AirM2M Communication Technology AIR208 GSM/GPRS Module User Manual

Shanghai AirM2M Communication Technology Co., Ltd GSM/GPRS Module

User Manual

Air208_Hardware Design Manual_V1.03
Air208 Hardware Design ManualPage2Totally 57 pagesVersionnumberModify record Date DateV1.0 Newly build 2017‐8‐10 jinyiV1.01 Modifies the main serial port on baud rate training content 2017‐9‐16 GuowenV1.02 Adds pin description of the boot key booting and shutdownmachine2017‐11‐03 GuowenV1.03 Updates pin diagram 2017‐12‐13 Loukanghua
Air208 Hardware Design ManualPage3Totally 57 pagesCatalog1. TABLE CATALOG ............................................................................................................................................................ 62.1. RELATED DOCUMENTS.............................................................................................................................................................73. SUMMARY................................................................................................................................................................................ 83.1. FUNCTION CHART.................................................................................................................................................................103.2. EVALUATION BOARD.......................................................................................................................................................114. APPLICATION INTERFACE....................................................................................................................................................... 114.1. PIN DESCRIPTION..................................................................................................................................................................124.2. WORKING MODE..................................................................................................................................................................184.3. POWER SUPPLY....................................................................................................................................................................194.3.1. Module power supply working characteristics........................................................................................................194.3.2. Reduce voltage drop................................................................................................................................................194.3.3. Power supply reference circuit.................................................................................................................................204.4. BOOT AND SHUTDOWN......................................................................................................................................................... 214.4.1. Boot..........................................................................................................................................................................214.4.2. Shutdown.................................................................................................................................................................224.5. POWER SAVING TECHNOLOGY.................................................................................................................................................244.5.1. Least functional mode.............................................................................................................................................244.5.2. Sleep Mode (Slow Clock Mode）.............................................................................................................................244.5.3. Sleep wake...............................................................................................................................................................254.6. MODE SWITCHING SUMMARY................................................................................................................................................254.7. SERIAL PORT....................................................................................................................................................................... 254.7.1. Main serial port....................................................................................................................................................... 274.7.2. Debug serial port..................................................................................................................................................... 294.7.3. Serial port application............................................................................................................................................. 304.8. AUDIO INTERFACE................................................................................................................................................................ 324.8.1. Preventing TDD noise and other noises...................................................................................................................324.8.2. Microphone interface reference circuit................................................................................................................... 334.8.3. Audio output interface reference circuit..................................................................................................................334.8.4.Audio Electrical characteristics................................................................................................................. 344.9. SIM CARD INTERFACE.....................................................................................................................................................354.9.1. SIM INTERFACE....................................................................................................................................................... 354.9.2. 6-pin SIM card holder.............................................................................................................................................364.10. RI SIGNAL ACTION........................................................................................................................................................ 384.11. NETWORK STATUS INDICATION.............................................................................................................................................404.12. PWM.............................................................................................................................................................................415. RADIO INTERFACE...................................................................................................................................................................415.1. RF REFERENCE CIRCUIT..........................................................................................................................................................425.2. RF CONDUCTION SENSITIVITY........................................................................................................................................ 44
Air208 Hardware Design ManualPage4Totally 57 pages5.3. RECOMMENDED RF WELDING METHOD....................................................................................................................................456. ELECTRICAL CHARACTERISTICS, RELIABILITY, RF CHARACTERISTICS....................................................................................466.1. ABSOLUTE MAXIMUM...........................................................................................................................................................466.2. WORKING TEMPERATURE....................................................................................................................................................... 466.3. VOLTAGE LIMIT VALUE...........................................................................................................................................................476.4. CURRENT CONSUMPTION.......................................................................................................................................................496.5. STATIC PROTECTION............................................................................................................................................................. 507. PHYCIAL DIMENSION..............................................................................................................................................................517.1. MODULE PHYCIAL DIMENSION................................................................................................................................................ 527.2. RECOMMENDED PCB ENCAPSULATION.................................................................................................................................... 537.3. MODULE FRONT VIEW...........................................................................................................................................................547.4. MODULE BOTTOM VIEW........................................................................................................................................................558. STORAGE AND PRODUCTION.................................................................................................................................................558.1. STORAGE............................................................................................................................................................................ 558.2. PRODUCTION WELDING.........................................................................................................................................................56
