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AC4790 User Manual - Digi-Key
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1. 20 FROST NITET RTT tp HM t Dr 21 UF Fiesel QUT TD ouest ER 27 Connan PERPE 21 P BD c pP RETE 21 CLANS uiuunt ote ea M C ni s a Mi i it IEEE i 21 CONFIGURING THE AGAT790 ese Dope deus bi roc ec Pic euro a uU ted 22 PC4790 Ai COMMAND S 22 EnlerAT ei era aa e eg alas iav Bore bust 23 GCOIDIBDADOd died eiie a dane eden T Id 23 ON THE FLY CONTROL COMMANDS CC COMMAND 4 040 00 0 23 COMMAND QUICK 2 2 24 EIHDWAIe HEVISION TOOU CSE 25 edu tess i o Motore cob D edat e 25 DIOGO CASE E ESNA ENN NNNM 25 Write Destination 00 6 58 0 0 1 25 HOAC DISSI BIO Sese Lr AR ME PE 25 VPEA POSH ECT 25 Head AFL Ol xvi tonto aste 25 WV AAC ODEON i
2. Byte Write Upon receiving this command a transceiver will write the data byte to the address specified but will not echo it back to the OEM Host until the EEPROM write cycle is complete The write can take as long as 10ms to complete Following the write cycle a transceiver will transmit the data byte to the OEM Host Multiple byte EEPROM writes are allowed up to a length of 128 bytes An EEPROM boundary exists between addresses 7Fh and 80h No single EEPROM write command shall write to addresses on both sides of that EEPROM boundary 22 Quick Tip Command CCh C1h 1 Data2 Data Number of bytes returned 4 Response CCh 1 Data2 Data Parameter Range Data1 EEPROM address Data2 Length 1 80h Data Data written The EEPROM is limited to 20 000 write cycles In order to avoid unnecessary writes it is recommended that you perform a read before issuing the write command to verify that the byte requires writing It is possible while performing an EEPROM write without a stable power supply that the EEPROM can become corrupted rendering the radio inoperable Heset Command The OEM Host issues this command to perform a soft reset of the transceiver Any transceiver settings modified by Commands will be overwritten by values stored in the EEPROM Command CCh FFh Number of bytes returned None Response None 28 EEPROM Parameters The OEM Host can program various parameters that are
3. EM 74 FIOW C OU MEETS 75 DUPER SE FUR PI E 15 INTERFACE TIMEOUT RIE PACKET 16 SYSTEM TIMINGAAND oi ed quede tati nih Dee us Meo d cete 16 MAXIMUM OVERALL SYSTEM THROUGHPU T a od us 16 uEcU Cum E nD e S M ed NEL aT 17 SYSTEM ID RE CHANNEBINUMBER M niai E 17 un E Dp RE Sn a ea liM E tae 18 HARDWARE INTERFAQGE Edel ved eid 20 Gin Generic Inputs 0 and 7 pins 4 and 14 respectively and Generic Outputs 0 and 1 pins OSD OCCHVIY 20 TXD Transmit Data RXD Receive Data PINS 2 and 3 20 CLS FIANOSNAMING TTE 20 OUT PP E 20
4. setae ji a RF Channels 0x00 0x0F RF Channels 0x10 0x2F RF Channels 0x30 0x37 Figure 4 RF Channel Numbers DES Data Encryption Standard Encryption is the process of encoding an information bit stream to secure the data content The DES algorithm is a common simple and well established encryption routine An encryption key of 56 bits is used to encrypt the packet The receiver must use the exact same key to decrypt the packet otherwise garbled data will be produced 17 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 7 byte 56 bits Encryption Decryption Key is located in EEPROM Bytes OxDO OxD6 It is highly recommended that this Key be changed from the default MAX POWER Max Power provides a means for controlling the RF output power of the AC4790 Output power and current consumption can vary by as much as 10 per transceiver for a particular Max Power setting Contact AeroComm for assistance in adjusting Max Power The following graphs show current consumption versus output power Output power can be represented in dBm decibels per meter and mW milliwatts The equations for converting between the two are shown below in Equations 2 amp 3 Power dBm 10log49 Power mW 2 Powar m 3 Figure 5 Current vs Output Power for AC4790 200 25 20 Current EEPROM mA Setting 125 1E Power
5. V Theory of peration MASTERLESS ARCHITECTURE The Masterless architecture is a true peer to peer architecture where any module that has data to transmit will initiate a communication Session with a transceiver s within its range transmit data and exit the Session This architecture eliminates the need for a master which dictates data flow control hence reducing additional system overhead and greatly improving efficiency Modes of Operation The AC4790 has three different operating modes Transmit Mode Receive Mode and Command mode When not in Transmit or Command Mode the radio will be in Receive Mode ready to receive data and awaiting a sync pulse from another transceiver A transceiver will enter either Transmit or Command Mode when its OEM Host sends data over the serial interface The state of the Command Data pin Pin 17 or the data contents determine which of the two modes will be entered Transmit Mode Figure 1 Modes of Operation Transmit Mode Any radio with data to transmit initiates a Session with other radios by transmitting a 25ms Sync Pulse Once a Session is established the radio enters Transmit Mode and transmits the data during the remaining 25 ms of the current hop remaining in Transmit Mode its Session Count expires When transmitting an Addressed packet the Session Count is defined by Session Count Refresh EEPROM address OxC4 number of Transmit Retries EEPROM address Ox4C When transmitti
6. 29 Table 10 Agency Identification 00 0 002 2 2 santa enn nnns 38 Table 11 AGAT90 Approved Antenna EISE raa oU DOR 38 LIST OF TABLES NES eR xc PE 8 Table 2 Input Voltage Characteristics AC4790 1000 amp 4790 1 1 9 Table Output Voltage Characteristics 9 Table 4 Session Count uo w KSXG T 11 Table upported SeLlal FOMMALS do stet Nu a 14 Table 6 Baud Rate Interface Timedut rsin a a A nnns nnne E nnns inna nas 14 Table 7 Maximum Overall System 16 Table 8 RF Chamel Number SettlriglS n era co cH Rn t has RR ox Ira basque tuit 17 Table 9 EEPROM Parameters EET 29 Table 10 Agency ldentification mVutiDOls eraat rele 38 Table 11 AGA7 90 Approved Antenna EISE eredi diee bebe rena gU tue 38 AC4790 Transceiver M odule The compact AC4790 900MHz transceiver can replace miles of cable in harsh industrial environments Using field proven FHSS technology which needs no additional FCC licensing in the Americas OEMs can easily make existing systems wireless with little or no HF expertise AC4790 Feature
7. 90 85 80 75 70 65 60 55 50 Signal at Receiver dBm Figure 8 RSSI Voltage vs Received Signal Strength Signal Strength dBm 46 9 53 9 4 UP Heset pin 15 UP Reset provides a direct connection to the reset pin on the AC4790 microprocessor and is used to force a soft reset For a valid reset reset must be asserted High for a minimum of 10ms Commandy Data pin 17 When logic High the transceiver interprets incoming OEM Host data as transmit data to be sent to other transceivers and their OEM Hosts When logic Low the transceiver interprets OEM Host data as command data AD In pin 18 AD In can be used as a cost savings to replace Analog to Digital converter hardware Reading of this pin can be performed locally using the Read ADC command found in the On the Fly Control Command Reference Session Status pin 20 Reports logic Low during a Session and logic High when not in Session The inverse of this pin can be obtained from pin GOO when Protocol Status is enabled 21 Configuring the AC 4790 The AC4790 can be configured using the CC Configuration Commands The CC Commands can be issued using either Hardware or Software Configuration To use Hardware Configuration pin 17 of a transceiver must be asserted Low Software Configuration can be used by entering AT Command Mode before issuing the CC Commands Figure 9 Configuration Flow of the 47906 Receive Made Use A
8. broadcast packet can also be used applications where one radio sends a string of data and in turn receives a response from or more of the receiving radios In simplest L network Random Back Off could be used to ensure that the responses do 1 not collide If two or more packets collide the radios will back off E retry the transmission in a random number of hops within the random 44 Appendix Ill API seed range 81h 01h 08h 04h FFh FFh FFh Radios A B C amp D receive the packet and send it to the OEM Host in the following format 81h 01h XXh XX h 01h 23h 45h Advanced For a more intelligent network a Time Division Multiple Access TDMA system could be implemented In this system various radios transmit data to a shared radio during an assigned time interval The system is synchronous so when a radio is transmitting it is the only one and has full access to the shared radio s bandwidth To utilize a TDMA system a radio must store its data for the period of time between its transmissions or bursts A typical format for data passing through a shared radio is shown below frame consists of arriving bursts from remote radios being served Each frame is then divided into multiple time slots The bursts do not have to have the same durations and can be longer for heavy traffic stations To prevent overlaps guard intervals can be inserted to absorb small timi
