STM3 User Manual
Contents
1. J d j j GND J 5 STM3 26 GND j J J j J GND Ye top view 25 GND RTC_IN 7 24 GND RTC_OUT 8 23 RF_OUT GND 9 22 GND GND 10 21 GND ON M vt LO co N OO o o E A rar UP UP UP UP Ur uP MUY NES Q Q Q Q N Q E Q Q Z Z Z hd Z Se Z 2 Zz ES o 0 o 1 0 CG 0 0 0 0 3 3 9 gt gt O Figure 7 STM3 Pinout Diagram CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 27 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 The following table describes STM3 pin descriptions Table 8 STM3 Pin Descriptions Pin Name Description Input Output Specification n 3 3V 5 Noise must be less 1 VCC_DIG Digital Power an 50mW peak to peak 2 SPL DI SPI Data Input Input 3 3V CMOS input 3 SPI DO SPI Data Output Output 3 3V CMOS output 4 SPL CLK SPI Clock Input 3 3V CMOS input 3 GND Ground Connect directly to a ground plane 6 GND Ground Connect directly to a ground plane Connect to a 32 768KHz crystal 7 RTC_IN 32 768KHz Input with a shunt capacitor or drive with a CMOS signal Connect to a 32 768KHz crystal 8 RTC_OUT 32 768KHz Drive with a shunt capacitor or leave unconnected 9 GND Ground Connect directly to a ground plane 10 GND Ground Connect directly2. CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 1 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 Revision History Revision 1 1 Revision Date 03 03 2010 Description of the Changes New Document 1 2 Review of content to see progress 1 3 Continued putting content into document 1 4 03 18 2010 Put in comments from Garrett amp Saad review Including Global changes e Chopin gt STM3 e Chopin Module gt Chopin device e Unit ID gt ESN e STU gt STM3 e Should shall present tense and will when applicable e High low power to standard power GE 99 e to identify pin names that may not be capitalized Replaced with all caps where found Reformatted all table headings to center alignment vertically horizontally Replaced pinout illustration with revised and reviewed drawing Highlighted all TBDs and put in notes identifying content to re review 1 5 Kerry Keksz Accepted edits and text changes Touched up Figure 7 Timing diagram Responded to comment questions Added content on ACK and NAK Minor edits made to new paragraph with Track Changes on 1 6 Kerry Keksz Put in Operating and Storage temperatures Global search replace to replace to STM3 replace air interface with OTA replace TTL with 3 3V CMOS and consistent use of Celsius and u font Updated RF Timing Spectrum C
3. Le N P X N N N A Mo A N N a 5N ee Y KH x Bes Sa Network Back Office Figure 1 System Overview CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 12 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 Figure 2 STM3 2 3 How it Works The STM3 device accepts commands and queries via a Universal Asynchronous Receiver Transmitter UART or a serial peripheral interface SPI communications channel The primary function of the device is to receive message data via one of the communications ports and then packetize and transmit the data to the satellite constellation Depending on the configuration set by the host the STM3 will repeat those messages up to 20 times at user selected intervals in order to improve the probability of the message successfully being decoded at a Gateway Receiver The number and interval of transmissions is set by user command and executed by the STM3 device To remain as power conscious as possible the default state of the STM3 device is sleep mode The STM3 microcontroller is awakened by a user signal and responds to request the when it is ready to receive commands Commands are then sent by the user and acted upon by the device When a command response transaction is complete the device re enters sleep mode While a message transmission cycle is under way the STM3 enters sleep mode between each transmission attemp
4. being turned on e The RF output power with the PA and synthesizer turned off is more than 120 dB below the nominal output power CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 15 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 e The synthesizer is not turned on more than 300us before the PA e The RF level between synthesizer turn on and PA turn on does not exceed 40dB below the nominal output power e The synthesizer is turned off no later than 10us after the PA is turned off e The RF ramp up time between 10 and 90 of the output power is less than 5us this is a limit not a slew rate requirement e The PN code is turned off no sooner than 5us before the PA is turned off The following figure illustrates the timing spectrum The spectrum complies with the EMC requirements of EMI EMC Compatibility described in section 11 The harmonic levels do not exceed 20 dBm when measured in a 5 MHz bandwidth Non harmonic related discrete spurs do not exceed 30 dBm when measured in a 100 kHz bandwidth lt 400 us gt Synthesizer Control lt 10us gt EE PA Control RE Envelppe 144 bit times gt gt 40 dB o lt 5 ys lt 5 ys di ge AE E ON Hi N EE N SC gt 120 dB j yA lt 5 US gt 5 EE a PN Control Figure 4 RF Timing Spectrum 3 5 Output Impedance The impedance of the R
5. Mode This mode occurs when the modem is waiting between transmission attempts of a packet 10pA 3 3V 25 C Current Consumption in TX Mode This mode occurs when the modem is actively transmitting 280mA 3 3V 25 C The power supply response time must be such that the output current can switch from 15mA to 280mA in less than 5 us CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 32 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 NOTES e STM3 is equipped with a voltage supervisory circuit This circuit holds the microprocessor in reset until the input voltage reaches 2 5V e Power can be removed from the STM3 at any time When power is removed any message waiting to be transmitted is lost CAUTION The STM3 power input pins are not protected against reverse polarity If the voltage at the ground pins exceeds the voltage at the VCC pins by more than 0 3V the device will be damaged 9 3 Power Source The power source or battery must be capable of providing a 280mA peak current pulse required by the transmitter in less than 5 us after the OC output falls to the ground potential Each transmit pulse lasts for at least 1 44 seconds with a minimum of 200 ms pause between each pulse CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 33 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 10 EN
