a Hardware Design SIM900B_HD_V1.
SIM900B Hardware Design Document Title: SIM900B Hardware Design Version: 1.03 Date: 2010-06-24 Status: Release Document Control ID: SIM900B_HD_V1.03 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.
SIM900B Hardware Design Contents Contents .....................................................................................................................................................................3 Version history...........................................................................................................................................................7 1 Introduction....................................................................................................................
SIM900B Hardware Design 3.12 LCD Display Interface ..............................................................................................................................44 3.13 Keypad Interface .......................................................................................................................................44 3.14 ADC ..........................................................................................................................................................45 3.
SIM900B Hardware Design Table Index TABLE 1: RELATED DOCUMENTS ............................................................................................................................... 8 TABLE 2: TERMS AND ABBREVIATIONS ................................................................................................................... 8 TABLE 3: SIM900B KEY FEATURES ...........................................................................................................................
SIM900B Hardware Design Figure Index FIGURE 1: SIM900B FUNCTIONAL DIAGRAM......................................................................................................... 16 FIGURE 2: TOP VIEW OF SIM900B EVB .................................................................................................................... 17 FIGURE 3: REFERENCE CIRCUIT OF THE VBAT INPUT ........................................................................................
SIM900 Hardware Design Version history Date Version Description of change Author 2010-04-08 1.01 Origin Huangqiuju 2010-05-31 1.02 Modify voltage domain ， current consumption and figure37 Huangqiuju 2010-06-23 1.03 §2.1, §3.3. §3.4 Modify the power supply range from 3.2V~4.8V to 3.1V~4.8V §3.7, Modify the VRTC pin connection when RTC backup is not needed. Huangqiuju SIM900_HD_V1.03 7 24.06.
SIM900B Hardware Design 1 Introduction This document describes the hardware interface of the SIMCom SIM900B module that connects to the specific application and the air interface. As SIM900B can be integrated with a wide range of applications, all functional components of SIM900B are described in great detail. This document can help you quickly understand SIM900B interface specifications, electrical and mechanical details.
SIM900B Hardware Design Abbreviation Description ADC Analog-to-Digital Converter AMR Adaptive Multi-Rate 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
SIM900B Hardware Design Abbreviation Description 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) RTC Real Time Clock RX Receive Direction SIM Subscriber Identification Module SMS Short Message Service TDMA Time Division Multiple Access TE Terminal Equipmen
SIM900B Hardware Design Phonebook abbreviations Abbreviation Description 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 1.3 Safety Caution The following safety precautions must be observed during all phases of the operation.
SIM900B Hardware Design Road safety comes first! Do not use a hand-held cellular terminal or mobile when driving a vehicle, unless it is securely mounted in a holder for hands free operation. Before making a call with a hand-held terminal or mobile, park the vehicle. GSM cellular terminals or mobiles operate over radio frequency signals and cellular networks and cannot be guaranteed to connect in all conditions, for example no mobile fee or a invalid SIM card.
SIM900B Hardware Design 2 SIM900B Overview Designed for global market, SIM900B is a quad-band GSM/GPRS engine that works on frequencies GSM 850MHz, EGSM 900MHz, DCS 1800MHz and PCS 1900MHz. SIM900B features GPRS multi-slot class 10/ class 8 (optional) and supports the GPRS coding schemes CS-1, CS-2, CS-3 and CS-4. With a tiny configuration of 40mm x 33mm x 3mm, SIM900B can meet almost all the space requirements in your applications, such as M2M, smart phone, PDA and other mobile devices.
SIM900B Hardware Design Temperature range z z z Normal operation: -30°C to +80°C Restricted operation: -40°C to -30°C and +80 °C to +85°C(1) Storage temperature -45°C to +90°C DATA GPRS: z z z z z z z z GPRS data downlink transfer: max. 85.6 kbps GPRS data uplink transfer: max. 42.8 kbps Coding scheme: CS-1, CS-2, CS-3 and CS-4 Supports the protocols PAP (Password Authentication Protocol) usually used for PPP connections. Integrates the TCP/IP protocol.
SIM900B Hardware Design (1) The SIM900B does work, but deviations from the GSM specification may occur. 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 2.