Air208 Hardware Design ManualPage5Totally 57 pagesChart CatalogCHART 1 ：FUNCTIONAL BLOCK DIAGRAM.................................................................................................10CHART 2 ：PIN ARRANGEMENT (FRONT VIEW）................................................................................. ...............12CHART 3 ：VOLTAGE AND CURRENT WAVEFORMSOFMODULE EMISSION........................................................... 19CHART 4 ：VBAT INPUT REFERENCE CIRCUIT.............................................................................................20CHART 5 ：POWER INPUT REFERENCE DESIGN....................................................................................................21CHART 6 ：OPEN SET DRIVER REFERENCE BOOT CIRCUIT........................................................................................22CHART 7 ：BUTTON BOOTREFERENCE CIRCUIT............................................................................................... ......22CHART 8 ：OPEN DRIVER REFERENCE EMERGENCY SHUTDOWN CIRCUIT.....................................................................23CHART 9 ：BUTTON EMERGENCY SHUTDOWNREFERENCE CIRCUIT.............................................................................24CHART 10 ：FULL‐FEATURED SERIAL PORT CONNECTION DIAGRAM ...........................................................................28CHART 11 ：SERIAL THREE‐WIRE CONNECTION DIAGRAM.........................................................................................28CHART 12 ：SCHEMATIC DIAGRAM OF SERIAL CONNECTION MODE WITH FLOW CONTROL...............................................29CHART 13 ：SOFTWARE DEBUGGING CONNECTION DIAGRAM....................................................................................29CHART 14 ：3.3V LEVEL CONVERSION CIRCUIT......................................................................................................30CHART 15 ：5VLEVEL CONVERSION CIRCUIT...........................................................................................................31CHART 16 ：RS232 LEVEL CONVERSION CIRCUIT....................................................................................................31CHART 17 ：AIN MICROPHONE CHANNEL INTERFACE CIRCUIT.......................................................................33CHART 18 ：REFERENCE LINE................................................................................................................................34CHART 19 ：USING A 6PIN SIM CARD REFERENCE SCHEMATIC (SIM).........................................................................35CHART 20 ：WITH THE DETECTION OF PIN SIM CARD REFERENCE CIRCUIT DIAGRAM....................................36CHART 21 ：AMPHENOL C707 10M006 512 2 SIMCASSETTE..............................................................................37CHART 22 ：THE MODULE IS USED AS CALLED PARTY RI TIMING FOR VOICE CALL............................................................38CHART 23 ：THE MODULE IS USED AS CALLED PARTY RI TIMING FOR DATA CALL.............................................................39CHART 24 ：RI TIMING OF MODULE CALLING...........................................................................................................39CHART 25 ：RI TIMING WHEN RECEIVING URC MESSAGE OR SMS...............................................................................39CHART 26 ：NETLIGHTREFERENCE CIRCUIT.........................................................................................................40CHART 27 ：RF REFERENCE CIRCUIT.........................................................................................................................42CHART 28 ：SUGGESTION ON RF WELDING METHOD...................................................................................................45CHART 29 ：AIR208 FRONT VIEW (UNIT: MM）.......................................................................................................52CHART 30 ：RECOMMENDED ENCAPSULATION (UNIT: MM)..........................................................................................53CHART 31 ：MODULE FRONT VIEW...........................................................................................................................54CHART 32 ：MODULE BOTTOM VIEW.........................................................................................................................55CHART 33 ：PASTE MAP.................................................................................................................................... ......56CHART 34 ：FURNACE TEMPERATURE CURVE................................................................................................................57
Air208 Hardware Design ManualPage6Totally 57 pages1. Table CatalogTABLE 1：RELATED DOCUMENTS..................................................................................................................................................... 7TABLE 2：MAINFEATURESOFTHEMODULE......................................................................................................................................8TABLE 3：AIR208 PIN ALLOCATION..............................................................................................................................................13TABLE 4：PIN DESCRIPTIO............................................................................................................................................................14TABLE5：GPIO CONFIGURATION TABLE............................................................................................................................................17TABLE 6：WORK MODE...............................................................................................................................................................18TABLE 7：MODE SWITCHING SUMMARY.........................................................................................................................................25TABLE8：SERIAL LOGIC LEVEL..........................................................................................................................................................26TABLE 9：DEFINITION OF SERIAL PORT PINS.....................................................................................................................................26TABLE10 ：AUDIO INTERFACEPIN DEFINITION.....................................................................................................................................32TABLE 11 ：TYPICAL CHARACTERISTICS OF ELECTRET MICROPHONES.....................................................................................................34TABLE 12 ：AUDIO INTERFACETYPICAL CHARACTERISTIC PARAMETERS.................................................................................................. 34TABLE13 ：SIM CARD INTERFACEPIN DEFINITION...........................................................................................................................35TABLE 14 ：RI SIGNAL ACTION.................................................................................................................................................38TABLE 15 ：NET_LED WORKING STATUS.....................................................................................................................................40TABLE 16 ：RF_ANTPIN DEFINITION...........................................................................................................................................41TABLE 17 ：RFCONDUCTION POWER.............................................................................................................................................44TABLE 18 ：RF CONDUCTION SENSITIVITY...............................................................................................................................44TABLE 19 ：MODULE WORKING FREQUENCY....................................................................................................................................45TABLE20 ：ABSOLUTE MAXIMUM.................................................................................................................................................... 46TABLE 21 ：WORKING TEMPERATURE..............................................................................................................................................46TABLE 22 ：MODULE POWER LIMIT VALUE...................................................................................................................................... 47TABLE 23 ：MODULE'S CURRENT CONSUMPTION..............................................................................................................................49TABLE 24 ：ESDP ERFORMANCE PARAMETERS (TEMPERATURE:25C,HUMIDITY:45%)）................................................................50
