Laird Connectivity 4X90200 RF Transceiver Module User Manual 4790 User s Manual

AeroComm Corporation RF Transceiver Module 4790 User s Manual

Contents

Users Manual 2

VERSION 1.7
ContentsAC4790 TRANSCEIVER MODULE 1AC4790 features 1Overview 1SPECIFICATIONS 3Pin Definitions 5Electrical Specifications 7THEORY OF OPERATION 8Masterless Architecture 8Modes of Operation 8Transmit Mode 8Receive Mode 9Command Mode 10API CONTROL 11API Transmit Packet 12API Send Data Complete 12API Receive Packet 12SERIAL INTERFACE 14Serial Communications 14Asynchronous Operation 14Parity 14OEM Host Data Rate 15Serial Interface Baud Rate 15Interface Timeout / RF Packet Size 16Flow Control 17Half Duplex / Full Duplex 17System Timing & Latency 17System Throughput 18Random Backoff 18Networking 19Max Power 20HARDWARE INTERFACE 21Pin Definitions 21Generic I/O 21TXD & RXD 21CTS 21RTS 21Test / 9600 Baud 22RSSI 22UP_Reset 23Command/Data 23AD In 23Session Status 23CONFIGURING THE AC4790 24AT Commands 24On-the-Fly Control Commands 25Command Descriptions 27EEPROM PARAMETERS 32DIMENSIONS 36Mechanical Drawings 36ORDERING INFORMATION 40Product Part Number Tree 40Developer Kit Part Numbers 40COMPLIANCY INFORMATION 41AC4790-1x1 41Agency Identification Numbers 41Approved Antenna List 41FCC / IC Requirements for Modular Approval 42OEM Equipment Labeling Requirements 42Antenna Requirements 43Warnings required in OEM Manuals 43Channel Warning 43APPENDIX I - SAMPLE POWER SUPPLY 44Bill of Materials 44Schematic 45PCB Layout 45APPENDIX II - 5V TO 3.3V LEVELS 47Voltage Level Conversion IC’s 47Passive Resistor Voltage Divider 47APPENDIX III - API 48Polling Network 48Addressed Transmit API 49Broadcast Transmit API 49Receive API 50Normal Receive Mode (non-API) 51Daisy Chain / Repeater Network 51Loopback Repeater 52Time Division Multiple Access Network 53APPENDIX IV - API TIMING DIAGRAMS 54Timing Diagrams 54
DOCUMENT INFORMATIONCopyright © 2007 AeroComm, Inc. All rights reserved.The information contained in this manual and the accompanying software programs are copyrighted and all rights arereserved by AeroComm, Inc. AeroComm, Inc. reserves the right to make periodic modifications of this product withoutobligation to notify any person or entity of such revision. Copying, duplicating, selling, or otherwise distributing anypart of this product or accompanying documentation/software without the prior consent of an authorizedrepresentative of AeroComm, Inc. is strictly prohibited.All brands and product names in this publication are registered trademarks or trademarks of their respective holders.This material is preliminaryInformation furnished by AeroComm in this specification is believed to be accurate. Devices sold by AeroComm arecovered by the warranty and patent indemnification provisions appearing in its Terms of Sale only. AeroComm makesno warranty, express, statutory, and implied or by description, regarding the information set forth herein. AeroCommreserves the right to change specifications at any time and without notice.AeroComm’s products are intended for use in normal commercial and industrial applications. Applications requiringunusual environmental requirements such as military, medical life-support or life-sustaining equipment are specificallynot recommended without additional testing for such application.Limited Warranty, Disclaimer, Limitation of LiabilityFor a period of one (1) year from the date of purchase by the OEM customer, AeroComm warrants the OEMtransceiver against defects in materials and workmanship. AeroComm will not honor this warranty (and this warrantywill be automatically void) if there has been any (1) tampering, signs of tampering; 2) repair or attempt to repair byanyone other than an AeroComm authorized technician.This warranty does not cover and AeroComm will not be liable for, any damage or failure caused by misuse, abuse,acts of God, accidents, electrical irregularity, or other causes beyond AeroComm’s control, or claim by other than theoriginal purchaser.In no event shall AeroComm be responsible or liable for any damages arising: From the use of product; From the lossof use, revenue or profit of the product; or As a result of any event, circumstance, action, or abuse beyond the controlof AeroComm, whether such damages be direct, indirect, consequential, special or otherwise and whether suchdamages are incurred by the person to whom this warranty extends or third party.If, after inspection, AeroComm determines that there is a defect, AeroComm will repair or replace the OEM transceiverat their discretion. If the product is replaced, it may be a new or refurbished product.
DOCUMENT INFORMATIONRevision DescriptionVersion 1.0 2/21/05 - Initial Release VersionVersion 1.1 3/4/05 - Updated Session Count Truth TableVersion 1.2 4/26/05 - Updated Transmit Mode SectionVersion 1.3 3/17/06 - Corrected API Send Data Complete. Added AustralianChannels. Added 1x1 documentation. Added Appendices I - IV.Version 1.4 6/25/06 - Updated API Section. Added Serial Communications.Added Max Power backup EEPROM byte - address 0x8E.Added Product ID EEPROM bytes - addresses 0x90 - 0x9F.Updated Compliancy Information. Updated Appendices I - IV.Version 1.5 8/3/06 - Added Table of Contents.Version 1.6 1/9/07 - Updated Approved Antenna List. Updated AgencyIdentification numbers.Version 1.7 7/8/07 - Updated Approved Antenna List. Updated AgencyIdentification numbers.
www.aerocomm.comAC4790 TRANSCEIVER MODULE1The compact AC4790 900MHz transceiver can replace miles of cable in harsh industrial environments. Using field-provenFHSS technology which needs no additional FCC licensing in the Americas, OEMs can easily make existing systems wirelesswith little or no RF expertise.AC4790 FEATURESNETWORKING AND SECURITY• Masterless: True peer-to-peer, point-to-multipoint, point-to-point• Retries and Acknowledgements• API Commands to control packet routing and acknowledgement on a packet-by-packet basis• Frequency Hopping Spread Spectrum for security and interference rejection• Customizable RF Channel number and system ID• Dynamic link analysis, remote radio discovery• Software controlled sensitivity• Hardware Protocol Status monitoring• Two generic input and output digital lines and integrated ADC functionsEASY TO USE• Continuous 76.8 kbps RF data stream• Software selectable interface baud rates from 1200 bps to 115.2 kbps• Low cost, low power and small size ideal for high volume, portable and battery powered applications• All modules are qualified for Industrial temperatures (-40°C to 80°C)• Advanced configuration available using AT commandsOVERVIEWThe AC4790 is a member of AeroComm’s ConnexRF OEM transceiver family. The AC4790 is a cost effective, highperformance, frequency hopping spread spectrum transceiver; designed for integration into OEM systems operatingunder FCC part 15.247 regulations for the 900 MHz ISM band.AC4790 transceivers operate in a Masterless architecture. The unique feature of this architecture is its dynamicSession extension and Collision Avoidance mechanism, which uses a proprietary scoring system to promotecontention free communication and ensure that each node has fair access to the network. This instinctive dynamicpeer-to-peer networking architecture enables several transceiver pairs to carry on simultaneous conversations on thesame network.To boost data integrity and security, the AC4790 uses AeroComm’s field-proven FHSS technology featuring optionalData-Encryption Standards (DES). Fully transparent, these transceivers operate seamlessly in serial cablereplacement applications. Communications include both system and configuration data via an asynchronous TTL oroptional RS-485 serial interface for OEM Host communications. Configuration data is stored in an on-board EEPROM
AC4790 TRANSCEIVER MODULE2and most parameters can be changed on the fly. All frequency hopping, synchronization, and RF system datatransmission/reception is performed by the transceiver.This document contains information about the hardware and software interface between an AeroComm AC4790transceiver and an OEM Host. Information includes the theory of operation, specifications, interface definition,configuration information and mechanical drawings. The OEM is responsible for ensuring the final product meets allappropriate regulatory agency requirements listed herein before selling any product.Note: Unless mentioned specifically by name, the AC4790 modules will be referred to as the “radio” or “transceiver”.Individual naming is used to differentiate product specific features. The host (PC/Microcontroller/Any device to whichthe AC4790 module is connected) will be referred to as “OEM Host”.
