
type active antenna.
GND Ground, shared with GSM part
GPIO
PIN NAME I/O DESCRIPTION
GPS_GPIO13 I/O Reserved. It is reserved for
GPS_GPIO14 I/O Reserved. It is reserved for
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Vmax=2.9V
Vmin=2.8V
Vnorm=2.85V
Imax=25mA
customer specific
applications. Leave it
open.
customer specific
applications. Leave it
open.
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Dual serial interface
PIN NAME I/O DESCRIPTION
GPS_TXA O Serial data output for port A
GPS_RXA I Serial data input for port A
GPS_TXB O Serial data output for port B
GPS_RXB I Serial data input for port B
Control signals
PIN NAME I/O DESCRIPTION
GPS_BOOTSEL I For re-programming the Flash, it
must be set to High
GPS_M-RST I Reset pin, active low. If used, it
causes the module to reset; if not
used, leave it open .
GPS_Timersync I an auxiliary clock input that supports
alternate oscillator calibration
systems. Alternate functions are CS3
and GPIO 15.
GPS_FREQ_XFER I Reserved Leave it open.
GPS_TimeMark O 1 PPS timemark output for
synchronizing to within 1
microsecond of GPS time.
NC All the pins named NC, Do not use,
leave it open.
Note, if this pin is pulled
down by a GPIO, then the
GPIO must have the
capability of inputting
1.5mA current.
Reserved for A-GPS. If
not used, leave it open.
If not used, leave it open.
Table26:ConsolidatedPINCharacteristics
PIN
GPS_TXA O
GPS_RXA I
GPS_TXB O
GPS_RXB I
Default
Direction
100KΩ
PULL UP
×
×

4.4 Turn on the GPS part of SIM508

To turn on the GPS module, the GPS_VCC must be higher than 2.3V, and should be kept on for
220mS at least. The theory of turnning on is shown in the following figure:
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Figure28: Turn on the GPS module

4.5 The theory of the GPS R TC circuit

The RTC is very important for the GPS module, because the data kept in the SRAM is depended
on the VRTC. Please keep the VRTC on if you want to use the function of hotstart, warmstart, or
Push-To-Fix mode. There is a RTC LDO in our SIM508 module, it can provide 1.5V voltage to the
SRAM. The theory of RTC circuit is shown in the following figure:
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Figure29:TheoryoftheGPSRTCcircuit

4.6 The theory of the RESET Circuit

There is a RESET IC in the SIM508 module. If the input of the reset IC is lower than 2.3V, the
“reset” pin will keep low; then the input voltage is higher than 2.3V, the RESET IC will output a
low level voltage for about 220mS as a reset signal. After that the reset output pin will be kept high.
So, if the user wants to reset SIM508 GPS part, the GPS_M-RST should be pulled down longer
than 10mS, and then pull it up. The theory of the RESET Circuit is shown in the figure:
Figure30:TheoryoftheRESETcircuit
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4.7 GPS operation modes

Table 27:GPS operation modes
Mode Function
Normal
operation
Power Down
mode
Push-to-Fix
mode (See
Note)
The receiver is continuously running in Normal mode, as long as the operating
voltage Vcc is supplied. Position fixes are generated at the maximum update
rate. This enables the receiver a warm- and hotstart. However, the cold- and
warmstart times of receiver do not differ significantly under good visibility
conditions.
In this mode the user can cut off the GPS_VCC to save more power
consumption. But the VRTC must always be on. When the user resumes the
GPS_VCC, the receiver wakes up, a valid position can be computed in the
normal hot-start time.
In this mode the receiver will turn on every a given minutes (this period can be
set form 10 minutes to 2 hours by software) to perform a system update
consisting of position, time, ephemeris data refreshing and RTC calibration.
When the PTF mode is enabled, upon power on or a new PTF cycle, the
receiver will stay on full power until the good navigation solution is computed.
The stand-by state will follow for the remainder of the period. For example, if it
took 36 seconds to fix position and refresh ephemeris on the default period of
30 minutes, the receiver will sleep for the 29 minutes and 24 seconds. When the
application needs a position report, it can toggle the GPS_M-RST pin to wake
up the receiver. When the receiver wakes up, a valid position can be computed
in the normal hot-start time.