SIM900B Hardware Design A ntenna connector S IM 900B Radio Frequency POWER KEYPADS Flash+ SRAM Baseband Engine LCD UART GPIO ADC AUDIO Board-to-board Connector SIM Figure 1: SIM900B functional diagram 2.3 SIM900B Evaluation Board In order to help you on the application of SIM900B, SIMCom can supply an Evaluation Board (EVB) that interfaces the SIM900B directly with appropriate power supply, SIM card holder, RS232 serial port, handset port, earphone port, antenna and all GPIO of the SIM900B.
SIM900B Hardware Design Figure 2: Top view of SIM900B EVB For details please refer to the SIM900B-EVB_UGD document. SIM900B_HD_V1.03 17 24.06.
SIM900B Hardware Design 3 Application Interface SIM900B is equipped with a 60-pin 0.5mm pitch board-to-board connector that connects to the cellular application platform. Sub-interfaces included in this board-to-board connector are described in detail in following chapters: z Power supply (please refer to Chapter 3.3) z Serial interfaces (please refer to Chapter 3.8) z Analog audio interfaces (please refer to Chapter 3.9) z SIM interface (please refer to Chapter 3.
SIM900B Hardware Design Iout(max)= 10mA GND Ground Power on or power off PIN NAME I/O DESCRIPTION DC CHARACTERISTICS PWRKEY I Power on/off detect, active low. VILmax=0.9V VIHmin=2.6V VImax=3.3V VILmin= 0V It is already pulled up internally (3V). PIN NAME I/O DESCRIPTION DC CHARACTERISTICS COMMENT MIC1P MIC1N I Positive and voice-band input Audio DC Characteristics refer to chapter 3.9.
SIM900B Hardware Design GPIO2/ KBC3 I/O GPIO3/ KBC2 I/O GPIO4/ KBC1 I/O GPIO6/ KBR3 I/O GPIO7/ KBR4 I/O GPIO8/ KBR2 I/O GPIO9/ KBR1 I/O KBR0 I KBC0 O VILmin= 0V VIHmax= VDD_EXT VOHmin= VDD_EXT-0.1V VOLmax=0.
SIM900B Hardware Design SIM_CLK O SIM clock VIHmin=0.85*SIM_VDD VILmin= 0V VIHmax= SIM_VDD VOHmin= SIM_VDD-0.1V VOLmax=0.1V VOHmax= SIM_VDD VOLmin= 0V SIM_RST O SIM reset SIM_PRESENCE I SIM detect VILmax=0.15 *VDD_EXT VIHmin=0.85*VDD_EXT VILmin= 0V VIHmax= VDD_EXT If unused open PIN NAME I/O DESCRIPTION DC CHARACTERISTICS COMMENT ADC0 I General purpose analog to digital converter. Input voltage range: 0V ~ 2.
SIM900B Hardware Design module is ready to send and receive. GSM TALK Connection between two subscribers is in progress. In this case, the power consumption depends on network settings such as DTX off/on, FR/EFR/HR, hopping sequences, antenna. GPRS STANDBY 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. GPRS DATA There is GPRS data transfer (PPP or TCP or UDP) in progress.
SIM900B Hardware Design The circuit design of the power supply depends strongly upon the power source where this power is drained. The following figure is the reference design of +5V input source power supply. The designed output for the power supply is 4.1V, thus a linear regulator can be used.
SIM900B Hardware Design 3.3.2 Minimizing Power Losses When designing the power supply for your application please pay specific attention to power losses. Ensure that the input voltage VBAT never drops below 3.2V even in a transmit burst where current consumption can rise to typical peaks of 2A. If the power voltage drops below 3.2V, the module may be switched off. The PCB traces from the VBAT pins to the power source must be wide enough to decrease voltage drops in the transmitting burst mode. 3.3.
SIM900B Hardware Design 3V 100K 1K POWERKEY 4.7k Turn on impulse Module 47k Figure 6: Turn on SIM900B using driving circuit S1 PWRKEY TVS1 Figure 7: Turn on SIM900B using button The power on scenarios illustrates as following figure. Pulldown >1s Delay > 2.2s VBAT V IH > 2.55V PWRKEY (INPUT) Serial Port SIM900B_HD_V1.03 V IL =1.2V Undefined 25 Active 24.06.