www.aerocomm.comSPECIFICATIONS2Table 1: AC4790 SpecificationsGeneral20 Pin Interface Connector Molex 87759-0030, mates with Samtec SMM-110-02-S-DRF Connector Johnson Components 135-3711-822Antenna AC4790-1x1: Customer must provide AC4790-200: MMCX Connector or integral antennaAC4790-1000: MMCX ConnectorSerial Interface Data Rate Baud rates from 1200 bps to 115,200 bpsPower Consumption (typical) Duty Cycle (TX=Transmit; RX=Receive) 10%TX 50%TX 100%TX 100%RXAC4790-1x1: 33mA 54mA 80mA 28mA AC4790-200: 38mA 68mA 106mA 30mAAC4790-1000: 130mA 650mA 1300mA 30mAChannels 3 Channel Sets comprising 56 total channelsSecurity One byte System ID. 56-bit DES encryption key.Interface Buffer Size Input/Output:256 bytes eachTransceiverFrequency Band 902 – 928 MHzRF Data Rate 76.8 kbps fixedRF Technology Frequency Hopping Spread SpectrumOutput Power Conducted (no antenna) EIRP (3dBi gain antenna)AC4790-1x1: 10mW typical 20mW typicalAC4790-200: 100mW typical 200mW typicalAC4790-1000: 743mW typical 1486mW typicalSupply Voltage AC4790-1x1: 3.3V, ±50mV rippleAC4790-200: 3.3 – 5.5V, ±50mV rippleAC4790-1000*: Pin 10: 3.3 – 5.5V ±50mV ripple Pin 11: 3.3 ±3%, ±100mV ripple* Pins 10 and 11 may be tied together, provided the supply voltage never falls below 3.3 V and iscapable of supplying 1.5 A of current.Sensitivity -100dBm typical @ 76.8kbps RF Data Rate-110dBm typical @ 76.8kbps RF Data Rate (AC4490LR-200/AC4490LR-1000)EEPROM write cycles 20000Initial Transceiver Sync time/Hop period 25ms / 50 ms
SPECIFICATIONS4Transceiver (Cont’d)Range, Line of Site (based on 3dBi gainantenna)AC4790-1x1: Up to 1 mileAC4790-200: Up to 4 milesAC4790LR-200: Up to 8 milesAC4790-1000: Up to 20 milesAC4790LR-1000: Up to 40 milesEnvironmentalTemperature (Operating) -40°C to 80°CTemperature (Storage) -50°C to +85°CHumidity (non-condensing) 10% to 90%PhysicalDimensions Transceiver with MMCX Connector: 1.65” x 1.9” x 0.20”Transceiver with Integral Antenna: 1.65” x 2.65” x 0.20”AC4790-1x1: 1.00” x 1.00” x 0.162”CertificationsAC4790-200A AC4490-200/AC4490LR-200 AC4790-1000 FCC Part 15.247 KQLAC4490-100 KQL4x90-200 KQLAC4490Industry Canada (IC) 2268C-AC4490 2268C-4x90200 2268C-AC44901000Table 1: AC4790 Specifications
5SPECIFICATIONSwww.aerocomm.comPIN DEFINITIONSThe AC4790 has a simple interface that allows OEM Host communications with the transceiver. The table belowshows the connector pin numbers and associated functions. The I/O direction is with respect to the transceiver. Alloutputs are 3.3VDC levels and inputs are 5VDC TTL (with the exception of AC4790-1x1 and AC4790-1000 transceiverswhich have 3.3V inputs). All inputs are weakly pulled High and may be left floating during normal operation (with theexceptions listed for the AC4790-1x1).Table 2: AC4790 Pin DefinitionsModule Pin1x1 Pin Type Signal Name Function1 4 O GO0 Session status if Protocol Status is enabled. Otherwise, genericoutput.2 6 O TXD Transmitted data out of the transceiverI/O RS485 A (True)1Non-inverted RS-485 representation of serial data3 7 I RXD Data input to the transceiverI/O RS485 B (Invert) 1Mirror image of RS-485 A4 52GI0 Generic Input pin5 3 GND GND Signal Ground6 O Do Not ConnectHas internal connection, for AeroComm use only.7 9 O CTS Clear to Send – Active Low when the transceiver is ready to acceptdata for transmission.8102IRTS Request to Send – When enabled in EEPROM, the OEM Host cantake this High when it is not ready to accept data from thetransceiver. NOTE: Keeping RTS High for too long can cause dataloss.919 OGO1 Received Acknowledge status pin if Protocol Status is enabled.Otherwise, generic output.10 2PWR VCC1 AC4790-1x1: 3.3V, ±50mV rippleAC4790-200: 3.3 – 5.5V, ±50mV ripple (Pin 10 is internallyconnected to Pin 11)AC4790-1000: 3.3 – 5.5V, ±50mV ripple11 11 PWR VCC2 AC4790-1x1: 3.3V, ±50mV rippleAC4790-200: 3.3 – 5.5V, ±50mV ripple (Pin 11 is internallyconnected to Pin 10)AC4790-1000: 3.3V ±3%, ±100mV ripple12 23 ITest Test Mode – When pulled logic Low and then applying power orresetting, the transceiver’s serial interface is forced to a 9600, 8-N-1rate. To exit, the transceiver must be reset or power-cycled with TestMode logic High.
SPECIFICATIONS613 12 ORSSI Received Signal Strength - An analog output giving an instantaneousindication of received signal strength. Only valid while in ReceiveMode.14 212IGI1 Generic Input pin15 16 IUP_RESET RESET – Controlled by the AC4790 for power-on reset if leftunconnected. After a stable power-on reset, a logic High pulse willreset the transceiver. 16 13 GND GND Signal Ground17 17 ICMD/Data When logic Low, the transceiver interprets OEM Host data ascommand data. When logic High, the transceiver interprets OEMHost data as transmit data.18 153IAD In 10 bit Analog Data Input19 1,8,20 24-28N/C Do Not ConnectHas internal connection, for AeroComm use only.20 18 OSession StatusWhen logic Low, the transceiver is in Session N/A 14 RF RF Port RF InterfaceN/A 22 IReset Active Low version of UP_RESET. If RESET is used, UP_RESETshould be left floating and if UP_RESET is used, RESET should beleft floating.1. When ordered with a RS-485 interface (not available on the AC4790-1x1).2. Must be tied to VCC or GND if not used. Should never be permitted to float.3. If used, requires a shunt 0.1μF capacitor at pin 15 followed by a series 1k resistor.Table 2: AC4790 Pin DefinitionsModule Pin1x1 Pin Type Signal Name Function
7SPECIFICATIONSwww.aerocomm.comELECTRICAL SPECIFICATIONSTable 3: Input Voltage CharacteristicsAC47901x1 / AC4790-1000M AC4790-200XSignal Name High Min.High Max.Low Min.Low Max.High Min.High Max.Low Min.Low Max. UnitRS485A/B N/A 12 -7 N/A N/A 12 -7 N/A VRXD 2.31 3.3 00.99 25.5 00.8 VGI0 2.31 3.3 00.99 25.5 00.8 VRTS 2.31 3.3 00.99 25.5 00.8 VTest 2.31 3.3 00.99 25.5 00.8 VGI1 2.31 3.3 00.99 25.5 00.8 VUP_RESET 0.8 3.3 00.6 0.8 5 0 0.6 VCommand/Data 2.31 3.3 00.99 25.5 00.8 VAD In N/A 3.3 0N/A N/A 3.3 0N/A VTable 4: Output Voltage CharacteristicsSignal Name Module Pin1x1Pin Type HighMin.LowMax. UnitGO0 119 O2.5 @ 8mA 0.4 @ 8mA VTXD 2 6 O 2.5 @ 2mA 0.4 @ 2mA VRS485A/B 2,3 N/A I/O 3.3 @ 1/8 Unit Load N/A VCTS 7 9 O 2.5 @ 2mA 0.4 @ 2mA VGO1 919 O2.5 @ 2mA 0.4 @ 2mA VRSSI 13 12 OSee Figure 1 See Figure 1 VSession Status 20 18 O2.5 @ 2mA 0.4 @ 2mA VGO0 119 O2.5 @ 8mA 0.4 @ 8mA V
www.aerocomm.comTHEORY OF OPERATION3MASTERLESS ARCHITECTUREThe Masterless architecture is a true peer-to-peer architecture, where any module that has data to transmit will initiatea communication Session with a transceiver(s) within its range, transmit data and exit the Session. This architectureeliminates the need for a master which dictates data flow control, hence reducing additional system overhead andgreatly improving efficiency.MODES OF OPERATIONThe AC4790 has three different operating modes; Receive, Transmit, & Command Mode. If the transceiver is notcommunicating with another radio, it will be in Receive Mode actively listening for a sync pulse from anothertransceiver. If the radio determines that it is a broadcast or addressed sync pulse, it will respond by going into sessionwith the radio. A transceiver will enter Transmit or Command mode when the OEM Host sends data over the serialinterface. The state of the Command/Data pin (Pin 17) or the data contents determine which of the two modes will beentered.Transmit ModeAll packets sent over the RF are either Addressed or Broadcast packets. Broadcast and Addressed delivery can becontrolled dynamically with the API Control byte and corresponding on-the-fly commands. To prohibit transceiversfrom receiving broadcast packets, Unicast only can be enabled.ADDRESSED PACKETSWhen sending an addressed packet, the RF packet is sent only to the receiver specified in destination address. Toincrease the odds of successful delivery, Transmit retries are utilized. Transparent to the OEM Host, the sending radiowill send the RF packet to the intended receiver. If the receiver receives the packet free of errors, it will return an RFacknowledge within the same 50 ms hop. If a receive acknowledgement is not received, the radio will use a transmitretry to resend the packet. The radio will continue sending the packet until either (1) an acknowledgement is receivedor (2) all transmit retries have been used. The received packet will only be sent to the OEM Host if and when it isreceived free of errors.BROADCAST PACKETSWhen sending a broadcast packet, the RF packet is sent out to every eligible transceiver on the network. To increasethe odds of successful delivery, Broadcast attempts are utilized. Transparent to the OEM Host, the sending radio willsend the RF packet to the intended receiver(s). Unlike transmit retries, all broadcast attempts are used; regardless ofwhen the RF packet is actually received and without RF acknowledgements. If the packet is received on the firstattempt, the receiver will ignore the remaining broadcast attempts. The received packet will only be sent to the OEMHost if and when it is received free of errors.When a radio has data to transmit, it sends out a sync pulse to initiate a session with one or more radios. This 25 mssync pulse is sent during the first half of each 50 ms hop and transparent to the OEM Host. Once a Session has beenestablished, the radio transmits the data during the remaining 25 ms of the current hop. The radio will stay in Transmitmode until its Session Count expires. When sending addressed packets, Session Count is defined as Session CountRefresh (EEPROM address 0xC4) + number of transmit retries (EEPROM address 0x4C). When sending broadcast
9THEORY OF OPERATIONwww.aerocomm.compackets, Session Count is equal to Session Count Refresh (EEPROM address 0xC4) + number of broadcast attempts(EEPROM address 0x4D). Once the radio exits the Session it returns to the default Receive Mode.Receive ModeIf a transceiver detects a sync pulse while in Receive Mode, it will join the Session and begin receiving data. While inReceive Mode, subsequent data of up to 128 bytes can be received every hop (50 ms).When a transceiver is in Session, its Session Count is decremented by one every hop. When the Session Countreaches zero, the transceiver exits the Session. In order to continue receiving data, the transceivers update theirSession Count every time data or an RF acknowledge is received. The SLock0 and SLock1 settings control SessionCount as shown below.* EEPROM DefaultNote 1: For Broadcast/Addressed packets, the Session Count for Full Duplex is 2x the value of Session Count in Half Duplex.Note 2: It is best to have all transceivers with the same Session Count Refresh (EEPROM Address 0xC4) value. Session Count Refresh must not be set to 0x00.Case 1: In this case, a radio loads its Session Count with its Session Count Refresh. This is suitable for Half Duplexcommunication where immediate response is not received from the remote radio.Case 2: In this case, a radio loads its Session Count with (its Session Count Refresh + its Transmit Retries). This caseis suitable for applications where there are high levels of interference and it is likely that transmit retries will benecessary to maintain reliable communications.When an addressed packet or a response to a broadcast packet is sent, the sending radio will listen for a successfulacknowledgement. If an acknowledgement is not sent, the radio will resend the packet until either anacknowledgement is received or it has exhausted all available transmit retries. If two radios are on the last hop of thecurrent session and a retry is required, it is possible that once the current session has ended the receiving radio couldgo into session with a different radio and miss the final packet of the previous session. Adding the radios Transmitretries to its Current Session Count will ensure that the radio does not exit the session when the remote radio is usinga Transmit Retry. Case 3: In this case a radio loads its Session Count with the remote radio's Session Count. This is suitable for fullduplex applications as the Session is extended as long as there is communication.Table 5: Session Count Truth TableCase Slock0 Slock1 Transceiver Receiving an Addressed PacketTransceiver Receiving a Broadcast Packet1 0 0 Radio loads its Current SessionCount with its Session CountRefreshRadio loads its Current Session Countwith its Session Count Refresh2 0 1 Radio loads its Current SessionCount with (its Transmit Retries +its Session Count Refresh)Radio loads its Current Session Countwith (its Broadcast Attempts + itsSession Count Refresh)3* 1 0 Radio loads its Current SessionCount with the remote radio’sSession CountRadio loads its Current Session Countwith the remote radio’s Session Count4 1 1 Radio loads its Current SessionCount with the remote radio’sCurrent Session CountRadio loads its Current Session Countwith the remote radio’s Current SessionCount
THEORY OF OPERATION10Note: This is the default case with which the radio ships and works well for almost all applications.Case 4: In this case, a radio loads its Session Count with the remote radio's current Session Count. This is suitablefor daisy chain applications and large networks in which radios cannot stay in session longer than needed.Command ModeA radio will enter Command Mode when data is received over the serial interface from the OEM Host and either theCommand/Data pin (pin 17) is logic Low or the received data contains the “AT+++” (Enter AT Command Mode)command. Once in Command Mode, all data received by the radio is interpreted as command data. Command Datacan be either EEPROM Configuration or On-The-Fly commands.
