SIM908_Hardware Design_V2.
Smart Machine Smart Decision Document Title SIM908 Hardware Design Version 2.00 Date 2012-05-07 Status Release Document Control ID SIM908_Hardware Design_V2.00 General Notes SIMCom offers this information as a service to its customers, to support application and engineering efforts that use the products designed by SIMCom. The information provided is based upon requirements specifically provided to SIMCom by the customers.
Smart Machine Smart Decision Contents Contents.................................................................................................................................................................... 3 Version History ........................................................................................................................................................ 7 1 Introduction................................................................................................................
Smart Machine Smart Decision 4.8.1 4.8.2 4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 SIM Card Application ......................................................................................................................... 33 Design Considerations for SIM Card Holder ...................................................................................... 34 LCD Display/SPI Interface.....................................................................................................................
Smart Machine Smart Decision Table Index TABLE 1: SIM908 GSM/GPRS ENGINE KEY FEATURES ........................................................................................... 8 TABLE 2: GPS ENGINE PERFORMANCE ................................................................................................................... 10 TABLE 3: CODING SCHEMES AND MAXIMUM NET DATA RATES OVER AIR INTERFACE ............................ 10 TABLE 4: OVERVIEW OF OPERATING MODES..........................................
Smart Machine Smart Decision Figure Index FIGURE 1: SIM908 FUNCTIONAL DIAGRAM ........................................................................................................... 12 FIGURE 2: SIM908 PIN OUT DIAGRAM (TOP VIEW) ............................................................................................... 13 FIGURE 3: DIMENSIONS OF SIM908（UNIT: MM）................................................................................................
Smart Machine Smart Decision Version History Date Version Description of change Author 2011-06-28 1.00 Origin LiGang 2011-08-26 1.01 Correct the NC pins; Correct the name of table 19; Ma Honggang 2011-08-29 1.02 Modify antenna design guide Ye Haibing 2011-09-02 1.03 Correct the figure 21 MA Honggang 2011-09-09 1.04 Add NC PIN53 MA Honggang 2011-09-22 1.05 Correct the pin44 name in figure 2 MA Honggang 2011-11-10 1.06 Modify GSM/GPS antenna interface Ye Haibing 2011-12-13 1.
Smart Machine Smart Decision 1 Introduction This document describes SIM908 hardware interface in great detail. This document can help user to quickly understand SIM908 interface specifications, electrical and mechanical details. With the help of this document and other SIM908 application notes, user guide, users can use SIM908 to design various applications quickly. 2 SIM908 Overview Designed for global market, SIM908 is integrated with a high performance GSM/GPRS engine and a GPS engine.
Smart Machine Smart Decision z document [1]. Compliant to GSM Phase 2/2+ Transmitting power z z Class 4 (2W) at GSM 850 and EGSM 900 Class 1 (1W) at DCS 1800 and PCS 1900 GPRS connectivity z z GPRS multi-slot class 10（default） GPRS multi-slot class 8 (option) Temperature range z z z Normal operation: -30℃ ~ +80℃ Restricted operation: -40℃~ -30℃ and +80℃ ~ +85℃ Storage temperature -45℃~ +90℃ Data GPRS z z z z z GPRS data downlink transfer: max. 85.6 kbps GPRS data uplink transfer: max. 42.
Smart Machine Smart Decision Table 2: GPS engine Performance Parameter Performance Description Min Horizontal Position Accuracy(a) Velocity Accuracy(b) Time To First Fix(c) Sensitivity Receiver Typ Autonomous Max 2.5 Unit m Speed - 0.01 - m/s Heading - 0.
Smart Machine Smart Decision 2.2 Operating Modes The table below summarizes the various operating modes of SIM908. Table 4: Overview of operating modes Mode Normal operation Function GSM/GPRS SLEEP Module will automatically go into sleep mode if the conditions of sleep mode are enabling and there is no on air 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.
Smart Machine Smart Decision 2.
Smart Machine Smart Decision GND GPS-ANT GND GND GPS-VANT-IN GPS-VANT-OUT VCHG TEMP-BAT DTR TXD DCD RI RXD CTS RTS GND GND VBAT VBAT GND 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 Pin out Diagram 79 3.