9. AEROCOMM AC4790 900 MHz OEM TRANSCEIVERS Specifications Subject to Change User s Manual Version 1 3 11160 THOMPSON AVENUE LENEXA KS 66219 800 492 2320 Www aerocomm com wireless aerocomm com DOCUMENT INFORMA TION Copyrig ht Copyright 2006 AEROCOMM Inc All rights reserved Information The information contained in this manual and the accompanying software programs are copyrighted and all rights are reserved by AEROCOMM Inc AEROCOMM Inc reserves the right to make periodic modifications of this product without obligation to notify any person or entity of such revision Copying duplicating selling or otherwise distributing any part of this product or accompanying documentation software without the prior consent of an authorized representative 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 preliminary Information furnished by AEROCOMM in this specification is believed to be accurate Devices sold by AEROCOMM are covered by the warranty and patent indemnification provisions appearing in its Terms of Sale only AEROCOMM makes no warranty express statutory and implied or by description regarding the information set forth herein AEROCOMM reserves the right to change specifications at any time and without notice AEROCOMM s products are intended for use in normal commercial and in
10. 0 614 C 0 100 0000 0000 2650 uma co dc CL F cc c p oe moos eI C clo tr ol 34 Figure 13 AC4790 1x1 Mechanical T anda p I FT 24 ngage RECOMMENDED PAD PATTERM ACGZIZ98 TX1 trom IUE UA LI e HI 200 rH 0860 1 Cr x1 Lr Hotes 1 VC C must not exceed DC 2 The pin ta be for RF ground 3 Operating temperature JDC to 800 3 Storage temperature GOC to 140 in BEEEHHB E LE CE D EE ERR 35 Figure 14 4790 1x1 PCB Considerations Note Keep di stance between 1x1 and antenna connector as short as possible for better Use eve ml large v hs GOP bok b tb bg ikk Kd to the bottom layer ag kn Md 1206 SMT cal 0805 0603 or ever 0402 part 5 skorki be MET PR coppe zymetrcal abort part and Gknidpbie the bottom ske of chee a pots bb po board the area Temiliate at Conector Caztomefz PC Board m b kectrip wkith gend the eite PCH THickness Mate s For 0 062 thick PC board microstrip width and spacing is 0 110 inche
11. Antenna Requirements WARNING This device has been tested with an MMCX connector with the antennas listed above When integrated in the OEMs product these fixed antennas require professional installation preventing end users from replacing them with non approved antennas Any antenna not in the previous table must be tested to comply with FCC Section 15 203 for unique antenna connectors and 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 operate the equipment 39 Agency Compliancy Information Warnings Required in OEM Manuals RF Exposure for Warning for Mobile Equipment A WARNING This equipment has been approved for mobile applications where the equipment should be used at distances greater than 20cm from the human body with the exception of hands wrists feet and ankles Operation at distances less than 20cm is strictly prohibited Channel Warning The OEM must prevent the end user from selecting a Channel not approved for use by the FCC IC 40 Appendix I Power Supply Application Note Appendix Power Supply Application N ote Here 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 6 volts to 18 volts and will o
12. so to does the system latency Finally when transceivers operate in addressed mode they will retry sending a packet up to the number of time specified in the transmit retry parameter specified in the EEPROM As the number of retries increases the system latency will increase also MAXIMUM OVERALL SYSTEM THROUGHPUT When operating as shown in the Table 7 Half Duplex Full Duplex an AC4790 transceiver is capable of Throughput bps Throughput bps each way achieving the listed throughput Radio not in continuous Session 25k 12 5k However in the presence of interference or at longer ranges the transceiver may Radio continuously in Session 22 5k not be able to meet the specified throughput Table 7 Maximum Overall System Throughput 16 RANDOM BACK OFF Random Back Off The transceivers utilize a Carrier Sense Multiple Access CSMA protocol with random back off and a selectable back off seed Therefore 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 times that it will wait before retrying the packet This random number is selected from a pool of numbers defined by the back 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 128 and 1 and 256 In a very dense network where more than two transceivers could experience a collision it is impor
13. will go High when a Session is initiated and remain High until the end of the Session When the 1 is configured as the Receive Acknowledge Status pin GO1 is normally Low and wil High upon receiving a valid Acknowledgement and remain High until the end rising edge of the next hop TXD Transmit Data and RXD Receive Data pins 2 and 3 respectively Serial TTL The AC4790 200 accepts 3 3 or 5VDC TTL level asynchronous serial data on the RXD pin and interprets that data as either Command Data or Transmit Data Data is sent from the transceiver at 3 3V levels to the OEM Host via the TXD pin The AC4790 1000 transceiver ONLY accepts 3 3V level signals RS 485 When equipped with an onboard RS 485 interface chip TXD and RXD become the half duplex RS 485 pins The transceiver 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 5485 and RXD is a mirror image of TXD RS485B The transceiver will still use RTS if enabled CTS Handshaking pin 7 The AC4790 has an interface buffer size of 256 bytes If the buffer fills up and more bytes are sent to the transceiver before the buffer can be emptied data loss will occur The transceiver prevents this loss by asserting CTS High as the buffer fills up and taking CTS Low as the buffer is emptied CTS On and CTS Off control the operation of CTS CTS On specifies the amount of by
14. 4 o 28 93 5 Ox 5 20 25 61 64 65 66 67 5 70 73 77 83 88 935 99 105 1105 114 5 1175 126 127 5 Transmit Current Consumption mA Figure 6 Current vs Output Power for AC4790 1000 30 Output Current EEPROM 25 Power mA Setting mW 743 1300 0x 50 Power dBm n 500 Ox OC 112 0x05 79 430 430 430 470 520 560 650 740 780 870 950 1000 1080 1130 1170 1260 1300 Current Vs Radiated Output Power for AC4790 1000M 18 Figure 7 Current vs Output Power for AC4790 1x1 15 10 13 745 5 20 6901 7166 71 9 7221 172 55 7303 17342 7387 7444 74 98 756 76 17 76 7 77 1 77 5 78 Transmit Current Consumption mA a Quick Tip 19 ardware nterface Below is a description of all hardware pins used to control the AC4790 G n Generic Inputs 0 and 7 pins 4 and 74 respectively and GOn Generic Outputs 0 and 7 pins 1 and 9 respectively Both Gln pins serve as generic input pins When Protocol Status byte C2h of EEPROM is disabled GOO amp GO 1 serve as generic outputs When Protocol Status is enabled pins GOO and GO1 serve as the Session Status and Receive Acknowledge Status pins respectively Reading and writing of these pins can be performed using CC Commands details can be found in the On the Fly Contro Command Reference Hardware Protocol Status When the GOO pin is configured as the Session Status pin is normally Low
15. A amp B has ended radio B initiates a session with radio C which in turn stores the data until the current session has ended Radio C will then initiate a session with radio D and so on Radio D can either send data back down the line to radio A forward it to another radio or end the chain A H D gt gt gt gt 12 34 56 MC 17 24 KE MAC 12 34 CD 12 34 EF A repeater can be implemented in the same manner as the Daisy Chain 11 Loopback repeater The simplest repeater to implement is the loopback repeater A loopback repeater can be created by connecting the radio s TX and RX lines together When the radio receives data it will retransmit the data to all available radios in range The repeater will forward the data to all available radios as well as back to the radio which sent the data to the repeater It is important to ensure that two such repeaters are never in range of each other as they will continuously transmit data back and forth to each other F Quick Tip When using a loopback repeater the radio which sent the data to the repeater will receive the data up to the repeater s number of broadcast attempts i e 4 broadcast attempts 4 received packets 111 Broadcast Packet This configuration has several variations and is ideal for applications which one radio sends a string of data to several radios where gt response is required
16. AC4790 1000M and the AC4790 1x1 have 3 3 V input levels However this can cause problems if a designer wants to use an older 5V circuit in the same design Some of the most common voltage conversion methods are described below 1 Voltage Level Conversion IC s This 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 hpu hpu C r Lwvoz44 The datasheet for the SN74LVC244A be downloaded from TI s website http focus ti com docs prod folders print sn74lvc244a html All inputs are weakly pulled high and are equipped with a 10 kO pullup resistor Aerocomm recommends that all unused inputs be pulled high 2 Passive Voltage Divider While a resistor voltage divider can successfully drop the 5V to the required 3 3V it will draw static current all of the time Typically this method is only suitable for one way 5V to 3 3V conversion When choosing the resistor values one should remember to include the radio s internal 10 kO resistor on the input signals 43 Appendix Ill API 111 Daisy Chain Repeater With the use of API commands a daisy chain or repeater can be implemented easily with the AC4790 Radio A would send a packet to radio B which would store the data in its buffer When the session between
