V E R S I O N 1.
Contents AC4790 TRANSCEIVER MODULE 1 AC4790 features 1 Overview 1 EEPROM PARAMETERS 32 DIMENSIONS 36 Mechanical Drawings 36 SPECIFICATIONS 3 Pin Definitions 5 Electrical Specifications 7 ORDERING INFORMATION 40 Product Part Number Tree 40 Developer Kit Part Numbers 40 THEORY OF OPERATION 8 Masterless Architecture 8 Modes of Operation 8 Transmit Mode 8 Receive Mode 9 Command Mode 10 API CONTROL 11 API Transmit Packet 12 API Send Data Complete 12 API Receive Packet 12 SERIAL INTERFACE 14 Serial Communica
DOCUMENT INFORMATION Copyright © 2007 AeroComm, Inc. All rights reserved. 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.
DOCUMENT INFORMATION Revision Description Version 1.0 2/21/05 - Initial Release Version Version 1.1 3/4/05 - Updated Session Count Truth Table Version 1.2 4/26/05 - Updated Transmit Mode Section Version 1.3 3/17/06 - Corrected API Send Data Complete. Added Australian Channels. 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.
AC4790 T RANSCEIVER M ODULE 1 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 RF expertise.
2 A C 4 7 9 0 TR A N S C E I V E R M O D U L E 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 an OEM Host. Information includes the theory of operation, specifications, interface definition, configuration information and mechanical drawings.
2 S PECIFICATIONS Table 1: AC4790 Specifications General 20 Pin Interface Connector Molex 87759-0030, mates with Samtec SMM-110-02-S-D RF Connector Johnson Components 135-3711-822 Antenna AC4790-1x1: Customer must provide AC4790-200: MMCX Connector or integral antenna AC4790-1000: MMCX Connector Serial Interface Data Rate Baud rates from 1200 bps to 115,200 bps Power Consumption (typical) AC4790-1x1: AC4790-200: AC4790-1000: Duty Cycle (TX=Transmit; RX=Receive) 10%TX 50%TX 100%TX 100%RX 33mA 54mA
4 SPECIFICATIONS Table 1: AC4790 Specifications Transceiver (Cont’d) Range, Line of Site (based on 3dBi gain antenna) AC4790-1x1: AC4790-200: AC4790LR-200: AC4790-1000: AC4790LR-1000: Up to 1 mile Up to 4 miles Up to 8 miles Up to 20 miles Up to 40 miles Environmental Temperature (Operating) -40°C to 80°C Temperature (Storage) -50°C to +85°C Humidity (non-condensing) 10% to 90% Physical Dimensions Transceiver with MMCX Connector: 1.65” x 1.9” x 0.20” Transceiver with Integral Antenna: 1.65” x 2.
SPECIFICATIONS 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 I/O 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).
6 SPECIFICATIONS Table 2: AC4790 Pin Definitions Module Pin 1x1 Pin Type Signal Name 13 12 O RSSI 14 212 I GI1 15 16 I UP_RESET 16 13 GND GND 17 17 I CMD/Data 18 153 I AD In 19 1,8,20 24-28 N/C Do Not Connect Has internal connection, for AeroComm use only.
SPECIFICATIONS ELECTRICAL SPECIFICATIONS Table 3: Input Voltage Characteristics AC47901x1 / AC4790-1000M AC4790-200X High Min. High Max. Low Min. Low Max. High Min. High Max. Low Min. Low Max. Unit RS485A/B N/A 12 -7 N/A N/A 12 -7 N/A V RXD 2.31 3.3 0 0.99 2 5.5 0 0.8 V GI0 2.31 3.3 0 0.99 2 5.5 0 0.8 V RTS 2.31 3.3 0 0.99 2 5.5 0 0.8 V Test 2.31 3.3 0 0.99 2 5.5 0 0.8 V GI1 2.31 3.3 0 0.99 2 5.5 0 0.8 V UP_RESET 0.8 3.3 0 0.6 0.
T HEORY OF O PERATION 3 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.
THEORY OF OPERATION packets, 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 Mode If a transceiver detects a sync pulse while in Receive Mode, it will join the Session and begin receiving data. While in Receive Mode, subsequent data of up to 128 bytes can be received every hop (50 ms).