4.8 Serial interface of the SIM508 GPS part

The GPS part of the SIM508 module offers two serial interfaces, Allows for different protocols to
operate on each port. For example：
Serial port A
z 2-wire serial interface z Includes the GPS_RXA(receive) and GPS_TXA (transmit) lines z Supported baud rate: 1200－115200 bps
z Protocol: Default SiRF binary ,57600bps
Serial port B
z 2-wire serial interface z Includes the GPS_RXB (receive) and TXB (transmit) lines z Supported baud rate: 1200 -115200bps，but 4800 - 38400bps is a common rate range
z Protocol: Default NMEA ,4800bps z Default output message: GGA,GSA, GSV,RMC,VTG z Update rate: Default 1Hz z Datum WGS84 default (User configurable)
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Notes: 1.Both interfaces are configured as 8 data bits, no parity and 1 stop bit..
2. The serial ports also can be configured to adapt to customer specific applications, such
3 .We can also help the user to change the protocol and baud rate of the two serial ports
as for DGPS ,and so on. More detail please contact with Simcom ltd.
by different firmware. For more detail please contact SIMCOM Ltd.

4.9 Start-up procedure

The start-up strategy of the SIM508 GPS part depends on the last position, current time and
ephemeris data, that the receiver has stored the external SRAM memory. There are three
different start-up procedures:

4.9.1 Coldstart

The coldstart takes place when the receiver has no knowledge of its last position or time. In
this case the GPS RTC has not been running and no valid ephemeris data or almanac data
is available (The receiver has never been navigating or no battery backup memory
available).

4.9.2 Warmstart

This start-up procedure is performed whenever the receiver is able to use the valid almanac
data, and has not in an important manner moved since the last valid position calculation. This
procedure starts if the receiver has been shut off for more than 2 hours, but the last position,
time and almanac are still acknowledged. This procedure is able to announce the current
visible satellites in advance. However, since ephemeris data are not available or cannot longer
be used, the receiver has to wait for the ephemeris broadcast to complete.

4.9.3 Hotstart

Hotstart is performed whenever the receiver still has access to valid ephemeris data and exact
time. This procedure starts if the receiver has been shut off for less than 2 hours and the GPS
RTC has been running during that time. Furthermore, during the previous session, the receiver
must have been navigating (to allow it to decode and store ephemeris data). In Hotstart, the
receiver can announce in advance the currently visible satellites, and is therefore able to
quickly obtain and track the signal. Due to the fact that ephemeris is already known, there is
no need to wait for the ephemeris broadcast to complete.
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5 Antenna interface

5.1 GSM Antenna

The RF interface has an impedance of 50Ω. To suit the physical design of individual applications
SIM508 offers two alternatives:
z Recommended approach: antenna connector on the component side of the PCB z Antenna pad and grounding plane placed on the bottom side.
To minimize the loss on the RF cable, it need be very careful to choose RF cable. We recommend
the insertion loss should be meet following requirement:
z GSM850/GSM900<1dB z DCS1800/PCS1900<1.5dB

5.1.1 Antenna connector

SIM508 use MURATA’s MM9329-2700 RF connector on the module side, we recommend user
use MURATA’s MXTK92XXXXX as matching connector on the application side. Please refer to
appendix for detail info about MURATA’s MXTK92XXXXX.
The antenna connector on the SIM508 is shown as the following figure:

5.1.2 Antenna pad

The antenna can be soldered to the pad, or attached via contact springs. To help you to ground the
antenna, SIM508 comes with a grounding plane located close to the antenna pad. The antenna pad
of SIM508 is shown as the following figure:
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Figure31: RF connector and RF pad
The GSM part of SIM508 material properties:
The GSM part of SIM508 PCB Material: FR4
Antenna pad: Gold plated pad
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5.1.3 Module RF output power

Table 28: The GSM part of SIM508 RF output power
Frequency Max Min
E-GSM900 33dBm ±2db 5dBm±5db
DCS1800 30dBm ±2db 0dBm±5db
PCS1900 30dBm ±2db 0dBm±5db

5.1.4 Module RF receive sensitivity

Table 29: The GSM part of SIM508 RF conducted receive sensitivity
Frequency Receive sensitivity
E-GSM900 < -106dBm
DCS1800 < -106dBm
PCS1900 < -106dBm

5.1.5 Module receive/transmit frequency

Table30: The GSM part of SIM508 receive/transmit frequency
Frequency Receive Transmit
E-GSM900
DCS1800
PCS1900
925 ～ 960MHz 880 ～ 915MHz
1805 ～ 1880MHz 1710 ～ 1785MHz
1930 ～ 1990MHz 1850 ～ 1910MHz
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5.2 GPS Antenna

5.2.1 GPS Antenna Connection

SIM508 provide an Antenna Connector for customer to connect GPS antenna via a proper
Microwave Coaxial Cable. About the connector’s type and the matched Microwave Coaxial Cable,
please refer to 5.1.1. The location of the GPS Antenna Connector can be found in the following
figure.
Figure32: RF connector