17. Complete API Send Data Complete is enabled when bit 2 of the API Control byte is enabled The transceiver sends the OEM Host the following data upon receiving an RF Acknowledge from the remote transceiver or exhausting all attempts 0x00 Failure RSSI RSSI 0x01 Success 1 The RSSI is how strong the remote transceiver heard the local transceiver RSSI is how strong the local transceiver heard the remote transceiver 2 Successful RF Acknowledge updates the Success Failure bit 3 When the transceiver is transmitting Broadcast Packets it will always return success after exhausting all Broadcast Attempts 4 Send Data Complete can be used as a software send data complete indicator 5 The transceiver could receive a failure even though the packet was received as it could have missed the RF Acknowledge from the remote transceiver Receive Packet API Receive Packet is enabled when bit 0 of the API Control byte is enabled Upon receiving a packet the radio sends its OEM Host the packet in the following format Payload Data Source MAC Length RSSI RSSI 2 1 0 Payload Data The RSSI is how strong the remote transceiver heard the local transceiver RSSI is how strong the local transceiver heard the remote transceiver 22 Quick Tip Note When both API Send Data Complete and API Receive Packet on the API Control are enabled Send Data Complete will be received before the transceiver gets an API Receive Packet This order
18. S EB Figure 3 Hardware Flow Control A 2 Quick Tip CAN 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 the radio CTS is taken High by the radio when its interface buffer is getting full Your hardware should 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 into account the amount of latency the radio adds to the system any additional latency caused by Transmit Retries or Broadcast Attempts how often you send data non delivery network timeouts and interface data rate Polled type networks where the Server host requests data from the Client host and the Client host responds are good candidates for avoiding the use of CTS This is because no one transceiver can monopolize the RF link Asynchronous type networks where any radio can send to another radio at any point in time are much more difficult to implement without the use of CTS HALF DUPLEX FULL DUPLEX When Half Duplex communication is chosen the AC4790 will send a packet out over the RF whenever it can This can cause packets sent by multiple transceivers at the same time to collide with each other over the prevent this Full Duplex communication can be chosen Full Duplex shares the bandwidth intelligently to enable two way collision free commu
19. may get reversed when the API Send Data Complete is missed and is being resent after the API Receive Packet is received 13 Serial nterface In order for an OEM Host and a transceiver to communicate over the serial interface they need to have the same serial data rate Refer to the following sections to ensure OEM Host Data Rate matches the Serial Interface Baud Rate Host Data Hate The OEM Host Data Rate is the rate with which the OEM Host and transceiver communicate over the bits serial interface This rate is independent of the RF 8 1 Paritydisabled baud rate which is fixed at 76 8 kbps Possible 7 N 2 Partydiabed values range from 1200 bps to 115 200 bps 7 EOMS 1 J Paritydisabled 2 2 Enabling Parity cuts throughput in half and the 9 N 1 Paiyensbled 2 Interface Buffer size in half following 8 N 2 J Parityenabled asynchronous serial data formats are supported 8 EOMS 1 Parity enabled C ark M corresponds to 1 and Space S corresponds to 0 Table 5 Supported Serial Formats Serial Interface Baud Rate This two byte value determines the baud rate used for communicating over the serial interface to a transceiver Table 6 Baud Rate Interface Timeout lists values for some common baud rates Baud rates below 1200 baud are not supported For a baud rate to be valid the calculated baud rate must be within 3 o
20. the Interface Buffer size in half OxFF system ID to communicate with each other RS 485 DE Ox7F 1 OxFF is active Low DE for control of external RS 485 OxFF hardware OxFF Disable RS 485 DE MAC ID programmed unique IEEE MAC Address Original Max 8 1 Set in production of original Max Power EEPROM setting This address Power can vary may be modified but should not be modified Product ID 0x90 15 Bytes 0x90 0x93 Product ID 4490 4486 4868 4790 Bytes 0x94 95 Prefix CL CN or AC Bytes 0x96 0x99 Power 200M 200A 1000 1x1 Note there will be a period in front of the 1x1 to keep the ield at four bytes Ox9C Interface 232 485 TTL Ox9D Ox9E Setup script 01 is stock Ox9F Reserved for future use always OxFF Control OxC1 1 00010000 0x10 Settings are bit 7 Broadcast Packets O Addressed Packets 1 Broadcast Packets bit 6 Probe O Disable Probe 1 Enable Probe bit 5 SLock1 Disable Disable 1 Enable bit 3 Unicast Packets Broadcast or Addressed Packets 1 Addressed Packets only bit 2 Send Data Complete Enable Disable 1 Enable bit 1 API Transmit Packet Enable Disable Transmit API Packet 1 Enable Transmit API Packet bit O API Receive Packet Enable Disable Receive API Packet 1 Enable Receive API Packet Protocol Status OxC2 1 0x00 OxE3 Determines i
21. the remote radio s Session Count Radio loads its Current Session Count with Radio loads its Current Session Count with the remote radio s Current Session Count the remote radio s Current Session Count EEPROM Default Note 1 For both 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 the transceivers with the same Session Count Refresh EEPROM address C4h value Session Count Refresh must not be set to Oh gt H elp M e Decide Case 1 In this case a radio loads its Session Count with its Session Count Refresh This is suitable for Half Duplex communication 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 case is suitable for applications where there are high levels of interference and it is likely that transmit retries will be necessary to maintain reliable communications When an addressed packet or a response to a broadcast packet is sent the sending radio will listen for a successful acknowledgement If an acknowledgement is not sent the radio will resend the packet until either an acknowledgement is received or it has exhausted all available transmit retries If two radios on the last hop of the current session and a retry is required it is possible that once the current session has ended the receiving r
22. their discretion If the product is replaced it may be a new or refurbished product DOCUMENT INFORMA TION Revision Version 1 0 Version 1 1 Version 1 2 Version 1 3 Description 2 21 2005 Initial Release Version 3 4 2005 Updated Session Count Truth Table in Section 4 4 26 2005 Updated Transmit Mode Section 3 27 2006 Corrected API Send Data Complete Added Australian Channels Added 1x1 documentation Added Original Max Power byte and Full Product ID 0x90 Changed Sense Adjust default to varies Added Appendix 1 Power Supply Application Note TABLE OF CONTENTS OVER ucc TUTTI 6 7 ESI m BRI SERRE 8 ELECTRICAE SPECIFICATION S Me M LED 9 THEORY OF OPERATION uva ue tns ste peo 10 OU soda EE OR aS Seat vau 10 MOOCS OF QOCTANON s oia ono 70 API Control 12 SERIALINTERFAGE EM ADD SIE 14 OPM als Nri 74 Sonal InIetace ROB ida a
23. waiting up to one second between the last transmit packet and the AT Command The Enter AT Command mode command is as follows 22 Quick Tip In order to send the Enter AT Command Mode command the RF Packet Size must be set to a minimum of six Exit AT Command Mode To exit AT Command Mode the OEM Host should Command OxCC 0x41 0x54 Ox4F OxOD send the following command Number of Bytes returned 4 Response OxCC 0x44 0 41 0x54 ON THE FLY CoNTROL COMMANDS CC COMMAND MODE The AC4790 transceiver contains static memory that holds many of the parameters that control the transceiver operation Using the 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 back to the settings stored in the EEPROM While in CC Command mode using pin 17 Command Data the RF interface of the transceiver is still active Therefore it can receive packets from remote transceivers while in CC Command mode 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 from other transceivers will not be received The transceiver uses Interface Timeout RF Packet Size to determine when a CC Command is complete Therefore there should be no delay between each character as it is sent from the OEM Host to the transceiver or the transceiver wi