6. NAK message An acknowledgement message ACK is a packet as described in Figure 5 where the contents of the command field are the same as the command being acknowledged A not acknowledgement message NAK is a packet as described in Figure 5 where the contents of the command field is OxFF CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 19 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 Table 4 Serial Packet Commands and Responses Command Description Usage Comment Command Data Bytes Answer Data Bytes 0x00 Host requests the STM3 to send the Up to 144 data bytes None data bytes contained in the message over the satellite network If the number of data bytes in the message is 9 or less the message is sent as a single packet If the number of data bytes is larger than 9 bytes multiple over the air packets are created and sent by the STM3 0x01 Host requests the modem to return None Four data bytes its ESN Contains the ESN as an unsigned integer This includes 3 bits for manufacturer ID and 23 bits for the unit ID The most significant bit is sent first The six most significant bits are always zeros Refer to section 4 11 for further details 0x02 This transmit power command has One data byte None been deprecated and remains in the interface for backwards 0x00 Standard Power compatibility The power level is 0x01 Standard Power always
7. STM3 device dimensions and requirements for integrating the STM3 device onto a printed circuit board This section includes pin outs This section is useful to all integrators Section 8 Mechanical Section 9 Power Supply This section provides mechanical specifications drawings are included in Appendix B Mechanical Drawings This section is useful to all designers and integrators who are integrating the STM3 device onto a printed circuit board and into a device This section describes power modes how they function and how an integrator can use them when integrating the STM3 device into the overall system This section also provides power requirements and parameters and is useful to all integrators Section 10 Environmental This section describes the STM3 device specifications and is useful to all Specifications integrators Section 11 EMI EMC This section describes compliance specifications to which the STM3 Compatibility device was designed to and lists the compliance testing conducted CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 10 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 1 6 Acronyms CMDC Comtech Mobile Datacom Corporation CMOS Complementary Metal Oxide Semiconductor CPLD Complex Programmable Logic Device CRC Cyclic Redundancy Check ESN Electronic Serial Number FCC Federal Communications Co
8. Standard This command does acknowledge power for backward compatibility 0x03 User requests the modem to abort None None the current transmission 0x04 Host interrogates STM3 for the None One data byte remaining number of transmission D attempts 0x00 No pending transmission OxXX Number of remaining transmission attempts 0x05 Host requests firmware version None Two data bytes number First byte Major revision Second byte Minor revision CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 20 of 38 Comtech Mobile Datacom Corporation Command Description Usage Comment Command Data Bytes CMDC DOC 1767 Rev 1 14 Answer Data Bytes 0x06 Setup message for configurable Nine data bytes None parameters First four bytes of the command are don t care and remain for backwards compatibility One byte to specify the RF Channel to be used in transmissions A 0 B 1 C 2 D 3 One byte to define the number of tries 1 5 One byte to define the minimum interval between tries Minimum value is 5 seconds maximum is 595 seconds Units are seconds 5 i e 1 5 seconds 119 595 seconds One byte to define the maximum interval between tries Minimum value is 10 seconds maximum is 600 seconds Units are seconds 5 i e 2 10 seconds 120 600 seconds Last byte of the command is don t care and remains for backwa
9. is ready to transmit the response to the command When the host has finished reading the response from the STM3 it should set the Chip Enable RTS_CE signal high and the STM3 will respond by setting the Ready CTS_RDY signal high The timing relationship for the SPI signals is illustrated in Figure 6 SPI Interface Timing Diagram The SPI interface may not function correctly if the following timing parameters are violated e Chip Enable may not be set low within 50 ms of power being applied to the STM3 device e Ifthe module responds by activating the Ready CTS RDY line within 20ms it is ready to accept data and communicate with the user equipment If no Ready CTS_RDY activation is received the user must assume that the module is busy and try again later Typically the module is only able to communicate when a message transmission is not in progress Each packet takes at least 1 44 seconds to transmit and a message may require multiple packets thus the STM3 may be busy for significant periods of time CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 22 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 gt A K 5 us lt Tready lt 20 ms gt k Tbusy lt 200us RTS_CE i Chip Enable gd CTS_RDY Ready mas M N MAN TR ENE amoo SANA ME Command Response Figure 6 SPI Interface Timi
10. to a ground plane 11 GND Ground Connect directly to a ground plane 12 GND Ground Connect directly to a ground plane 13 GND Ground Connect directly to a ground plane 3 3V 5 Noise must be less 14 VCC_RFl Power for RF Circuitry than SOmVpeak to peak Tie to OC_OUT controlled switch 15 GND Ground Connect directly to a ground plane 3 3V 5 Noise must be less 16 VCC_RF2 Output Amplifier Power than 50mV peak to peak Tie to OC_OUT controlled switch 17 GND Ground Connect directly to a ground plane Open Collector output High 18 OC_OUT PA Notification Signal Output impedance while idle Ground when transmitting 19 GND Ground Connect directly to a ground plane 20 GND Ground Connect directly to a ground plane 21 GND Ground Connect directly to a ground plane 22 GND Ground Connect directly to a ground plane 23 RF OUT RF Output Tie to antenna with 50 ohm 5 trace keep less than 1 CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 28 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 Pin Name Description Input Output Specification 24 GND Ground Connect directly to a ground plane 25 GND Ground Connect directly to a ground plane 26 GND Ground Connect directly to a ground plane 27 NC No Connection Do not connect 28 NC No Connection Do not connect 29 NC No Connection Do not connect 30 NC N
11. CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 23 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 4 11 STM3 Electronic Serial Number The ESN field consists of the following sub fields shown in the following table Table 5 ESN Structure Sub Field Number of Bits Bits Manufacturer ID 3 25 23 Unit ID 23 22 0 CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 24 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 5 TEST INPUTS 5 1 Purpose of this Section This section provides an understanding of test inputs and the test modes available on the STM3 device This section describes test modes how they function and how they may be used during integration and testing 5 2 TEST1 and TEST2 Modes Inputs TEST1 and TEST2 are provided to put the STM3 device in one of three test modes These test modes may be useful during integration testing but their use is not recommended in a field deployed system The test inputs are checked at power up so they must be set prior to powering up the module The inputs are logic level inputs and internal weak pull ups are provided to put the module in the normal operation mode when the terminals are not connected The frequency on which the transmitter operates while in these test modes is the same as is configured by the configuration command see Table 2 Cha
12. F Output is matched to 50Q 5 over the band from 1611 25 to 1618 75 MHz 3 6 RF Antenna For optimum energy transfer to the satellite an LHCP Left Hand Circular Polarized antenna is recommended An integrator must ensure that their overall antenna system CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 16 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 does not exceed a maximum gain of 5dBi in the spatial area between 25 degrees and 90 degrees per requirements set forth by Global Star and the FCC The recommended antenna is the Spectrum Control PA25 1615 025SA This antenna should be mounted on a 70mm x 70mm ground plane as stated in the manufacturer s antenna catalog The antenna may be mounted on the same PCB as the STM3 or the antenna may be on a separate PCB If the antenna is mounted on the same PCB as the STM3 it is recommended that the STM3 be placed on the opposite side of the PCB from the antenna This will more easily allow the PCB to be compatible with the 70mm x 70mm antenna requirement If the antenna is on a separate PCB the 50 ohm coax cable should not have more than 0 5dB of loss RG 223 cable is recommended for this connection The length of the RG 223 should not exceed 36 inches 37 RF Antenna Feed The RF energy exits the STM3 at pin 23 of the device which has a characteristic impedance of 50 ohms This pad should be connected to the antenna through
13. ICAL es ees es de ese ve Se wese Ede Eet SL PURPOSE OF THIS SECTION si EE GN Ee iia 8 2 MECHANICAL SPECIFICATIONS ee ee se ee ese ee ee ee ee ee ee ee ge ee ee ee ee ee Re Re ee ee ee ee RR Re ee ee 8 3 RECOMMENDED PCB FOOTPRINT ees ese ee ee ee ee se ee ee ge ee ee ee ee ee Re Re ee ee ee RR Re ee ee 8 4 GENERAL STM3 MOUNTING GUIDELINES esse ee ee ve ee ee ee ee ee ee ee ese ee ee ee ee RR ge ee ee 9 POWER SUPPLY NE EE EE EE EE N ER Ee 9 1 PURPOSE OF THIS SECTION ee ees ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee 9 2 DEPOWERMODES EES IE a De ee Ge Ee GE EG ee ed 03 POWER SOURCE os Ge Ee n a Ada iaa aaa 10 ENVIRONMENTAL SPECIFICATIONS uusse esse sesse sees se sees se ees se ese e See se ees see se 10 1 PURPOSE OF THIS SECTION esse ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee 10 2 POWER SPECIFICATIONS eise ee ee ee ee se ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee 10 3 ENVIRONMENTAL AND MECHANICAL SPECIFICATIONS ees ese ee ee ee ee ee ee 11 EMI EMC COMPATIBILITY oe seke osse iese Bee Ge ode aas ede eg age ke Ge se ie bede dee 11 1 PURPOSE OF THIS SECTION esse ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee 11 2 COMPLIANCE STANDARD APPENDIX A CRC CALCULATION ALGORITHM sesse sesse esse sees sesse ss ese ee APPENDIX B MECHANICAL DRA WINGS ue sesse esse se esse see se esse sees se ee
14. NUA D HE PURPOSE OF THIS SECTION cccessessssscesecccessessnsecececcceeeesesseseeeseceesseesesseseeeseesesenes INTENT OF THIS DOCUMENT iesen Eed ii ta CONVENTION Si A A a DESCRIPTION OF DOCUMENT CONTENTS rana ee nara ee ee ee ee ee ee ee ee FIRMWARE VERSION APPLICABILITY ees ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee VAE LOINDA KEE INTRODUCTION TO THE STM3 osssssssssssssssssssssssssssssssssssssssosssosssssssssoso PURPOSE OF THIS SECTION ccceesesscececcceceessssececesecsesesenseseeeseceeseeessseeeeeeeeseeeees DESCRIPTION CES MNA Ee e ee EG Es Go id HOW IT WORKS ES Es ee Ee ee ed A Gee gee Re Ge ees BASIC ARCHITECTURE ie ee Ao Ses iS ee ee ee ee Ee De ee Bee id TYPICAL INTEGRATION pna Ee DEE GE ee a eS oi OVER THE AIR INTERFACE Ges 0525 Ee ees eed Ee a RE SPECIFICATIONS esse seen lees eeue ee as PURPOSE OF THIS SECTION ees ese ee ee ee se ee ee ee ee ee RR Re Re ee ee ee Re Re ee ee ee ee ee RE FREQUENG Visual Sos RGA Se Ee ge SU Gee ee ee os ARTES OGE ese Ls BRE dye As SR EE A OE EG REXIMING ia eo Ne Ge AA OA OUTPUTIMPEDANCE a a EN EE ODE be la eS Sac RE ANTENNA EA DS dE USERINTEREAGE esse ss dese es ee eegen de ede ees soene de og os ese PURPOSE OF THIS SECTION siii T ee ee ee es Dee gee evista ee ee ee SERTA COMMUNICATIONS Ee oi ee des See eed EE bs de dee ey ee eed ee ee Ps de SERIA PACKET FORMAT intra n ass inc Es ees Ee ee be eg ee eek UART SERIAL PORT CONFIGURATION ees
15. Si MOBILE DATACOM mai CORPORATION STM3 User Manual Document Number CMDC DOC 1767 Document Revision 1 14 Date September 30 2010 O Comtech Mobile Datacom Corporation Comtech All Rights Reserved This document contains information which is privileged confidential and or proprietary to Comtech This information is commercially sensitive in nature is not made generally available for public review The information contained herein is protected among other things by the Trade Secrets Act as codified and any improper use distribution or reproduction is specifically prohibited Comtech makes no representations or warranties either express or implied as to the information s adequacy sufficiency or freedom from defect of any kind including freedom from any patent infringement that may result from the use of such information nor shall Comtech incur any liability or obligation whatsoever by reason of such information Comtech s disclosure of this information shall in no manner grant to the receiving party any right title interest or license in or to the information other than its use in accordance with the purposes specifically set forth in writing between Comtech and the receiving party Under no condition should the information contained herein be provided in any manner whatsoever to any third party without the prior express written permission of Comtech and the concurrent execution of a suitable Non Disclosure Agreement