10 THEORY OF OPERATION 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.
THEORY OF OPERATION Figure 1: Pending RF and Data in Buffer Flow Yes Discard Packet Receive full packet and check CRC Receive Mode R e ce ive M o d e Pending RF Received D a ta in B u ffe r Broadcast Packet Discard Packet C o m m a n d /D a ta M ode P in 1 7 L o w Addressed Packet A T+++ Matching Destination MAC R F D a ta Yes Yes Duplicate Packet Yes Send Packet over RF Validate CRC B ro a d c a s t P a ck e t A d d re ss e d P a c k e t T ra n s m it P a ck e t T ra n s m it P a c
12 THEORY OF OPERATION API Transmit Packet API 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 mesh networks. 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 following format to transmit a packet over the RF.
THEORY OF OPERATION ENGINEER’S TIP When both API Send Data Complete and API Receive Packet are enabled, the Send Data Complete will be received before the transceiver sees the Receive API Packet. This order may get reversed when the API Send Data Complete is missed and is being resent after the API Receive Packet is received. www.aerocomm.
S ERIAL I NTERFACE 4 In order for the 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 that the OEM Host data rate matches the serial interface baud rate. SERIAL COMMUNICATIONS The AC4790 is a TTL device which can be interfaced to a compatible UART (microcontroller) or level translator to allow connection to serial devices.
SERIAL INTERFACE Figure 3: Even Parity Bit Note: Enabling parity cuts throughput and the interface buffer in half. OEM HOST DATA RATE The 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 to 115,200 bps. Note: Enabling Parity cuts throughput in half and the Interface Buffer size in half.
16 SERIAL INTERFACE 6 14.
SERIAL INTERFACE 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.
18 SERIAL INTERFACE should be a strong consideration when designing the system. ENGINEER’S 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.
SERIAL INTERFACE ENGINEER’S TIP What 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 value Worst case latency (Full Duplex) = 100 ms * Number of retries * Max. random value NETWORKING System ID - System ID (EEPROM address 0x76) is similar to a password character or network number and makes network eavesdropping more difficult.
20 SERIAL INTERFACE 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. ENGINEER’S TIP The 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 original factory setting.
H ARDWARE I NTERFACE 5 Below is a description of all hardware pins used to control the AC4790. PIN DEFINITIONS Generic I/O Both GIn pins serve as generic input pins. When Protocol Status (byte 0xC2 of EEPROM) is disabled, GO0 & GO1 serve as generic outputs. When Protocol Status is enabled, pins GO0 and GO1 alternatively serve as the Session Status and Receive Acknowledge Status pins, respectively. Reading and writing of these pins can be performed using CC Commands.
22 HARDWARE INTERFACE 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 / 9600 Baud 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).
HARDWARE INTERFACE Figure 4: RSSI Voltage vs. Received Signal Strength 1.2 1 Voltage (VDC) 0.8 0.6 0.4 0.2 0 -105 -100 -95 -90 -85 -80 -75 -70 -65 -60 -55 -50 Signal at Re ce iv e r (dBm) UP_Reset 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.
6 C ONFIGURING THE AC4790 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.
CONFIGURING THE AC4790 On-the-Fly Control Commands The AC4790 transceiver contains static memory that holds many of the parameters that control the transceiver operation. 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 back to the settings stored in the EEPROM.
26 CONFIGURING THE AC4790 Table 10: Command Quick Reference Command Name Command (All Bytes in Hex) Return (All Bytes in Hex) AT Enter CommandMode 0x41 0x54 0x2B 0x2B 0x2B 0x0D 0xCC 0x43 0x4F 0x4D Exit AT CommandMode 0xCC 0x41 0x54 0x4F 0x0D - 0xCC 0x44 0x41 0x54 Status Request 0xCC 0x00 0x00 - - - 0xCC Firmware Version 0x00 0x03 - Change Channel 0xCC 0x01 New Channel - - 0xCC Broadcast Packets 0xCC 0x08 - 0xCC 0x00 or 0x01 - - Write Destination Address
CONFIGURING THE AC4790 COMMAND DESCRIPTIONS E n t e r AT C o m ma n d M o d e Prior to sending this command, the OEM Host must ensure that the transceiver’s RF transmit buffer is empty. If the buffer is not empty, the radio 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 the last packet and the AT command.
28 CONFIGURING THE AC4790 R ea d D e st i n at i o n Ad d r es s The OEM Host issues this command to the transceiver to read the destination address. Command: 0xCC 0x11 Note: Only the three Least Significant Bytes of the MAC Address are used for packet delivery. Response: 0xCC MAC3 MAC2 MAC1 Number of Bytes Returned: 4 Parameter Range: 0x00 - 0xFF corresponding to 3 LSB’s of destination MAC Address A ut o D es t i na t i o n The Host issues this command to change the Auto Destination setting.