5.2.2 GPS Antenna Choice Consideration

To obtain excellent GPS reception performance, A GOOD antenna will ALWAYS be required.
The antenna is the most critical item for successful GPS reception in a weak signal environment.
Proper choice and placement of the antenna will ensure that satellites at all elevations can be seen,
and therefore, accurate fix measurements are obtained. Most customers contract with antenna
design houses to properly measure the radiation pattern of the final mounted configuration in a
plastic housing with associated components near the antenna. Linear antennas are becoming more
popular, and the gain is reasonable, since a smaller ground plane can be used. Chose a linear
antenna with a reasonably uniform hemispherical gain pattern of >-4dBi. Use of an
lower gain than this will give less than desirable results. Please note that a RHCP antenna with a
gain of -3dBic, equates to a linear polarized antenna of -0dBi. Proper ground plane sizing is a
critical consideration for small GPS antennas. Proper placement of the GPS antenna should always
be the FIRST consideration in integrating the SIM508 GPS Module.
antenna with
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If the customer’s design will allow for a ceramic RHCP patch antenna with an appropriately sized
ground plane, and the patch is normally oriented towards the sky, then that particular solution
usually works the best. Please note that if the patch antenna ground plane is less than 60x60mm,
then compromises to the beam width and gain pattern could result. Usually the gain becomes very
directional, and looses several dB of performance. Since results can vary, measuring the antenna
radiation pattern in the final housing in an appropriate anechoic chamber will be required.
Some customers do not have the size availability to implement a patch antenna approach. In that
instance, use of a Linear Polarized (LP) antenna is the next best alternative. There are new ceramic
LP antennas on the market that exhibit reasonable gain characteristics once properly mounted in
the housing, and when mated to an appropriate sized ground. That is the key point to consider here.
“When mated to an appropriate sized ground”.
Usually, the ground plane requirements are smaller for a LP antenna when compared to a patch,
but once again, proper testing in an anechoic chamber is a mandatory requirement. These ceramic
elements will need to be located near the end of the ground plane, and will require several mm of
clearance between the closest component.
It is important to note that use of a LP antenna will result in a minimum of 3dB of gain loss when
compared to a RHCP antenna at a defined elevation. This is due to the right hand gain rule of
antenna propagation.
Use of PIFA antenna is another LP possibility, but the PIFA usually exhibits a considerable
amount of gain nulls, or “holes” in the radiation pattern. This will be undesirable for obtaining a
low circular error probability (CEP), since the antenna may not allow the receiver to capture the
desired satellite at the ideal orientation due to these noted gain nulls.
Once again, careful testing in an appropriate anechoic chamber is required.
If the customer’s design is for automotive applications, then an active antenna can be used and
located on top of the car in order for guarantee the best signal quality.
For detailed Antenna designing consideration, please refer to related antenna vendor’s design
recommendation. The antenna vendor will offer further technical support and tune their antenna
characteristic to achieve successful GPS reception performance depends on the customer’s design.
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6 Electrical, reliability and radio characteristics

6.1 Absolute maximum ratings

Absolute maximum rating for power supply and voltage on digital and analog pins of SIM508 are
list in table31 and table 32.
Table31: Absolute maximum ratings (GSM part)
Parameter Min Max Unit
Peak current of power supply 0 4.0 A
RMS current of power supply (during one TDMA- frame) 0 0.7 A
Voltage at digital pins -0.3 3.3 V
Voltage at analog pins -0.3 3.0 V
Voltage at digit/analog pins in POWER DOWN mode -0.25 0.25 V
Table32: Absolute maximum ratings (GPS part)
Parameter Min Max Unit
Voltage at GPS_VCC -0.3 5 V
Current at GPS_VCC_RF
25

6.2 Operating temperatures

The operating temperature is listed in table33:
Table 33: SIM508 operating temperature
Parameter Min Typ Max Unit
Ambient temperature -20 25 55 ℃
Restricted operation* -20 to -25 55 to 75 ℃
Storage temperature -40 +85 ℃
mA
* SIM508 can work, but the deviation from the GSM specification may occur.
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6.3 Power supply rating