11THEORY OF OPERATIONwww.aerocomm.comFigure 1: Pending RF and Data in Buffer FlowAPI CONTROLAPI Control is a powerful feature that the Masterless Protocol offers. When enabled, the API Transmit Packet, APISend Data Complete and API Receive Packet features provide dynamic packet routing and packet accounting abilityto the OEM Host, thereby eliminating the need for extensive programming on the OEM Host side. This ability of theprotocol makes it ideal for any legacy system. API operation utilizes specific packet formats; specifying various vitalparameters used to control radio settings and packet routing on a packet-by-packet basis. The API features can beused in any combination that suits the OEM’s specific needs.Receive ModeBroadcast PacketReceive full packet and check CRC Addressed PacketMatching Destination MACValidate CRCDuplicate PacketSend RF AcknowledgeSend Packet over RFDuplicate PacketDiscard PacketDiscard PacketSend Packet over RFPending RF ReceivedYesYesYesYesYesYesReceive ModePin 17 LowData in BufferAT+++RF DataBroadcast Packet Addressed PacketTransmit PacketTransmit PacketDecrement Broadcast AttemptsBroadcast Attempts = 0Receive ACKDecrement Transm it AttemptsTransmit Attem pts = 0Command/Data Mode
THEORY OF OPERATION12API Transmit PacketAPI Transmit Packet is a powerful command that allows the OEM Host to send data to a single or multiple (broadcast)transceivers on a packet-by-packet basis. This can be useful for many applications; including polling and/or meshnetworks. Refer to the API Appendix for further details.API Transmit Packet is enabled when bit-1 of the API Control byte is enabled. The OEM Host should use the followingformat to transmit a packet over the RF.1If the OEM Host does not encode the header correctly, the transceiver will send the entire string (up to 0x80 bytes) and will look for the header in the next data.2Although the 7 bytes of overhead are not sent over the RF, they are kept in the buffer until the packet is sent. Keep this in mind so as not to overrun the 256-byte buffer.3Setting the MAC to 0xFF 0xFF 0xFF will broadcast the packet to all available transceivers.API Send Data CompleteAPI Send Data complete can be used as a software acknowledgement indicator. When a radio sends an addressedpacket, it will look for a received acknowledgement (transparent to OEM Host). If an acknowledgement is notreceived, the packet will be retransmitted until one is received or all retries have been used.For applications where data loss is not an option, the OEM Host may wish to monitor the acknowledgement processusing the API Send Data Complete. If an acknowledgement is not received (Failure), the OEM Host can send thepacket to the transceiver once again.API Send Data Complete is enabled when bit-2 of the API Control byte is enabled. The transceiver sends the OEMHost the following data upon receiving an RF acknowledge or exhausting all attempts.1The RSSI is how strong the remote transceiver heard the local transceiver; RSSI* is how strong the local transceiver heard the remote transceiver.2Successful RF Acknowledge updates the Success/Failure bit.3A success will always be displayed when sending broadcast packets after all broadcast attempts have been exhausted.API Receive PacketBy default, the source MAC is not included in the received data string sent to the OEM Host. For applications wheremultiple radios are sending data, it may be necessary to determine the origin of a specific data packet. When APIReceive Packet is enabled, all packets received by the transceiver will include the MAC address of the source radio aswell as an RSSI indicator which can be used to determine the link quality between the two.API Receive Packet is enabled when bit-0 of the API Control byte is enabled. Upon receiving a packet the radio sendsits OEM Host the packet in the following format:0x81Payload Data Length (0x01 - 0x80)Session Count RefreshTransmit Retries/Broadcast AttemptsDestination MAC (2,1,0)Payload Data0x82 RSSI RSSI* 0x00: Failure0x01: Success0x81Payload Data Length (0x01 - 0x80)RSSI RSSI* Source MAC (2,1,0)Payload Data
13THEORY OF OPERATIONwww.aerocomm.comENGINEER’S TIPWhen both API Send Data Complete and API Receive Packet are enabled, the Send DataComplete will be received before the transceiver sees the Receive API Packet. This order mayget reversed when the API Send Data Complete is missed and is being resent after the APIReceive Packet is received.
www.aerocomm.comSERIAL INTERFACE4In order for the OEM Host and a transceiver to communicate over the serial interface they need to have the sameserial data rate. Refer to the following sections to ensure that the OEM Host data rate matches the serial interfacebaud rate.SERIAL COMMUNICATIONSThe AC4790 is a TTL device which can be interfaced to a compatible UART (microcontroller) or level translator to allowconnection to serial devices. UART stands for Universal Asynchronous Receiver Transmitter and its main function isto transmit or receive serial data.Asynchronous OperationSince there is no seperate clock in asynchronous operation, the receiver needs a method of synchronizing with thetransmitter. This is achieved by having a fixed baud rate and by using START and STOP bits. A typical asynchronousmode signal is shown below.Figure 2: Asynchronous Mode SignalThe UART outputs and inputs logic level signals on the TX and RX pins. The signal is high when no data is beingtransmitted and goes low when transmission begins.The signal stays low for the duration of the START bit and is followed by the data bits; LSB first. The STOP bit followsthe last data bit and is always high. After the STOP bit has completed, the START bit of the next transmission canoccur.ParityA parity bit is used to provide error checking for a single bit error. When a single bit is used, parity can be either evenor odd. Even parity means that the number of ones in the data and parity sum to an even number and vice-versa. Theninth data bit can be used as a parity bit if the data format requires eight data bits and a parity bit as shown below.
15SERIAL INTERFACEwww.aerocomm.comFigure 3: Even Parity BitNote: Enabling parity cuts throughput and the interface buffer in half.OEM HOST DATA RATEThe OEM Host Data Rate is the rate with which the OEM Host and transceiver communicate over the serial interface.This rate is independent of the RF baud rate, which is fixed at 76.8 kbps. Possible values range from 1200 bps to115,200 bps. Note: Enabling Parity cuts throughput in half and the Interface Buffer size in half. The followingasynchronous serial data formats are supported:SERIAL INTERFACE BAUD RATEThis two-byte value determines the baud rate used for communicating over the serial interface to a transceiver. TheTable below lists values for some common baud rates. Baud rates below 1200 baud are not supported. For a baudrate to be valid, the calculated baud rate must be within ±3% of the OEM Host baud rate. If the Test pin (Pin 12) ispulled logic Low at reset, the baud rate will be forced to 9,600. The RF baud rate is fixed at 76.8 Kbps and isindependent of the interface baud rate. For Baud Rate values other than those shown below, the following equationscan be used:Table 6: Supported Serial FormatsData Bits Parity Stop Bits Transceiver Programming Requirements8 N 1 Parity Disabled7 N 2 Parity Disabled7E, O, M, S 1Parity Disabled9 N 1 Parity Enabled8 N 2 Parity Enabled8E, O, M, S 1Parity Enabled7E, O, M, S 2Parity EnabledMark (M) corresponds to 1 & Space (S) corresponds to 0
SERIAL INTERFACE16INTERFACE TIMEOUT / RF PACKET SIZEInterface Timeout (EEPROM address 0x58), in conjunction with RF Packet Size (EEPROM address 0x5B), determineswhen a buffer of data will be sent out over the RF as a complete RF packet, based on whichever condition occurs first.Interface Timeout – Interface Timeout specifies a maximum byte gap between consecutive bytes. When that byte gapis exceeded, the bytes in the transmit buffer are sent out over the RF as a complete packet. Interface Timeout isadjustable in 0.5ms increments and has a tolerance of ±0.5ms. Therefore, the Interface Timeout should be set to aminimum of 2. The default value for Interface Timeout is 0x04 (2ms) and should be adjusted accordingly whenchanging the transceiver baud rate.RF Packet Size – When the number of bytes in the transceiver transmit buffer equals RF Packet Size, those bytes aresent out as a complete RF packet. It is much more efficient to send a few large packets rather than several shortpackets as every packet the transceiver sends over the RF contains extra header bytes which are not included in theRF Packet Size. RF packet size can be set to a maximum of 0x80 and must be set to a minimum of 0x06 in order tosend the Enter AT Command mode command.Table 7: Baud Rate / Interface TimeoutBaud Rate BaudL (0x42)BaudH (0x43)Minium Interface Timeout (0x58) Stop Bit Delay (0x3F)115,200 0xFE 0x00 0x02 0xFF57,60011. 57,600 is the default baud rate0xFC 0x00 0x02 0x0338,400 0xFA 0x00 0x02 0x0828,800 0xF8 0x00 0x02 0x0E19,200 0xF4 0x00 0x03 0x1914,400 0xF0 0x00 0x04 0x239,600 0xE8 0x00 0x05 0x394800 0xD0 0x00 0x09 0x7A2400 0xA0 0x00 0x11 0xFC1200 0x40 0x00 0x21 0x0022. 0x00 will yield a stop bit of 421 uS. The stop bit at 1200 baud should actually be 833 uS.BAUD 14.7456 6×1064 DesiredBaud×-----------------------------------------------=BaudH Always 0=BaudL Low 8 bits of BAUD (base 16)=
17SERIAL INTERFACEwww.aerocomm.comFLOW CONTROLFlow control refers to the control of data flow between transceivers. It is the method used to handle data in thetransmit/receive buffer and determines how data flow between the transceivers is started and stopped. Often, onetransceiver is capable of sending data much faster than the other can receive and flow control allows the slowerdevice to tell the faster device when to pause and resume data transmission.When a transceiver has data to send, it sends a Ready To Send signal and waits for a Clear To Send response fromthe receiving unit. If the receiving radio is ready to accept data it will assert its CTS low. CTS will be reasserted whenthe buffer contains the number of bytes specified by CTS_OFF (EEPROM address 0x5D). These signals are sentapart from the data itself on separate wires.HALF DUPLEX / FULL DUPLEXWhen Half Duplex communication is chosen, the AC4790 will send a packet out over the RF whenever it can. This cancause packets sent by multiple transceivers at the same time to collide with each other over the RF. To prevent this,Full Duplex communication can be chosen. Full Duplex shares the bandwidth intelligently to enable two-waycollision-free communication without any collision. This is done by calculating the amount of time until the next hop toensure that it has time to send the packet; if there is enough time, it will send the packet and if not, it will wait until itsnext appropriate hop. The radio which initiates the session transmits during the even hops while the remainingradio(s) will transmit during the odd hops. Although the RF hardware is still technically half duplex, the bandwidthsharing it makes the transceiver seem full duplex. Enabling Full Duplex can cause overall throughputs to be cut inhalf.SYSTEM TIMING & LATENCYCare should be taken when selecting transceiver architecture, as it can have serious effects on data rates, latency,and overall system throughput. The importance of these three characteristics will vary from system to system andENGINEER’S TIPCan I implement a design using just Txd, Rxd and Gnd (Three-wire Interface)?Yes. However, it is strongly recommended that your hardware monitor the CTS pin of theradio. CTS is taken High by the radio when its interface buffer is getting full. Your hardwareshould stop sending at this point to avoid a buffer overrun (and subsequent loss of data).You can perform a successful design without monitoring CTS. However, you need to take intoaccount the amount of latency the radio adds to the system, any additional latency caused byTransmit Retries or Broadcast Attempts, how often you send data, non-delivery networktimeouts and interface data rate. Polled type networks, where the Server host requests datafrom the Client host and the Client host responds, are good candidates for avoiding the use ofCTS. This is because no one transceiver can monopolize the RF link. Asynchronous typenetworks, where any radio can send to another radio at any point in time, are much moredifficult to implement without the use of CTS.