16. This allows a low output current low quiescent current low dropout regulator LDO to be connected to the digital input It also allows a high current high quiescent current switch mode power supply to be connected to the RF input A system integrator can use the open collector output on the STM3 to turn on the RF regulator before a transmission occurs This feature allows system integrators to quickly design a cost effective power supply for the STM3 while fully utilizing the low power consumption of the STM3 device in standby mode The input power requirements and power consumption of the STM3 are summarized in the following table Table 9 Power Modes and Usage Parameter Requirement Digital Input Voltage 3 3V 5 Noise must be less than 50mV peak to RF Input Voltage VCC_RF1 and VCC_RF2 peak Consumes up to 30mA 3 3V 5 Noise must be less than 50mV peak to peak Tie to OC_OUT controlled switch Typically consumes 250mA Supply Noise 280 mA output 50 mV peak to peak If the power source is a switch mode power supply the switching frequency is selected to be more than 150 kHz Current Consumption in Alert Mode This mode occurs when the modem is actively processing data 30mA 3 3V 25 C Current Consumption in Standby Mode This mode occurs when the modem is not doing anything Activation of RTS_CE is required to leave this mode 6uA 3 3V 25 C Current Consumption in Waiting
17. VIRONMENTAL SPECIFICATIONS 10 1 Purpose of this Section This section describes STM3 device environmental specifications 10 2 Power Specifications Power Parameters Specification RF Power RMS power 18 dBm 2 db during transmission tested over both temperature and supply voltage ranges Serial Port Voltage applied to communication terminals must not be below 0 3V or above VCC 0 3V 10 3 Environmental and Mechanical Specifications Environmental and Mechanical Specification Parameters Operating Temperature 30 to 60 C Storage Temperature 40 to 85 C Humidity 0 to 95 non condensing CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 34 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 11 EMI EMC COMPATIBILITY 11 1 Purpose of this Section This section describes the requirements and specifications that the STM3 device was designed and tested to 11 2 Compliance Standards The STM3 device has been designed to meet the following FCC and ETSI compliance standards e FCC Part 15 109 and 25 and e ICES 003 CAN CSA CEI IEC CISPR 22 02 and Canada RSS170 e ETSI EN 301 489 20 V1 2 1 2002 11 Specification e ETSI EN 301 441 V1 1 1 2000 05 Specification e ETSI TBR41 Specification e MIL STD 810F High Temp Low Temp Operation and Storage This device has been tested for compliance and certified under FCC Part 25 Any changes or modificat
18. a 50 ohm impedance trace on the integrator s circuit board The following design is for standard 0 063 FR 4 board material with a dielectric er 4 6 and 1 oz copper Picket fence vias should be placed at the edge of the ground plane surrounding the RF trace to stitch the top and bottom ground planes together Table 3 RF Trace Parameters Range mils Length of the trace L Max 1000 Width of the center trace W om Width between the trace and ground plane G CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 17 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 4 USER INTERFACE 4 1 Purpose of this Section This section describes the user interface including connectivity and requirements how it functions and how to integrate and configure the STM3 device 4 2 Serial Communications There are two serial interface options for connecting the STM3 device and the user equipment a Universal Asynchronous Receiver Transmitter UART and an SPI bus interface Only one of the two interfaces may be active at any time The STM3 device enters UART interface mode if the STM3 UART receiver line UART RXD is detected by the STM3 to be pulled to VCC at the time the device is powered on If this line is left unconnected or pulled to GND the STM3 enters SPI communications mode when power is applied to the device Two handshaking lines are used in addition to the dedicated serial
19. atile memory Table 7 Non Volatile Parameters Name Description Factory Default Value RF Channel Selects the unit channel Channel A Number of Tries Number of tries each OTA 3 Interface Packet is sent Range 1 to 5 Min Interval Minimum interval between 300 transmission attempts in seconds Range 5 seconds to 595 seconds with 5 second resolution Max Interval Maximum interval between 600 transmission attempts in seconds Range 10 seconds to 600 seconds with 5 second resolution CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 26 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 7 INTERFACES AND CONNECTORS 7 1 Purpose of this Section This section provides a mechanical configuration illustration and describes STM3 interface connections and pin outs to support integration of the module into an overall system 7 2 Surface Mount Pad Designations All interfaces to the board are via edge located surface mount pads Figure 7 depicts the mechanical configuration for the signals defined in Table 8 STM3 Pin Descriptions 36 H CTS_RDY 35 H UART_RXD 34 UART_TXD 33 RTS_CE 32 VCC_DIG 40 K RESET 39 C TesT2 38 C TEST 37 C GND 31 C GND VCC_DIG SPIDI 2 29 NC SPI_DO 3 28 NC SPI_CLK 4 27 NC
20. communication lines in each communication mode When in UART mode the RTS_CE line acts as a Request to Send line and the CTS_RDY line signals a Clear to Send condition When in SPI mode the RTS_CE line acts as a Chip Enable line and the CTS_RDY line signals a Ready condition More detail about each of these handshaking lines can be found in their respective serial interface detail sections The serial port interface requirements are as follows e Voltage applied to communication terminals may not be below 0 3V or above VCC 0 3V e Input Low Voltage must be less than 20 of VCC e Input High Voltage must be greater than 80 of VCC e Output Low Voltage is less than 0 4V e Output High Voltage is greater than VCC 0 3V when I is less than 2mA NOTE RS232 input levels are not supported RS232 data must be converted to 3 3V CMOS logic levels as it is sent and received from the unit The user equipment may also turn the unit ON and OFF by removing the power from the STM3 Each command from the host system to the STM3 is sent in a serial packet Upon receiving the command the STM3 answers to the host and if applicable executes the command CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 18 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 4 3 Serial Packet Format All serial port communications when using the UART interface or the SPI interface are packetized and u
