a Hardware Design SIM900_HD_V1.
SIM900 Hardware Design Document Title: SIM900 Hardware Design Version: 1.01 Date: 2009-12-26 Status: Release Document Control ID: SIM900_HD_V1.01 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.
SIM900 Hardware Design Contents Contents .....................................................................................................................................................................3 Version history...........................................................................................................................................................7 1 Introduction.....................................................................................................................
SIM900 Hardware Design 3.13 ADC ..........................................................................................................................................................43 3.14 Behaviors of the RI ...................................................................................................................................44 3.15 Network Status Indication .........................................................................................................................44 3.
SIM900 Hardware Design Table Index TABLE 1: RELATED DOCUMENTS ............................................................................................................................... 8 TABLE 2: TERMS AND ABBREVIATIONS ................................................................................................................... 8 TABLE 3: SIM900 KEY FEATURES..............................................................................................................................
SIM900 Hardware Design Figure Index FIGURE 1: SIM900 FUNCTIONAL DIAGRAM ........................................................................................................... 14 FIGURE 2: TOP VIEW OF SIM900 EVB ....................................................................................................................... 15 FIGURE 3: REFERENCE CIRCUIT OF THE VBAT INPUT ........................................................................................
SIM900 Hardware Design Version history Date Version Description of change Author 2009-12-26 1.01 Origin Lee SIM900_HD_V1.01 7 26.12.
SIM900 Hardware Design 1 Introduction This document describes the hardware interface of the SIMCom SIM900 module that connects to the specific application and the air interface. As SIM900 can be integrated with a wide range of applications, all functional components of SIM900 are described in great detail. This document can help you quickly understand SIM900 interface specifications, electrical and mechanical details.
SIM900 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,
SIM900 Hardware Design 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) RTC Real Time Clock RX Receive Direction SIM Subscriber Identification Module SMS Short
SIM900 Hardware Design 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 SIM900_HD_V1.01 11 26.12.
SIM900 Hardware Design 2 SIM900 Overview Designed for global market, SIM900 is a quad-band GSM/GPRS engine that works on frequencies GSM 850MHz, EGSM 900MHz, DCS 1800MHz and PCS 1900MHz. SIM900 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 24mm x 24mm x 3mm, SIM900 can meet almost all the space requirements in your applications, such as M2M, smart phone, PDA and other mobile devices.
SIM900 Hardware Design z z Restricted operation: -40°C to -30°C and +80 °C to +85°C(1) Storage temperature -45°C to +90°C 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 SIM900 supports the protocols PAP (Password Authentication Protocol) usually used for PPP connections. The SIM900 integrates the TCP/IP protocol. Support Packet Switched Broadcast Control Channel (PBCCH) CSD transmission rates: 2.4, 4.8, 9.
SIM900 Hardware Design (1) The SIM900 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.
SIM900 Hardware Design 2.3 SIM900 Evaluation Board In order to help you on the application of SIM900, SIMCom can supply an Evaluation Board (EVB) that interfaces the SIM900 directly with appropriate power supply, SIM card holder, RS232 serial port, handset port, earphone port, line in port, antenna and all GPIO of the SIM900. Figure 2: Top view of SIM900 EVB For details please refer to the SIM900-EVB_UGD document. SIM900_HD_V1.01 15 26.12.
SIM900 Hardware Design 3 Application Interface SIM900 is equipped with a 68-pin SMT pad that connects to the cellular application platform. Sub-interfaces included in this SMT pad 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 3.10) Electrical and mechanical characteristics of the SMT pad are specified in Chapter 5.
SIM900 Hardware Design Iout(max)= 10mA GND Ground Power on or power off PIN NAME I/O DESCRIPTION DC CHARACTERISTICS PWRKEY I Voltage input for PWRKEY. PWRKEY should be pulled low to power on or power off the system. The user should keep pressing the key for a short time when power on or power off the system because the system need margin time in order to assert the software. VILmax=0.15*VDD_EXT VIHmin=0.