SIM900B Hardware Design Figure 8: Timing of turn on system using PWRKEY When power on procedure completes, the SIM900B will send out following result code to indicate the module is ready to operate when set as fixed baud rate. RDY This result code does not appear when autobauding is active. 3.4.
SIM900B Hardware Design 3.4.2.2 Turn Off SIM900B Using AT Command AT command “AT+CPOWD=1”can be use to turn off the module. This command lets the module log off from the network and allows the module to enter into a secure state and save data before completely disconnecting the power supply. Before the completion of the switching off procedure the module will send out result code: NORMAL POWER DOWN After this moment, the AT commands can’t be executed.
SIM900B Hardware Design DOWN mode, and only the RTC is still active. POWER DOWN can also be indicated by VDD_EXT pin, which is a low level voltage in this mode. To monitor the temperature, the “AT+CMTE” command can be used to read the temperature when the module is power on. For details please refer to document [1] 3.4.
SIM900B Hardware Design If SIM900B has been set to minimum functionality by “AT+CFUN=0”, the RF function and SIM card function will be closed. In this case, the serial port is still accessible, but all AT commands correlative with RF function or SIM card function will not be accessible. If SIM900B has been set by “AT+CFUN=4”, the RF function will be closed, the serial port is still active. In this case all AT commands correlative with RF function will not be accessible.
SIM900B Hardware Design 3.7 RTC Backup The RTC (Real Time Clock) power supply of module can be provided by an external capacitor or a battery (rechargeable or non-chargeable) through the VRTC. Note: If the RTC function is enabled, a battery or capacitor should be connected with the VRTC pin. If this function is not needed, a 4.7uF capacitor is recommended to connect to the VRTC pin. The following figures show various sample circuits for RTC backup.
SIM900B Hardware Design SIM900B VRTC 10K RTC Core Large-capacitance Capacitor Figure 14: RTC supply from capacitor z Li-battery backup Coin-type Rechargeable Capacitor such as XH414H-IV01E form Seiko can be used. 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 15: Seiko XH414H-IV01E Charge Characteristic 3.
SIM900B Hardware Design Serial port Debug port Name Pin Function DCD 28 Data carrier detection DTR 38 Data terminal ready RXD 40 Receive data TXD 42 Transmit data RTS 44 Request to send CTS 46 Clear to send RI 48 Ring indicator DBG_RXD 47 Receive data DBG_TXD 49 Transmit data SIM900B provides two unbalanced asynchronous serial ports. One is the serial port and the other is the debug port.
SIM900B Hardware Design MODULE (DCE) CUSTOMER (DTE) Serial port Serial port1 TXD TXD RXD RTS CTS DTR DCD RXD RTS CTS DTR DCD RI RING Debug port Serial port2 DBG_TX TXD RXD DBG_RX Figure 16: Connection of the serial interfaces 3.8.1 Function of serial port & debug port supporting Serial port z Modem device. z Contains data lines TXD and RXD, State lines RTS and CTS, Control lines DTR, DCD and RI. z Serial port can be used for CSD FAX, GPRS service and send AT command of controlling module.
SIM900B Hardware Design The serial port 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 baud rate is not detected unless DTE and DCE are correctly synchronized as described above. Note: use “AT+IPR=x “to set a fixed baud rate and save the configuration to non-volatile flash memory.
SIM900B Hardware Design Figure 18: RS232 level converter circuit 3.
SIM900B Hardware Design used to set the side-tone level. In addition, “AT+CLVL” can be used to adjust the output gain level of both receiver and speaker at the same time, use AT+CHFA to activate one of the two audio channels and deactivate the other one.. For more details, please refer to document [1]. Note: Use AT command AT+CHFA to select_audio channel: 0— AIN1/AOUT1 (normal audio channel), the default value is 0. 1— AIN2/AOUT2(aux_audio channel) .
SIM900B Hardware Design 3.9.2 Microphone Interfaces Configuration Close to Microphone GND GND GND Differential layout ESD ANTI 10pF 33pF 10pF 33pF MICxP MODULE Electret Microphone MICxN AGND ESD ANTI 33pF 10pF AGND GND GND GND Figure 21: Microphone interface configuration 3.9.