Smart Machine Smart Decision 3.2 Pin Description Table 5: Pin description Pin name Pin number I/O Description Comment 62, 63 I Power supply 3.2V ~ 4.8V Power supply VBAT VRTC 42 I/O Power supply for RTC It is recommended to connect with a battery or a capacitor (e.g. 4.7uF). VDD-EXT 44 O 2.8V output power supply If it is unused, keep open. GPS-VANT-OUT 75 O 2.8V output for GPS active antenna If it is unused, keep open.
Smart Machine Smart Decision I2C interface I2C-SDA 56 O I2C serial bus data I2C-SCL 55 I/O I2C serial bus clock If these pins are unused, keep open. Keypad interface / GPIOs GPIO1/KBR0 31 GPIO1/keypad row 0 GPIO2/KBR1 32 GPIO2/keypad row 1 GPIO3/KBR2 33 GPIO3/keypad row 2 I/O GPIO4/KBC0/ SIM_PRESENCE GPIO4/keypad column 0/ SIM card detection 34 GPIO5/KBC1 35 GPIO5/keypad column 1 GPIO6/KBC2 36 GPIO6/keypad column 3 If these pins are unused, keep open.
Smart Machine Smart Decision 3.3 Package Dimensions Figure 3: Dimensions of SIM908（Unit: mm） Figure 4: Recommended PCB footprint outline（Unit: mm） SIM908_Hardware Design_V2.00 16 2012.05.
Smart Machine Smart Decision 3.4 Mechanical Dimensions of the RF Connector The RF connector in the module side is an ultra small surface mount coaxial connectors (Part Number: U.FL-R-SMT, vended by HRS). It has high performance with wide frequency range, surface mountable and reflows solder able. Following figure are the related parameters. Certainly user can visit http://www.hirose-connectors.com/ for more information.
Smart Machine Smart Decision 4 4.1 GSM Application Interface Power Supply GND The power supply range of SIM908 is from 3.2V to 4.8V. The transmitting burst will cause voltage drop and the power supply must be able to provide sufficient current up to 2A. For the VBAT input, a bypass capacitor (low ESR) such as a 100 µF is strongly recommended; this capacitor should be placed as close as possible to SIM908 VBAT pins. The following figure is the reference design of +5V input power supply.
Smart Machine Smart Decision Figure 9: VBAT voltage drop during transmit burst 4.1.1 Minimizing Voltage Drop of VBAT When designing the power supply in user’s application, pay special attention to power losses. Ensure that the input voltage never drops below 3.1V even when current consumption rises to 2A in the transmit burst. If the power voltage drops below 3.1V, the module may be shut down automatically.
Smart Machine Smart Decision Figure 12: Powered on/down module using button The power on scenarios is illustrated as following figure. Figure 13: Timing of power on module When power on procedure is completed, SIM908 will send following URC to indicate that the module is ready to operate at fixed baud rate. RDY This URC does not appear when autobauding function is active. Note: User can use AT command “AT+IPR=x” to set a fixed baud rate and save the configuration to non-volatile flash memory.
Smart Machine Smart Decision From CHARGE-ONLY MODE to NORMAL MODE In Charge mode during normal operation, all operations and AT commands are available. 4.2.2 Power down SIM908 SIM908 will be powered down in the following situations： z Normal power down procedure: power down SIM908 by the PWRKEY pin. z Normal power down procedure: power down SIM908 by AT command “AT+CPOWD=1”. z Abnormal power down: over-voltage or under-voltage automatic power down.
Smart Machine Smart Decision 4.2.2.3 Over-voltage or Under-voltage Power down The module software monitors the VBAT voltage constantly. If the voltage ≤ 3.3V, the following URC will be reported: UNDER-VOLTAGE WARNNING If the voltage ≥ 4.7V, the following URC will be reported: OVER-VOLTAGE WARNNING If the voltage < 3.2V, the following URC will be reported, and the module will be automatically powered down. UNDER-VOLTAGE POWER DOWN If the voltage > 4.