SERIAL INTERFACE18should be a strong consideration when designing the system.SYSTEM THROUGHPUTWhen operating as shown below, an AC4790 transceiver is capable of achieving the listed throughput. However, inthe presence of interference or at longer ranges, the transceiver may be unable to meet the specified throughput.RANDOM BACKOFFRandom Back-Off – The transceivers utilize a Carrier Sense Multiple Access (CSMA) protocol with random back-offand a selectable back-off seed. In the event of a collision, the transceiver will back off and retry the packet.Specifically, when two transceivers detect a collision, each transceiver will choose a random number of packet timesthat it will wait before retrying the packet. This random number is selected from a pool of numbers defined by theback-off seed and consists of a number between 1 and 2, 1 and 4, 1 and 8, 1 and 16, 1 and 32, 1 and 64, 1 and 128and 1 and 256. In a very dense network, where more than two transceivers could experience a collision, it is importantto have a higher random back-off seed. ENGINEER’S TIPIn High-density applications, what amount of latency should be expected?It is not easy to predict the exact amount of latency in high-density applications. There aremany variables that affect system latency. The three variables that most affect the latency arethe network load, the distance between transceivers, and whether the transceivers areoperating in a broadcast or addressed mode. There is no fixed answer as to how much latencywill be introduced in the system when considering high-density applications. In these caseswe can just offer qualitative analysis of the latency in high-density applications. As the networkload increases, then the number of collisions that will occur increases. As the number ofcollisions increase, then the system latency increases. As the distance between thetransceivers increases, so to does the system latency. Finally, when transceivers operate inaddressed mode they will retry sending a packet up to the number of time specified in thetransmit retry parameter specified in the EEPROM. As the number of retries increases, thesystem latency will increase also.Table 8: Maximum System ThroughputRf Status Half Duplex Throughput (bps)Full Duplex Throughput (bps) each wayRadio not in continuous session 25k 12.5kRadio continuously in session 45k 22.5k
19SERIAL INTERFACEwww.aerocomm.comNETWORKINGSystem ID - System ID (EEPROM address 0x76) is similar to a password character or network number and makesnetwork eavesdropping more difficult. A transceiver will not establish a Session or communicate with a transceiveroperating on a different System ID or Channel Number.RF Channel Number - Channels 0x00 - 0x0F and 0x30 - 0x37 hop on 26 different frequencies. Channels 0x10 - 0x2Fuse 50 different frequencies.DES (Data Encryption Standard) - DES (Data Encryption Standard) – Encryption is the process of encoding aninformation bit stream to secure the data content. The DES algorithm is a common, simple and well-establishedencryption routine. An encryption key of 56 bits is used to encrypt the packet. The receiver must use the exact samekey to decrypt the packet; otherwise garbled data will be produced.To enable DES, EEPROM Byte 0x45, bit 6 must be set to a value of 1. To disable DES, set bit 6 to a value of 0. The 7byte (56 bits) Encryption/Decryption Key is located in EEPROM Bytes 0xD0 – 0xD6. It is highly recommended that thisKey be changed from the default.ENGINEER’S TIPWhat effects will Random Backoff have on system latency?As the random backoff value increases, the overall system latency increases.Worst case latency (Half Duplex) = 50 ms * Number of retries * Max. random valueWorst case latency (Full Duplex) = 100 ms * Number of retries * Max. random valueTable 9: RF Channel Number SettingsChannel Set11. All Channels in a Channel Set use the same frequencies in a different order.RF Channel Number Range (0x40)Frequency Details & Regulatory requirements Countries0 (AC4790 - 1x1 AC4790 - 200)0x00 - 0x0F 902 - 928 MHz (26 hop bins) US / Canada1 (AC4790 - 1x1 AC4790 - 1000)0x10 - 0x2F 902 - 928 MHz (50 hop bins) US / Canada2 (AC4790 - 1x1 AC4790 - 200 AC4790 - 1000)0x30 - 0x37 915 - 928 MHz (26 hop bins) US / Canada (-1x1 / -200)Australia(-1x1/-200/-1000)
SERIAL INTERFACE20MAX POWERMax Power provides a means for controlling the RF output power of the AC4790. Output power and currentconsumption can vary by as much as ±10% per transceiver for a particular Max Power setting. Contact AeroCommfor assistance in adjusting Max Power. ENGINEER’S TIPThe max power is set during Production and may vary slightly from one transceiver to another.The max power can be set as low as desired but should not be set higher than the originalfactory setting. A backup of the original power setting is stored in EEPROM address 0x8E.
www.aerocomm.comHARDWARE INTERFACE5Below is a description of all hardware pins used to control the AC4790.PIN DEFINITIONSGeneric I/OBoth GIn pins serve as generic input pins. When Protocol Status (byte 0xC2 of EEPROM) is disabled, GO0 & GO1serve as generic outputs. When Protocol Status is enabled, pins GO0 and GO1 alternatively serve as the SessionStatus and Receive Acknowledge Status pins, respectively. Reading and writing of these pins can be performedusing CC Commands.HARDWARE PROTOCOL STATUSWhen the GO0 pin is configured as the Session Status pin, GO0 is normally Low. GO0 will go High when a Session isinitiated and remain High until the end of the Session. When the GO1 pin is configured as the Receive AcknowledgeStatus pin, GO1 is normally Low and GO1 will go High upon receiving a valid RF Acknowledgement and will remainHigh until the end (rising edge) of the next hop.TXD & RXDSERIAL TTLThe AC4790-200 accepts 3.3 or 5VDC TTL level asynchronous serial data on the RXD pin and interprets that data aseither Command Data or Transmit Data. Data is sent from the transceiver, at 3.3V levels, to the OEM Host via the TXDpin. Note: The AC4790-1000 & AC4790-1x1 transceivers ONLY accept 3.3V level signals.RS-485When equipped with an onboard RS-485 interface chip, TXD and RXD become the half duplex RS-485 pins. Thetransceiver interface will be in Receive Mode except when it has data to send to the OEM Host. TXD is the non-inverted representation of the data (RS485A) and RXD is a mirror image of TXD (RS485B). The transceiver will still useRTS (if enabled).CTSThe AC4790 has an interface buffer size of 256 bytes. If the buffer fills up and more bytes are sent to the transceiverbefore the buffer can be emptied, data loss will occur. The transceiver prevents this loss by asserting CTS High as thebuffer fills up and taking CTS Low as the buffer is emptied. CTS On and CTS Off control the operation of CTS. CTS Onspecifies the amount of bytes that must be in the buffer for CTS to be disabled (logic High). Even while CTS isdisabled, the OEM Host can still send data to the transceiver, but it should do so carefully. Note: The CTS On/Off bytes of the EEPROM can be set to 1, in which case CTS will go high as data is sent in and lowwhen buffer is empty.RTSWith RTS disabled, the transceiver will send any received data to the OEM Host as soon as it is received. However,some OEM Hosts are not able to accept data from the transceiver all of the time. With RTS enabled, the OEM Host can
HARDWARE INTERFACE22prevent the transceiver from sending it data by disabling RTS (logic High). Once RTS is enabled (logic Low), thetransceiver can send packets to the OEM Host as they are received. Note: Leaving RTS disabled for too long can cause data loss once the transceiver’s 256 byte receive buffer fills up.Test / 9600 BaudWhen pulled logic Low before applying power or resetting, the transceiver’s serial interface is forced to a 9600, 8-N-1(8 data bits, No parity, 1 stop bit). To exit, the transceiver must be reset or power-cycled with Test pin logic High. Thispin is used to recover transceivers from unknown baud rates only. It should not be used in normal operation. Insteadthe transceiver Interface Baud Rate should be programmed to 9600 baud if that rate is desired for normal operation.The Test/9600 pin should be used for recovery purposes only as some functionality is disabled in this mode.RSSIINSTANTANEOUS RSSIReceived Signal Strength Indicator is used by the OEM Host as an indication of instantaneous signal strength at thereceiver. The OEM Host must calibrate RSSI without an RF signal being presented to the receiver. Calibration isaccomplished by following the steps listed below.1) Power up only one transceiver in the coverage area.2) Measure the RSSI signal to obtain the minimum value with no other signal present.3) Power up another transceiver and begin sending data from that transceiver to the transceiver being measured.Make sure the two transceivers are separated by approximately ten feet.4) Measure the peak RSSI, while the transceiver is in Session, to obtain a maximum value at full signal strength.VALIDATED RSSIAs RSSI is only valid when the local transceiver is receiving an RF packet from a remote transceiver, instantaneousRSSI can be very tricky to use. Therefore, the transceiver stores the most recent valid RSSI value. The OEM Hostissues the Report Last Good RSSI command to request that value. Additionally, validated RSSI can be obtained fromReceive Packet and Send Data Complete API commands and from the Probe command. Validated RSSI is notavailable at the RSSI pin. The following equation approximates the RSSI curve:Signal Strength (dBm) = (-46.9 VRSSI)× 53.9–