Air208 Hardware Design ManualPage7Totally 57 pages2. IntroductionThis document defines the Air208 module and hardware interface specification, electrical and mechanical details.With the help of this document, combining with the application manual and user guide, customers can quickly applyAir208 module for wireless applications.2.1. Related documentsTable 1：Related documentsItem File name Remarks1Detailed explanation of Air208_AT instruction set Has been published2Air208 Reference design Has been published3 Air208 module encapsulation Has been published4Luat_AIR2XXupgradingtool1.1 Has been published5TraceReference design Has been published6 LuaForWindows_v5.1.5‐51 Has been published7 Coolwatcher debugging tools and instructions _V1.1 Has been published8 Platform compilation environment and installation steps Has been published9 CSDTK3.7_Cygwin1.5.25_Svn_1.5.4_Full_Setup Has been published
Air208 Hardware Design ManualPage8Totally 57 pages3. SummaryAir208module is the two band GSM/GPRS module, its working frequency bands are:GSM850MHz, WC^ϭ900MHz. Air208 supports GPRS multi slot level 12 and GPRS encoding formats CS‐1, CS‐2, CS‐3andCS‐4.With the ultra small size of 17.6mm * 15.7mm * 2.3mm, Air208 is able to meet all the needs of M2M, including cars and personal tracking services, wireless POS, smart metering, industrial PDA and other M2M applications.Air208 is built‐in 32MbNorFlash + 32MbSRAM.Air208 is a chip‐on‐module, with a LCC package that can be embedded in customer applications with itspin‐on‐land, providing a rich hardware interface between the module and the customer's motherboard.Air208 module uses a power‐saving technology, current consumption in sleep mode DRX = 5, as low as 1.14mA.Air208 embeds protocols such as TCP UDP PPP HTTPS SSL and built‐in extended AT commands to make it easierfor users to use these Internet protocols.Air208 complies with the RoHS standard.Table 2：Main features of the moduleFeature DescriptionBand♦Quad‐band：GSM850，3CSϭϵϬϬ♦Automatic frequency band search♦Band selection can be set by AT command♦Meets GSM Phase 2/2+Transmitting power♦Class4 (2W)：♦Class 1 (1W)：Power supply ♦DC 3.8VPower saving modecurrent consumption♦1.40mA@DRX=2♦1.14 mA@ DRX=5♦1.03 mA@ DRX=9GPRS Connectioncharacteristic♦GPRS multi slot level is 12 (default)♦GPRS mobile level BGSM850WCS1ϵ00
Air208 Hardware Design ManualPage9Totally 57 pagesGPRS Datacharacteristics♦Downlink GPRS data transmission: maximum 85.6 kbps♦GPRS data uplink transmission: maximum 85.6 kbps♦Coding format：CS‐1，CS‐2，CS‐3andCS‐4♦Support PAP (cryptographic authentication protocol) protocols commonly used forPPP connections♦Embedded protocol：TCP/UDP/FTP/PPP and so onTemperature range♦Normal working temperature：‐40°C ~ +85°C♦storagetemperature：‐45°C ~ +90°CSMS Text and PDU modesSIM CARD INTERFACE SupportsSIM/USIM card：1.8V，3VCharacteristic 50 ΩAudio interface Supports call, recording and playback function, can directly drive 8 ohm hornSerial port♦Full function serial portFor AT command and GPRS dataAdaptive baud rate：From 2400 bps to 921600 bps♦Debug serial portFor software upgradeFor software debuggingReal time clockDimensionReal time clock17.6×15.7×2.3mm Weight：1.25g
Air208 Hardware Design ManualPage10 Totally 57 pages3.1. Function ChartFollowing is Air208Functional block diagram，describing its main function：♦storage♦GSM RF♦Power Management♦Interface section— SIM card interface—Audio interface— UART interface— Power supply—RF interface— Boot and shutdownChart 1：Functional block diagram
Air208 Hardware Design ManualPage11 Totally 57 pages3.2. Evaluation BoardIn order to help test and use Air208, Airm2m provides a set of evaluation boards. They includes Air208 module,EVB_Air208, UART to USB cable and so on.4. Application interfaceThe module uses LCC package, 42 SMT welding coil pins, and the following chapter details the functions ofthefollowing interfaces:♦power supply (refer to power supply section)♦Switch machine (refer to switch section)♦power saving technology (refer to power saving technology section)♦Serial port (refer to serial section)♦Audio interface(refer to audio section)♦SIM CARD INTERFACE(refer to SIM card section)
Air208 Hardware Design ManualPage12 Totally 57 pages4.1. Pin descriptionGND 13 SIM_DET 14 SIM_DAT 15 SIM_CLK 16 SIM_RST 17 SIM_VDD 18GND 19RESET 20GND 21 UART1_TXD 1 UART1_RXD 2 UART1_RTS 3 UART1_CTS 4 UART1_DCD 5 UART1_DTR 6 UART1_RI 7GND 8 MICP 9MICN 10SPKP 11SPKN 1233 GND32 ANT31 GND30 GND29 GPIO_6 28 VRTC27 GND26 HOST_TXD25 HOST_RXD 24 CHG_DET23 UART2_RXD22 UART2_TXD42 STATUS41 NET_LED40 VDDIO39 PWRKEY38 ADC37 GND36 GND35 VBAT34 VBATAir208Chart 2：Pin arrangement (front view）
Air208 Hardware Design ManualPage13 Totally 57 pagesTable 3：Air208 Pin allocationPin Pin name Input/Output Pin No. Pin name Input/Output1UART1_TXD/GPIO_1 I22 UART2_TXD/GPIO_5 O2 UART1_RXD/GPIO_0 O23 UART2_RXD/GPIO_4 I3UART1_RTS/GPIO_2O24 CHG_DET I4UART1_CTS/GPIO_3I25 HOST_RXD I5 UART1_DCD/GPIO_31 O26 HOST_TXD O6 UART1_DTR/GPIO_29 I27 GND7 UART1_RI/GPIO_30 O28 GPIO_6 I/O8GND 29 VRTC I9MICP I30 GND10 MICN I31 GND11 SPKP O32 ANT I/O12 SPKN O33 GND13 GND 34 VBAT I14 SIM_DET/GPIO_7 I35 VBAT I15 SIM_DAT I/O 36 GND16 SIM_CLK I/O 37 GND17 SIM_RST O38 ADC I18 SIM_VDD O39 PWRKEY I19 GND 40 VDDIO O20 RESET I41 NET_LED/GPIO_33 O21 GND 42 STATUS/GPIO_11 O
Air208 Hardware Design ManualPage14 Totally 57 pagesTable 4：Pin descriptioowerSupplyPin name Pin No. I/O Pin description Electrical characteristics RemarkVBAT 34 35 I Module's main power supplyVBAT=3.4V~4.2 VVmax= 4.2VVmin=3.4VVnorm=3.8VThe module has amaximum load currentof 1.6A in burst modeVDDIO 41 O Output 2.8V，10mA Vmax=2.95V1.Hang when not inusage2.Ifthispinisusedforexternal power supply,it is recommended toshunt a 2~4.7uFdecoupling capacitor,and the load currentshould not exceed10mAGND8131921 2730 3133 36Module GNDPower buttonPin name Pin no. I/O Pin description Electrical characteristics RemarkPWRKEY 39 I Internal pull‐up, pull the pinlower than 1.5s modulebootVILmax=0.4VRESET 20 IHardware shutdown pin,active low。The moduleshutdown after pulldownmore than 200msVmax= 1.5VVmin=1.1VVnorm=1.35VNo external pull‐ups arerequiredAudio interfacePin name Pin no. IPin description Electrical characteristics RemarkMICPMICN 910 IDifferential audio inputSPKPSPKN 11 12 O Differential audio output,you can directly drive the 8ohm speakerThe main serial portPin name Pin no. I/O Pin description Electrical characteristics Remark
Air208 Hardware Design ManualPage15 Totally 57 pagesUART1_TXD(GPIO_1)(SPI2_CS0) 1OModule to send dataVILmin=-0.3VVILmax=0.25×VDDIOVIHmin=0.75×VDDIOVIHmax=VDDIO+0.3VOHmin=0.85×VDDIOVOLmax=0.15×VDDIORXD needs external 10Kohm resistor to pull toVDDIO.If communication isused only in TXD, RXDand GND, it isrecommended that RTSbe grounded through10K ohm resistance;The module defaults tosleep and power saving.If you want to send ATinstructions to themodule duringhibernation, you needto lower the DTR towake up the module;If you do not want themoduletogotosleep,you can ground the DTRthrough a 10K resistor.Other pins can be hangwhen is not in usage.UART1_RXD(GPIO_0)(SPI2_CLK) 2IThe module receives thedataUART1_CTS(GPIO_3)(SPI2_DO) 4OClear sendUART1_RTS(GPIO_2)(SPI2_CS1) 3IThe DTE requests to senddata to the moduleUART1_DTR(GPIO_29) 6IDTEisreadyUART1_DCD(GPIO_31) 5OCarrier detection (this pinrepresents thecommunication link)UART1_RI(GPIO_30) 7OModule output ringing hintUART2Pin name Pin no. I/O Pin description Electrical characteristics RemarkUART2_RXD(GPIO_4)(SPI2_DI)(LPG)23 IHardeare UART2VILmin=-0.3VVILmax=0.25×VDDIOVIHmin=0.75×VDDIOVIHmax=VDDIO+0.3VOHmin=0.85×VDDIOVOLmax=0.15×VDDIOHang when not in usageUART2_TXD(GPIO_5)(PWM) 22 ODebug serial portPin name Pin no. I/O Pin description Electrical characteristics RemarkHOST_RXD 25 IFor software debugging andfirmware downloadVILmin=-0.3VVILmax=0.25×VDDIOVIHmin=0.75×VDDIOVIHmax=VDDIO+0.3VOHmin=0.85×VDDIOVOLmax=0.15×VDDIOHang when not in usageHOST_TXD 26 OSIM CARD INTERFACEPin name Pin no. I/O Pin description Electrical characteristics RemarkSIM_VDD 18 O Power supply voltage ofSIM cardThemoduleautomaticallyselects 1.8V or 3.0VSIM CARD INTERFACEItis recommended to useTVStubeforESD