SIM900B Hardware Design 3.9.4 Referenced Electronic Characteristic Table 10: MIC Input Characteristics Parameter Min Typ Max Unit Working Voltage 1.2 1.5 2.0 V Working Current 200 500 uA External Microphone Load Resistance 1.2 2.2 Internal biasing DC Characteristics Differential input voltage k Ohms 2.5 V THD <1% at F=1KHz; pre-amp gain = 20 dB; PGA gain = 14 dB 15.
SIM900B Hardware Design Output swing Voltage(differentia l) 2.2 V RL=32 Ohm THD=0.1% - 91 - mW RL=32 Ohm THD=1% - 96 - mW 3.10 Buzzer The BUZZER 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 shown as following figure: VBAT MODULE 4.
SIM900B Hardware Design 3.11 SIM Card Interface 3.11.1 SIM Card Application The user can use AT Command to get information in SIM card. For more information, please refer to document [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.
SIM900B Hardware Design 220nF SIM_VDD MODULE SIM_RST 22R SIM_CLK 22R MOLEX-91228 VCC GND RST VPP CLK I/O PRESENCE GND SIM_PRESENCE 22R SIM_DATA SIM CARD SMF05C 22pF Figure 24: Reference circuit of the 8 pins SIM card If the SIM card detection function don’t use, the SIM_PRESENCE pin can be keep open. The reference circuit about 6 pins SIM card illustrates as following figure.
SIM900B Hardware Design Figure 26: Amphenol C707 10M006 512 2 SIM card holder Table 14: Pin description (Amphenol SIM card holder) Pin Name Signal Description C1 SIM_VDD SIM Card Power supply, it can identify automatically the SIM Card power mode，one is 3.0V±10%, another is 1.8V±10%. Current is about 10mA. 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.
SIM900B Hardware Design Figure 27: Molex 91228 SIM card holder Table 15: Pin description (Molex SIM card holder) Pin Name Signal Description C1 SIM_VDD SIM Card Power supply, it can identify automatically the SIM Card power mode，one is 3.0V±10%, another is 1.8V±10%. Current is about 10mA.
SIM900B Hardware Design 3.12 LCD Display Interface SIM900B provides a serial LCD display interface that supports serial communication with LCD device. When used as LCD interface, the following table is the pin definition. LCD interface timing should be united with the LCD device.
SIM900B Hardware Design GND KBC0 KBC1 KBC2 KBC3 KBC4 MODULE KBR1 KBR2 KBR3 KBR4 Figure 28: Reference circuit of the keypad interface *Note: 1. This function is not supported in the default firmware. There must be customized firmware if you want. Please contact SIMCom for more details. 2.KBR0&KBC0 is used to power off the module, so do not connect them for other application. 3. keypad is the second function of this pin , the default function is GPIO. 3.
SIM900B Hardware Design 3.15 Behaviors of the RI Table 19: Behaviours of the RI State RI respond Standby HIGH Voice calling Change LOW, then: （1）Change to HIGH when establish calling. （2）Use AT command ATH, the RI pin changes to HIGH. （3）Sender hangs up, change to HIGH. Data calling Change LOW, then： （1）Change to HIGH when establish calling. （2）Use AT command ATH, the RI changes to HIGH. SMS When receive SMS, The RI will change to LOW and hold low level about 120 ms, then change to HIGH.
SIM900B Hardware Design Table 20: Working state of the NETLIGHT State SIM900B function Off SIM900B is not running 64ms On/ 800ms Off SIM900B does not find the network 64ms On/ 3000ms Off SIM900B find the network 64ms On/ 300ms Off GPRS communication The reference circuit is shown as the following figure: VBAT MODULE 300R 4.7K NETLIGHT 47K Figure 31: Reference circuit of NETLIGHT SIM900B_HD_V1.03 47 24.06.
SIM900B Hardware Design 3.17 General Purpose Input Output (GPIO) SIM900B provides a limited number of General Purpose Input/Output signal pin.
SIM900B Hardware Design 4 Antenna Interface The RF interface has an impedance of 50Ω. To suit the physical design of individual applications, SIM900B offers alternatives: z z Recommended approach: antenna connector on the component side of the PCB Antenna pad and grounding plane placed on the bottom side. Figure 32 : The RF interface of module The antenna can be soldered to the pad, or attached via contact springs.