23HARDWARE INTERFACEwww.aerocomm.comFigure 4: RSSI Voltage vs. Received Signal StrengthUP_ResetUP_Reset provides a direct connection to the reset pin on the AC4790 microprocessor and is used to force a softreset. For a valid reset, reset must be asserted High for a minimum of 10ms.Command/DataWhen logic High, the transceiver interprets incoming OEM Host data as transmit data to be sent to other transceiversand their OEM Hosts. When logic Low, the transceiver interprets OEM Host data as command data.AD InAD In can be used as a cost savings to replace Analog-to-Digital converter hardware. Reading of this pin can beperformed locally using the Read ADC command found in the On-the-Fly Control Command Reference.Session StatusReports logic Low during a Session and logic High when not in Session. The inverse of this pin can be obtained frompin GO0 when Protocol Status is enabled.00.20.40.60.811.2-105 -100 -95 -90 -85 -80 -75 -70 -65 -60 -55 -50Signal at Receiver (dBm)Voltage (VDC)
www.aerocomm.comCONFIGURING THE AC47906The AC4790 can be configured using the CC Configuration Commands. The CC Commands can be issued usingeither Hardware or Software Configuration. To use Hardware Configuration, pin 17 of a transceiver must be assertedLow. Software Configuration can be used by entering AT Command Mode before issuing the CC Commands.Figure 5: AC4790 Configuration FlowAT COMMANDSThe AT Command mode implemented in the AC4790 creates a virtual version of the Command/Data pin. The “EnterAT Command Mode” Command asserts this virtual pin Low (to signify Command Mode) and the “Exit AT CommandMode” Command asserts this virtual pin High (to signify Data). Once this pin has been asserted Low, all On-the-FlyCC Commands documented in the manual are supported.Use AT CommandsReceive ModeTake Pin 17 Low (Hardware Configuration)AT+++ (Software Configuration)Send CC Commands Exit Command ModeIn AT Command ModeSend CC CommandSend Another CC CommandSend Exit AT Command Mode Command Take Pin 17 HighReceive ModeYesYesYesYes
25CONFIGURING THE AC4790www.aerocomm.comOn-the-Fly Control CommandsThe AC4790 transceiver contains static memory that holds many of the parameters that control the transceiveroperation. Using the “CC” command set allows many of these parameters to be changed during system operation.Because the memory these commands affect is static, when the transceiver is reset, these parameters will revert backto the settings stored in the EEPROM. While in CC Command mode using pin 17 (Command/Data), the RF interfaceof the transceiver is still active. Therefore, it can receive packets from remote transceivers while in CC Commandmode and forward these to the OEM Host. While in CC Command mode using AT Commands, the RF interface of the transceiver is active, but packets sent fromother transceivers will not be received. The transceiver uses Interface Timeout/RF Packet Size to determine when aCC Command is complete. Therefore, there should be no delay between each character as it is sent from the OEMHost to the transceiver or the transceiver will not recognize the command. If the OEM Host has sent a CC Commandto the transceiver and an RF packet is received by the transceiver, the transceiver will send the CC Commandresponse to the OEM Host before sending the packet. However, if an RF packet is received before the InterfaceTimeout expires on a CC Command, the transceiver will send the packet to the OEM Host before sending the CCCommand response.When an invalid command is sent, the radio scans the command to see if it has a valid command followed by bytesnot associated with the command, in which case the radio discards the invalid bytes and accepts the command. In allother cases, the radio returns the first byte of the invalid command back to the user and discards the rest.
CONFIGURING THE AC479026Table 10: Command Quick ReferenceCommand Name Command (All Bytes in Hex) Return (All Bytes in Hex)AT EnterCommandMode0x41 0x54 0x2B 0x2B 0x2B 0x0D 0xCC 0x43 0x4F 0x4DExit AT CommandMode 0xCC 0x41 0x54 0x4F 0x0D -0xCC 0x44 0x41 0x54Status Request 0xCC 0x00 0x00 - - - 0xCC Firmware Ver-sion0x00 - 0x03 -Change Channel 0xCC 0x01 New Channel - - 0xCC New Channel -BroadcastPackets0xCC 0x08 0x00: Broadcast0x01: Addressed-0xCC 0x00 or 0x01 - -Write Destination Address 0xCC 0x10 Byte 4 of Dest. MACByte 5 Byte 60xCC Byte 4 of Dest. MACByte 5 Byte 6Read Destination Address 0xCC 0x11 - - - - 0xCC Byte 4 of Dest. MACByte 5 Byte 6Auto Destination 0xCC 0x15 bit-0: Auto Destinationbit-4: Enable Auto Destination0xCC bit-0: Auto Destinationbits-1-7: 0Read API Control 0xCC 0x16 - - - - 0xCC API Control -Write API Control 0xCC 0x17 API Control - - 0xCC API Control -Read Digital Inputs 0xCC 0x20 - - - - 0xCC bit-0: GI0bit-1: GI1- -Read ADC 0xCC 0x21 0x01: AD In0x02: Temp0x03: RSSI- - 0xCC MSB of 10 bit ADCLSB of 10 bit ADCWrite Digital Outputs0xCC 0x23 bit-0: GO0bit-1: GO1- - 0xCC bit-0: GO0bit-1: GO1- -Set Max Power 0xCC 0x25 New Max Power -0xCC Max Power - -Enter Probe 0xCC 0x8E 0x00: Enter Probe0x01: Exit Probe-0xCC 0x00 or 0x01 - -Read Temperature 0xCC 0xA4 - - - - 0xCC Temp (C) - -EEPROM Byte Read 0xCC 0xC0 Start Address Length 0xCC Starting AddressLength DataEEPROM Byte Write 0xCC 0xC1 Start Address Length Data Starting Address Length Data writtenSoft Reset 0xCC 0xFF - - - - - - - -
27CONFIGURING THE AC4790www.aerocomm.comCOMMAND DESCRIPTIONSEnter AT Command ModePrior to sending this command, the OEM Host must ensure that thetransceiver’s RF transmit buffer is empty. If the buffer is not empty, theradio will interpret the command as data and it will be sent over the RF.This can be accomplished by waiting up to one second between thelast packet and the AT command.Command: 0x41 0x54 0x2B 0x2B 0x2B 0x0DNumber of Bytes Returned: 4Response: 0xCC 0x43 0x4F 0x4DExit AT Command ModeThe OEM Host should send this command to exit AT Command modeand resume normal operation.Command: 0xCC 0x41 0x54 0x4F 0x0DNumber of Bytes Returned: 4Response: 0xCC 0x44 0x41 0x54Firmware Version RequestThe OEM Host issues this command to request the firmware of thetransceiver.Command: 0xCC 0x00 0x00Number of Bytes Returned: 3Response: 0xCC Version XXParameter Range: XX = 0x00 - 0x03 (Ignore)Change ChannelThe OEM Host issues this command to change the channel of thetransceiver.Command: 0xCC 0x01 ChannelNumber of Bytes Returned: 2Response: 0xCC ChannelBroadcast PacketsThe OEM Host issues this command to change the transceiveroperation between Addressed Packets and Broadcast Packets. IfAddressed Packets are selected, the transceiver will send all packets tothe transceiver designated by the Destination Address programmed inthe transceiver. If Broadcast Packets are selected, the transceiver willsend its packets to all transceivers on that network. Setting bit-7 of APIControl to 1 can also enable Broadcast Packets.Command: 0xCC 0x08 Data1Number of Bytes Returned: 2Response: 0xCC Data1Parameter Range: Data1 = 0x00 for Addressed, 0x01 forBroadcastWrite Destination AddressThe OEM Host issues this command to the transceiver to change theDestination Address. Note: Only the three Least Significant Bytes of the MAC Address areused for packet delivery.Command: 0xCC 0x10 MAC3 MAC2 MAC1Number of Bytes Returned: 4Response: 0xCC MAC3 MAC2 MAC1Parameter Range: 0x00 - 0xFF corresponding to 3 LSB’s ofdestination MAC Address