Air208 Hardware Design ManualPage16 Totally 57 pagesSIM_RST 17 O SIMcard Reset3V:VOLmax=0.36VOHmin=0.9×SIM_VDD1.8V:VOLmax=0.2×SIM_VDDVOHmin=0.9×SIM_VDDSIM_DAT 15 I/O SIM card data cable3V：VOLmax=0.4VOHmin= SIM_VDD-0.41.8V：VOLmax=0.15×SIM_VDDVOHmin=SIM_VDD-0.4SIM_CLK 16 O SIM card clock cable3V：VOLmax=0.4VOHmin=0.9×SIM_VDD1.8V：VOLmax=0.12×SIM_VDDVOHmin=0.9×SIM_VDDSIM_DET (GPIO_7)(UART2_CTS)(I2C_SDA)14 ISIM card in positiondetection VOHmin=0.85×VDDIOVOLmax=0.15×VDDIO Hang when not in usageADCPin name Pin no. I/O Pin description Electrical characteristics RemarkADC0 38 I Analog to digitalconverterInput range 0~1.85V10bittolerance scope +—20mv Hang when not in usageGPIOPin name Pin no. I/O Pin description Electricalcharacteristics RemarkNET_LED(GPIO_33)(32K_OUT) 41 ONetwork statusindication VOHmin=0.85×VDDIOVOLmax=0.15×VDDIO Hang when not inusageSTATUS(GPIO_11) 42 OOperating statusdetection VOHmin=0.85×VMMCVOLmax=0.15×VMMC Hang when not inusageGPIO_6(UART2_RTS)(I2C_CLK) 29 I/O Reserved VOHmin=0.85×VDDIOVOLmax=0.15×VDDIO Hang when not inusageRadio interfacePin name Pin no. I/O Pin description Electrical characteristics RemarkANT 32 I/O GPRS RF signal input andoutput50 ohm characteristicimpedance
Table5：GPIO Configuration tableAir208PINNO.GPIOnumberName.PowerDomainPull‐UpPull‐Up/DownResistorAt Reset After Reset Function0 Function1 Function2 Function3H/L/Hiz pull PinState H/L/Hiz pull PinStateFunction0 Type PULL ADDRESS Function1 Type PULL ADDRESS Function2 Type PULL ADDRESS Function3 Type PULL ADDRESS2GPIO0GPIO_0/UART1_RXDVDDIO2.8V2.8V, 166K HUPINPUT HUPINPUT GPIO_0 I/O UP 0x01A2A090(0x0) UART1_RXD I UP 0x01A2A090(0x1) SPI2_CLK I/O UP 0x01A2A090(0x2)1GPIO1 GPIO_1/UART1_TXD 2.8V, 166K L DN INPUT L DN INPUT GPIO_1 I/O DN 0x01A2A094(0x0) UART1_TXD O OFF 0x01A2A094(0x1) SPI2_CS_0 I/O UP 0x01A2A094(0x2)3GPIO2 GPIO_2/UART1_RTS 2.8V, 166K L DN INPUT L DN INPUT GPIO_2 I/O DN 0x01A2A098(0x0) UART1_RTS I UP 0x01A2A098(0x1) SPI2_CS_1 I/O UP 0x01A2A098(0x2) PWL_1 O OFF 0x01A2A098(0x3)4GPIO_3 GPIO_3/UART1_CTS 2.8V, 166K L DN INPUT L DN INPUT GPIO_3 I/O DN 0x01A2A09C(0x0) UART1_CTS O OFF 0x01A2A09C(0x1) SPI2_DI_0 I/O DN 0x01A2A09C(0x2) LPSCO_1 O OFF 0x01A2A09C(0x3)23 GPIO_4 GPIO_4/UART2_RXD 2.8V, 166K HUPINPUT HUPINPUT GPIO_4 I/O UP 0x01A2A0A0(0x0) UART2_RXD I UP 0x01A2A0A0(0x1) SPI2_DI_1 I UP 0x01A2A0A0(0x2) LPG O UP 0x01A2A0A0(0x3)22 GPIO_5 GPIO_5/UART2_TXD 2.8V, 166K L DN INPUT L DN INPUT GPIO_5 I/O DN 0x01A2A0A4(0x0) UART2_TXD O OFF 0x01A2A0A4(0x1) LCD_TE I DN 0x01A2A0A4(0x2) PWT O OFF 0x01A2A0A4(0x3)29 GPIO_6 GPIO_6/UART2_RTS/I2C3_SCL 2.8V, 33K L DN INPUT L DN INPUT GPIO_6 I/O DN 0x01A2A0A8(0x0) UART2_RTS I UP 0x01A2A0A8(0x1) I2C3_SCL I/O UP 0x01A2A0A8(0x2) TCO_3 O OFF 0x01A2A0A8(0x3)14 GPIO_7 GPIO_7/UART2_CTS/I2C3_SDA 2.8V, 33K L DN INPUT L DN INPUT GPIO_7 I/O DN 0x01A2A0AC(0x0) UART2_CTS O OFF 0x01A2A0AC(0x1) I2C3_SDA I/O UP 0x01A2A0AC(0x2) TCO_4 O OFF 0x01A2A0AC(0x3)\GPIO_8 SSD_CLK/SPI1_CLKVMMC1.8/1.9/2.0/2.6/2.8/3.0/3.3V1.9V, 166K L OFF OUTPUT 26MHz OFF OUTPUT SDMMC_CLK O OFF 0x01A2A04C(0x0) GPIO_8 I/O DN 0x01A2A04C(0x1) SPI1_CLK I/O DN 0x01A2A04C(0x2) I2C1_SCL I/O UP 0x01A2A04C(0x3)\ GPIO_9 SSD_CMD/SPI1_CS0 1.9V, 50K H UP INPUT H UP INPUT SDMMC_CMD I/O UP 0x01A2A050(0x0) GPIO_9 I/O DN 0x01A2A050(0x1) SPI1_CS_0 I/O UP 0x01A2A050(0x2) I2C1_SDA I/O UP 0x01A2A050(0x3)\ GPIO_10 SSD_DATA0/SPI1_CS1 1.9V, 50K H UP INPUT H UP INPUT SDMMC_DATA_0 I/O UP 0x01A2A054(0x0) GPIO_10 I/O DN 0x01A2A054(0x1) SPI1_CS_1 I/O UP 0x01A2A054(0x2)42 GPIO_11 SSD_DATA1/SPI1_DI_O 1.9V, 50K H UP INPUT H UP INPUT SDMMC_DATA_1 I/O UP 0x01A2A058(0x0) GPIO_11 I/O DN 0x01A2A058(0x1) SPI1_DI_0 I/O DN 0x01A2A058(0x2)\ GPIO_12 SSD_DATA2/SPI1_DI_1 1.9V, 50K H UP INPUT H UP INPUT SDMMC_DATA_2 I/O UP 0x01A2A05C(0x0) GPIO_12 I/O DN 0x01A2A05C(0x1) SPI1_DI_1 I DN 0x01A2A05C(0x2)\ GPIO_13 SSD_DATA3 1.9V, 50K H UP INPUT H UP INPUT SDMMC_DATA_3 I/O UP 0x01A2A060(0x0) GPIO_13 I/O DN 0x01A2A060(0x1)\GPIO_14GPIO_14/I2S_BCKVLCD1.8/2.8V1.9V, 166K H OFF OUTPUT H OFF OUTPUT LCD_RSTB O OFF 0x01A2A064(0x0) GPIO_14 I/O DN 0x01A2A064(0x1) DAI_RST I DN 0x01A2A064(0x2) I2S_BCK I/O DN 0x01A2A064(0x3)\ GPIO_15 GPIO_15/I2S_LRCK 1.9V, 166K H OFF OUTPUT H OFF OUTPUT SPI_LCD_CS O OFF 0x01A2A068(0x0) GPIO_15 I/O DN 0x01A2A068(0x1) DAI_CLK O OFF 0x01A2A068(0x2) I2S_LRCK I/O DN 0x01A2A068(0x3)\ GPIO_16 GPIO_16/I2S_DI 1.9V, 166K H OFF OUTPUT H OFF OUTPUT SPI_LCD_SCK O OFF 0x01A2A06C(0x0) GPIO_16 I/O DN 0x01A2A06C(0x1) DAI_DI I DN 0x01A2A06C(0x2) I2S_DI I DN 0x01A2A06C(0x3)\ GPIO_17 GPIO_17/I2S_DO 1.9V, 166K L DN OUTPUT L DN OUTPUT SPI_LCD_DIO I/O DN 0x01A2A070(0x0) GPIO_17 I/O DN 0x01A2A070(0x1) DAI_DO O OFF 0x01A2A070(0x2) I2S_DO O OFF 0x01A2A070(0x3)\ GPIO_18 GPIO_18 1.9V, 166K H OFF OUTPUT H OFF OUTPUT SPI_LCD_SDC O OFF 0x01A2A074(0x0) GPIO_18 I/O DN 0x01A2A074(0x1)\GPIO_19 GPIO_19/I2C2_SCLVCAM1.8/2.8V1.9V, 33K H OFF OUTPUT H OFF OUTPUT CAM_PWDN O OFF 0x01A2A078(0x0) GPIO_19 I/O DN 0x01A2A078(0x1) I2C2_SCL I/O UP 0x01A2A078(0x2)\ GPIO_20 GPIO_20/I2C2_SDA 1.9V, 33K L OFF OUTPUT L OFF OUTPUT CAM_RSTB O OFF 0x01A2A07C(0x0) GPIO_20 I/O DN 0x01A2A07C(0x1) I2C2_SDA I/O UP 0x01A2A07C(0x2)\ GPIO_21 GPIO_21 1.9V, 166K L OFF OUTPUT L OFF OUTPUT CAM_CLK O OFF 0x01A2A080(0x0) GPIO_21 I/O DN 0x01A2A080(0x1)\ GPIO_22 GPIO_22 1.9V, 166K H DN OUTPUT H DN OUTPUT SPI_CAM_SCK I/O DN 0x01A2A084(0x0) GPIO_22 I/O DN 0x01A2A084(0x1)\ GPIO_23 GPIO_23 1.9V, 166K L DN INPUT L DN INPUT SPI_CAM_DI_0 I DN 0x01A2A088(0x0) GPIO_23 I/O DN 0x01A2A088(0x1) SPI_CAM_DI_1 I DN 0x01A2A088(0x2)\ GPIO_24 GPIO_24 1.9V, 166K L DN INPUT L DN INPUT SPI_CAM_DI_1 I DN 0x01A2A08C(0x0) GPIO_24 I/O DN 0x01A2A08C(0x1) SPI_CAM_DI_0 I DN 0x01A2A08C(0x2) SPI_CAM_SSN I/O DN 0x01A2A08C(0x3)\GPIO_25GPIO_25VDDIO2.8V2.8V, 166K L DN INPUT L DN INPUT KEYIN_0 I DN 0x01A2A0B0(0x0) GPIO_25 I/O DN 0x01A2A0B0(0x1)\ GPIO_26 GPIO_26 2.8V, 166K L DN INPUT L DN INPUT KEYIN_1 I DN 0x01A2A0B4(0x0) GPIO_26 I/O DN 0x01A2A0B4(0x1)\ GPIO_27 GPIO_27 2.8V, 166K L DN INPUT L DN INPUT KEYIN_2 I DN 0x01A2A0B8(0x0) GPIO_27 I/O DN 0x01A2A0B8(0x1)\ GPIO_28 GPIO_28 2.8V, 166K L DN INPUT L DN INPUT KEYIN_3 I DN 0x01A2A0BC(0x0) GPIO_28 I/O DN 0x01A2A0BC(0x1)6GPIO_29 GPIO_29 2.8V, 166K L DN INPUT L DN INPUT KEYIN_4 I DN 0x01A2A0C0(0x0) GPIO_29 I/O DN 0x01A2A0C0(0x1)7GPIO_30 GPIO_30 2.8V, 166K L DN INPUT L DN INPUT KEYOUT_0 I/O DN 0x01A2A0C4(0x0) GPIO_30 I/O DN 0x01A2A0C4(0x1)5GPIO_31 GPIO_31 2.8V, 166K L DN INPUT L DN INPUT KEYOUT_1 I/O DN 0x01A2A0C8(0x0) GPIO_31 I/O DN 0x01A2A0C8(0x1)\ GPIO_32 GPIO_32 2.8V, 166K L DN INPUT L DN INPUT KEYOUT_2 I/O DN 0x01A2A0CC(0x0) GPIO_32 I/O DN 0x01A2A0CC(0x1)41 GPIO_33 GPIO_33/32K_OUT 2.8V, 166K L DN INPUT L DN INPUT KEYOUT_3 I/O DN 0x01A2A0D0(0x0) GPIO_33 I/O DN 0x01A2A0D0(0x1) DBG_CLK(32Kclockout) O OFF 0x01A2A0D0(0x5)\ GPIO_34 GPIO_34 2.8V, 166K L DN INPUT L DN INPUT KEYOUT_4 I/O DN 0x01A2A0D4(0x0) GPIO_34 I/O DN 0x01A2A0D4(0x1) HST_CLK I DN 0x01A2A0D4(0x5)25 GPIO_35 HST_RXD/GPIO_35 VDDIO2.8V2.8V, 166K H UP INPUT H UP INPUT HST_RXD I UP 0x01A2A0D8(0x0) GPIO_35 I/O DN 0x01A2A0D8(0x1)26 GPIO_36 HST_TXD/GPIO_36 2.8V 166K H UP OUTPUT H UP OUTPUT HST_TXD I/O UP 0x01A2A0DC(0x0) GPIO_36 I/O DN 0x01A2A0DC(0x1)
4.2. Working modeThe table below briefly describes the various modes of work mentioned in the next few chapters.Table 6：Work modeMode FunctionNormal workGSM/GPRS SLEEPIf the DTR pin is high and there is no interrupt (for example, GPIO interrupt or serialdata wake‐up interrupt), the module will automatically enter the sleep mode. Sleepmode, the module is still able to receive packets, short messages and calls.GSM IDLE Software running normally. Module registration on GSM network, no data, voiceand SMS interaction.GSM TALKGSM connection to work properly. Have data or voice or SMS interaction. In thismode, the power consumption of the module depends on the strength of theenvironmental signal, dynamic DTX control and the working frequency of the radio.GPRS IDLE Module is not registered to GPRS network. Modules cannot be accessed throughGPRS channels.GPRS STANDBY The module registers on the GPRS network, but does not activate the PDP context(the module does not get the IP address).GPRS READY The PDP context is successfully activated (the module has acquired the IP address),but no data is transferred. In this state, the module can send or receive data.GPRS DATAGPRS data transfer. In this mode, the power dissipation of the module depends onthe power control level, the working RF frequency band and the GPRS multi slotconfiguration.Shutdown modeBy sending the "AT+CPOWD=1" command, using the PWRKEY pin or using "RESET" 1 "pins to achieve thenormal shutdown. The Power Supply management chip turns off the baseband power supply and retains onlythe RTC power supply. The software is not running, the serial port can not access. Maintain VBATPower Supplypower supply.Minimumfunction mode(keep powersupply voltage)Without power down, the "AT+CFUN" command can be used to set the module into the least functional mode.In this mode, the radio doesn't work, or the SIM card doesn't work, or both of them don't work, but the serialport is still accessible. The power consumption is very low in this mode.