21. e STM3 device The antenna should be placed on the opposite side of the printed circuit board from the STM3 and the trace to the antenna should be less than 1 e Although the STM3 input and output pins are heavily bypassed to prevent the RF leakage from re entering the unit through these ports The cables should not be allowed across or near the antenna element It is a very good idea to affix all cables as far away from the antenna as the installation permits The power supply cables are most prone to pick up antenna radiated signals e Carefully choose the type of plastic used for the STM3 application enclosure Additionally pay attention to the distance between the enclosure and the STM3 antenna Do not let the plastic directly touch the antenna if at all possible NOTE Plastic acts on the RF signal that exits the antennas differently than air does this effect will de tune the antenna or substantially reduce the radiated output power of the STM3 CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 31 of 38 Comtech Mobile Datacom Corporation 9 POWER SUPPLY 9 1 Purpose of this Section CMDC DOC 1767 Rev 1 14 This section describes power modes how they function and how an integrator can use them when integrating STM3 into the overall system This section also provides power requirements and parameters 92 DC Power Modes The STM3 device has separate RF and digital voltage inputs
22. evice and integration instructions This document provides a general introduction and understanding of the following e STM3 functions and architecture e STM3 integration and connectivity e Understanding of the User Interface LA Conventions Typographical conventions used in this document are as follows Commands All interface commands are in Black Courier Font Commands are case sensitive All commands must be entered in lower case User Input All commands and parameters the user enters appear in Black Bold Courier font Field Names STM3 field names appear in italics lt argument gt All interface commands that have an optional or required argument are indicated by slanted brackets lt argument gt CAPITAL LETTERS Used for emphasis for example DO NOT spray water on the module 14 Description of Document Contents This document is organized into functional sections described in Table 1 Some sections of the document are targeted for integrators who know very little about the Comtech SENS network other sections are for more experienced integrators who are interested in configuring the STM3 device 1 5 Firmware Version Applicability The contents of this document describe the features and functionality of the STM3 firmware version 1 19 CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 9 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 Table 1 Document Struc
23. hout this document WARNINGS CAUTIONS NOTES and TIPS WARNINGS are for procedures that if not followed may result in personal injury or death CAUTIONS are for procedures that if not followed may result in hardware or software damage or failure NOTES are included to provide the operator with additional information intended to simplify a step or entire procedure TIPS are included for the operator detailing useful information about using the equipment and software FCC IC NOTES The STM3 is a transmitter module designed for mobile or fixed operations STM3 devices will be manufactured with labels that include product information including FCC ID and IC ID of UQR CMDCSTM3 and 8863A CMDCSTM3 respectively Purchasers of the STM3 devices are required to do one of the following while integrating the STM3 module into their products e Provide visibility of the STM3 module through a window or e Provide an easy way to get to the module when an access panel or door is removed or e Place a label on the outside of the final integrator product that contains the following texts Contains FCC ID UQR CMDCSTM3 and Contains IC 8863A CMDCSTM3 GLOBALSTAR NOTE CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 4 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 Purchasers or integrators of the STM3 are required to have the products that i
24. ion Information in this section is provided so that the designer can verify performance of the completed product It is the product designer s responsibility to ensure that the RF performance of the STM3 device is not compromised when designing the final product 32 RF Frequency The RF frequency is adjustable by the user interface via configuration software and can be set to one of the four values listed in Table 2 using the associated channel identifier These frequencies are associated with a channel identifier as defined in the following table Table 2 Channel and Frequency Channel Frequency MHz A 1611 25 B 1613 75 C 1616 25 D 1618 75 The frequency accuracy is 5 ppm in the temperature range defined in section 10 The frequency setting accuracy at 25C is 1 5 ppm in less than 400 us The frequency does not vary by more than 0 3 ppm during the transmission of a single packet The STM3 device transmits only after the Phase Lock Loop PLL has indicated that a lock has been achieved 33 RF Power The output power is a fixed setting and does not allow for adjusting the output power of the STM3 The average power transmitted during the 1 44s packet duration is 18 dBm 2dB RMS 34 RF Timing The following describes the RF timing specifications which are consistent with the RF output power described in section 3 3 RF Power e The PN code is applied within 5us of the Power Amplifier PA
25. ions to the module not expressly approved by Comtech Mobile Datacom may void the user s authority to operate the equipment CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 35 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 Appendix A CRC Calculation Algorithm Computes 16 bit CRC value for an array of bytes using the polynomial selected for the STM3 The first argument is a pointer to the array of data that the function should compute the CRC for The second argument is the number of bytes in that array The function returns the CRC ready for insertion into a command to the STM3 or for comparison against a response from the STM3 MISRA C types are used to clearly communicate the size of the variables uint16 t CrcCalculate uint8_t array uint8_t length uint16_t cre OxFFFF uint8_t x Step through each byte in the array while length XOR the CRC with the next byte in the array cre cre uintl6_t array Step through each bit in the byte for x 0 x lt 8 x if cre amp 0x0001 cre cre gt gt 1 0x8408 else crc gt gt 1 Invert and return the calculated CRC return crc CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 36 of 38 CMDC DOC 1767 Rev 1 14 e pas 208 eje oofa fele Comtech Mobile Datacom Corporation Appendix B Mechanical D