Smart Machine Smart Decision 4.3 Power Saving Mode SIM908 have two sleep modes: sleep mode 1 is enabled by hardware pin DTR; sleep mode 2 is only enabled by serial port regardless of the DTR. In sleep mode, the current of module is very low. The AT command “AT+CFUN=” can be used to set SIM908 into minimum functionality. When SIM908 is in sleep mode and minimum functionality, the current of module is lowest.
Smart Machine Smart Decision z z z Pull down DTR pin. The serial port will be active after DTR pin is pulled to low level for about 50ms. Receive a voice or data call from network. Receive a SMS from network. 4.3.4 Sleep Mode 2 (AT+CSCLK=2) Be sure that GPS function is closed, then AT+CSCLK=2 can set module to the sleep mode 2. In this mode, SIM908 will continuously monitor the serial port data signal.
Smart Machine Smart Decision Battery temperature measurement is a customization function which is supported by the software in the module. In above figure, the RTEMP is a NTC thermistor, and it is recommended to use MURATA NCP15XH103F03RC. Its impedance is 10Kohm at 25℃. Refer to the above figure for the reference circuit. 4.4.1 Battery Pack Characteristics SIM908 has optimized the charging algorithm for the Li-Ion battery that meets the characteristics listed below.
Smart Machine Smart Decision It is very simple to implement charging function, user just needs to connect the charger to the VCHG Pin and connect the battery to the VBAT Pin. SIM908 battery charging happens after detecting charger supply and the presence of battery. If there is no charger supply or no battery present, charging function will not be enabled. Normally, there are three main states in the whole charging procedure.
Smart Machine Smart Decision Charge-only Mode Connect charger to module’s VCHG Pin while SIM908 is in POWER DOWN mode. IMPORTANT: Here Charge-only mode is charging when power is down, it means that not all software tasks are running. 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. Note: VBAT can not provide more than 5mA current while SIM908 module is during the DDLO charge state.
Smart Machine Smart Decision Figure 17: RTC supply from capacitor z Non-chargeable battery for RTC Figure 18: RTC supply from non-chargeable battery z Rechargeable battery for RTC Figure 19: RTC supply from rechargeable battery Coin-type rechargeable battery is recommended, such as XH414H-IV01E from Seiko can be used. Typical charge-discharge curves for this battery are shown in the following figure. Figure 20: Seiko XH414H-IV01E charge-discharge characteristic SIM908_Hardware Design_V2.
Smart Machine Smart Decision 4.6 Serial Interfaces SIM908 provides two unbalanced asynchronous serial ports. One is the serial port and the other is the debug port. The module is designed as a DCE (Data Communication Equipment). The following figure shows the connection between module and client (DTE). Figure 21: Connection of the serial interfaces If only RXD and TXD are used in user’s application, other serial pins should be kept open. Please refer to following figure.
Smart Machine Smart Decision Autobauding allows SIM908 to automatically detect the baud rate of the host device. Pay more attention to the following requirements: z Synchronization between DTE and DCE: When DCE powers on with autobauding enabled, user must firstly send character “A” to synchronize the baud rate. It is recommended to send “AT” until DTE receives the “OK” response, which means DTE and DCE are correctly synchronized. For more information please refer to the AT command “AT+IPR”.
Smart Machine Smart Decision 4.7 Audio Interfaces SIM908 provides two analog inputs, MIC1P/1N and MIC2P/2N, which could be used for electret microphone. The module also provides two analog outputs, SPK1P/1N and SPK2P/2N. The output can directly drive 32Ω receiver. AT command “AT+CMIC” is used to adjust the input gain level of microphone. AT command “AT+SIDET” is used to set the side-tone level. In addition, AT command “AT+CLVL” is used to adjust the output gain level.
Smart Machine Smart Decision 4.7.2 Microphone Interfaces Configuration These components should be placed to microphone as close as possible ESD ANTI Electret Microphone 10pF 33pF 10pF 33pF The lines in bold type should be accorded to differential signal layout rules MIC1P MODULE MIC1N 10pF ESD ANTI 33pF Figure 26 : Microphone reference circuit Microphone input also could be used to LINE-IN input. For details, please refer to document [6]. 4.7.