Air208 Hardware Design ManualPage19 Totally 57 pages4.3. Power Supply4.3.1. Module power supply working characteristicsPower Supply design is a very important part of GSM / GPRS module design. Since there is a burst of 577us (ie1/8 TDMA cycle (4.615ms)) every 4.615ms when GSM is transmitting. During the burst phase, Power Supply must beable to provide high peak currents to ensure that the voltage does not drop to the module's minimum operatingvoltage.For the Air202 module, the peak current of the module will reach 1.6A at the maximum transmit power level,which will cause the VBAT terminal voltage to drop. In order to ensure stable and normal operation of the module, itis recommended that the maximum voltage drop at the module VBAT terminal should not exceed 400mV.Chart 3：Voltage and current waveforms of module emission4.3.2. Reduce voltage dropModule's power supply VBAT input voltage range is 3.4V~4.2V, but in the RF module usually produces PowerSupply voltage drop phenomenon in VBATPower Supply, this is due to the impedance of the Power Supply androuting path, is difficult to avoid. Therefore, special attention must be paid to the power supply design of the moduleto ensure that the VBAT voltage will not drop below 3.0V. When the voltage drops below 3.0V, the power‐down maybe shut down or restarted. At the VBAT input, it is recommended to connect a 100uF tantalum capacitor with low ESR(ESR = 0.7Ω) and a 100nF, 33pF, 10pF filter capacitor (0603 package) in parallel with the VBAT input reference circuit.And recommend that VBAT PCB traces as short and wide enough, the equivalent impedance decreases VBAT line,ensuring the maximum transmit power at high current will not produce too big voltage drop, voltage drop generallycontrolled within 400mV. Recommended VBAT alignment width of not less than 2mm, and the longer the alignment,the wider the line width.Note: The module's hardware shutdown voltage is 3.0V.
Air208 Hardware Design ManualPage20 Totally 57 pagesChart 4：VBAT INPUT REFERENCE CIRCUIT4.3.3. Power supply reference circuitThe power supply design is crucial to the power supply to the module and must be selected with Power Supplycapable of delivering at least 2A current capability. If the input voltage and the voltage difference between the supplyvoltage of the module is not very large, it is recommended to select the LDO as the Power Supply Supply. If there is alarge pressure difference between the input and output, then use the switch Power Supply converter.LDO power supply：The following figure is +5V Reference design powered by Micrel's LDO, model MIC29302WU. Its output voltage is4.16V, and the peak load current is 3A. In order to ensure the stability of the output Power Supply, it is recommendedto reserve a voltage regulator at the output terminal, and close to the module VBAT pin. It is suggested that thevoltage regulator with reverse breakdown voltage of 5.1V and dissipation power of more than 1W is selected.
Air208 Hardware Design ManualPage21 Totally 57 pagesChart 5：Power Input Reference DesignDC-DC power supply：Below is the DCDC Power Supply Reference design switch, the JW5033H switch is Power Supply chip Jiehuate company, its maximum output current at 2A, while the input voltage range. Note that the selection of C25 depends on the input voltage to select the withstand voltage.Chart 6：DCDCPower Input Reference Design4.4. Boot and shutdown4.4.1. BootAir208 module can be powered on via the PWRKEY pin. The off state long press the power button above 2Smodule will enter the boot process, the software will detect the VBAT pin voltage if VBAT pin voltage is greater thanthe software set the boot voltage (default 3.55V), will continue to boot up until the system boot is complete;otherwise, will stop the execution of the boot operation, the system will shut down.By default, the AT command version is adaptive baud rate (AT + IPR = 0). In adaptive baud rate mode,the boot initialization message "RDY" will not be sent back to the master. After the module is powered on, youcan send an AT command to the module to train the baud rate to be the same as the master. The masterneeds to send the "at" character to the module to train it (be careful to lower the "at"). Generally send a at thebaud rate can be trained over, the module will be reported initialization information. Since then you can usethe normal AT command, uppercase and lowercase can be.4.4.1.1 PWRKEY Pin bootAfter VBAT is powered on, the PWRKEY pin can start the module. After PWRKEY pin is pulled low for 2s, thePWRKEY pin can be released. You can determine whether the module is powered on by detecting the level of the
Air208 Hardware Design ManualPage22 Totally 57 pagesVDDIO pin. It is recommended to use an open collector driver to control the PWRKEY pin. The picture below isReference circuit：Chart 6：Open set driver reference boot circuitAnother way to control the PWRKEY pin is to use a button switch directly. A TVS should be placed near thebutton to protect the ESD.The picture below is Reference circuit：Chart 7：Button bootReference circuit4.4.2. ShutdownThe following ways can shut down the module：♦Normal shutdown: Use the PWRKEY pin to shut down.♦Low‐voltage automatic shutdown: shutdown when the module detects low voltage.♦Emergency shutdown: shut down by RESET pin.♦AT command shutdown.
Air208 Hardware Design ManualPage23 Totally 57 pages4.4.2.1 PWRKEY Pin shutdownWhen the PWRKEY pin is pulled down for more than 2S, the module will perform shutdown operation.During the shutdown process, the module needs to log off the GSM network. The logout time is related to thecurrent network status. The measured time is about 2s ~ 12s. Therefore, it is recommended to extend the system by12s before powering off or restarting, so as to ensure that the software to save important data before completepower‐off.4.4.2.2 Low voltage automatic shutdownWhen the module is in running state When the VBAT pin voltage is lower than the software set shutdown voltage (the default setting is 3.0V), the software will shut down the module to prevent various abnormal running under the condition of low voltage.4.4.2.3 AT command shutdownThe user can close the module with "AT + CPOWD = 1". After the module is shut down, the moduleenters shutdown mode and no further AT commands can be executed. Power-down mode can be used toindicate VDDIO pin, low indicates that the module has entered shutdown mode4.4.2.4 RESET mergency shutdownThe thirty‐fourth pin of Air208 module is reset pin, and its function is hardware shutdown.It can be shutdown by pulling down the RESET pin 200ms or so. The OC driver circuit is recommended to controlthe RESET pin. The picture below is Reference circuit：Chart 8：Open driver reference emergency shutdown circuit
Air208 Hardware Design ManualPage24 Totally 57 pagesAnother way to control the RESET pin for emergency shutdown is to use a pushbutton switch directly. Place aTVS tube near the button for ESD protection. The picture below is Reference circuit：Chart 9：Button emergency shutdownReference circuit4.5. Power saving technologyAccording to the system requirements, there are two ways to make the module into a low power state. For theAT version, the "AT+CFUN" command enables the module to enter the least functional state.4.5.1. Least functional modeMinimal function mode can minimize the module function, this mode can be set by sending "AT + CFUN = <fun>"command. <fun> parameters can choose 0,1,4♦0：Minimum function (turn offRF and SIM card)；♦1：Full function (default)；♦4：Turn off the RF sending and receiving functions；If the module is set to the least functional mode with "AT + CFUN = 0", the functions of the radio section and theSIM card section will be switched off. The serial port is still valid, but the RF part and the SIM card part related to theAT command is not available.If the module is set using "AT + CFUN = 4", the RF section will be turned offand the serial port will still be active.All RF commands related to the RF section are not available.After the module is set by "AT + CFUN = 0" or "AT + CFUN = 4", the module can be returned to the full functionby the "AT + CFUN = 1".4.5.2. Sleep Mode (Slow Clock Mode）Air202 Supports sleep mode. For AT version, the sleep mode is controlled by the DTR pin. When DTR is high level,the module is allowed to sleep. When DTR is high, the module enters sleep mode at about 30s when no action istaken. DTR is high level When the module goes low, the module wakes up. At the same time, the AT command can bewoken up continuously by the main serial port, but some AT commands will be lost.