26. mended PCB footprint is 1 23 x 1 23 see Figure 8 Recommended PCB Pad Landing For mechanical drawings see Appendix B Mechanical Drawings Recommended PCB Footprint The following figure shows the recommended PCB footprint for the STM3 device It is not recommended that any signal on the user host board pass underneath the STM3 device when it is mounted Also it is recommended that there be an unbroken ground plane underneath the STM3 on the mounted side of the circuit board CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 30 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 1 23 31 24 H ma TYP 100 123 2 54 F 31 24 DI TYP 080 2 03 F g Eee ee eee TYP lt 075 1 80 ee Sa TTT y Figure 8 Recommended PCB Pad Landing 8 4 General STM3 Mounting Guidelines This section provides suggestions and ideas for general mounting methods Some of the suggestions are standard practice but are provided to remind the integrator of their importance e Avoid designing an STM3 mounting method that allows the patch antenna to point directly at the STM3 circuit board The electric and magnetic fields produced by the antenna are very large The STM3 shields may not provide sufficient attenuation of the antenna radiated signal if the antenna points directly at the unit e Carefully consider placement of the antenna and th
27. mmission LDO Low Dropout LHCP Left Hand Circularly Polarized OC Open Collector OTA Over the Air PA Power Amplifier PCB Printed Circuit Board PLL Phase Lock Loop RF Radio Frequency RMS Root Mean Squared SENS Sensor Enabled Notification System SPI Serial Peripheral Interface STM3 SENS Transmitter Module 3 UART Universal Asynchronous Receiver Transmitter VSWR Voltage Standing Wave Ratio CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 11 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 2 INTRODUCTION TO THE STM3 2 1 Purpose of this Section The purpose of this section is to introduce the integrator to the STM3 device and how it works This includes a system overview of the STM3 environment a description of the STM3 device and how it works its architecture and a typical integration and operating environment as well as an understanding of the Over the Air OTA interface 2 2 Description of STM3 The STM3 device provides simplex modem functionality that sends packet switched data containing user information through a satellite constellation to ground stations and then to the end user via the Internet see Figure 1 Figure 2 is a photo of the STM3 device Endpoint Device Satellite Network Gateway Receivers End Customer N 5N N A a K p kW a N y D ja Y
28. multiple times called transmission attempts The number of transmission attempts and the interval range between transmission attempts are adjustable parameters see Table 7 Non Volatile Parameters These parameters are selected by the integrator to balance the best throughput for each application with the amount of energy required for the multiple transmissions The interval between transmission attempts is randomly selected uniform distribution between the minimum and maximum values defined in Table 7 Non Volatile Parameters The seed for the random interval is based on the Electronic Serial Number ESN of the STM3 When several OTA interface packets are required for a message the packets are transmitted in the sequence pictured in Figure 3 Note that each OTA packet can hold up to 9 bytes of user data so this example represents the case where the user message is between 19 and 27 bytes therefore requiring three packets for transmission Additionally this example shows a transmission configuration of 2 transmission attempts Packet 1 Packet 2 Packet 3 Packet 1 Packet 2 Packet 3 First First SC First Last Attempt Last Last Attempt 5to cool FEN Fed Jaen 200ms l L ed Figure 3 Multiple Packet Transmission Sequence CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 14 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 3 RF SPECIFICATIONS 3 1 Purpose of this Sect
29. ncorporate the STM3 module certified by Globalstar before they can be activated tested or otherwise used on the Globalstar satellite constellation Integrators are fully responsible for all regulatory and business licensing requirements wherever the products are sold or used Once a product is approved the integrator will need to provide Globalstar with regularly updated lists of STM3 ESNs in these products so that end customers will be able to activate and use the products Integrators are highly encouraged to work with Globalstar through Comtech preferably beginning in the product design stage to understand the system specifications and requirements design in the correct features plan for regulatory approvals and plan for transmission of manufacturing information as their products are produced Comtech s point of contact for any Globalstar certification is e SENS Product Realization Manager e sprm comtechmobile com e Voice 1866 631 6010 CAUTION RF exposure hazard This unit must be operated with a minimum separation distance of 20 cm from a person s body CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 5 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 1 1 1 1 2 1 3 1 4 1 5 1 6 dd 22 2 3 2 4 2 5 2 6 3 1 3 2 3 3 3 4 3 5 3 6 3 7 4 1 4 2 4 3 4 4 4 5 4 6 4 7 4 8 4 9 Table of Contents ABOUT THIS MA
30. ng Diagram 4 8 Open Collector Output Characteristics The OC_OUT terminal may be used as a signal to control external circuitry such as an LED to indicate packet transmissions or as a signal to a power supply to indicate the impending high current requirement of the device This pin changes from a high impedance state to a drain connected to the ground 1 ms before the transmission of a packet and remains active for the packet duration Integrators may use this signal to count active transmissions as an alternative to serially querying for remaining transmissions The open collector output requires users to externally pull up the signal to a voltage reference using a weak pull up This terminal is capable of sinking 1mA and can withstand an input voltage of 15V 4 9 CRC Computation Each serial port packet is terminated by a 16 bit CRC The code given in Appendix A CRC Calculation Algorithm can be used to implement this CRC 4 10 Antenna Port The STM3 device has no RF connector RF output is provided as a 50 ohm pad on the STM3 device board edge The nominal load impedance is 50 ohms The STM3 device may sustain damage if the Voltage Standing Wave Ratio VSWR is infinite under any phase condition It is recommended that a user never transmit a packet without a 50 ohm load attached to the RF output The STM3 device delivers at least 80 of its nominal incident power when the VSWR is less than or equal to 2 0 in all phase conditions