CONFIGURING THE AC4790 R ea d D i g it a l I n p u t s The OEM Host issues this command to read the state of both digital input lines. Command: 0xCC 0x20 Number of Bytes Returned: 2 Response: 0xCC Data1 Parameter Range: Data1 = bit-0: GI0, bit-1: GI1 R ea d R a d io T ab l e 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 it received a packet from.
30 CONFIGURING THE AC4790 R ea d A D C The OEM Host issues this command to read any of the three onboard 10-bit A/D converters. Because the RF is still active in On-the-Fly Command Mode, the transceiver will not process the command until there is no activity on the network. The Read RSSI command is therefore useful for detecting interfering sources but will not report the RSSI from a remote transceiver on the network.
CONFIGURING THE AC4790 EE PROM Byte Re ad Upon receiving this command, a transceiver will respond with the desired data from the addresses requested by the OEM Host.
7 EEPROM P ARAMETERS The OEM Host can program various parameters that are stored in EEPROM which become active after a power-on reset. The table below gives the locations and descriptions of the parameters that can be read/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 one transceiver’s EEPROM to another transceiver as doing so may cause the transceiver to malfunction.
EEPROM PARAMETERS Table 12: EEPROM Parameters Parameter Control 1 EEPROM Address Length (Bytes) 0x56 1 Range Default 0x43 Description Settings are: bit-7: Aerocomm Use Only bit-6: Aerocomm Use Only bit-5: Aerocomm Use Only bit-4: Auto Destination 0 = Use destination address 1 = Use auto destination bit-3: Aerocomm Use Only bit-2: RTS Enable 0 = Ignore RTS 1 = Transceiver obeys RTS bit-1: Duplex 0 = Half Duplex 1 = Full Duplex bit-0: Auto Config 0 = Use EEPROM values 1 = Auto Configure values Interf
34 EEPROM PARAMETERS Table 12: EEPROM Parameters EEPROM Address Length (Bytes) Product ID 0x90 15 API Control 0xC1 1 Parameter Range Default Description 0x90 - 0x93: Product ID 0x94 - 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 the field at four bytes 0x9A - 0x9C: Interface (232, 485, TTL) 0x9D - 0x9E: Setup script (01 is stock) 0x9F: Reserved for future use; always 0xFF 0x10 Settings are: bit-7: Broadcast pa
EEPROM PARAMETERS Table 12: EEPROM Parameters EEPROM Address Length (Bytes) Probe Report 0xC9 1 0x00 0xFF - DES Key 0xD0 7 0x00 0xFF - Parameter Range Default 0xE3 www.aerocomm.com Description When set to 0xE3, upon receiving a probe the transceiver sends a Probe Report to the OEM Host.
8 D IMENSIONS MECHANICAL DRAWINGS Interface Connector - 20 pin OEM Interface connector (Molex 87759-0030, mates with Samtec SMM-110-02-S-D MMCX Jack - Antenna Connector (Johnson Components 135-3711-822)AC4790 (with MMCX connector) Mechanical Figure 6: AC4790 (with MMCX connector) Mechanical 2 0 p in h e a d e r , 0 .0 2 0 s q . p o s ts o n 0 .0 7 9 in c h (2 m m ) c e n te rs 0 .1 5 7 0 .1 8 0 0 .0 6 7 0 .0 6 2 0 .0 0 0 M M C X ja c k 0 .1 2 5 d ia n o n -p la te d h o le s (2 ) p la c e s 1 .
DIMENSIONS Figure 7: AC4790 with integral gigaAnt Antenna (on bottom) Mechanical 20 pin header, 0.020 sq. posts on 0.079 inch (2mm) centers 0.180 0.086 0.000 -0.152 0.157 0.062 0.000 GigaAnt Snap-In Antenna 0.125 dia non-plated holes (4) places 1.650 1.650 1.550 pins 1 2 1.180 1.010 J1 0.100 0.000 www.aerocomm.com 2.650 2.345 2.550 2.030 1.875 0.435 0.100 0.150 0.000 0.