Air208 Hardware Design ManualPage25 Totally 57 pages4.5.3. Sleep wakeWhen the module is in sleep mode, the following method can wake up the module.♦The AT version pulls the DTR pin down and wakes the module. The 20ms port is activated after the DTR pin ispulled down♦Receive calls or GPRS data to wake up the module.♦Receive SMS to wake up module.4.6. Mode switching summaryTable 7：Mode switching summaryCurrent mode Next modeShutdown Normal mode Sleep modeShutdown Use PWRKEY bootNormal modeUse the PWRKEY pin, or use theRESET pin, or the VBAT voltage islower than the shutdown voltageSoftware call sleep interface, ATversion does not do action for30s it will sleep automaticallySleep modeUse PWRKEY or RESET pin or VBATvoltage is lower than shutdownvoltageGPIO pin interrupt, timer, receiveSMS or GPRS data4.7. Serial portThe module provides two general asynchronous transceivers: the main serial port UART1 and the auxiliary serialport UART2. Module Supports fixed baud rate and adaptive baud rate. Adaptive baud rate Supports range 4800bps to115200bps.Main serial port♦UART1_TXD：Send data to the RXD end of the DTE device♦UART1_RXD：Receive data from the TXD end of the DTE device♦UART1_RTS：TheDTErequeststosenddatatoDCE♦UART1_CTS：Clear send♦UART1_DTR：DTE is ready and notify DCE (this pin can be used to wake up the module）♦UART1_RI：Ringing (DCE has incoming call or URC or short message will send signal to notify DTE）♦UART1_DCD：Carrier detection (when the communication link between DCE and DTE is established）
Air208 Hardware Design ManualPage26 Totally 57 pages♦By default, the hardware flow control of the module is closed. When the client needs hardware flow control, pinsRTS, CTS must be connected to the client, and the AT command "AT+IFC=2,2" can be used to open the hardwareflow control. The AT command "AT+IFC=0,0" can be used to shut down the flow control. Please refer todocument [AT]）Auxiliary serial port UART2♦UART2_TXD：Send data to the serial port of DTE♦UART2_RXD：Receive data from serial port of DTE♦Serial logic level is shown as the following table：Table8：Serial logic levelParameter Minimum value Maximum value UnitVIL 00.25×VDDIOVVIH 0.75×VDDIO VDDIO +0.3 VVOL 00.15×VDDIO VVOH 0.85×VDDIO VDDIO VTable 9：Definition of serial port pinsInterface Name pinFunctionMain serial portUART1UART1_DTR 12 DTE is readyUART1_TXD 8 Send data by serial portUART1_RXD 9 Serial port receives dataUART1_CTS 6 Clear sendUART1_RTS 7 DTE requests to send dataUART1_DCD 10 Carrier detectionUART1_RI 11 Ringing indicationAuxiliaryserial portUART2UART2_RXD 27 Serial port receives dataUART2_TXD 28 Serial port sends data
Air208 Hardware Design ManualPage27 Totally 57 pages4.7.1. Main serial port4.7.1.1 Main serial port features♦It includes data line TXD and RXD, hardware flow control line RTS and CTS, other control lines DTR, DCD and RI.♦8 data bits, no parity, a stop bit.♦Hardware flow control is turned off by default。♦To send AT commands, GPRS data transmission, CSD fax and so on.♦Supports baud rate as follows:1200,2400,4800,9600,14400,19200,28800,38400,57600,115200,230400,460800,921600♦AT command version By default, the module is adaptive baud rate (AT + IPR = 0). In adaptive baud rate mode,initialization information (beginning with "RDY") will not be sent back to the master after booting. 2‐3secondsafter the module is powered on, AT commands can be sent to the module. The host computer needs to send the"AT" character to the module to train the baud rate of the host computer first. At this moment, the module willreport the initialization information indicating that the training is successful. The user can send an "AT + IPR = x:& W" command to the module (x is the baud rate, such as 9600). The function of this command is to set a fixedbaud rate and save it. After completing these configurations, Module boot, the serial port will automaticallyreturn URC initialization information (beginning with "RDY"）。Synchronization between the module and the host computer：：When the module is powered on with adaptive baud rate turned on, it is best to wait 2 ~ 3 seconds before sending"AT" character. When the module reports the initialization information, it indicates that the training of baud rate issuccessful and the synchronization is completed with the host computer.In adaptive baud rate mode, the master must first synchronize if it needs a power‐on message. Otherwise, theinitialization information will be omitted：♦Serial port configuration is 8 data bits, no parity, 1 stop bit (factory configuration）♦Only the string "AT" when the module is switched on can train the baud rate. ("At", "At" or "aT" can not berecognized）.♦Baud rate training is successful, you can identify the uppercase, lowercase or uppercase and lowercase ATcommand combination.♦In adaptive baud rate mode, URC information such as "RDY", "+ CFUN: 1" and "+ CPIN: READY" will not bereported if the module is powered on without synchronization.♦It is not recommended to switch to adaptive baud rate mode when fixed baud rate mode.♦In adaptive baud rate mode, it is not recommended to switch to software multiplex mode4.7.1.2 Main serial port connection modeMain serial portThe main serial port connection mode is more flexible, as follows are three commonly usedconnection mode.Full‐featured serial port in accordance with the following connection, this mode is mainly used in modem mode(PPP dial‐up).
Air208 Hardware Design ManualPage28 Totally 57 pagesChart 10：Full‐featured serial port connection diagramPlease refer to the following connection mode for three wire serial port：Chart 11：Serial three‐wire connection diagramPlease refer to the following circuit connection with flow control serial port connection, this connection canincrease the reliability of large amounts ofdata transmission, to prevent data loss.
Air208 Hardware Design ManualPage29 Totally 57 pagesChart 12：Schematic diagram of serial connection mode with flow control4.7.2. Debug serial port♦Data cable：HOST_TXD and HOST_RXD♦Debug port is for software debugging only, baud rate is configured to 921600bps♦The serial port will automatically output log information to the outsidePlease refer to following ways to debug serial port connection：Chart 13：Software debugging connection diagram
Air208 Hardware Design ManualPage30 Totally 57 pages4.7.3. Serial port applicationFor the 3.3V voltage system in the case of the serial port level matching circuit reference is as follows, it isstrongly recommended to use RXD modules such as the input port on the resistor divider, the voltage is divided to2.8V.If it is 3V system, according to the principle of partial pressure, it is recommended to change the 5.6K resistanceto the 10K resistor. It is also suggested that 1K resistors must be connected in series when customers don't allowpartial pressure.Chart 14：3.3V Level conversion circuit5V system level matching, level matching between the module and peripherals can refer to the followingconnections, the dotted line below can refer to the above solid line circuit (the dotted line module to send thereference module TXD circuit design, the dotted line module Receive reference module RXD circuit design).VCC_MCU is the client's I / O voltage level. VDDIO is the module output I / O voltage level.