SIM900 Hardware Design I2C bus data SDA I/O open KBR0~KBR4 O KBC0~KBC4 I Keypad interface PIN NAME I/O DESCRIPTION DC CHARACTERISTICS COMMENT RXD I Receive data TXD O Transmit data RTS I Request to send CTS O Clear to send RI O Ring indicator DSR O Data Set Ready DTR Pin has been pulled up to VDD_EXT. If unused keep pin open DCD O Data carry detect VILmax=0.15 *VDD_EXT VIHmin=0.85*VDD_EXT VILmin= 0V VIHmax= VDD_EXT VOHmin= VDD_EXT-0.1V VOLmax=0.
SIM900 Hardware Design pad to SIM card holder. SIM_PRESE NCE I SIM detect VILmax=0.15 *VDD_EXT VIHmin=0.85*VDD_EXT VILmin= 0V VIHmax= VDD_EXT If unused keep open PIN NAME I/O DESCRIPTION DC CHARACTERISTICS COMMENT ADC I General purpose analog to digital converter. Input voltage range: 0V ~ 3V If unused keep open PIN NAME I/O DESCRIPTION DC CHARACTERISTICS COMMENT NRESET I External low) VILmax=0.15 *VDD_EXT VIHmin=0.
SIM900 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.
SIM900 Hardware Design Figure 3: Reference circuit of the VBAT input 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.
SIM900 Hardware Design Figure 5: VBAT voltage drop during transmit burst 3.3.1 Power Supply Pins Three VBAT pins are dedicated to connect the supply voltage and fifteen GND pins are dedicated to connect ground. VRTC pin can be used to back up the RTC. 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.
SIM900 Hardware Design Note: The AT command must be set after the SIM900 is power on and Unsolicited Result Code “RDY” is received from the serial port. However if the SIM900 is set autobauding, the serial port will receive nothing. The AT commands can be set after the SIM900 is power on. You can use AT+IPR=x;&W to set a fixed baud rate and save the configuration to non-volatile flash memory.
SIM900 Hardware Design Figure 8: Timing of turn on system using PWRKEY When power on procedure completes, the SIM900 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. 3.4.1.2 Turn on SIM900 Using the PWRKEY Pin and PWRKEY_OUT Pin (Power on) User can turn on SIM900 by connecting PWRKEY Pin and PWRKEY_OUT Pin for a short time and then release.
SIM900 Hardware Design PWRKEY_OUT MODULE SIM900 PWRKEY Figure 10: Turn on SIM900 using button The power on scenarios illustrates as following figure. Figure 11: Timing of turn on system using PWRKEY and PWRKEY_OUT 3.4.
SIM900 Hardware Design 3.4.2.1 Turn Off SIM900 Using the PWRKEY Pin (Power down) You can turn off the SIM900 by driving the PWRKEY to a low level voltage for a short time and then release. You also can urn off the SIM900 by connecting PWRKEY and PWRKEY_OUT for a short time and then release. Please refer to the turn on circuit. The power down scenario illustrates as following figure.
SIM900 Hardware Design Figure 13: Timing of turn off system using PWRKEY and PWRKEY_OUT 3.4.2.2 Turn Off SIM900 Using AT Command You can use an AT command “AT+CPOWD=1” 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.
SIM900 Hardware Design +CMTE:-2 After this moment, the AT commands can’t be executed. The module logs off from network and enters POWER DOWN mode, and 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 read the temperature when the module is power on. For details please refer to document [1] 3.4.
SIM900 Hardware Design card function will not be accessible. If SIM900 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. After SIM900 has been set by “AT+CFUN=0” or “AT+CFUN=4”, it can return to full functionality by “AT+CFUN=1”. For detailed information about “AT+CFUN”, please refer to document [1]. 3.5.
SIM900 Hardware Design (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. Otherwise the VRTC pin can be keep open. The following figures show various sample circuits for RTC backup. Figure 16: RTC supply from non-chargeable battery Figure 17: RTC supply from rechargeable battery Figure 18: RTC supply from capacitor SIM900_HD_V1.01 30 26.12.
SIM900 Hardware Design 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 19: Seiko XH414H-IV01E Charge Characteristic 3.
SIM900 Hardware Design The GSM module 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 following figure shows). Autobauding supports baud rate from 1200bps to 115200bps.