SIM900B Hardware Design 4.1 Module RF Output Power Table 22: SIM900B conducted RF output power Frequency Max Min GSM850 33dBm ±2db 5dBm±5db EGSM900 33dBm ±2db 5dBm±5db DCS1800 30dBm ±2db 0dBm±5db PCS1900 30dBm ±2db 0dBm±5db 4.2 Module RF Receive Sensitivity Table 23: SIM900B conducted RF receive sensitivity Frequency Receive sensitivity（Typical） Receive sensitivity(Max) GSM850 -109dBm -107dBm EGSM900 -109dBm -107dBm DCS1800 -109dBm -107dBm PCS1900 -109dBm -107dBm 4.
SIM900B Hardware Design Table 25: Absolute maximum ratings Parameter Min Max Unit VBAT - 5.5 V Peak current of power supply 0 3.0 A Voltage at digit pins* -0.3 3.1 V II* - 10 mA IO* - 10 mA *For digital interface pins, such as keypad, GPIO, UART and LCD. 5.
SIM900B Hardware Design Voltage ripple IVBAT Average current supply Peak supply current (during Tx burst) Normal condition, power control level for Pout max @ f<200kHz @ f>200kHz 50 2 POWER DOWN mode SLEEP mode(BS-PA-MFRMS=2 ) (BS-PA-MFRMS=5 ) (BS-PA-MFRMS=9 ) 50 1.5 1.2 1.
SIM900B Hardware Design Voice Call GSM 850/EGSM 900 @power level #5 <300mA,Typical 250mA @power level #12,Typical 110mA @power level #19,Typical 80mA DCS 1800/PCS 1900 @power level #0 <200mA,Typical 180mA @power level #7,Typical 94mA @power level #15,Typical 76mA GPRS Data DATA mode, GPRS ( 1 Rx,1 Tx ) CLASS 8 GSM 850/EGSM 900 @power level #5 <300mA,Typical 235mA @power level #12,Typical 102mA @power leve#19,Typical 74mA DCS 1800/PCS 1900 @power level #0 <200mA,Typical 170mA @power level #7,Typical
SIM900B Hardware Design Part Contact discharge Air discharge VBAT ±5KV ±10KV GND ±5KV ±10KV RXD, TXD ±2KV ±8KV Antenna port ±5KV ±10KV SPK_P/N MIC_P/N ±4KV ±8KV PWRKEY ±2KV ±8KV Other port TBD TBD SIM900B_HD_V1.03 54 24.06.
SIM900B Hardware Design 6 Mechanics This chapter describes the mechanical dimensions of SIM900B. 6.1 Mechanical Dimensions of SIM900B Following shows the Mechanical dimensions of SIM900B (top view, side view and bottom view). Figure 33: Top an Side Mechanical dimensions of module （Unit: mm） SIM900B_HD_V1.03 55 24.06.
SIM900B Hardware Design Figure 34：Mechanical dimensions of module PCB decal（Unit: mm） 6.2 Top View of the SIM900B Figure 35: Top view of the SIM900B SIM900B_HD_V1.03 56 24.06.
SIM900B Hardware Design 6.3 Mounting SIM900B onto the application platform Use the connector SUNCAGEY BB530-06001-20R to fix the SIM900B onto the customer platform 6.4 Board-to-board connector We recommend to use SUNCAGEY Company’s BB530-06001-20R as the board-to-board connector. They are fully compatible each other. This high density SMT connector is designed for parallel PCB-to-PCB applications.
SIM900B Hardware Design Figure 37 Board-to-board connector physical photo SIM900B_HD_V1.03 58 24.06.
SIM900B Hardware Design 6.5 RF connector The RF connector in module side is a 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 solderable. Following is parameter (Figure 36). Certainly the user can visit http://www.hirose-connectors.com/ for more information.
SIM900B Hardware Design Unit:mm Figure 39: U.FL series RF adapter cable SIM900B_HD_V1.03 60 24.06.
SIM900B Hardware Design 6.6 PIN Assignment of SIM900B Table 30: PIN assignment PIN NO. PIN NAME I/O PIN NO.
SIM900B Hardware Design 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 3235 3300 Fax: +86 21 3235 3301 URL: www.sim.com/wm SIM900B_HD_V1.03 62 24.06.
