SIM900 Hardware Design

Fanbing.Kong@sim.com Jan.,2010

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SIM900 Hardware Overview

(Top View)

The GPRS/GSM engine for the global market. Quad-band : GSM850, EGSM900, DCS1800, PCS1900GPRS multi-slot : Class 10 / Class 8GPRS class : Class BGPRS coding schemes : CS-1, CS-2, CS-3, CS-4 Voice coders : HR, FR, EFR, AMR

Noise SuppressionEcho Cancellation

Encryption : A5/1, A5/2, A5/3RF : SAIC (Single antenna interference cancellation) Input voltage: 3.4~4.5VSleep mode current consumption: 1.5mAOperation temperature: -30℃~+80 ℃

Application:M2MSmart phoneTracker

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SIM900 Hardware Feature

Tiny Configuration Size: 24 X 24X 3 mm (SMT), Weight: 3.4g,

Packing : Auto-tray, Tape & Reel Low Power Consumption

Sleep Mode : 1.5 mAHigh-Speed Processing

ARM926EJ-S (156MHz), Ceva-Teak(DSP)

Multiple Periphery Interface68Pins(UART, SPI, I2C, PWM, GPIO, ADC)

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Platform SolutionChipset Solution PNX4851 :

A single-chip integrated baseband processor and transceiver ICRF7161 :

RF Power Amplifier supporting quad-bandMemory Chipset (ST/SA) :

NOR Flash + RAM Memory

Software SolutionRTOS :

RTK-EProtocol Stack:

3GPP GSM/GPRS R99

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CertificationSIM900 Certification Schedule :

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Pins Diagram

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Power SupplyVBAT --- Input Pin

Design Rule : Vmax = 4.5V, Vmin = 3.4V, Vnorm = 4.0V, Peak Current : 2 A

Any voltage drops that may occur in a transmit burst should notexceed 400mV.

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Power SupplyThe Power Supply Circuit of the evaluation board

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Power Supply

VDD_EXT --- Output PinVoltage Reference for the Digital Interface. Output Voltage : Vmax = 2.95 V, Vmin = 2.6 V, Vnorm = 2.80 V, Design Rule : Iout(max) = 10mALogic Voltage Level :

VILmax=0.15 *VDD_EXT, VIHmin=0.85*VDD_EXT, VILmin= 0V, VIHmax= VDD_EXT, VOHmin= VDD_EXT - 0.1V, VOLmax=0.1V VOHmax= VDD_EXT, VOLmin= 0V

VRTC --- Input or Output Pin – Power input pin, – Design Rule : Vmax=3.15V, Vmin=2.0V, Vnorm=3.0V

Iout(max)= 300uA, Iin=2 uA

GND --- Ground

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Turn on, Turn off, ResetPWRKEY --- Input Pin

be used to turn on or turn off SIM900

Timing of turning on

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Turn on, Turn off, Reset

Timing of turning off

NRESET --- Input PinReset SIM900 : Driving the pin low for at least 50uS.

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Serial PortTXD, RXD, CTS, RTS, DSR, DTR, DCD, RI

TXD, RXD --- Data LineCTS, RTS --- Hardware Flow Control LineDTR --- Sleep Mode Control LineDCD --- Data ModeRI --- Incoming Call, SMS, Arouse host.DSR --- Reserve

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SIM InterfaceSIM_VDD, SIM_DATA, SIM_CLK, SIM_RST, SIM_PRESENCE

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RF interfaceRF_ANT

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RF Interface

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Audio InterfaceMIC_P, MIC_N, SPK_P, SPK_N

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Debug PortDBG_TXD, DBG_RXD

– Updating Firmware & Capturing Debugging Trace. – It’s recommended the interface is lead to a connector.

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OthersADC

– Input Voltage Range : 0 ~ 3 V– AT+CADC?

+CADC: 1,50

NETLIGHT

GPRS communication64ms On/ 300ms Off

SIM900 find the network64ms On/ 3000ms Off

SIM900 does not find the network64ms On/ 800ms Off

SIM900 is not runningOff

SIM900 functionState

PWRKEYOUT, DISP_DATA,DISP_CLK,DISP_C/D,DISP_CS,LINEIN_R,LINEIN_L,PWM1, PWM2, KBR0~KBR4, KBC0~KBC4, GPIO11, GPIO12

---these pins are available in the customized firmware!

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Evaluation Board Kit

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Update FirmwareSIM900 Flash Loader

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Capture Debug LogSpyTracer

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Q&A