CONFIGURING THE AC479028Read Destination AddressThe OEM Host issues this command to the transceiver to read thedestination address.Note: Only the three Least Significant Bytes of the MAC Address areused for packet delivery.Command: 0xCC 0x11Number of Bytes Returned: 4Response: 0xCC MAC3 MAC2 MAC1Parameter Range: 0x00 - 0xFF corresponding to 3 LSB’s ofdestination MAC AddressAuto DestinationThe Host issues this command to change the Auto Destination setting.When issuing this command, the Auto Destination setting will only bechanged if the corresponding enable bit is set (Control1 Parameter,EEPROM address 0x56, bit-4).Command: 0xCC 0x15 Data1Number of Bytes Returned: 2Response: 0xCC Data2Parameter Range: Data1 = bit-0: Auto Destination, bit-4:Enable Auto Destination modification; Data2 = bit-0: NewAuto Destination setting, bits 2 - 7:0Read API ControlThe OEM Host issues this command to read the API Control byte. Command: 0xCC 0x16Number of Bytes Returned: 2Response: 0xCC API ControlWrite API ControlThe OEM Host issues this command to write the API Control byte. Command: 0xCC 0x17Number of Bytes Returned: 2Response: 0xCC API ControlSet Max PowerThe OEM Host issues this command to limit the maximum transmitpower emitted by the transceiver. This can be useful to minimizecurrent consumption and satisfy certain regulatory requirements. Theradios are shipped at maximum allowable power.Command: 0xCC 0x25 Max PowerNumber of Bytes Returned: 2Response: 0xCC Max PowerRead TemperatureThe OEM Host issues this command to read the onboard temperaturesensor. The transceiver reports the temperature in oC where 0x00 -0x80 corresponds to 0 - 80 oC and where 0xD8 - 0x00 corresponds to -40 - 0 oC.Command: 0xCC 0xA4Number of Bytes Returned: 2Response: 0xCC TemperatureParameter Range: Temperature = 0xD8 - 0x80
29CONFIGURING THE AC4790www.aerocomm.comRead Digital InputsThe OEM Host issues this command to read the state of both digitalinput lines.Command: 0xCC 0x20Number of Bytes Returned: 2Response: 0xCC Data1Parameter Range: Data1 = bit-0: GI0, bit-1: GI1Read Radio TableThe OEM Host issues this command to read the Radio Table thatresides on the transceiver. The Radio Table stores information for up tothe last 8 transceivers that it received a packet from. This informationcan be useful for determining alternative data paths.Stale Count: The Stale Count Reload (0x04) determines the amount oftime that a transceiver stays active in the Radio Table. The Stale Count(min: 0x00; max: dependent on EEPROM setting) for a radio is set to 0when a packet is received; and then incremented by one every 100 msthereafter. When the Stale Count of a transceiver reaches the StaleCount Reload (0x04), the transceiver is considered stale. A Radio Tablecan hold information for up to 8 different transceivers; however if thetable is full and a ninth radio appears, the first stale radio is replacedwith the new radio. If none of the radios are stale, the oldest radio isreplaced by the new radio.Command: 0xCC 0x18Number of Bytes Returned: VariesResponse: 0xCC #Transceivers MAC2 MAC1 MAC0 RSSIRSSI* StaleCount MAC2 MAC1 MAC0...etc.Table 11: Received Signal StrengthSignal Strength (dBm) RSSI Value (Hex) Signal Strength (dBm) RSSI Value (Hex)40x0E -62 0x2B-2 to 1 0x0D -66 0x40-12 to -6 0x0C -69 0x55-36 to -22 0x0B -72 0x62-42 to -39 0x0C -76 0x71-46 0x0D -79 0x78-49 0x0E -82 0x84-52 0x11 -86 0x9A-56 0x17 -89 0xAD-59 0x1C -92 0xBD
CONFIGURING THE AC479030Read ADCThe OEM Host issues this command to read any of the three onboard10-bit A/D converters. Because the RF is still active in On-the-FlyCommand Mode, the transceiver will not process the command untilthere is no activity on the network. The Read RSSI command istherefore useful for detecting interfering sources but will not report theRSSI from a remote transceiver on the network. The equations forconverting these 10 bits into analog values are as follows:Analog Voltage = (10 bits / 0x3FF) * 3.3VTemperature (oC) = ((Analog Voltage - 0.3) / 0.01) - 30RSSI value (dBm) = -105 + (0.22 * (0x3FF - 10 bits))Command: 0xCC 0x21 Data1Number of Bytes Returned: 3Response: 0xCC Data2 Data3Parameter Range: Data1 = 0x00: AD In, 0x01: Temperature,0x02: RSSI; Data2 = MSB of requested 10-bit ADC value;Data3 = LSB of requested 10-bit ADC valueWrite Digital OutputsThe OEM Host issues this command to write both digital output lines toparticular states.Note: This command should only be used when Protocol Status (0xC2)is not set to 0xE3.Command: 0xCC 0x23 Data1Number of Bytes Returned: 2Response: 0xCC Data1Parameter Range: Data1 = bit-0: GO0, bit-1: GO1ProbeEnabling bit-6 of API Control will enable this command. When the OEMHost issues this command, the transceiver sends out a query every 500ms. The transceivers, upon receiving the query, randomly choose aquery to respond to. After responding to a Probe, the transceiver willwait at least 10 seconds before responding to another probe.Apart from the transceiver response, there are two other responses thatprovide crucial information to the OEM Host. This information can beused to monitor the network and determine alternate routing paths.Probe ReportRemote transceiver’s response to its OEM host upon receiving a Probequery.Note: Only valid when Probe Report (address 0xC9) is set to 0xE3.Transceiver’s ResponseUpon hearing the remote transceiver’s probe acknowledge, thetransceiver sends a response to the OEM Host.Command: 0xCC 0x8E Data1Number of Bytes Returned: 2Response: 0xCC Data1Parameter Range: 0x00 = Disable Probe, 0x01 = EnableProbeCommand: N/ANumber of Bytes Returned: 5Response: 0x86 RSSI MAC3 MAC2 MAC1Parameter Range: MAC3 MAC2 MAC1 = 3 LSB’s of radiosending the Probe queryCommand: N/ANumber of Bytes Returned: 6Response: 0x87 RSSI RSSI* MAC3 MAC2 MAC1Parameter Range: RSSI = How strong remote heard localtransceiver; RSSI* = How strong local heard remotetransceiver
31CONFIGURING THE AC4790www.aerocomm.comEEPROM Byte ReadUpon receiving this command, a transceiver will respond with thedesired data from the addresses requested by the OEM Host.Command: 0xCC 0xC0 Data1 Data2Number of Bytes Returned: 4+Response: 0xCC Data1 Data2 Data3Parameter Range: Data1 = EEPROM address; Data2 =Length (0x00 - 0x80); Data3 = Requested dataEEPROM Byte WriteUpon receiving this command, a transceiver will write the data byte tothe specified address but will not echo it back to the OEM Host until theEEPROM write cycle is complete (up to 10 ms).Multiple byte writes of up to 128 bytes are allowed. An EEPROMboundary exists between addresses 0x7F and 0x80. No singleEEPROM write command shall write to addresses on both sides of thatEEPROM boundary.Command: 0xCC 0xC1 Data1 Data2Number of Bytes Returned: 4+Response: 0xCC Data1 Data2 DataParameter Range: Data1 = EEPROM address; Data2 =Length (0x00 - 0x80); Data3 = Data writtenResetThe OEM Host issues this command to perform a soft reset of thetransceiver. Any transceiver settings modified by CC commands willrevert to the values stored in the EEPROM.Command: 0xCC 0xFFNumber of Bytes Returned: NoneResponse: None
www.aerocomm.comEEPROM PARAMETERS7The OEM Host can program various parameters that are stored in EEPROM which become active after a power-onreset. The table below gives the locations and descriptions of the parameters that can be read/written by the OEMHost. Factory default values are also shown. Do not write to any EEPROM addresses other than those listed below.Do not copy one transceiver’s EEPROM to another transceiver as doing so may cause the transceiver to malfunction.Table 12: EEPROM ParametersParameter EEPROM AddressLength (Bytes) Range Default DescriptionProduct ID 0x00 40 40 bytes - Product identifier string. Includes revisioninformation for software and hardware.Stop Bit Delay 0x3F 10x00 -0xFF0xFF For systems employing the RS-485 interface or Parity, theserial stop bit might come too early. Stop bit delay controlsthe width of the last bit before the stop bit occurs.0xFF = Disable Stop Bit Delay (12 us)0x00 = (256 * 1.6 us) + 12 us0x01 - 0xFE = (value * 1.6 us) + 12 usChannel Number 0x40 10x00 -0x371x1: 0x00200: 0x001000: 0x10Set 0 = 0x00 - 0x0F (US/Canada): 1x1/200Set 1 = 0x10 - 0x2F (US/Canada): 1x1/1000Set 2 = 0x30 - 0x37 (US/Canada): 1x1/200; Australia: 1x1/200/1000Baud Rate Low 0x42 10x00 -0xFF0xFC Low byte of the interface baud rate. Default baud rate is57,600.Baud Rate High 0x43 10x00 0x00 High byte of interface baud. Always 0x00Control 0 0x45 10x00 Settings are:bit-7: 0bit-6: DES Enable0 = Disable1 = Enablebits 5-0: 0Transmit Retries 0x4C 10x01 -0xFF0x10 Maximum number of times a packet is sent out whenAddressed packets are selected.Broadcast Attempts0x4D 10x01 -0xFF0x04 Maximum number of times a packet is sent out whenBroadcast packets are selected.Stale Count Reload 0x4F 10x01 -0xFF0x40 Determines the amount of time that a transceiver will keep aradio active in its Receive Table. This value is reset everytime a packet is received from that radio.