Smart Machine Smart Decision Differential input voltage THD <1% at F=1KHz; pre-amp gain = 20 dB; PGA gain = 14 dB 15.9 mVrms THD <5% at F=1KHz; pre-amp gain = 0 dB; PGA gain = 0 dB 740 mVrms Table 11: Audio output characteristics Parameter Normal Output(SPK) 4.8 4.8.1 Conditions Min Typ Max Unit RL=32Ω THD=0.1% - 91 - mW RL=32Ω THD=1% - 96 - mW Output swing voltage (single ended) 1.1 Vpp Output swing voltage (differential) 2.
Smart Machine Smart Decision The SIM_PRESENCE pin is used for detection of the SIM card hot plug in. User can select the 8-pin SIM card holder to implement SIM card detection function. AT command “AT+CSDT” is used to enable or disable SIM card detection function. For details of this AT command, please refer to document [1]. If the SIM card detection function is not used, user can keep the SIM_PRESENCE pin open. The reference circuit of 6-pin SIM card holder is illustrated in the following figure.
Smart Machine Smart Decision Table 12: Pin description (Amphenol SIM card holder) Pin name Signal Description C1 SIM-VDD SIM card power supply C2 SIM-RST SIM card reset C3 SIM-CLK SIM card clock C5 GND Connect to GND C6 VPP Not connect C7 SIM-DATA SIM card data I/O For 8 pins SIM card holder, SIMCom recommends to use Molex 91228.User can visit http://www.molex.com for more information about the holder.
Smart Machine Smart Decision C7 SIM-DATA SIM card data I/O C8 SIM-PRESENCE Detect SIM card presence 4.9 LCD Display/SPI Interface SIM908 provides a serial LCD display interface. It could also be used as SPI interface in the embedded AT application. For details about embedded AT application, please refer to document [7]. Note: This function is not supported in the standard firmware. If user wants this function, the firmware must be customized. Please contact SIMCom for more details. 4.
Smart Machine Smart Decision 4.11 ADC SIM908 provides an auxiliary ADC, which can be used to measure the voltage. User can use AT command “AT+CADC” to read the voltage value. For details of this AT command, please refer to document [1]. Table 15: ADC specification Parameter Min Typ Max Unit Voltage range 0 - 2.8 V ADC Resolution - 10 - bits Sampling rate - - 200K Hz 4.12 RI Behaviors Table 16: RI behaviors State RI response Standby High Voice call The pin is changed to low.
Smart Machine Smart Decision HIGH RI Establish the call Hang up the call LOW Idle Ring Figure 34: RI behaviour of data calling as a receiver Figure 35: RI behaviour of URC or receive SMS However, if the module is used as caller, the RI will remain high. Please refer to the following figure. Figure 36: RI behaviour as a caller 4.13 Network Status Indication The NETLIGHT pin can be used to drive a network status indication LED.
Smart Machine Smart Decision Figure 37: Reference circuit of NETLIGHT 4.14 General Purpose Input/Output (GPIO) SIM908 provides up to 6 GPIO pins. The output voltage level of the GPIO can be set by the AT command “AT+ SGPIO”. The input voltage level of the GPIO can also be read by the AT command “AT+ SGPIO”. For more details, please refer to document [1].
Smart Machine Smart Decision 4.17 GSM Antenna Interface The RF interface has an impedance of 50Ω. To suit the physical design of individual applications, SIM908 offers alternatives z z Recommended approach: GSM RF connector GSM_ANT pad. GPS_ANT PAD GSM GPS Antenna connector Antenna connector GSM_ANT PAD Figure 38: The RF interface of module If the GSM RF connector is used, the GSM_ANT pad should be left not connected, the customer’s main board under the GSM_ANT pad should be copper keep out.
Smart Machine Smart Decision In this figure, the components R101,R102,C101 and C102 is used for antenna matching, the components’ value only can be got after the antenna tuning. Usually, matching components’ value is provided by antenna vendor, the default value of R101 and R102 are 0Ω, and reserve the place of C101 and C102 without soldering. The RF test connector in figure 39 is used for conducted RF performance test, and should be placed as close as possible to the module’s RF_ANT pad.