Table 34: Power supply rating (GSM part)
Parameter Description Conditions Min Typ Max Unit
VBAT
IVBAT
Supply voltage Voltage must stay within the
min/max values, including
voltage drop, ripple, and spikes.
Voltage drop
during transmit
burst
Voltage ripple Normal condition, power
Average supply
current)
IDLE mode (Not connect
Normal condition, power
control level for Pout max
control level for Pout max
@ f<200kHz
@ f>200kHz
POWER DOWN mode
SLEEP mode
console）
EGSM 900
GSM 1800/1900
IDLE mode（connect console）
EGSM 900
GSM 1800/1900
3.4 4.0 4.5 V
400 mV
35
3.5
23
23
33
33
50
2
mV
uA
mA
mA
mA
TALK mode
EGSM 900
GSM 1800/1900
DATA mode, GPRS(3 Rx,2Tx)
EGSM 900
GSM 1800/1900
DATA mode, GPRS(4 Rx,1Tx)
EGSM 900
GSM 1800/1900
Peak supply
current (during
transmission
slot every 4.6ms)
Power control level 2 3.1 A
260
200
470
340
275
220
mA
mA
mA
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Table35: Power supply rating (GPS part)
Parameter Description Conditions Min Typ Max Unit
GPS_VCC Supply voltage 3.0 3.3 5 V
IGPS_VCC Average supply
current
Note: Basing on current standard GSW3 soft version , the power saving mode of GPS part is not available , that results 65 mA IGPS_VCC remained while the GPS receiver is running in normal mode. .
Continuous mode (with antenna
feeding on GPS_VCC_RF)
65 110 mA

6.4 Current Consumption

6.4.1 The current consumption of the SIM508 GSM part.

Table
36: Current consumption (GSM part)
Voice Call
GSM 900 @power level #5 <350mA,Typical 260mA
@power level #10,Typical 130mA
@power level #19,Typical 86mA
GSM1800/1900 @power level #0 <300mA,Typical 200mA
@power level #10,Typical 87mA
@power level #15,Typical 80mA
GPRS Data DATA mode, GPRS ( 1 Rx,1 Tx )CLASS 8
GSM 900 @power level #5 <350mA,Typical 260mA
@power level #10,Typical 125mA
@power level #19,Typical 84mA
GSM1800/1900 @power level #0 <300mA,Typical 200mA
@power level #10,Typical 83mA
@power level #15,Typical 76mA
DATA mode, GPRS ( 3 Rx, 2 Tx )CLASS 10
GSM 900 @power level #5 <550mA,Typical 470mA
@power level #10,Typical 225mA
@power level #19,Typical 142mA
GSM1800/1900 @power level #0 <450mA,Typical 340mA
@power level #10,Typical 140mA
@power level #15,Typical 127mA
DATA mode, GPRS ( 4 Rx,1 Tx )CLASS 8
GSM 900 @power level #5 <350mA,Typical 270mA
@power level #10,Typical 160mA
@power level #19,Typical 120mA
GSM1800/1900 @power level #0 <300mA,Typical 220mA
@power level #10,Typical 120mA
@power level #15,Typical 113mA
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6.4.2 The current consumption of the SIM508 GPS part

To save more current consumption, we suggest the user to design their system in one of the
two mode:1.Power Down mode; 2.Push-To-Fix mode

6.4.2.1 Power down Mode

The circuit of this mode is shown in the figure:
Figure33:PowerDownmode
When the user wants to save more current consumption of the GPS part, he can pull down the
POWER_CTRL of the MCU to stop the LDO outputting. And this operation will cut off the power
of the GPS part. Note that the VRTC must be kept on.

6.4.2.2 Push-To-Fix mode

The circuit of this mode is shown in figure (35)
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Figure34:Push‐To‐Fixmode
The user can also save power by sending the “Push-To-Fix” command to the GPS part of the
SIM508.
The Push-to-Fix mode puts the receiver into a background duty cycle mode that provides a
periodic refresh of position, GPS time, ephemeris, and RTC calibration every 10 seconds to 2
hours. Typical PTF operation is illustrated in Figure (36).
The PTF period is 30 minutes by default but can be anywhere between 10 seconds and 2 hours.
When the PTF mode is enabled, upon power on or a new PTF cycle, the receiver will stay on full
power until the good navigation solution is computed. The stand-by state will follow for the
remainder of the period. If it took 36 seconds to fix position and refresh ephemeris on the default
period of 30 minutes, the receiver will sleep for the 29 minutes and 24 seconds. When the
application needs a position report, it can toggle the GPS_M-RST pin to wake up the receiver.
When the receiver wakes up, it can produce a valid position in the normal hot-start time.
Power consumption in the PTF mode
Again, a typical setting of 1800 seconds PTF interval is considered.
Assuming it takes 8 seconds to compute a good position since the start of a cycle, the average current and power consumption of each typical cycle is：
Iavg = (65 mA * 8160 ms + 1 mA * 1791840 ms) / 1800 seconds = 1.290 mA
Pavg = 3.3 V * 1.290 mA = 4.257 mW
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Figure35:PowerconsumptioninthePTFmode
Note: When the user wants to use Power Down mode or Push-To-Fix mode , the RTC battery must be 2.5V+.If the RTC battery level is lower than 2.5V,the SIM508 module will not go into PTF mode.