33EEPROM PARAMETERSwww.aerocomm.comControl 1 0x56 10x43 Settings are:bit-7: Aerocomm Use Onlybit-6: Aerocomm Use Onlybit-5: Aerocomm Use Onlybit-4: Auto Destination0 = Use destination address1 = Use auto destinationbit-3: Aerocomm Use Onlybit-2: RTS Enable0 = Ignore RTS1 = Transceiver obeys RTSbit-1: Duplex 0 = Half Duplex 1 = Full Duplexbit-0: Auto Config0 = Use EEPROM values1 = Auto Configure valuesInterface Timeout 0x58 10x02 -0xFF0x04 Specifies a byte gap timeout, used in conjunction with RFPacket Size to determine when a packet coming over theinterface is complete (0.5 ms per increment).RF Packet Size 0x5B 10x01 -0x800x80 Used in conjunction with Interface Timeout; specifies themaximum size of an RF packet.CTS On 0x5C 10x01 -0xFF0xD2 CTS will be deasserted (High) when the transmit buffercontains at least this many characters.CTS Off 0x5D 10x00 -0xFE0xAC Once CTS has been deasserted, CTS will be reasserted(Low) when the transmit buffer is contains this many or lesscharacters.Max Power 0x63 10x00 -0x60Set inProduction& can varyUsed to increase/decrease the output power. Thetransceivers are shipped at maximum allowable power.Parity 0x6F 10xE3,0xFF0xFF 0xE3 = Enable Parity0xFF = Disable ParityNote: Enabling parity cuts throughput and the interfacebuffer size in half.Destination ID 0x70 60x00 -0xFFSpecifies destination for RF packetsSystem ID 0x76 10x00 -0xFF0x01 Similar to network password. Radios must have the samesystem ID to communicate with each other.RS-485 DE 0x7F 10xE3,0xFF0xFF 0xE3 = GO0 is active Low DE for control of external RS-485hardware0xFF = Disable RS-485 DEMAC ID 0x80 60x00 -0xFFFactory programmed unique IEEE MAC address.Original Max Power0x8E 1Set inProductionand can varyCopy of original max power EEPROM setting. This addressmay be referenced but should not be modified.Table 12: EEPROM ParametersParameter EEPROM AddressLength (Bytes) Range Default Description
EEPROM PARAMETERS34Product ID 0x90 15 0x90 - 0x93: Product ID0x94 - 0x95: Prefix (CL, CN, or AC)0x96 - 0x99: Power (200M, 200A, 1000, 1x1)Note: There will be a period in front of the 1x1 to keep thefield at four bytes0x9A - 0x9C: Interface (232, 485, TTL)0x9D - 0x9E: Setup script (01 is stock)0x9F: Reserved for future use; always 0xFFAPI Control 0xC1 10x10 Settings are:bit-7: Broadcast packets0 = Addressed Packets1 = Broadcast Packetsbit-6: Probe0 = Disable Probe1 = Enable Probebit-5: SLock10 = Disable1 = Enablebit-4: SLock00 = Disable1 = Enablebit-3: Unicast Packets0 = Broadcast or Addressed delivery1 = Addressed packets onlybit-2: Send Data Complete Enable0 = Disable1 = Enablebit-1: API Transmit Packet Enable0 = Disable1 = Enablebit-0: API Receive Packet Enable0 = Disable1 = EnableProtocol Status 0xC2 10x00 -0xFF0xE3 Determines if the GO0 & GO1 server as generic output or asprotocol status.Session Count Refresh0xC4 10x00 -0xFF0x08 Specifies the number of hops a transceiver stays in sessionwith another transceiverRandom Back-Off 0xC3 10x00 -0xFF0x00 The random amount of time a transceiver waits when acollision occurs before resending the packet again.0x00: Disable Random Backoff0x01: Wait 1-2 packet times, then retry0x03: Wait 1-4 packet times, then retry0x07: Wait 1-8 packet times, then retry0x0F: Wait 1-16 packet times, then retry0x1F: Wait 1-32 packet times, then retry0x3F: Wait 1-64 packet times, then retry0x7F: Wait 1-128 packet times, then retry0xFF: Wait 1-256 packet times, then retrySesnse Adjust 0xC8 10x00 -0xFFSet inProductionand can varyThe minimum RSSI required by a transceiver to establish asession upon hearing a long beacon.Table 12: EEPROM ParametersParameter EEPROM AddressLength (Bytes) Range Default Description
35EEPROM PARAMETERSwww.aerocomm.comProbe Report 0xC9 10x00 -0xFF0xE3 When set to 0xE3, upon receiving a probe the transceiversends a Probe Report to the OEM Host.DES Key 0xD0 70x00 -0xFF56-bit Data Encryption keyTable 12: EEPROM ParametersParameter EEPROM AddressLength (Bytes) Range Default Description
www.aerocomm.comDIMENSIONS8MECHANICAL DRAWINGSInterface Connector - 20 pin OEM Interface connector (Molex 87759-0030, mates with Samtec SMM-110-02-S-DMMCX Jack - Antenna Connector (Johnson Components 135-3711-822)AC4790 (with MMCX connector) MechanicalFigure 6: AC4790 (with MMCX connector) Mechanical0.0000.1000.1500.4351.9001.8750.8250.125 dia non-plated holes (2) places0.0000.1001.0101.6501.550 pins1 21.6500.0000.0670.0000.1570.0620.180MMCX jackJ120 pin header, 0.020 sq. posts on 0.079 inch (2mm) centers1.3201.7600.100 dia non-plated hole (1) place, under shieldMMCX jack 0.145 dia
37DIMENSIONSwww.aerocomm.comFigure 7: AC4790 with integral gigaAnt Antenna (on bottom) Mechanical0.0000.1000.1501.8752.5502.6500.4350.125 dia non-plated holes (4) places0.0000.1001.0101.6501.550 pins1 21.6500.0000.0000.1570.062J120 pin header, 0.020 sq. posts on 0.079 inch (2mm) centers-0.1520.0000.1800.0861.1802.0302.345GigaAnt Snap-In Antenna
DIMENSIONS38Figure 8: AC4790-1x1 Mechanical0.0000.2000.3000.0000.0801.0001.080cut corner indicates pin 10.0310.0000.131AC4790-1X11.0000.0000.100 typ.0.2001.0000050680045030.2200.2600.10 typ.0.8600.080 x 0.040 padtypicalRECOMMENDED PAD PATTERN (viewed from top)0.0000.0800.2200.8601.0001.080Module Outline28127234567262524232221 20 19 18 17 16 15891011121314N/CCTSRTSVCC (note 1)RSSIGND (note 2)RF_PORTAD_INUP_RESETCMD/DATASESSION STATUSDO1NCDI1N/CN/CN/CN/CN/C9600_BAUD (TST_MODE)RESETRXDTXDDI0DO0GNDVCC (note 1)NCNotes:1) VCC must not exceed +3.3V DC.2) This GND pin to be used for RF ground.3) Operating temperature -40C to +80C3) Storage temperature -60C to +140C
39DIMENSIONSwww.aerocomm.comFigure 9: AC4790-1x1 PCB ConsiderationsGndGndGndPN: AC4790X-1X1SN: 005068004503uStrip Gnd0.1100.1100.1101206 SMT Chip Capacitors, can use 0805, 0603 or even 0402 parts. Shunt parts should be symetrical about series part and close as possible.Terminate at RF Antenna ConnectorNote: Must provide solid copper Ground plane on the bottom side of pc board in this area. Use several large vias (0.030" hole) to tie top side ground to the bottom layer ground plane. Must continue microstrip width and grounds along the entire length.Customer's PC BoarPCB THickness Notes: For 0.062 thick PC board microstrip width and spacing is 0.110 inches.For 0.031 thick PC board microstrip width and spacing is 0.055 inches.Note: Keep distance between 1x1 Module and antenna connector as short as possible for better performance.
www.aerocomm.comORDERING INFORMATION9PRODUCT PART NUMBER TREEDEVELOPER KIT PART NUMBERSAll of the above part numbers can be ordered as a development kit by prefacing the part number with “SDK-”. As anexample, part number AC4790-200A can be ordered as a development kit using the part number: SDK-AC4790-200A.All developer’s kits include (2) transceivers, (2) development boards, (2) 7.5 VDC unregulated power supplies, (2)serial cables, (2) USB cables, (2) antennas, configuration/testing software and integration engineering support.
www.aerocomm.comCOMPLIANCY INFORMATION10AC4790-1X1Due to the RF antenna trace residing on the OEM Host PCB, the FCC will not grant modular approval for the AC4790-1x1 and requires the OEM to submit their completed design for approval. Contact AeroComm for the approvalprocedure.AGENCY IDENTIFICATION NUMBERSAgency compliancy is a very important requirement for any product development. AeroComm has obtained modularapproval for its products so the OEM only has to meet a few requirements to be eligible to use that approval. Thecorresponding agency identification numbers and approved antennas are listed below.APPROVED ANTENNA LISTThe following antennas are approved for use with the AC4790 as identified. The OEM is free to choose anothervendor’s antenna of like type and equal or lesser gain as a listed antenna and still maintain compliance.Table 13: Agency Identification NumbersPart Number US/FCC Canada/ICAC4790-200A KQLAC4490-100 2268C-AC4490AC4490-200/AC4490LR-200 KQL-4x90-200 2268C-4x90200AC4790-1000 KQL-AC4490 2268C-AC44901000To reduce potential radio interference to other users, the antenna type and its gain should be so chosen that theequivalent isotropically radiated power (e.i.r.p.) is not more than that permitted for successful communication.This device has been designed to operate with the antennas listed below, and having a maximum gain of 11.0 dBd.Antennas not included in this list or having a gain greater than 11.0 dBd are strictly prohibited for use with thisdevice. The required antenna impedance is 50 ohms.
COMPLIANCY INFORMATION42FCC / IC REQUIREMENTS FOR MODULAR APPROVALIn general, there are two agency classifications of wireless applications; portable and mobile.Portable - Portable is a classification of equipment where the user, in general, will be within 20 cm of the transmittingantenna. Portable equipment is further broken down into two classes; within 2.5 cm of human contact and beyond2.5 cm (Note: Ankles, feet, wrists, and hands are permitted to be within 2.5 cm of the antenna even if the equipment isdesignated as being greater than 2.5 cm). The AC4790 is not agency approved for portable applications. The OEM isrequired to have additional testing performed to receive this classification. Contact AeroComm for more details.Mobile - Mobile defines equipment where the user will be 20 cm or greater from the transmitting equipment. Theantenna must be mounted in such a way that it cannot be moved closer to the user with respect to the equipment,although the equipment may be moved. (Note: Ankles, feet, wrists, and hands are permitted to be within 20 cm ofmobile equipment).-1020B5812-04 Flavus gigaAnt Microstrip -0.5 X - - --Y22831Comtelco Yagi 6 dBd - X X X-Y2283A0915-10RP Comtelco Yagi 6 dBd - X X X-SG101N9152Nearson Omni 5 - X X X-SG101NT-915 Nearson Omni 5 - X X X-GM113 V.Torch Omni 3.5 - X X --PC8910NRTN Cushcraft Yagi 11 dBd - - X --ANT-DB1-RMS Antenna Factor Monopole 3 - X X -1. Strictly requires professional installation.2. Strictly requires professional installation.2268C-AC44901000Table 14: AC4790 Approved AntennasAeroCommPart NumberManufacturer Part Number Manufacturer Type Gain (dBi)200A200M200LR1000M0600-00019 S467FL-5-RMM-915S Nearson 1/2 Wave Dipole 2 - X X X0600-00025 S467FL-5-RMM-915 Nearson 1/2 Wave Dipole 2 - X X X0600-00024 S467AH-915 Nearson 1/2 Wave Dipole 2 - X X X0600-00027 S467AH-915R Nearson 1/2 Wave Dipole 2 - X X X0600-00028 S161AH-915R Nearson 1/2 Wave Dipole 2.5 - X X X0600-00029 S161AH-915 Nearson 1/2 Wave Dipole 2.5 - X X X0600-00030 S331AH-915 Nearson 1/4 Wave Dipole 1 - X X X
43COMPLIANCY INFORMATIONwww.aerocomm.comLabel and text information should be in a size of type large enough to be readiily legible, consistent with thedimensions of the equipment and the label. However, the type size for the text is not required to be larger than eightpoint.ANTENNA REQUIREMENTSWARNING: This device has been tested with an MMCX connector with the above listed antennas. When integratedinto the OEM’s product, these fixed antennas require professional installation preventing end-users from replacingthem with non-approved antennas. Antenna Y2283 & SG101N915 strictly require professional installation. Anyantenna not in the previous table must be tested to comply with FCC Section 15.203 for unique antenna connectorsand Section 15.247 for emissions. Contact AeroComm for assistance.Caution: Any change or modification not expressly approved by AeroComm could void the user's authority to operatethe equipment.WARNINGS REQUIRED IN OEM MANUALSWARNING: This equipment has been approved for mobile applications where the equipment should be used atdistances greater than 20 cm from the human body (with the exception of hands, feet, wrists, and ankles). Operationat distances of less than 20 cm is strictly prohibited and requires additional SAR testing.CHANNEL WARNINGThe OEM must prevent the end-user from selecting a channel not approved for use by the FCC.OEM EQUIPMENT LABELING REQUIREMENTSWARNING: The OEM must ensure that FCC labeling requirements are met. This includes a clearly visible label on theoutside of the OEM enclosure specifying the appropriate AeroComm FCC identifier for this product as well as the FCCnotice below. The FCC identifiers are listed above.Contains FCC ID: KQLAC4490-100 / KQLAC4490 / KQL-4X90200Operation is subject to the following two conditions: (1) this device may not causeinterference, and (2) this device must accept any interference, including interferencethat may cause undesired operation of the device.