24. 0 02 S D Jack Antenna connector Johnson Components 135 3711 822 Figure 10 AC4790 with MMCX connector Mechanical 20 pin header 0 020 posts 0 079 2mm centers 0 125 dia non plated holes 0 100 dia non plated hole 1 21 places place under shield 1550 1 650 1 550 C C o C 1 300 tiglo g 1 010 0 i 0 825 al C e my C C jack 0 145 dia 25900 0 100 E 0 000 0 000 ooo iu C indc oom m p O D e c roo 0 occ 0 x o 32 Figure 11 4790 with integral gigaAnt antenna on top Mechanical 20 pin header 0 020 sq posts 0 079 inch mm centers Gigant Snap In Antenna 04157 0 212 E 0 180 0 062 0000 0 000 DA 0 052 0 125 dia non plated holes 4 places 1 650 1 550 1 550 o 7 a7 Of e E L 59a 1 180 1 010 C 2 5 E C 0 100 S 9 49 MESE e 0 100 0 150 1 875 2 030 2 345 2 550 2 650 33 Figure 12 4790 with integral gigaAnt antenna on bottom Mechanical 20 pin header 0 020 sq posts 0 079 inch fmm centers 0 157 rc 0 180 j 1088 0 000 0 000 a Z a 2146 Gigant Snap In Antenna 0 125 dia non plated holes 4 places 1 650 1 650 1 550 Lj Antenna Pad 0 10 0 09 1 180 1010 o 1 080 O
25. 3 MAC2 Parameter Range 0 00 OxFF corresponding to 3 LSB s of destination MAC Address Auto Destination The Host issues this command to change the settings for Auto Destination When issuing this command the Auto Destination setting will only be changed if the corresponding enable bit is set Controli Parameter EEPROM Address 56h bit 4 Command OxCC 0x15 Datat Number of Bytes Returned Response OxCC Data2 Parameter Range Data1 Bit Auto Destination Bit 4 Enable Auto Destination Modification Data2 Bit 0 New Auto Destination Setting Bit 1 New Auto Channel Setting Bits 2 7 0 Head API Control The OEM Host issues this command to the transceiver to read the API Control byte Command OxCC 0x16 Number of bytes returned 2 Response OxCC API Control 25 Write API Control The OEM Host issues this command to the transceiver to write the API Control byte Command OxCC 0x17 Number of bytes returned 2 Response OxCC API Control Set Max Power The OEM Host Issues this command to limit the maximum transmit power emitted by the transceiver This can be useful to minimize current consumption and satisfy certain regulatory requirements The radios are shipped at maximum allowable power Command OxCC 0x25 New Max Power Number of bytes returned 2 Response CCh New Max Power Read Temperature The OEM Host issues this command to read the onboard temperature sensor The transceiver repo
26. EN REC EM N A 22 Reset Active Low version of UP RESET If RESET is used UP RESET should be left floating and if UP used RESET should be left floating Input to the transceiver Output from the transceiver 1 When ordered with RS 485 interface not available on the 4790 1 1 Must be tied to VCC or GND if not used Should never be permitted to float 3 If used requires a shunt 0 1uF capacitor at pin 15 followed by a series 1kQ resistor ELECTRICAL SPECIFICATIONS Table 2 Input Voltage Characteristics AC4790 1000 amp AC4790 1x1 AC47901x1 AC4790 1000M AC4790 200X Low Low High High Low Low RS485A B HEEL LA LATAS E EE RD 291 33 0 2 55 0 0 e 55 Tet 21 33 0 2 55 o 08 v GM 291 33 0 2 55 o os v RESET 83 o 06 08 5 CommamyUsa 231 33 0 2 55 o 08 v NA 33 0 NA NA 33 0 NA v Table 3 Output Voltage Characteristics All Module 1x1 High Low GO 1 19 O 2584 04 8ma w 2 o 0492m V RS485AB 23 0 33G1 8Unitoad V ee 7 9 O 2592m 04Q2mA V GO 9 19 O 250 04Q2mA V 1 12 O See Figures V _Sessorrsrams 20 18 O 2592mA 04 2
27. K Radiot Radios RED Radiol Saazinn Ack Badicc Radics Radiol Radiol Session Radiol Ack Radiol Radink Badip fadiok RAD Session Padio RE TX Rediok TED Radiot Sexxinn Ack Hop BReadioE EF TE Radio TAD Radiol Session Radiol Ack Radiol Radiol Radiat EID Radiol Sesion RBediol Ack Radiol Radiol TE Session Count 1 Retries 1 The timing diagrams above show the radios performance with varying Session Count and Retry values Data was sent from Radio A B C D and then from D C B A 48
28. OxCC 0x21 Datat Number of bytes Returned 3 Response OxCC Data2 Data3 Parameter Range Data1 0x00 AD In 0 x01 Temperature 0x02 RSSI Data2 MSB of requested 10 bit value Data3 LSB of requested 10 bit ADC value Write Digital Outputs The OEM Host issues this command to write both digital output lines to particular states Note This command should be used only when Protocol Status 0xC2 is not set to Command OxCC 0x23 Datat Number of bytes returned 2 Response OxCC Data1 Parameter Range 1 bit 0 GOO bit 1 GO1 Probe Enabling bit 6 of API Control will enable this command When the OEM Host issues this command the transceiver sends out a query every 500ms The transceivers which receive this query will randomly choose a query to respond to This helps prevent multiple transceivers from trying to respond to the same Probe at the same time After responding to a Probe the transceivers will wait for approximately 10sec before responding to any other probe Note While executing the Probe command the transceiver can perform normal RF communications Command OxCC Ox8E Data Number of bytes returned 2 Response OxCC Data1 Parameter Range 1 0 00 Disable Probe 0 01 Enable Probe Apart from the Transceiver response for the command there are two other responses that return vital data to the OEM Hosts This data is very useful to monitor the network an
29. T Commands Yes AT Software Take Fin 17 Low Hardware Configuration Configuration Commands Yes Send CC Command Mode Send Exit AT Command Mode Take Pin 17 Command Receive Made 4790 AT COMMANDS The AT Command mode implemented in the 4790 creates a virtual version of the Command Data pin The Enter AT Command Mode Command asserts this virtual pin Low to signify Command Mode and the Exit AT Command Mode Command asserts this virtual pin High to signify Data Once this pin has been asserted Low all On the Fly CC Commands documented in the manual are supported When in AT Command Mode the user cannot send or receive RF packets However an ambiguity of approximately 10ms exists where if the Enter AT Command Mode Command has been sent to the transceiver at the same time an RF packet is being received the RF packet could be sent to the OEM Host before the Enter AT Command Mode Command response is sent to the OEM Host 22 Enter AT Command Mode Prior to sending the Enter AT Command Mode Command 0x41 0x54 Ox2B Ox2B Ox2B OxOD Command to the transceiver the OEM Host must Number of Bytes Returned 4 ensure that the HF transmit buffer of the Response 0x43 Ox4F Ox4D transceiver is empty if the buffer is not empty the Enter AT Command Mode Command will be interpreted as packet data and transmitted out over the RF This can be accomplished by
30. adio could go into session with a different radio and miss the final packet of the previous session Adding the radios Transmit retries to its Current Session Count will ensure that the radio does not exit the session when the remote radio is using a Transmit Retry Case 3 In this case a radio loads its Session Count with the remote radio s Session Count This is suitable for full duplex applications as the Session is extended as long as there is communication Note 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 suitable for daisy chain applications and large networks in which radios cannot stay in session longer than needed 11 Command Mode A radio will enter Command Mode when data is received over the serial interface from the OEM Host and either the Command Data pin pin 17 is logic Low or the received data contains the Enter AT Command Mode command Once in Command Mode all data received by the radio is interpreted as command data Command Data can be either EEPROM Configuration or On The Fly commands Receive Mode Pending RF Received Command Mode Broadcast Packet Discard Packet Discard Packet Addressed Packet Matching nny Destination Send Packet over Validate CRC RF Transmit Packet Transmit Packet D
31. d API Control OxCC Ox16 OxCC 0 17 bit O Auto Destination bit 4 Enable Auto Destination API Control API Control OxCC API Control Write API Control Of Transceivers in Table max8 Read Radio Table OxCC 0 18 OxCC Inputs Read ADC OxCC 0 21 0x02 Temp 0x03 RSSI Write Digital bit 0 GOO Set Max Power OxCC 0x25 New Max Power Returned for all the radios in the Table bit 0 GIO ED LSB of 0xCC 10 bit ADC bit 0 GOO o0 o o OxCC Max Power exit Probe 0x01 enter probe Oe Read Temperature OxCC OxA4 OxCC EEPROM Byte Length Starting Data at those OxCC Starting Address 0 256 OxCO Adress Length addresses Length EEPROM Byte Starting Data bytes Starting Data written to last Write Address e to be written Address sengt byte Soft Reset Firmware Revision Request The OEM Host issues this command to request the firmware of the transceiver Command OxCC 0x00 0x00 Number of bytes returned 3 Response OxCC Version XX Parameter Range XX 0x00 0x03 ignore this byte Change Channel The OEM Host issues this command to change the channel of the transceiver Command OxCC 0x01 Channel Number of bytes returned 2 Response OxCC Channel Broadcast Packets The OEM Host issues this command to change the transceiver operation between Addressed Packets and Broadcast Pac