SIM900 Hardware Design 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, DSR and RI. z Serial port can be used for CSD FAX, GPRS service and send AT command of controlling module. Also serial port can be used for multiplexing function. SIM900 supports only basic mode of multiplexing so far.
SIM900 Hardware Design add a switch between the PWRKEY and the GND. The PWRKEY should be connected to the GND when SIM900 is upgrading software. Please refer to the following figures. Figure 21: Connection of software upgrade and software debug The serial port and the debug port don’t support the RS_232 level and it only supports the CMOS level. Please refer to the table 10 for details about the voltage level.
SIM900 Hardware Design 3.9 Audio Interfaces Table 9: Pin define of the Audio interface AIN/AOUT LINE IN Pin Name Pin Number Function MIC_P 19 Microphone1 input + MIC_N 20 Microphone1 input - SPK_P 21 Audio1 output+ SPK_N 22 Audio1 output- LINEIN_R 23 Right Channel input LINEIN_L 24 Lift Channel input The module provides one analog input channel, AIN, which may be used for microphone. The electret microphone is recommended when the interface is used for microphone.
SIM900 Hardware Design Figure 24: Speaker interface with amplifier configuration 3.9.2 Microphone Interfaces Configuration Figure 25: Microphone interface configuration SIM900_HD_V1.01 36 26.12.
SIM900 Hardware Design 3.9.3 Earphone Interface Configuration Figure 26: Earphone interface configuration 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 Conditions Min Typ Max Unit RL=32 Ohm THD=0.
SIM900 Hardware Design 3.10 SIM Card Interface 3.10.1 SIM Card Application You 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.
SIM900 Hardware Design Figure 27: Reference circuit of the 8 pins SIM card If you don’t use the SIM card detection function, you can leave the SIM_PRESENCE pin open. The reference circuit about 6 pins SIM card illustrates as following figure. Figure 28: Reference circuit of the 6 pins SIM card 3.10.2 Design Considerations for SIM Card Holder For 6 pins SIM card holder, we recommend to use Amphenol C707 10M006 512 2 .You can visit http://www.amphenol.com for more information about the holder.
SIM900 Hardware Design Figure 29: Amphenol C707 10M006 512 2 SIM card holder Table 13: 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.
SIM900 Hardware Design Figure 30: Molex 91228 SIM card holder Table 14: 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.
SIM900 Hardware Design 3.11 LCD Display Interface SIM900 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.
SIM900 Hardware Design Figure 31: Reference circuit of the keypad interface *Note: This function is not supported in the default firmware. There must be customized firmware if you want. Please contact SIMCom for more details. 3.13 ADC SIM900 provides one 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. We can use AT command “AT+CADC” to read the voltage value on ADC.
SIM900 Hardware Design 3.14 Behaviors of the RI Table 18: 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 1200 ms, then change to HIGH.
SIM900 Hardware Design listed in following table: Table 19: Working state of the NETLIGHT State SIM900 function Off SIM900 is not running 64ms On/ 800ms Off SIM900 does not find the network 64ms On/ 3000ms Off SIM900 find the network 64ms On/ 300ms Off GPRS communication We provide a reference circuit for you, shown as following figure: VBAT SIM900 MODULE 300R 4.7K NETLIGHT 47K Figure 34: Reference circuit of NETLIGHT 3.
SIM900 Hardware Design Table 20: Pin define of the GPIO interface Pin Name Pin Number Default Function Second Function* Default State GPIO1/ KBR4 40 GPIO1 Pull down GPIO2/ KBR3 41 GPIO2 GPIO3/ KBR2 42 GPIO3 GPIO4/ KBR1 43 GPIO4 GPIO5/ KBR0 44 GPIO5 GPIO6/ KBC4 47 GPIO6 GPIO7/ KBC3 48 GPIO7 GPIO8/ KBC2 49 GPIO8 GPIO9/ KBC1 50 GPIO9 GPIO10/ KBC0 51 GPIO10 KBR4 KBR3 KBR2 KBR1 KBR0 KBC4 KBC3 KBC2 KBC1 KBC0 GPIO11 67 GPIO11 Pull down GPIO12 68 GPIO12 Pull down Pull d
SIM900 Hardware Design 3.18 PWM SIM900 contains two DC Pulse-Width Modulators (PWMs) which can be used in conjunction with an external transistor for driving a vibrator, or a backlight LED for illuminating an LCD display or keyboard. Each PWM features 7-bit resolution and a maximum conversion rate is 3.25 MHz. Each PWM uses two 7-bit unsigned binary numbers: one for the output period and one for the pulse width or the duty cycle.