31. nnel and Frequency Test modes are shown in the following table Table 6 Test Modes TEST1 TEST2 Test Mode Not Connected Not Connected Normal Operation High High Normal Operation Low High A single test packet is transmitted The test packet complies with the OTA Packet format with a user information field equal to the hex stream Ox80A AFOFOFOA AFOFOFO where the most significant digit is transmitted first Low Low Test packets are continuously transmitted for 30 seconds Each test packet complies with the OTA Packet format with a user information field equal to the hex stream Ox80AAFOFOFOA AFOFOFO where the most significant digit is transmitted first High Low An un modulated carrier is transmitted for 30 seconds The carrier level may be less than the nominal power output CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 25 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 6 CONFIGURABLE FEATURES 6 1 Purpose of this Section This section describes how to configure the STM3 device and identifies and describes programmable features and parameters 6 2 System Configuration The STM3 device is configured using commands that are sent in serial packet format as defined in Table 4 The STM3 may be configured by UART or SPI as selected by the user Table 7 Non Volatile Parameters lists parameters that are stored in non vol
32. o Connection Do not connect 31 GND Ground Connect directly to a ground plane 32 VCC_DIG Digital Power E Ce 33 RTS CE EN d Input 3 3V CMOS input 34 UART_TXD UART TX Output 3 3V CMOS output 35 UART RXD UART RX Input 3 3V CMOS input 36 CTS_RDY Clear to Send Ready Output 3 3V CMOS output 37 GND Ground Connect directly to a ground plane 38 TESTI Test Mode Pin 1 Ground or not connected 39 TEST2 Test Mode Pin 2 Ground or not connected Hold to ground for 10mS to reset 40 RESET RESET unit not connected for normal operation CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 29 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 8 8 1 MECHANICAL Purpose of this Section This section provides STM3 dimensions specifications and requirements for integrating the device onto a PCB This includes specifications for the PCB landing and mounting guidelines 8 2 8 3 Mechanical Specifications The STM3 device is a printed circuit board 62 mil nominal with outer dimensions of 1 15 x 1 15 The overall thickness of the device with the RF shield can installed is 0 158 All connections made to the board are via the castellated edge terminals on the circuit board There are no other connectors The circuitry is covered by a metal enclosure The enclosure provides venting and drainage for washing operations used during assembly The recom
33. ontent edits throughout per SME review CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 2 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 1 7 Saad Anis Accepted all comments and made minor changes throughout Removed current consumptions on V_RF1 And V_RF2 until measurements are verified 1 8 Chris Thorne Added details of SPI interface 1 9 Garrett Chandler Corrected CTS_RDY and RTS_CE pin names Corrected table and figure cross references 1 10 Anthony Valenzano Updated power levels Updated firmware version Changed tries to 5 Changed antenna gain to 5dBi Added recommended antenna Added recommendations for external antennas Corrected current consumption Total current consumption should be the digital consumption current plus the RF power consumption Garrett Chandler Updated firmware version number Saad Anis Added Certification Section Information Garrett Chandler Saad Anis Clean up formatting of document and content Moved notice of certification requirements to Notices section of document Added FCC IC Notes and reformatted Globalstar Notes CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 3 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 Notices The following terms are used in specific context throug
34. rawings ms 005 1102 Li effi 1180 827088 888 BA Ba e e DS Q d LK an 05 BE Zog So or a Jefe LC 88 25 j 40x 048 as ele oro ei ser Figure 9 Module Dimensions CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 37 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 40X 20NS 20FS 40X 20NS 20FS ALL AROUND 80 PLACES 80X 033 REF HF 40X 20NS 20FS 024 REF ALL AROUND 40X 20NS 20FS Figure 10 Castellation Detail Figure 11 Isometric View CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 38 of 38
35. rds compatibility 0x07 Query setup message for retrieving None the settings of the configurable parameters Nine data bytes Contents are exactly the same as the command data bytes in command 0x06 OxFF This value is only used for an N A None answer and corresponds to a non acknowledgment 4 4 UART Serial Port Configuration The serial port on the STM3 is configured to communicate with a host with the following UART configuration 9600 baud 8 data bits no parity and 1 stop bit 4 5 UART Serial Port Timing The STM3 device is taken out of sleep mode by a high to low transition on the Request to Send RTS_CE input The STM3 indicates it is ready to accept commands by setting the Clear to Send CTS_RDY line low At that time the user may send a command over the UART When the message packet is complete the user raises the Request to Send RTS_CE line The device will return Clear to Send CTS_RDY to a high state following the completion of the command and respond with an ACK NAK or appropriate reply CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 21 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 If the packet sent is a Transmit Packet the STM3 begins its transmission sequence following the return of the response packet to the user The UART may not function correctly ifthe following timing parameters are violated e Reque
36. s se es ee se ese sees CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 7 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 List of Figures Figur ds System OOIE A EE RE Ge ehh eng Ge in Ne E EE Figure 3 Multiple Packet Transmission Beguenee iese ses se ee ee Re AR GR ee ee Fig re EE ee e EE Fi tte A EG ee Figure 6 SPI Interface Timing Diarra Figure 7 STM3 Pinout Dist Rr eb Ee ei Figure 8 Recommended PCB Pad Landing ooooonocnncccocanocconcnononononnnonnnonncnncconono nono ee ee Fistre Vs Mod le Re E Ee EE Figure steen Figur Klee EE ee Table 1 Document SA ta ler da sh o a O Table 2 Channel and Frequency dal ias Table 3 RE Trace Parma Table 4 Serial Packet Commands and Responses cccccecsseesseeeteceeeeeeeeeeeeeseceseeeees A AN TADO IM DE ha an cat ata Table 7 Non Volatile Parameters ind Table 8 SEM3 Pin Descriptions ssis e ninenin iin iaa a E ge Table 9 Power Modes and Usage oi N RE Dee Ge ee aeee CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 8 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 1 ABOUT THIS MANUAL 1 1 Purpose of this Section The purpose of this section is to introduce the user to the terminology and organization of this manual 1 2 Intent of this Document This document is intended for integrators who are seeking a general overview of CMDC s STM3 d