32. d make decisions on rerouting data packets accordingly Response 1 Remote Transceiver s response to its OEM Host on receiving a Probe This response helps a radio identify the radio that probed it This response also returns RSSI value which is helpful in determining the strength of the wireless link between radios Byte 1 0x86 Byte 2 RSSI How strong the remote transceiver heard the local transceiver Bytes 3 5 3 bytes of MAC Address of the radio sending the Probe Note This response is received only when Probe Report 0xC9 is set to Response2 Transceiver s response to its OEM Host on hearing the Remote transceivers reply Probe Acknowledge This response helps a radio identify the radio that received its probe This response also returns RSSI and RSSI values which can be analyzed to determine how strong the link is Byte 1 0x87 Byte 2 RSSI How strong the remote transceiver heard the local transceiver Byte 3 RSSI How strong the local transceiver heard the remote transceiver Byte 4 Byte 6 3 bytes of MAC Address of the remote transceiver EEPROM Byte Head Upon receiving this command a transceiver will respond with the desired data from the address requested by the OEM Host Command Data1 Data2 Number of bytes returned 4 Response OxCC Data1 Data2 Data3 Parameter Range Data1 EEPROM address Data2 Length 0x01 0x80 Data3 Requested data 27
33. dinE Radip Radici Bedic Radice Radiot Radic Radiol Radial Radiol BRadiob Radiol Rediok endix IV API Timing Diagrams Appendix V API Timing Diagrams T T F T i i i i 1 a T session I DT TT 12121 TEES EB RE TX l i r a TXD Hu sein m rs ey TXD Session Hop n a m ili Session RF TE Session Count 8 Retries 3 my p f RXT Senxinun Lb ope T r m i i mmm TATA TACT YT wm TE mE I s 2 1 ACE H soe mcam RE TH WE m tL ili NE Sesion 1 i i i i C nmn ell d i i samim E MEX m mm omm lop IH mE Session Count 3 3 47 Appendix IV API Timing Diagrams Bsdio Radio Radiol Session Radiaj ack Radich Hop BadioA RE BedioE TED Radic FED Readies Sesi n Redick Ack EascdinE Hop Redick T
34. dustrial applications Applications requiring unusual environmental requirements such as military medical life support or life sustaining equipment are specifically not recommended without additional testing for such application Limited Warranty Disclaimer Limitation of Liability For a period of one 1 year from the date of purchase by the OEM customer AeroComm warrants the OEM transceiver against defects in materials and workmanship AeroComm will not honor this warranty and this warranty will be automatically void if there has been any 1 tampering signs of tampering 2 repair or attempt to repair by anyone 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 the original purchaser In no event shall AeroComm be responsible or liable for any damages arising From the use of product From the loss of use revenue or profit of the product or As a result of any event circumstance action or abuse beyond the control of AeroComm whether such damages be direct indirect consequential special or otherwise and whether such damages 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 transceiver at
35. e equipment is further broken into two classes within 2 5cm of human contact and beyond 2 5cm NOTE Ankles feet wrists and hands are permitted to be within 2 5cm of the antenna even if the equipment is designated as being greater than 2 5cm The AC4790 is not agency approved for portable applications The OEM is required to have additional testing performed to receive this classification Contact Aerocomm for details Mobile Mobile defines equipment where the user will be 20cm or greater from the transmitting antenna The antenna 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 20cm of mobile equipment OEM Equipment Labeling Requirements A WARNING The Original Equipment Manufacturer OEM must ensure that FCC labeling requirements are met This includes a clearly visible label on the outside of the OEM enclosure specifying the appropriate FCC identifier for this product as well as the FCC Notice below The FCC identifiers are listed above in the Agency Identification Numbers chart A WARNING This device complies with Part 15 of the FCC Rules Operation is subject to the following two conditions 1 This device may not cause harmful interference and 2 This device must accept any interference received including interference that may cause undesired operation
36. ed will be referred to as OEM Host S pecifications GENERAL 20 Pin Interface Connector Molex 87759 0030 mates with Samtec SMM 110 02 S D Johnson Components 135 3711 822 Antenna AC4790 1x1 Customer must provide 4790 200 Connector or integral antenna 4790 1000 Serial Interface Data Rate Baud rates from 1200 bps to 115 200 bps Power Consumption typical Duty Cycle TX Transmit RX Receive 10 50 10096TX 100 AC4790 1x1 33mA 54mA 80mA 28mA 4790 200 38mA 68mA 106mA 30mA 4790 1000 130 650mA 1300mA 30mA Interface Buffer Size 3 Channel Sets comprising 56 total channels One byte System ID 56 bit DES encryption key Input Output 256 bytes each TRANSCEIVER Frequency Band HF Data Rate 902 928 MHz 76 8 kbps fixed RF Technology Frequency Hopping Spread Spectrum Output Power Supply Voltage Conducted no antenna EIRP gain antenna AC4790 1x1 10mW typical 20mW typical AC4790 200 100mW typical 200mW typical AC4790 1000 743mW typical 1486mW typical AC4790 1x1 3 3V x50mv ripple 4790 200 3 3 5 5 50 ripple 4790 1000 Pin 10 3 3 5 5V 50mV ripple Pin 11 3 3 396 100 ripple Pins 10 and 11 may be tied together provided the supply voltage never falls below 3 3 V and is capable of supplying 1 5 A of current 100dBm typical 76 8kbps RF Data Rate Initial Transceiver Sync
37. een nnn nnn nnn nnns 39 OEM Equipment Labeling 39 Antenna Hegel bells sto os 39 Warnings Heqguired OEM Manuals M nas 39 Warnings Required in 5 40 EET 40 APPENDIX I POWER SUPPLY APPLICATION INOTE faa ndn ttm fon e tutu 41 APPENDIX II CONVERTING FROM 5V LEVELS TO 3 3V LEVELS eese enne nnns 43 EE 44 APPENDIX IV API TIMING DIAGRAMS 47 LIST OF FIGURES EM c EE 8 Table 2 Input Voltage Characteristics AC4790 1000 amp 4790 1 1 9 Table Output Voltage Characteristics 9 Table 4 Session Count Truth Table sui eoi oat ot RE 11 Table Supported Seral FOHITSES A iet d NEUE 14 Table 6 Baud Rate Interface 14 Table 7 Maximum Overall System 16 Table 8 RF Channel Number Settings ione Pero ELE e ap EU UE 17 Table 9 EEPROM
38. f the and 1 serve as generic output or OxFF serve as the protocol status Session Count 4 1 0x00 0x08 his byte specifies the number of hops a transceiver stays in Refresh OxFF Session with another transceiver 30 EEPROM Length Random Back OxC3 1 0x0 0x00 he Random amount of time a transceiver waits when a Off OxFF collision occurs before resending the packet again 0x00 Disable Random Backoff 0x01 Wait 1 2 packet times then retry 0x03 Wait 1 4 packet times then retry 0x07 Wait 1 8 packet times then retry OxOF Wait 1 16 packet times then retry Ox1F Wait 1 32 packet times then retry Ox3F Wait 1 64 packet times then retry Ox7F Wait 1 128 packet times then retry OxFF Wait 1 256 packet times then retry Sense Adjust OxC8 1 0 00 Setin production and The minimum RSSI required by a transceiver to establish a OxFF can vary Session Status on hearing a long beacon Probe Report OxC9 1 0x00 hen this byte is set to upon receiving a probe the OxFF ransceiver sends a Probe Report to its OEM Host DES LEM I OxxO OD 1D 2D 3D 4D 5D 5 8 Off 0 00 Once CTS has been deasserted CTS will be reasserted OxFE Low when the transmit buffer contains this many or less characters 31 Dimensions Critical parameters are as follows Interface Connector 20 pin OEM interface connector Molex 87759 0030 mates with Samtec SMM 11
39. f the OEM Host baud rate If the Test pin Pin 12 is pulled logic Low at reset the baud rate will be forced to 9 600 The RF baud rate is fixed at 76 8 Kbps and is independent of the interface baud rate For Baud Rate values other than those shown in Table 6 the following equation can be used 6 Baud 0x100 1 64 x Desired baud Baud Always 0 Baud L Low 8 Bits of BAUD base 16 Table 6 Baud Rate Interface Timeout BaudL 0x42 BaudH 0x43 Minimum Ns d Timeout Stop bit Delay 0x3F 57 600 is the default baud rate 0x00 will yield a stop bit of 421uS The stop bit at 1200 baud should be actually 833us 14 Flow Control Flow control refers to the control of data flow between transceivers It is the method used to handle data in the transmit receive buffer and determines how data flow between the transceivers is started and stopped Often one transceiver is capable of sending data much faster than the other can receive and Flow control allows the slower device 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 from the receiving unit If the receiving radio is ready to accept data it will assert its CTS low These signals are sent apart from the data itself on separate wires Host 35 s ETE 5
40. fer equals RF Packet Size those bytes are sent out as a complete RF packet It is much more efficient to send a few large packets rather than many short packets as each packet sent over the RF contains extra header bytes which are not included in the RF Packet Size RF packet size can be set to a maximum of 0x80 SYSTEM TIMING AND LATENCY Care 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 and should be a strong consideration when designing the system 4 Quick Tip IN 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 are many variables that affect system latency The three variables that most affect the latency are the network load the distance between transceivers and whether the transceivers are operating in a broadcast or addressed mode There is no fixed answer as to how much latency will be introduced in the system when considering high density applications In these cases we can just offer qualitative analysis of the latency in high density applications As the network load increases then the number of collisions that will occur increases As the number of collisions increase then the system latency increases As the distance between the transceivers increases