Air208 Hardware Design ManualPage31 Totally 57 pagesChart 15：5VLevel conversion circuitWhen the module communicates with the PC, you need to add an RS232Level conversion circuit between them.Because the module's serial port configuration is not RS232 level, only SupportsCMOS level. The following figureshows the module with PC communication, serial port level conversion circuit.Chart 16：RS232 Level conversion circuit
noise at DCS1800MHz.capacitor suppliers, select the most suitable value to filter out work in GSM900MHz, High frequencyAir208 Hardware Design ManualPage32 Totally 57 pages4.8. Audio interfaceThe module provides an analog audio input channel and a channel analog output channel, Supports call,recording and playback functions。Table10：Audio interfacePin definitionInterface Interface name Interface no. FunctionAINMICP 9 Audio input positive endMICN 10 Audio input negative endAOUTSPKP 11 Audio output positive endSPKN 12 Audio output negative endAIN can be used as a microphone input or an analog audio signal input. Microphones usually use electretmicrophones. AIN1 is a differential input.AOUT channels can directly drive 8 ohm speakers. The AOUT channel is differential output.4.8.1. Preventing TDD noise and other noisesAs for handheld speakerphone and handsfree microphones It is recommended to use a built‐in RF filter dualcapacitor (such as 10pF and 33pF) electret microphone to filter out radio frequency interference from theinterference source will greatly improve the coupling TDD noise. The 33pF capacitor is used to filter outhigh‐frequency interference when the module is operating at 900MHz. If you do not add this capacitor, you may hearTDD noise during the call. At the same time 10pF capacitor is used to filter out the work in the 1800MHz frequencyhigh frequency interference. It should be noted that, because the capacitance of the resonance point depends largelyon the material of the capacitor and the manufacturing process, so the choice of capacitor, you need to consult theThe severity of high frequency interference at GSM transmission usually depends mainly on the customerapplication design. In some cases, GSM900 TDD noise is more serious, and in some cases, DCS1800 TDD noise is moreserious. Therefore, customers can filter the results of the election according to the needs of the filter capacitor, andsometimes do not need to paste this type of filter capacitor.PCB RF filter capacitor placed on the position as close as possible to Audio devices or Audio interface, alignmentas short as possible, to go through the filter capacitor and then to other points.Position the antenna away from the Audio component and the Audio traces as far as possible to reduce radiatedinterference. The Power Supply traces should not be parallel to the Audio traces. The Power Supply traces should beas far away as possible from the Audio lines.Differential Audio traces must follow the Layout rules for differential signals.
Air208 Hardware Design ManualPage33 Totally 57 pages4.8.2. Microphone interface reference circuitAIN channel built‐in electret microphone bias voltage. Microphone channel reference circuit shown below：Chart 17：AIN MICROPHONE CHANNEL INTERFACE CIRCUIT4.8.3. Audio output interface reference circuitSPKAudio Output Interface can be directly driven with 8 ohm speaker.Chart 18：Reference line
Air208 Hardware Design ManualPage34 Totally 57 pages4.8.4. Audio Electrical characteristicsTable 11：Typical characteristics of electret microphonesParameter Minimum Typical Maximum UnitWorking voltage 1.0 1.25 2.0 VWorking current 500 MaImpedance 2.2 KΩTable 12：Audio interfaceTypical characteristic parametersParameter Minimum Typical Maximum UnitAOUTSingle‐endedoutputLoad8ΩReference level 02.4VppDifferentialoutputLoad8ΩReference level 04.8Vpp
Air208 Hardware Design ManualPage35 Totally 57 pages4.9. SIM CARD INTERFACEThe SIM card interface supports the functions of the GSM Phase1 specification, as well as the functions of theGSM Phase 2+ specification and the FAST64 kbps SIM card (used in the SIM application toolkit).The SIM card is powered by the internal power supply of the module to support 1.8V and 3.0V power supply.4.9.1. SIM INTERFACEThe following table describes the SIM interface pin definitions.Table13：SIM CARD INTERFACEPin definitionPin name Pin no. FunctionSIM_VDD 18 SIM card power supply automatic detects SIM card operating voltage. Theaccuracy is 3.0V ± 10% and 1.8V ± 10%. The maximum supply current is10mA.SIM_RST 17 SIM card Reset pinSIM_DATA 15 SIM card data cableSIM_CLK 16 SIM card clock lineSIM_DET14 SIM card in position detectionThe figure below is the reference circuit SIM interface, using of 6pin SIM card connector.Chart 19：Using a 6pin SIM Card Reference Schematic (SIM)
Air208 Hardware Design ManualPage36 Totally 57 pagesIf you need to use sim card in place detection, the recommended circuit is as follows.Chart 20：With the detection of PIN SIM card reference circuit diagramIn SIM CARD INTERFACE circuit design, in order to ensure the SIM card's good functional performance and is notdamaged, the circuit design is recommended to follow the following design principles：♦SIM card holder and the module can not be too far away from the ornaments, the closer the better, try to ensurethat SIM card signal cable is not exceed 20cm.♦The SIM card signal cable is routed away from the RF cable and the VBAT power cable.♦The wiring width of SIM_VDD is not less than 0.3mm and the bypass circuit between SIM_VDD and SIM_GNDshould not exceed 1uF and be placed close to the SIM card holder.♦In order to prevent possible SIM_CLK signal crosstalk on the SIM_DATA signal, the two wiring should not be tooclose, increase the shielding between the two traces. And SIM_RST signal also needs protection.♦In order to ensure good ESD protection, it is recommended to add TVS tube, and placed near SIMcassette. Theselected ESD device has a parasitic capacitance of no more than 50pF, such as WILL (http://www.willsemi.com)ESDA6V8AV6. A 22 ohm resistor can be connected in series between the module and the SIM card to suppressstray EMI and enhance ESD protection. The SIM card's peripheral circuitry must be as close as possible toSIMcassette.4.9.2. 6-pin SIM card holderUsing a 6‐pin SIM card holder, Amphenol's C70710M0065122 is recommended. Visit http://www.amphenol.comfor more information.
Air208 Hardware Design ManualPage37 Totally 57 pagesChart 21：Amphenol C707 10M006 512 2 SIM cassette
Air208 Hardware Design ManualPage38 Totally 57 pages4.10. RI SIGNAL ACTIONTable 14：RI SIGNAL ACTIONStatus RI responseStandbyHigh levelVoice call After switching to low level：（1）When the call is switched on to a high level（2）Use the AT command ATH hang up the voice, RI goes high（3）The caller hangs up, RI first goes high, then pulls low for 120ms, receives an auto‐reply URC message"NO CARRIER" and then goes high（4）When SMS is received, it becomes high levelDatatransmissionAfter switching to low level：（1）It changes to high level when data connection is set up.（2）Use the AT command ATH to suspend data connections, and RI to a high level（3）The caller hangs up, RI first into high level, then pull to a low level for 120ms, received automaticreply message "NO URC CARRIER", and then into high level（4）When SMS is received, it becomes high levelSMS When a new message is received, RI goes low for 120ms and then goes high.URC Some URC information can trigger RI to pull low 120msIf the module is used as a calling party, the RI remains high except when receiving URC messages or textmessages. When the module is used as the called party, the timing of RI is as follows：Chart 22：The module is used as called party RI timing for voice call
Air208 Hardware Design ManualPage39 Totally 57 pagesChart 23：The module is used as called party RI timing for data callChart 24：RI timing of module callingChart 25：RI timing when receiving URC message or SMS
Air208 Hardware Design ManualPage40 Totally 57 pages4.11. Network status indicationNET_LEDpin signal can be used to indicate the status of the network lights. The working status of this pin is shown inthe following table：Table 15：NET_LED working statusStatus Module functionShutdown The module is not runningBright 64ms，off 800ms Can not find the networkBright 64ms，off 3000ms Registered on networkBright 64ms，off 300ms GPRS cimmunicationnot registered on the GSM network：Chart 26：NETLIGHTReference circuit