Smart Machine Smart Decision 5.2 GPS Power on/down Scenarios 5.2.1 Power on GPS engine User can power on GPS engine by sending AT command “AT+CGPSPWR=1”. 5.2.2 Power down GPS engine User can power down GPS engine by sending AT command “AT+CGPSPWR=0”. 5.3 GPS-VANT-OUT and GPS-VANT-IN GPS-VANT-OUT is a 2.8V output for active external antenna, if the active external antenna works at 2.8V voltage supply domain, user can connect the GPS-VANT-OUT and GPS-VANT-IN directly.
Smart Machine Smart Decision In this figure, the components R101, C101 and C102 is used for antenna matching, the components’ value only can be got after the antenna tuning. Usually, matching components’ value is provided by antenna vendor, the default value of R101 is 0Ω, and users need to reserve the place of C101 and C102 without soldering. The traces in bold type should be treated as 50Ω impedance controlled line in PCB layout. 5.4.
Smart Machine Smart Decision product and other conditions. 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 depending on the customer’s design. 6 Electrical, Reliability and Radio Characteristics 6.
Smart Machine Smart Decision 6.4 SIM Card Interface Characteristics Table 23: SIM card interface characteristics Symbol Parameter Min Typ Max Unit IIH High-level input current -10 - 10 uA IIL Low-level input current -10 - 10 uA VIH High-level input voltage 1.4 - - V 2.4 - - V VIL Low-level input voltage - - 0.4 V 2.4 V VOH High-level output voltage VOL Low-level output voltage 6.5 1.7 - - V 2.7 - - V - - 0.1 V - - 0.
Smart Machine Smart Decision 6.8 Current Consumption (VBAT = 3.8V, GPS engine is powered down) Table 27: GSM current consumption* Symbol Parameter Conditions Value Unit IVRTC VRTC current VBAT disconnects. Backup battery is 3 V 2 uA Power down mode 50 uA Sleep mode BS-PA-MFRMS=9 1.2 BS-PA-MFRMS=5 1.5 BS-PA-MFRMS=2 1.
Smart Machine Smart Decision 6.9 Electro-Static Discharge SIM908 is an ESD sensitive component, so more attention should be paid to the procedure of handling and packaging. The ESD test results are shown in the following table.
Smart Machine Smart Decision 14 15 ±3 ±4 15 13 ±3 ±4 16 11 ±5 ±6 17 9 ±5 ±6 18 7 ±5 ±6 19-31 5 ±5 ±6 Table 30: SIM908 DCS 1800 and PCS 1900 conducted RF output power DCS 1800 and PCS 1900 PCL Tolerance (dB) for conditions Nominal output power (dBm) Normal Extreme 29 36 ±2 ±2.
Smart Machine Smart Decision 6.10.2 Module RF Receive Sensitivity The following table shows the module’s conducted receive sensitivity, it is tested under static condition. Table 31: SIM908 conducted RF receive sensitivity Frequency Receive sensitivity（Typical） Receive sensitivity(Max) GSM850 -109dBm -107dBm EGSM900 -109dBm -107dBm DCS1800 -109dBm -107dBm PCS1900 -109dBm -107dBm 6.10.
Smart Machine Smart Decision Table 33: illustration of module label Item Description A Logo of SIMCom B Module name C Module part number D Module serial number and bar code E Module IMEI and bar code F FCC authenticated ID G CE authenticated logo SIM908_Hardware Design_V2.00 50 2012.05.
Smart Machine Smart Decision Appendix A.
Smart Machine Smart Decision B.
Smart Machine Smart Decision URC Unsolicited Result Code USSD Unstructured Supplementary Service Data 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) ON SIM (or ME) own numbers (MSISDNs) list RC Mobile Equipment list of received calls SM SIM phonebook NC Not connect C.
Smart Machine Smart Decision Contact us: Shanghai SIMCom Wireless Solutions Ltd. Add: SIM Technology Building, No.633, Jinzhong Road,Changning District,Shanghai P.R. China 200335 Tel: +86 21 3252 3300 Fax: +86 21 3252 3301 URL: www.sim.com/wm SIM908_Hardware Design_V2.00 54 2012.05.