41. ir access to the network This instinctive dynamic peer to peer networking architecture enables several transceiver pairs to carry on simultaneous conversations on the same network To boost data integrity and security the AC4790 uses AeroComm s field proven FHSS technology featuring optional Data Encryption Standards DES Fully transparent these transceivers operate seamlessly in serial cable replacement applications Communications include both system and configuration data via an asynchronous TTL or optional RS 485 serial interface for OEM Host communications Configuration data is stored in an on board EEPROM and most parameters can be changed on the fly All frequency hopping synchronization and RF system data transmission reception is performed by the transceiver This document contains information about the hardware and software interface between an AeroComm AC4790 transceiver and 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 all appropriate 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 which the AC4790 module is connect
42. kets If Addressed Packets are selected the transceiver will send all packets to the transceiver designated by the Destination Address programmed in the transceiver If Broadcast Packets are selected the transceiver will send its packets to all transceivers on that network Setting bit 7 of API Control to 1 can also enable Broadcast Packets Command OxCC 0x08 Datat Number of bytes returned 2 Response OxCCh Datat Parameter Range Data1 00 for Addressed 01 for Broadcast 22 Quick Tip When bit 7 of the API Control is used to set the Broadcast Addressed Packets of a transceiver the radio must be reset before issuing this command However bit 7 can still be used to change the Broadcast Addressed Packets if resetting the transceiver is not desired Write Destination Address The OEM Host issues this command to the transceiver to change the Destination Address Note Only the three Least Significant Bytes of the MAC Address are used for packet delivery Command OxCC 0x10 MAC2 MAC1 Number of bytes returned 4 Response MAC3 2 Parameter Range Ox00 OxFF corresponding to 3 LSB s of destination MAC Address Head Destination Address The OEM Host issues this command to the transceiver to read the Destination Address Note Only the three Least Significant Bytes of the MAC Address are used for packet delivery Command OxCC Ox1 1 Number of bytes returned 4 Response MAC
43. ll not recognize the command If the OEM Host has sent a CC Command to the transceiver and an RF packet is received by the transceiver the transceiver will send the CC Command response to the OEM Host before sending the packet However if an RF packet is received before the Interface Timeout expires on a CC Command the transceiver will send the packet to the OEM Host before sending the CC Command response When an invalid command is sent the radio scans the command to see if it has a valid command followed by bytes not associated with the command in which case the radio discards the invalid bytes and accepts the command In all other cases the radio returns the first byte of the invalid command back to the user and discards the rest 23 Command uick Reference Command All Bytes in Hex Return All Bytes in Hex 5 0x41 0x2B oxcc 0x43 4 Ox4D Command Mode 0x54 0x00 OxCC Firmware Version OUS 0 03 Ignore this byte New Channel E New Channel n Exit AT Command Mode OxCC Ox41 Firmware Version OxCC Request OxCC 0 01 Change Channel 0x00 0x01 Broadcast Write Destination piles E OxCC 0x10 destinations Byte 5 Byte 6 Byte 4 of destination s MAC Byte5 Byte 6 Address MAC OxCC Byte 4 of destination s MAC 5 Byte 6 bit 0 Auto Destination M bits 1 7 0 OxCC Read Destination Rea
44. lly polled 1 Master to radio A using TX API 81h 01h 08h 04h 12h 34h 56h 45 Radio A receives the packet which tells it to begin transmitting its information back to the master unit and the session expires after 8 hops Master switches to radio B using TX API 81h 01h 08h 04h 12h 34h AAh Radio B receives the packet which tells it to begin transmitting its information back to the master unit and the session expires after 8 hops Master switches to radio C using TX API 81h 01h 08h 04h 12h 34h AAh Radio C receives the packet which tells it to begin transmitting its information back to the master unit and the session expires after 8 hops Master switches to radio D using TX API 81h 01h 08h 04h 12h 34h EFh Radio D receives the packet which tells it to begin transmitting its information back to the master unit and the session expires after 8 hops Appendix Ill API Radio A sends the information Radio B sends the information Radio C sends the information Radio D sends the information 46 Radio RadicA Radio Radio Radio A Radios Radio Radiol RadioB Redick Radiol Radiol Radial Radiol Radiol Radiol Radiol Radiol Radiol Radial RadioD Radinh RadicA Hadin Radiok RadioB Ra
45. ment AeroComm has obtained modular approval for its products so the OEM only has to meet a few requirements to be eligible to use that approval The corresponding agency identification numbers and approved antennas are listed in the table below Table 10 Agency Identification Numbers US FCC CAN IC 4790 200 KQLACA490 100 2268C AC4490 4790 1000 KQL AC4490 2268C 44901000 APPROVED ANTENNA LIST The following antennas are approved for operation with the AC4790 as identified The OEM is free to choose another vendor s antenna of equal or lesser gain and similar type as an antenna appearing in the table and still maintain compliance Table 11 AC4790 Approved Antenna List AeroComm Part Gain Number Manufacturer Part Number Manufacturer Type dBi 0600 00019 S467FL 5 RMM 915S Nearson 2 Wave Dipole 0600 00025 S467FL 5 RMM 915 5 C4790 200M 4790 200 C4790 1000M 1 0600 00024 S467AH 915S Nearson e Wave 2 X X Dipole Dipole 1 0600 00028 S161AH 915R Nearson 2 Wave 25 X X Dipole 0600 00029 S161AH 915 Nearson 2 Wave JMJ Dipole Dipole _ p 02085812 04 Flavus ae 38 Agency Compliancy Information FCC INDUSTRY CANADA IC REQUIREMENTS FOR MODULAR APPROVAL In 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 20cm of the transmitting antenna Portabl
46. ng a Broadcast packet Session Count is defined by Session Count Refresh EEPROM address 4 Broadcast Attempts EEPROM address Ox4D Once the radio exits the Session it returns to Receive Mode Addressed Packets The RF packet is sent out to the receiver designated by the Destination Address Transmit Retries are used to increase the odds of successful delivery to the intended receiver Transparent to the OEM Host the sending transceiver will send the RF packet to the intended receiver If the receiver receives the packet free of errors it will return an HF Acknowledge If the sender does not receive this acknowledge it will assume the packet was never received and retry the packet This will go on until the packet is successfully received or the transmitter exhausts all of its retries The received packet will only be sent to the OEM Host if and when it is received free of errors Broadcast Packets The RF packet is broadcast out to all eligible receivers on the network Broadcast Attempts are used to increase the odds of successful delivery to the intended receiver s Transparent to the OEM Host the sending transceiver will send the RF packet to the intended receiver If the receiver detects a packet error it will throw out the packet This will go on until the packet is successfully received or the transmitter exhausts all of its attempts Once the receiver successfully receives the packet it will send the packet to the OEM Host It will thro
47. ng errors in burst arrivals Implementation 1 Server sends broadcast packet which includes sync pulse 2 Remote radios hear the sync pulse and join the session 3 Radio A transmits data during time interval t 1 4 Radio B transmits data during time interval t 2 5 Radio N transmits data during time interval t N 1 This type of implementation requires careful planning and should allow enough time for each radio to retry if necessary If Full Duplex is enabled the radio which initiates the session will transmit during the even numbered hops while the remote radios will transmit during the odd numbered hops TOMA Frame Tine z bot V Polling N etwork The Transmit and Receive commands can be used for applications where it is necessary for one unit to poll several others for data The radio requesting the poll can use the Transmit API command to dynamically switch from one radio to another The remote radio will receive the poll request and transmit the appropriate response to the polling radio If the Receive feature is enabled the polling unit will send the remote response to the OEM host which can then determine the MAC address of the sending radio and relay the information as needed Once the polling radio is finished communicating with the remote radio the Transmit API command can once again be used to change the destination address This process continues until all radios have been successfu