37. se ee ese ee ee ee ee ee ee ee ee ee RR Re Re ee ee ee UART SERTAT PORT TIMING ies iss bes bes adi SPI SERIAL PORT CONFIGURATION oococcoooonnnnnncncnnononannnnonononconononnnnonononconononnananononos SPEPORT TIMING EE OPEN COLLECTOR OUTPUT CHARACTERISTICS ese ese ee ee ee es ee se n ee ee ee ee ee ee CRO COMPUTATION N ER RR RE EE 4 10 ANTENNA PORT se vee ee eed ia 4 11 STM3 ELECTRONIC SERIAL NUMBER esse ese sesse ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee 5 S L 5 2 TEST INPUTS a ios PURPOSE OF THIS SECTION esse ese sesse ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee TEST1 AND TEST2 MODES sesse SES N ee Ge De Se ee Ge ee dees ee See Se ae Gee ee sg Gede de CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 6 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 6 CONFIGURABLE FEATURES ssssscccsccsccssesestvivacevetsusssoccacesdsessdcsuscccvessssenssesssooes 6 1 PURPOSE OF THIS SECTION ccccccccccccssssesceccccccccussussssccccecceseeusssscecceseeesuuenseecceseeees 6 2 SYSTEM CONFIGURATION ee ee ee ee ee ee ee ee ee ee ee ee ee ee 7 INTERFACES AND CONNECT ORG cccccsssssssssssssssscscssssssssssssssssessessessoses 7 1 PURPOSE OF THIS SECTION eed ee se ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee 7 2 SURFACE MOUNT PAD DESIGNATIONS ese ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee 8 MECHAN
38. st to Send RTS_CE may not be set low within 50 ms of power being applied to the STM3 device e Ifthe module responds by activating the Clear to Send CTS_RDY line within 20ms it is ready to accept data and communicate with the user equipment If no Clear to Send CTS_RDY activation is received the user must assume that the module is busy and try again later Typically the module is only able to communicate when a message transmission is not in progress Each packet takes at least 1 44 seconds to transmit and a message may require multiple packets thus the STM3 may be busy for significant periods of time 4 6 SPI Serial Port Configuration The SPI interface on the STM3 is configured as a slave device and will communicate with a host which provides the SPI clock for all data transfers both input to the STM3 and output from the STM3 Data changes on the rising edge of the SPI clock and is sampled on the falling edge The maximum speed for the SPI clock is 100 kHz 4 7 SPI Port Timing The STM3 device is taken out of sleep mode by a high to low transition on the Chip Enable RTS_CE input The STM3 indicates that it is ready for data transfers by setting the Ready CTS_RDY signal low After receipt of the Ready signal the SPI host may send a command over the SPI interface When the STM3 has detected a complete command it will set the Ready signal high for a short period 200 us and then will return the signal to the low condition when it
39. t until all attempts are made at which time it permanently enters sleep mode until the user initiates another command transaction 2 4 Basic Architecture The STM3 device is built on a 1 15 x 1 15 printed circuit board PCB The circuitry is covered by a metal radio frequency RF shield as shown in Figure 2 The STM3 circuitry consists of a microcontroller for command processing and system control and a complex programmable logic device CPLD that integrates the data with CMDC Confidential and Proprietary Information Use and Disclosure Restrictions Apply Page 13 of 38 Comtech Mobile Datacom Corporation CMDC DOC 1767 Rev 1 14 the spreading code The CPLD is followed with a synthesizer a mixer and a power amplifier to up convert and amplify the baseband data for transmission 2 5 Typical Integration The STM3 device is intended to be a module in a larger system The system must have means of providing adequate power low noise and relatively high current and must possess an electrical signaling mechanism compatible with the module The system into which the STM3 is integrated also must provide a path for the RF energy to move from the STM3 to an appropriate antenna Caution also must be exercised to ensure that transmitted and leakage RF energy do not cause interference with the nominal operation of the components on the user s circuit board 2 6 Over the Air Interface Once a packet is created it is sent over the air
40. tilize the same encoding and format These communication packets have a defined structure as shown in Figure 5 Preamble Length Command Data CRC 1 byte 1 byte 1 byte 0 144 bytes 2 bytes e 5 to 149 Bytes N Figure 5 Packet Format The fields that make up the packet are as follows e The Preamble is a fixed pattern OxAA e The Length is the total number of bytes in the serial packet including preamble and CRC e The Command tells the STM3 device what function to perform The command descriptions are contained in Table 4 Serial Packet Commands and Responses e The Data field contains data if any associated with the command e The 2 byte CRC Cyclic Redundancy Check allows the module to determine if transmission errors have occurred Details on calculating the CRC are found in Appendix A CRC Calculation Algorithm The most significant byte of the CRC is located in the last byte of the communications packet and the least significant byte of the CRC is located in the next to last byte of the communications packet Each command from the host to the STM3 elicits a response If all of the arguments of the command are within acceptable ranges and the CRC is validated the STM3 will respond with either an ACK if the command requires no other response or the reply message that corresponds with that command If an argument is found to be out of range the CRC is not valid or the command is not recognized the STM3 will reply with a
41. ture Section Description Section 1 About This Manual Provides an understanding of this manuals intent organization terminology and conventions used throughout this document This section is useful to all readers of this document Section 2 Introduction to Provides a description of the STM3 device the system architecture and how the STM3 device works This section also provides typical integration operating environment and interface information This section is useful for all integrators Section 3 RF This section provides RF performance related specifications for integrating the STM3 device into a device This section is useful to all designers and integrators Section 4 User Interface This section describes the user interface including connectivity and requirements how it functions and how to integrate and configure the STM3 device This section is useful to all integrators Section 5 Test Inputs This section describes test inputs and modes along with their functionality This section is useful to integrators and those testing the module after integration and configuration Section 6 Configurable Features This section describes how to configure the STM3 device using commands This section includes configurable features commands and their parameters This section is useful to integrators and software developers Section 7 Interfaces and Connectors This section describes
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