Air208 Hardware Design ManualPage41 Totally 57 pages4.12. PWMAir208supports 2 PWM outputs: PWM, LPG, multiplexed by UART2_RX and UART2_TXD respectivel.UART2Pin name Pin no. I/O Pin description Electrical characteristics RemarkUART2_RXD(LPG) 23 IHardware UART2VILmin=-0.3VVILmax=0.25×VDDIOVIHmin=0.75×VDDIOVIHmax=VDDIO+0.3VOHmin=0.85×VDDIOVOLmax=0.15×VDDIOHang when not inusageUART2_TXD(PWM) 22 OLPG (Light Pulse Generation) For low frequency applications such as driving LED flashes, only a fixed sevenkinds of cycle (Unitms) can be set: 125,250,500,1000,1500,2000,2500,3000. And 15 kinds of high time.PWM, frequency range (80‐65535HZ), and various duty cycles can be set.Please refer to the corresponding AT command document.5. Radio interfacepin 32 is the RF antenna input. RFInterface50 ohm impedance matching.Table 16：RF_ANTPin definitionPin namePin no. FunctionRF_ANT 32RF pad
Air208 Hardware Design ManualPage42 Totally 57 pages5.1. RF reference circuitChart 27：RF reference circuitAir208 pads must be microstrip or other types of RF traces and the impedance must be controlled to about 50ohms. For better RF performance, ground pads are on each side ofthe RF input port.Care must be taken to minimize the losses on the RF traces or RF cables. The recommended insertion loss mustmeet the following conditions：♦EGSM850<1dB♦DCS1900<1.5dBAir208 also built an RF connector to facilitate users to directly connect the module RF coaxial antenna, and save the board on the RF routing：
Air208 Hardware Design ManualPage43 Totally 57 pages
Air208 Hardware Design ManualPage44 Totally 57 pagesCorresponding coaxial connector as shown below：5.2. RF CONDUCTION SENSITIVITYTable 18：RF CONDUCTION SENSITIVITYBand Receiving sensitivityEGSM850DCS1900< -108.5dBm< -108.5dBm
Air208 Hardware Design ManualPage45 Totally 57 pages5.3. Recommended RF welding methodIf the RF connector for connecting the external antenna is connected to the module by soldering, be sure topay attention to the stripping method and soldering method of the connecting wire. In particular, if the soldering issufficient, follow the correct soldering method shown in the figure below, In order to avoid due to poor weldingcaused by line loss increases.Chart 28：Suggestion on RF welding method
Air208 Hardware Design ManualPage46 Totally 57 pages6. Electrical characteristics, reliability, RF characteristics6.1. Absolute MaximumThe following table shows the module digital, analog pin Power Supply supply voltage and current Maximumtolerance value.Table20：Absolute MaximumParameter Minimum Maximum UnitVBAT ‐0.3 4.2 VPower supply peak current 0 2 APower supply average current (TDMA oneframe time)00.7ADigital pin voltage ‐0.3 3.3 VAnalog pin voltage ‐0.3 3.0 VOff / Off mode digital / analog pin voltage ‐0.25 0.25 V6.2. working temperatureTable 21：working temperatureTemperature Minimum Typical Maximum UnitNornal workingtemperature‐40 25 85 ℃storagetemperature ‐45 90 ℃
Air208 Hardware Design ManualPage47 Totally 57 pages6.3. Voltage limit valueTable 22：Module power limit valueParametDescription Condition Minimum Typical Maximum UnitVBATSupply voltageThe voltage must be within this range,including voltage drops, ripple, andspikes3.4 3.8 4.2VBurst voltagedrop at launchGSM900 MaximumTransmitpower level400 mVIVBATAveragesupplycurrentShutdownmodePower on for thefirst time 34 uAShutdown afterboot(RTC worksnormally)101 uABottom current 0.8 mAStandby currentDRX=2 1.4 mADRX=5 1.14 mADRX=9 1.03 mAFlight Mode AT+CFUN=4 0.896 mAMinimum function modeAT+CFUN=00.763 mAGPRS mode(2 send，2receive)EGSM 900 1) 315.9 mADCS1800 2) 208.7 mAGPRS mose(4 receive，1send)EGSM 900 1) 203.5 mADCS1800 2) 150.1 mAPeak current/ GSM900 transmitGSM900 MaximumTransmitpower level1.8 2 A
Air208 Hardware Design ManualPage48 Totally 57 pagestime slot)1) 1) power level 52)power level 0
Air208 Hardware Design ManualPage49 Totally 57 pages6.4. Current consumptionTable 23：Module's current consumptionCondition Current consumptionGPRS data transmissionData transmission mode, GPRS ( 2 receive, 2 send) CLASS8 & CLASS 12EGSM850 @Power level5，<550mA，Typicalvalue 315.9mA@Power level10，Typicalvalue 158.2mA@Power level19，Typicalvalue 83.5mADCS1900 @Power level0，<450mA，Typicalvalue208.7mA@Power level5，Typicalvalue125mA@Power level15，Typicalvalue78.4mAData transfer mode, GPRS ( 4 receive, 1send) CLASS8 & CLASS 12EGSM850@Power level5，<350mA，Typicalvalue203.5mA@Power level10，Typicalvalue101.3mA@Power level19，Typicalvalue62.4mADCS1900 @Power level0，<300mA，Typicalvalue150.1mA@Power level5，Typicalvalue79.4mA@Power level15，Typicalvalue55.8mA
Air208 Hardware Design ManualPage50 Totally 57 pages6.5. Static ProtectionIn the module application, due to the human body static electricity, static electricity generated between themicroelectronic electrostatic friction, through various means of discharge to the module, may cause some damage tothe module, so ESD protection must pay attention to, whether in the production assembly, testing , R & D process,especially in product design, should take ESD protectionmeasures.ForexampleESDprotectionshouldbeaddedincircuit design at the Interface or vulnerable to ESD point. To wear anti‐ESD gloves in production and so on.The following table shows the ESD withstand voltage of the module PIN pin.Table 24：ESDP erformance parameters (temperature: 25 C, humidity: 45%)）Pin name Contact discharge Air dischargeVBAT,GND ±5KV ±10KVRF_ANT ±5KV ±10KVTXD, RXD ±2KV ±4KVOthers ±0.5KV ±1KV
Air208 Hardware Design ManualPage51 Totally 57 pages7. phycial dimensionThis section describes the module's phycial dimension and the recommended package dimensions for thecustomer's design using the module.
Air208 Hardware Design ManualPage52 Totally 57 pages7.1. Module phycial dimensionChart 29：Air208 Front view (unit: mm）
Air208 Hardware Design ManualPage53 Totally 57 pages7.2. Recommended PCB encapsulationChart 30：Recommended encapsulation (Unit: mm)Note: make sure the spacing between module on the PCB and other components is 3mm at least.
Air208 Hardware Design ManualPage54 Totally 57 pages7.3. Module front viewChart 31：Module front view
Air208 Hardware Design ManualPage55 Totally 57 pages7.4. Module bottom viewChart 32：Module bottom view8. Storage and production8.1. StorageAir208shipped in vacuum sealed bags. The storage of the module needs to follow the following conditions：The module can be stored in a vacuum‐sealed bag for 12 months at ambient temperatures below 40 ° C and airhumidity less than 90%.When the vacuum sealed bags open, if the following conditions are met, the module can be directly reflow or otherhigh‐temperature processes：♦Module ambient temperature below 30 degrees Celsius, air humidity less than 60%, the factory completed patchwithin 72 hours.Air humidity is less than 10%.
Air208 Hardware Design ManualPage56 Totally 57 pagesIf the module is in the following conditions, it is necessary to bake before the patch：♦When the ambient temperature is 23 degrees Celsius (5 degrees Celsius allowed fluctuations), the humidityindicator shows humidity greater than 10%♦When the vacuum sealed bag is opened, the module ambient temperature is below 30 degrees Celsius and theair humidity is less than 60%, but the factory failed to complete the patch within 72 hoursWhen the vacuum sealed bag is opened, the module storage air humidity is greater than 10%.If the module needs to be baked, please bake for 48 hours at 125 degrees Celsius (allowing 5 degrees Celsiusfluctuation).Note: The module packaging can not withstand such a high temperature, remove the module package before themodule is baked. If you only need a short baking time, please refer to the IPC / JEDECJ‐STD‐033 specification.8.2. Production weldingPrinted scraper on the screen printing solder paste, solder paste through the screen openings to the PCB on theleakage, printing scraper strength needs to be adjusted properly, in order to ensure the quality of module paste,Air202 module pad part of the corresponding stencil thickness should be 0.2mm.Chart 33：Paste mapTo avoid repeated heating damage to the module, it is recommended that the customer PCB board be reflowedafter the first side ofthe module. The recommended Furnace temperature curve is shown below：
Air208 Hardware Design ManualPage57 Totally 57 pagesChart 34：Furnace temperature curveFCC Statement Any Changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment. This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) This device must accept any interference received, including interference that may cause undesired operation. FCC Radiation Exposure Statement: This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment .This equipment should be installed and operated with minimum distance 20cm between the radiator& your body. FCC Label InstructionsThe outside of final products that contains this module device must display a label referring to the enclosed module. This exterior label can use wording such as: "Contains Transmitter Module FCC ID: 2AEGG-AIR208 or “Contains FCC ID:2AEGG-AIR208 , Any similar wording that expresses the same meaning may be used. 

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