48. nication by calculating the amount of time until the next hop to ensure that it has time to send the packet If there is enough time it will send the packet if not it will wait until its next appropriate hop The radio which initiates the session transmits during the even hops while the remaining radio s will transmit during the odd hops Although the RF hardware is still technically half duplex the bandwidth sharing makes the transceiver seem full duplex Enabling Full Duplex can cause overall throughputs to be cut in half 15 Hop Frame 1 2 3 4 b RF_Transmit gt b RF_Transmit gt Session Host HF Transmit V V V V 4 Session Guest HF Transmit V V V V Note All transceivers on the same network must have the same setting for Full Duplex INTERFACE TIMEOUT RF PACKET SIZE Interface Timeout EEPROM address 0x58 in conjunction with RF Packet Size EEPROM address 0x5B determines when 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 gap is exceeded the bytes in the transmit buffer are sent out over the RF as a complete packet Interface Timeout is adjustable in 0 5ms increments and has a tolerance of 0 5ms The default value for Interface Timeout is 0x04 2ms RF Packet Size When the number of bytes in the transceiver transmit buf
49. rts the temperature in where 0 80h corresponds to 0 80 and where D8h Oh corresponds to 40 0 Command OxCC 4 Number of bytes returned 2 Response OxCC Temperature Parameter Range Temperature OxD8 0x80 Read Digital Inputs The OEM Host issues this command to read the state of both digital input lines Command OxCC 0x20 Number of bytes returned 2 Response OxCC Datat Parameter Range Data1 bit 0 GIO bit 1 bits 2 7 0 Head Hadio Table The OEM Host issues this command to read the Radio Table that resides on the transceiver The Radio Table stores information for up to the last 8 transceivers that sent it a packet This information is very useful for providing alternative data paths Command OxCC 0x18 Byte 1 Byte 2 of transceivers in this table 0 00 0 08 Byte 3 Mac 2 1 0 of transceiver 1 Byte 4 55 Byte 5 RSSI Byte 6 Stale Count of transceiver 1 Byte 7 Mac 2 1 0 of transceiver 2 Byte 8 RSSI Byte 9 RSSI Byte 9 Stale Count of transceiver 2 and so on Stale Count The Stale Signal RSSI Value Count Reload 4 Strength determines the amount dBm of time a radio will stay active in the Radio Table The Stale Count min 0x00 max depends on the EEPROM Setting for a 86 to 22 radio is set to 0 when packet is received it then gets incremented by one eve
50. ry 100ms When the Stale Count of a radio reaches the Stale Count Reload Ox4F the radio is considered Stale Radio Table can hold up to a maximum of 8 radios information however if the Radio Table is full and 9th radio is received the first radio that is Stale is replaced with the new radio If none of the radios are stale the oldest radio in the table is replaced with the new radio 2 Quick Tip The RSSI is how strong the remote transceiver heard the local transceiver RSSI is how strong the local transceiver heard the remote transceiver The table above can be used to convert the RSSI to the corresponding signal strength dBm is equal to approximately four steps Note Notice the trend between 4dBm and 12dBm does not follow the curve This is because RSSI 26 Head The OEM Host issues this command to read any of the three onboard 10 bit A D converters Because the RF is still active on the fly Command Mode the transceiver will not process the command until there is no activity on the network Therefore the Read RSSI command is useful for detecting interfering sources but will not report the RSSI seen from a remote transceiver on the network The equations for converting these 10 bits into analog values are as follows Analog Voltage 10 bits OX3FF 3 3V Temperature Analog Voltage 0 3 0 01 30 RSSI Value dBm 105 0 22 10 bits Command
51. ryption bits ois 0 0 iuis GENI 96 9 NN OxFF Addressed Packets is selected Attempts OxFF Packets is selected Stale 4 0x01 0 40 Determines the amount of time a transceiver will keep Count Reload OxFF another transceiver say transceiver A active in its Radio able This counter is reset every time a packet is received rom that transceiver A Control 1 0x56 010000116 0x43 Settings are bit 7 AeroComm Use Only bit 6 1 bit 5 0 bit 4 Auto Destination Use Destination Address 1 Automatically set Destination to last radio received from bit 3 0 bit 2 RTS Enable RTS Ignored 1 Transceiver obeys RTS bit 1 Duplex 0 Half Duplex Use EEPROM values 1 Auto Configure Values 29 Interface Timeout 0x58 1 0x02 0x04 Specifies a byte gap timeout used in conjunction with RF e US Size to determine when a packet coming over the interface is complete 0 5ms per increment 0x80 maximum size of an RF packet JE will be deasserted High when the transmit buffer OxFF contains at least this many characters CTS Off Ox5D 1 0x00 OxAC Once CTS has been deasserted CTS will be reasserted when the transmit buffer contains this many or less characters 0x60 can vary ransceivers are shipped at maximum allowable power Parity Ox6F 1 OxE3 OxFF Enable Parity OxFF OxFF Disable Parity Note Enabling Parity cuts throughput in half and
52. s Far 0 031 thick PC board microstrip width and spacing is 0 055 inches 36 Agency Compliancy Information Ordering I nformation PRODUCT PART NUMBER TREE 4 790 XXXXX XXX Interface 485 2 Wire H5485 Blank 3 3V TTL Antenna Option A Integral Antenna 200 Only M MMCX Connector Blank AC4790 1x1 No Antenna Output Power 200 200 mW US Canada Only 1000 1000 mW 3 3V MMCX Only 1x1 Multichip Module 10 mW DEVELOPER KiT PART NUMBERS All the above part numbers can be ordered as a development kit by prefacing the part number with SDK As an example part number 4790 200 can be ordered as a development kit using the following part number SDK AC4790 200A All Developer Kits include 2 transceivers 2 Serial Adapter Boards 2 6VDC unregulated power supplies 2 Serial cables 2 USB cables 2 S467FL 6 RMM 915S dipole antennas with 6 pigtail and MMCX connector configuration testing software and integration engineering support 37 Agency Compliancy Information Agency Compliancy nformation 4790 1 1 Due to the RF antenna trace residing on the OEM Host PCB the FCC will not grant modular approval for the AC4490 1x1 and requires the OEM to submit their completed design for approval Contact AeroComm for the approval procedure AGENCY IDENTIFICATION NUMBERS Agency compliancy is a very important requirement for any product deploy
53. s Networking 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 functions Easy to Use Continuous 76 8 kbps RF data stream Software selectable interface baud rates from 1200 bps to 115 2 kbps 7 Low cost low power and small size ideal for high volume portable and battery powered applications A All modules are qualified for Industrial temperatures 40 C to 80 C 7 Advanced configuration available using AT commands OVERVIEW The AC4790 is a member of AeroComm s ConnexRF OEM transceiver family The AC4790 is a cost effective high performance frequency hopping spread spectrum transceiver designed for integration into OEM systems operating under 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 dynamic Session extension and Collision Avoidance mechanism which uses a proprietary scoring system to promote contention free communication and ensure that each node has fa
54. stored in EEPROM which become active after a power on reset Table 9 EEPROM Parameters gives the locations and descriptions of the parameters that can be read or written by the OEM Host Factory default values are also shown Do not write to any EEPROM addresses other than those listed below Do not copy a transceivers EEPROM data to another transceiver Doing so may cause the transceiver to malfunction Table 9 EEPROM Parameters EEPROM Length E e ID 40 bytes Product identifier string Includes revision information for software and hardware Basil bit Delay 0x00 OxFF For systems using the RS 485 interface or Parity the serial OxFF stop bit might come too early especially at slower interface baud rates Stop bit Delay controls the width of the last bit before the stop bit occurs OxFF Disable Stop bit Delay 12us 0x00 256 1 6us 12us 1 OxFE value 1 6us 12us Channel Number 0x40 0x00 AC4790 1x1 0 00 0 0x00 OxOF US Canada AC4790 1x1 200 Ox2F 4790 200 0x00 1 0 10 Ox2F US Canada AC4790 1x1 1000 AC4790 1000 0x10 Set 3 0x30 0x37 US Canada AC4790 1x1 200 Australia 4790 1 1 200 1000 Baud Rate Low 0x42 0x00 OxFC Low Byte of the interface baud rate Default baud rate is OxFF 57 600 Baud Rate Baud Rate High AlwaysOx00 0x00 ELI 0 0x45 MEM S S are bit 7 0 bit 6 DES Enable Disable Encryption 1 Enable Data Enc
55. tant to have a higher random back off seed gt Quick Tip WHAT EFFECTS WILL RANDOM BACK OFF HAVE ON SYSTEM LATENCY As the Random Back Off value increases the overall latency also increases Worst Case Latency Half Duplex 50 ms Hop Number of Retries Maximum Random Value e Worst Case Latency Full Duplex 100 ms Hop Number of Retries Maximum Random Value SYSTEM ID RF CHANNEL NUMBER System ID System ID EEPROM address 0x76 is similar to a password character or network number and makes network eavesdropping more difficult A transceiver will not establish a Session or communicate with another transceiver on a different System ID or Channel Number RF Channel Number Channels 0x00 OxOF and 0x30 0x37 only use 26 hops Channels 0x10 Ox2F use 50 hops Other than that Channel Number EEPROM address 0x40 can be considered as another byte of System ID channels a channel set hop on the same frequencies only in a different order Table 8 RF Channel Number Settings Channel Set RF Channel Number Range Frequency Details and Countries 0x40 Regulatory Requirements 0 AC4790 1x1 AC4TSO 200 0x00 OxOF 902 928MHz 26 hop bins US Canada AC4790 1x1 AC4790 1000 0x10 Ox2F 902 928MHz 50 hop bins US Canada US Canada 2 AC4790 1x1 1x1 200 4790 200 0x30 0x37 915 928 MHz 22 Hop Bins 1 1 200 1000 Australia dug F 1 I PEE