www.aerocomm.comAPPENDIX I - SAMPLE POWER SUPPLYIBelow is a simple switching power supply that provides enough current to easily power any Aerocomm OEM module.It utilizes low cost, off the shelf components that fit into a small area. This supply has an input voltage range of +6volts to +18 volts and will output +3.4 volts at 1.5 amps. Included is a schematic, bill of materials with manufacture's name and part numbers and a sample PCB layout. It isimportant to follow the layout suggestions and use large areas of copper to connect the devices as shown in thelayout. It is also important to hook up the ground traces as shown and use multiple vias to connect input and outputcapacitors to the bottom side ground plane. If the input voltage will be less than 12 volts then C1 and C2 can be replaced with a single 100uF 20 volt capacitor(same part number as C7). This will reduce board space and lower costs further. If you are powering an AC5124module, R1 can be changed to a 373 ohm 1% resistor. This will change the output to +5 volts at 1.0 amps. BILL OF MATERIALSTable 15: Power Supply Bill of MaterialsQty Reference Value Description Mfg. Mfg. part number 1 R1 210 Res, 0603, 210, 1/16W, 1% KOA RK73H1JT2100F 1 R2 127 Res, 0603, 127, 1/16W, 1% KOA RK73H1JT1270F 2 C1 C2 47uF Cap, Tant, 7343, 47uF, 35V AVX TPSE476M035R0200 3 C3 C4 C5 0.1uF Cap, Cer, 0603, 0.1uF, Y5V, 25V Murata GRM39Y5V104Z025AD 1 C6 3300pF Cap, Cer, 0603, 3300pF, X7R, 50V Murata GRM39X7R332K050AD 1 C7 100uF Cap, Tant, 7343, 100uF, 20V Kemet T491X107K020A5 1 D1 B230/A Diode, SMB, B230/A, 2A, Schott-key Diodes, Inc. B230/A 1 D2 LL4148 Diode, MELF, LL4148, Switch Diode Diodes, Inc. LL4148 1 L1 15uH Xfmr, 2P, SMT, 15uH, 2A Coiltronics UP2.8B150 1 U1 CS51413 IC, CS51413, 8P, SO, Switch Reg Ctrl. On-Semi-cond. CS51413
45APPENDIX I - SAMPLE POWER SUPPLYwww.aerocomm.comSCHEMATICPCB LAYOUT
APPENDIX I - SAMPLE POWER SUPPLY46
www.aerocomm.comAPPENDIX II - 5V TO 3.3V LEVELSIIAll inputs on the AC4790-200 & AC4790-1000 are weakly pulled high via 10 kohm resistors. The AC4790-200 has 5Vinputs while the AC4790-1000 & AC4790-1x1 have 3.3V inputs. The AC4790-200 uses an octal buffer to drop the 5V tothe required 3.3V level; the -1000 and -1x1 leave this to the OEM.Some of the most common voltage conversion methods are described below.VOLTAGE LEVEL CONVERSION IC’SThis is the easiest and most efficient method. Aerocomm recommends the TI SN74LVC244A Octal Buffer/Driver.Inputs can be driven from either 3.3 or 5V systems, allowing the device to be used in a mixed 3.3/5V system.PASSIVE RESISTOR VOLTAGE DIVIDERWhile a resistor voltage divider can successfully drop the 5V to the required 3.3V, it will draw static current all of thetime. Typically this method is only suitable for one-way 5V to 3.3V conversion. When choosing the resistor values,one needs to include the radio’s internal 10 kohm resistors on the input signals.74LVC2442Y0GND92Y010 GND1Y32A01Y32A012111OE11A0232Y341A1VCC2OE1Y02A3201918172Y251A2672Y181A31Y12A21Y22A116151413Y018Y11614 Y212 Y3A0A1A2A32468OE1Input AInput BInput CInput D74LVC244
www.aerocomm.comAPPENDIX III - APIIIIThe API feature set of the AC4790 provides powerful packet routing capabilities to the OEM Host. The number of APIconfigurations is endless as individual radios can all be configured differently to suit the OEM Host’s varying needs.Some of the most common implementations are described in the following pages.POLLING NETWORKMany applications require multiple locations to report back to a single access point. One solution would be to enterCommand mode, change the transceiver’s destination address and then exit Command mode to resume normaloperation. When it is time to communicate with another transceiver, the process would be repeated; costing time andinevitably reduction in throughput as unnecessary commands are issued. As an alternative, the Transmit APIcommand can be used to control packet routing on a packet-by-packet basis.The simplest implementation consists of a smart Shared Access Point (SAP) with a microcontroller or processor ofsome type which has transmit API enabled. The SAP controls which transceiver(s) each packet is routed to.Broadcast packets should be used when all remotes are to receive the same message and addressed packets whencommunication with a single remote only is desired. An example of each is shown in the following pages.MAC 12 34 56Shared Access PointMAC 12 34 A3MAC 12 34 A2MAC 12 34 A1MAC 12 34 A6MAC 12 34 A4MAC 12 34 A5Channel: 0x10System ID: 0x011 23456
49APPENDIX III - APIwww.aerocomm.comAddressed Transmit API1To poll radio 1, the SAP transmits the packet using the following format:2To poll radio 2, the SAP transmits the packet using the following format:3To poll radio 2, the SAP transmits the packet using the following format:4This continues until all radios have successfully been polled by the SAP.Broadcast Transmit APITo send out a universal poll request or data packet, the OEM may wish to utilize the broadcast portion of the TransmitAPI command. The Broadcast command is similar to the addressed command; only with the Destination MACAddress set to all 0xFF.
APPENDIX III - API50The remote response is dependent on the OEM’s specific needs and equipment. In many cases, remote radios areconnected to dumb devices without the intelligence to filter out or append specific portions of a packet that istransmitted or received. Since the 7 bytes of overhead in the Transmit API command are not sent over the RF, theremotes will receive only the payload data, “STATUS”. If auto destination is enabled on the remote radio, thetransceiver will automatically change its destination address to that of the radio it last received a packet from. Whenthe remote device sends its response, it will therefore automatically be routed back to the SAP.Depending on the API configuration of the SAP, the packet will be received in one of two formats:Receive APIWhen Receive API is enabled, the transceiver will receive the reply data + the MAC address of the source radio andtwo RSSI values; RSSI is how strong the remote transceiver heard the local transceiver and RSSI* is how strong thelocal heard the remote transceiver.It may be useful to the OEM Host to determine which radio each packet originated from. When Receive API isenabled, every packet received by the transceiver will be received in the above format.
51APPENDIX III - APIwww.aerocomm.comNormal Receive Mode (non-API)If Receive API is not enabled, the transceiver will receive the reply data only (i.e. “ALLGOOD”) from each transceiver.DAISY CHAIN / REPEATER NETWORKFor applications spanning long distances and cases where the desired radio is not within range of the sending radio,a daisy chaing type network can be implemented. With the use of API commands, a processor and external buffer, adaisy chain or repeater can easily be implemented to store and forward the data to the desired radio. The examplebelow assumes that radio A has a packet which needs to be received by radio D (far right).1Radio A transmits the string “FIND D” to Radio B using the Transmit API command.MAC 12 34 56 MAC 12 34 A3MAC 12 34 A2MAC 12 34 A11 2 3
APPENDIX III - API522Radio B receives the packet “FIND D”, and stores it in the buffer until the current session with Radio A has ended. Once the current session ends, Radio B forwards the packet from its buffer to Radio C.3Radio C receives the packet “FIND D”, and stores it in the buffer until the current session with Radio B has ended. Once the current session ends, Radio C forwards the packet from its buffer to Radio D.4Radio D receives the packet “FIND D” and sends the appropriate response back down the line to Radio A.LOOPBACK REPEATERThe simplest repeater to implement is a loopback repeater. A loopback repeater can be created by connecting thetransceiver’s RXD and TXD lines together. When the radio receives data, it will retransmit the data to all availabletransceivers on the network. It is important not to have two loopback repeaters in range of each other as they willcontinuously transmit data back and forth.MAC 12 34 56 MAC 12 34 A3MAC 12 34 A2MAC 12 34 A1Loopback RepeaterA B C
53APPENDIX III - APIwww.aerocomm.comIf radios B & C in the above picture are not within range of radio A, they will not be able to receive or respond tocommunications from radio A. A loopback repeater can be added between the three such that it is in range of bothradio A and radios B & C. When the repeater receives a packet from radio A, it will transmit the packet out to radios B& C. If the repeater is set to Broadcast mode, radio A will receive a copy of each packet that it sends. If the repeaterhas a specific destination address (i.e. 12 34 A2), then radio A will not receive the packet as its MAC address will notmatch the specified destination address.TIME DIVISION MULTIPLE ACCESS NETWORKFor a more intelligent network, a TDMA system can be implemented. In this system various radios transmit data to aShared Access Point (SAP) during an assigned time interval. The system is synchronous so that only one radio istransmitting at a time and has full access to the SAP’s bandwidth. In a TDMA network, each radio must store its datafor the amount of time between its transmissions or bursts. A typical format for data passing through a SAP is shownbelow. A frame consists of arriving bursts from remote radios and each frame is then divided into multiple time slots.The bursts can be of varying lengths and can be longer for heavy-traffic stations. To prevent overlaps, guard intervalscan be inserted to absorb small timing errors in burst arrivals.Example:•Shared Access Point (SAP) sends broadcast packet which includes a sync pulse•Remote radios hear the sync pulse and join the session•Radio A transmits during time interval t = 1•Radio B transmits during time interval t = 2•Radio N transmits during time interval t = N - 1This type of implementation requires careful planning and should allow enough time for retries if necessary. When fullduplex is enabled, the radio which initiated the Session (SAP) will transmit during the even numbered hops and theremote radios will transmit only during odd numbered hops.123456GB1 Radio A Data GB2 Radio B Data GB3 GB4Radio C Data6 1TDMA Frame1 Timeslot
www.aerocomm.comAPPENDIX IV - API TIMING DIAGRAMSIVTIMING DIAGRAMSSession Count = 8, Retries = 3Session Count = 3, Retries = 3
55APPENDIX IV - API TIMING DIAGRAMSwww.aerocomm.comSession Count = 2, Retries = 2Session Count = 1, Retries = 1

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