6.5 Electrostatic discharge

Normally the module is designed inside customer terminal, so about Electrostatic Discharge (ESD)
should be considered base on the requirement of terminal product. But for the module is protected
against Electrostatic Discharge in conveyance and customer production, and some second level
ESD protect design inside module.
The remaining ports are not special ESD protection in module, so the user should consider in the
final product, and therefore, they are only protected according to the Human Body Model
requirements.
37: The ESD endure statue measured table (Temperature: 25 , Humidity:45% )℃
Table
Part Contact discharge Air discharge
VBAT,GND ±4KV ±8KV
KBR0-4, DTR, RXD, TXD, RTS,
SPI_DATA, SPI_CLK
Antenna port ±2KV ±4KV
Other port ±1KV
SIM508_HD_V2.01 Page 66 of 73
±2KV ±4KV
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7 Mechanics

This chapter describes the mechanical dimensions of SIM508.

7.1 Mechanical dimensions of SIM508

Following are SIM508 top view and side view. These show you Mechanical dimensions of
SIM508.
Figure36:SIM508TOPviewandSIDEview
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7.2 Mounting SIM508 onto the application platform

Use the connector 56363-0878 and four mounting pads fix the SIM508 onto customer platform.

7.3 Board-to-board connector

We recommend user adopt Molex Company’s 54363-0878 type as the Board to board connector.
These high density SMT connectors are designed for parallel PCB-to-PCB applications. They are
ideal for use in VCRs, notebook PCs, cordless telephones, mobile phones, audio/visual and other
telecommunications equipment where reduced size and weight are important. Following is
parameter of 54363-0878. For more, you can login

7.3.1 Mechanical dimensions of 54363-0878

http://www.molexcom for more information.
Figure37:54363‐0878board‐to‐boardconnectorpinside
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Figure38: board to board connector physical photo
：
Note
The connector54363-0878 is used in socket side (SIM508 module) and 55201-0878 is
used pin side (user side).
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7.3.2 Adapter cabling

Figure39:MM9329‐2700B
Figure40:RFconnectorMXTK
Formoreinformationabouttheconnector,pleasevisit
SIM508_HD_V2.01 Page 70 of 73
http://www.murata.com/

7.3.3 PIN assignment of board-to-board connector of SIM508

Table
38: Pin assignment of SIM 508
PIN NO. PIN NAME PIN NO. PIN NAME
2 GND 1 VBAT 4 GND 3 VBAT 6 GND 5 VBAT
8 GND 7 VBAT 10 GND 9 VBAT 12 AUXADC1 11 CHG_IN 14 BACKUP 13 TEMP_BAT 16 NETLIGHT 15 NC 18 KCOL0 17 PWRKEY 20 KCOL1 19 STATUS 22 KCOL2 21 GPIO5 24 KCOL3 23 BUZZER 26 KCOL4 25 VSIM 28 KROW0 27 SIM_RESET 30 KROW1 29 SIM_DATA 32 KROW2 31 SIM_CLOCK 34 KROW3 33 SIM_PRESENCE 36 KROW4 35 GPIO32 38 DISP_EN 37 DCD 40 DISP_CLK 39 DTR 42 DISP_D0 41 RXD 44 DISP_A0 43 TXD 46 NLCDRESET 45 RTS 48 DEBUG_RX 47 CTS 50 DEBUG_TX 49 RI 52 AGND 51 AGND 54 MIC1P 53 SPK1P 56 MIC1N 55 SPK1N 58 MIC2P 57 SPK2P 60 MIC2N 59 SPK2N 62 GPS_WAKEUP 61 GPS_TIMEMARK 64 GPS_BOOTSEL 63 GPS_FREQ_XFER 66 GPS_M-RST 65 GPS_TIMERSYNC 68 GPS_TXB 67 NC 70 GPS_RXB 69 NC 72 GPS_TXA 71 NC 74 GPS_RXA 73 GPS_GPIO13 76 GPS_VCC_RF 75 GPS_GPIO14 78 GPS_VANT 77 GPS_VRTC 80 GPS_VCC 79 GPS_VCC
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The following figure is a top-view of SIM508 module. With the indication of Pin 1, 2, 79 and 80.
Figure41:physicalSIM508
SIM508_HD_V2.01 Page 72 of 73
Figure42:ReferenceCircuitwithexternalMCU(exampleapplication)
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