56. tas a tech este DM EE EE 26 OO TX DEM xit haa M M d A has ME LA 26 PICA TOMOA UN M 26 PACAT N T t 26 8 0 ERREUR 26 EE 2 UTE BOTHE OULU TTC Hem 2 6o NN 27 EEPROM BVE HOS sc o Pen eas eee eee eee O 27 PEPAOM BE WEB sut 28 a COMMMAIO RECTE 28 EEPROM PARAMETERS a tiom rt 29 DIMENSIONS zea aus 32 37 FRODUCT PART NUMBER T REE e ead xu dua a 37 DEVEEOPERSIE PART NUMBERS ti conma b eoa daa 37 AGENCY COMPLIANCY 38 PCA TOO page EE 38 AGENCY IDENTIFICATION NUMBERS sess dequo e 38 APPROVED ANTENNA LISTA du Etc DNA ride EUM E 38 FCC INDUSTRY CANADA IC REQUIREMENTS FOR MODULAR APPROVAL sese
57. tes that must be in the buffer for CTS to be disabled logic High Even while CTS is disabled the OEM Host can still send data to the transceiver but it should do so carefully Once CTS is disabled it will remain disabled until the buffer is reduced to the size specified by CTS Off 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 low when buffer is empty RTS Handshaking pin 8 With 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 OEM Host can prevent the transceiver from sending it data by disabling RTS logic High Once RTS is enabled logic Low the transceiver 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 pin 12 When 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 2 Quick Tip This pin is used to recover transceivers from unknown baud rates only and should not be used during normal operation If the desired baud rate is 9600 the transceiver s Serial Interface Baud Rate sho
58. the OEM Host can take this High when it is not ready to accept data from the transceiver NOTE Keeping RTS High for too long can cause data loss C S E Received Acknowledge status pin if Protocol Status is enabled Otherwise generic output 4790 1 1 3 3V 50mV ripple VCC1 4790 200 3 3 5 5V 50mV ripple Pin 10 is internally connected to Pin 11 4790 1000 3 3 5 5V x50mv ripple AC4790 1x1 3 3V 50mV ripple VCC2 4790 200 3 3 5 5V 50mV ripple Pin 11 is internally connected to Pin 10 AC4790 1000 3 3V 3 10 0 ripple Test Mode When pulled logic Low and then applying power or resetting the 12 23 Test transceiver s serial interface is forced to a 9600 8 N 1 rate To exit the transceiver must be reset or power cycled with Test Mode logic High Received Signal Strength An analog output giving an instantaneous indication of RSSI received signal strength Only valid while in Receive Mode Generic Generic Input pin Input pin RESET Controlled by the AC4790 for power on reset if left unconnected After a UP RESET stable power on reset a logic High pulse will reset the transceiver SgniGoud When logic Low the transceiver interprets OEM Host data as command data Command Data When logic High the transceiver interprets OEM Host data as transmit data 1 8 20 24 DUNG E Has internal connection for AeroComm use only Wi WEE N
59. time Hop period 25ms 50 ms Range Line of Site based on 3dBi gain antenna AC4790 1x1 1 mile AC4790 200 4 miles AC4790 1000 20 miles EEPROM write cycles 20000 ENVIRONMENTAL Oo o O 10 to 90 Dimensions Transceiver with MMCX Connector 1 65 x 1 9 x 0 20 Transceiver with Integral Antenna 1 65 x 2 65 x 0 20 4790 1 1 1 00 x 1 00 x 0 162 Less than 0 75 ounce CERTIFICATIONS P AC4790200 4790 1000 15 247 KQLAC4490 100 KQLAC4490 Industry Canada IC 2268C AC4490 2268C AC44901000 PIN DEFINITIONS The AC4790 has a simple interface that allows OEM Host communications with the transceiver The table below shows the connector pin numbers and associated functions The direction is with respect to the transceiver All outputs are 3 3VDC levels and inputs are 5VDC TTL with the exception of AC4790 1x1 and AC4790 1000 transceivers which have 3 3V inputs All inputs are weakly pulled High and may be left floating during normal operation with the exceptions listed for the AC4790 1x1 Table 1 Pin Definitions 50 Lo ea 40 a _ Ic a Clear to Send Active Low when the transceiver is AE to accept data for transmission Request to Send When enabled in EEPROM
60. uld be programmed to 9600 baud 20 RSSI pin 13 Instantaneous RSSI Received Signal Strength Indicator is used by the OEM Host as an indication of instantaneous signal strength at the receiver The OEM Host must calibrate RSSI without an RF signal being presented to the receiver Calibration is accomplished 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 RSSI As RSSI is only valid when the local transceiver is receiving an RF packet from a remote transceiver instantaneous RSSI can be very tricky to use Therefore the transceiver stores the most recent valid RSSI value The OEM Host issues the Heport Last Good RSS command to request that value details can be found in the On the Fly Control Command Reference Additionally validated RSSI can obtained from 0 2 Receive Packet and Send Data Complete commands and from the Probe command 105 100 Validated RSSI is not available at the RSSI pin The following equation approximates the RSSI curve Voltage VDC o o o e
61. uplicate Packet Broadcast Packet Addressed Packet Decrement Broadcast Receive ACK Attempts Send Packet over Send RF RF Acknowledge Broadcast Decrement Attempts 0 Transmit Attempts Transmit Attempts 0 Figure 2 Pending RF amp Data in Buffer Flow API Control API Control is a powerful feature that the Masterless Protocol offers When enabled the API Transmit Packet API Send Data Complete and API Receive Packet features provide dynamic packet routing and packet accounting ability to the OEM Host 12 thereby eliminating the need for extensive programming on the OEM Host side This ability of the protocol makes it ideal for legacy system API Transmit Packet Transmit Packet is enabled when bit 1 of the Control byte is enabled The Host should use the following format to transmit a packet over the RF Payload Data l Transmit S Session Count Destination Length Retries Broadcast Payload Data Refresh MAC 2 1 0 0x01 0x80 Attempts 1 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 2 Although 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 to not overrun the 256 byte buffer 3 Setting MAC to FFh FFh FFh will broadcast the packets to all available transceivers API Send Data
62. utput 3 4 volts at 1 5 amps Included is a schematic bill of material with manufacture s name and part numbers and a sample PC board layout It is important to follow the layout suggestions and use large areas of copper to connect the devices as shown in the layout It is also important to hook up the ground traces as shown and use multiple vias to connect input and output capacitors 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 AC5124 module R1 can be changed to a 373 ohm 196 resistor This will change the output to 5 volts at 1 0 amps Bill of Materials Mfg number R2 Res 0603 127 1 16W 196 KOA RK73H1JT1270F C1 C2 Cap Tant 7343 47 35V TPSE476M035R0200 C3 C4 C5 Cap Cer 0603 0 1uF Y5V 25V GRM39Y5V104Z025AD C6 o ean 060 U1 IC 551413 8P SO Switch Reg Ctrl Switching Power Supply 3 4 V_OUT 15 W INPUT 6 to 18V 230 C551413 41 Appendix I Power Supply Application Note GND EIN VOUT Bottom Side Artwork Viewed from the Top Appendix Il Converting from 5V to 3 3V 11 Converting from 5V levels to 3 3V levels Converting from 5V to 3 3V The
63. w out any duplicates caused by further Broadcast Attempts The received packet will only be sent to the OEM Host if it is received free of errors If API or hardware acknowledgement is enabled a broadcast packet will always report success 10 Receive Mode If the transceiver detects a sync pulse while in Receive Mode it will join the Session and start receiving data While in Receive Mode subsequent data RF Acknowledge of up to 128 bytes can be received every hop When a transceiver is in Session its Session Count is decremented by one every hop When the Session Count reaches zero the transceiver exits the Session In order to continue receiving data the transceivers update their Session Count every time data RF Acknowledge is received The SLockO and SLock1 EEPROM parameter settings control Session Count as shown in the Session Count Truth Table below Table 4 Session Count Truth Table SLock1 Transceiver receiving an addressed packet Transceiver receiving a broadcast packet Radio loads its Current Session Count with Radio loads its Current Session Count with its its Session Count Refresh Session Count Refresh Radio loads its Current Session Count with Radio loads its Current Session Count with its Transmit Retries its Session Count its Broadcast attempts its Session Count Refresh Refresh Radio loads its Current Session Count with Radio loads its Current Session Count with the remote radio s Session Count
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