SIM900 Hardware Design controlled in 50Ω. To help you to ground the antenna, SIM900 comes with a grounding plane located close to the antenna pad. The Pin 60 is the RF antenna pad. SIM900 material properties: SIM900 PCB Material: FR4 Antenna pad: Gold plated pad 4.2 Module RF Output Power Table 23: SIM900 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.
SIM900 Hardware Design 5 Electrical, Reliability and Radio Characteristics 5.1 Absolute Maximum Ratings The absolute maximum ratings stated in Table 28 are stress ratings under non-operating conditions. Stresses beyond any of these limits will cause permanent damage to SIM900. Table 26: 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.
SIM900 Hardware Design IVBAT Voltage drop during transmit burst Normal condition, power control level for Pout max Voltage ripple Normal condition, power control level for Pout max @ f<200kHz @ f>200kHz Average current supply Peak supply current (during Tx burst) 400 mV 50 2 mV POWER DOWN mode SLEEP mode 30 1.
SIM900 Hardware Design Table 29: SIM900 current consumption Voice Call GSM 850/EGSM 900 @power level #5 <300mA,Typical 250mA @power level #10,Typical 110mA @power level #19,Typical 76mA DCS 1800/PCS 1900 @power level #0 <200mA,Typical 168mA @power level #10,Typical 89mA @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 240mA @power level #10,Typical 110mA @power level #19,Typical 83mA DCS 1800/PCS 1900 @power level #0 <200mA
SIM900 Hardware Design Table 30: The ESD endure statue measured table (Temperature: 25℃, Humidity:45% ) Part Contact discharge Air discharge VBAT ±5KV ±10KV GND ±4KV ±10KV RXD, TXD ±3KV ±6KV Antenna port ±5KV ±10KV SPK_P/N MIC_P/N ±2KV ±6KV PWRKEY ±1KV ±6KV Other port TBD TBD 6 Mechanics This chapter describes the mechanical dimensions of SIM900. 6.1 Mechanical Dimensions of SIM900 Following shows the Mechanical dimensions of SIM900 (top view, side view and bottom view).
SIM900 Hardware Design Figure 37：Bottom Mechanical dimensions of module （Unit: mm） Figure 38: Recommended PCB decal（Unit: mm） Note: Keep out area A is package keep out area. Keep out area B and keep out C are route keep out area. SIM900_HD_V1.01 53 26.12.
SIM900 Hardware Design 6.2 Top and Bottom View of the SIM900 Figure 39: Top view of the SIM900 6.
SIM900 Hardware Design Table 31: PIN assignment Pin Number Pin Name Pin Number Pin Name 1 PWRKEY 35 PMW1 2 PWRKEY_OUT 36 PWM2 3 DTR 37 SDA 4 RI 38 SCL 5 DCD 39 GND 6 DSR 40 GPIO1/KBR4 7 CTS 41 GPIO2/KBR3 8 RTS 42 GPIO3/KBR2 9 TXD 43 GPIO4/KBR1 10 RXD 44 GPIO5/KBR0 11 DISP_CLK 45 GND 12 DISP_DATA 46 GND 13 DISP_D/C 47 GPIO6/KBC4 14 DISP_CS 48 GPIO7/KBC3 15 VDD_EXT 49 GPIO8/KBC2 16 NRESET 50 GPIO9/KBC1 17 GND 51 GPIO10/KBC0 18 GND 52
SIM900 Hardware Design 6.4 The Ramp-Soak-Spike Reflow Profile of SIM900 Figure 41: The ramp-soak-spike reflow profile of SIM900 SIM900_HD_V1.01 56 26.12.
SIM900 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 SIM900_HD_V1.01 57 26.12.