DIMENSIONS NC DO1 SESSION STATUS CMD/DATA UP_RESET AD_IN Module Outline DI1 Figure 8: AC4790-1x1 Mechanical 21 20 19 18 17 16 15 0.131 RESET 22 14 RF_PORT 9600_BAUD (TST_M ODE) 23 13 GND (note 2) N/C 24 12 RSSI N/C 25 11 VCC (note 1) N/C 26 10 RTS N/C 27 9 CTS N/C 28 8 N/C 0.031 0.000 cut corner indicates pin 1 1 2 3 4 5 6 7 NC VCC (note 1) GND DO0 DI0 TXD RXD 1.000 AC4790-1X1 RECOMMENDED PAD PATTERN (viewed from top) 0.200 005068004503 1.
DIMENSIONS Figure 9: AC4790-1x1 PCB Considerations Note: Keep distance between 1x1 Module and antenna connector as short as possible for better performance. Use several large vias (0.030" hole) to tie top side ground to the bottom layer ground plane. 1206 SMT Chip Capacitors, can use 0805, 0603 or even 0402 parts. Shunt parts should be symetrical about series part and close as possible. Note: Must provide solid copper Ground plane on the bottom side of pc board in this area.
O RDERING I NFORMATION 9 PRODUCT PART NUMBER TREE DEVELOPER KIT PART NUMBERS All of the above part numbers can be ordered as a development kit by prefacing the part number with “SDK-”. As an example, 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.
10 C OMPLIANCY I NFORMATION AC4790-1X1 Due to the RF antenna trace residing on the OEM Host PCB, the FCC will not grant modular approval for the AC47901x1 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 development.
2268C-AC44901000 42 COMPLIANCY INFORMATION Table 14: AC4790 Approved Antennas Gain (dBi) 2 0 0 A 2 0 0 M 2 0 0 L R 1 0 0 0 M 1/2 Wave Dipole 2 - X X X Nearson 1/2 Wave Dipole 2 - X X X S467AH-915 Nearson 1/2 Wave Dipole 2 - X X X 0600-00027 S467AH-915R Nearson 1/2 Wave Dipole 2 - X X X 0600-00028 S161AH-915R Nearson 1/2 Wave Dipole 2.5 - X X X 0600-00029 S161AH-915 Nearson 1/2 Wave Dipole 2.
COMPLIANCY INFORMATION OEM EQUIPMENT LABELING REQUIREMENTS WARNING: The 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 AeroComm FCC identifier for this product as well as the FCC notice below. The FCC identifiers are listed above.
I A PPENDIX I - S AMPLE P OWER S UPPLY Below 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 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.
APPENDIX I - SAMPLE POWER SUPPLY SCHEMATIC PCB LAYOUT www.aerocomm.
46 APPENDIX I - SAMPLE POWER SUPPLY
II A PPENDIX II - 5V TO 3.3V L EVELS All inputs on the AC4790-200 & AC4790-1000 are weakly pulled high via 10 kohm resistors. The AC4790-200 has 5V inputs while the AC4790-1000 & AC4790-1x1 have 3.3V inputs. The AC4790-200 uses an octal buffer to drop the 5V to the 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’S This is the easiest and most efficient method.
III A PPENDIX III - API The API feature set of the AC4790 provides powerful packet routing capabilities to the OEM Host. The number of API configurations 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 NETWORK Many applications require multiple locations to report back to a single access point.
APPENDIX III - API Addressed Transmit API 1 To poll radio 1, the SAP transmits the packet using the following format: 2 To poll radio 2, the SAP transmits the packet using the following format: 3 To poll radio 2, the SAP transmits the packet using the following format: 4 This continues until all radios have successfully been polled by the SAP. Broadcast Transmit API To send out a universal poll request or data packet, the OEM may wish to utilize the broadcast portion of the Transmit API command.
50 APPENDIX III - API The remote response is dependent on the OEM’s specific needs and equipment. In many cases, remote radios are connected to dumb devices without the intelligence to filter out or append specific portions of a packet that is transmitted or received. Since the 7 bytes of overhead in the Transmit API command are not sent over the RF, the remotes will receive only the payload data, “STATUS”.
APPENDIX III - API Normal 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 NETWORK For 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.
52 APPENDIX III - API 2 Radio 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. 3 Radio 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.
APPENDIX III - API If radios B & C in the above picture are not within range of radio A, they will not be able to receive or respond to communications from radio A. A loopback repeater can be added between the three such that it is in range of both radio 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.
A PPENDIX IV - API T IMING D IAGRAMS TIMING DIAGRAMS Session Count = 8, Retries = 3 Session Count = 3, Retries = 3 www.aerocomm.
APPENDIX IV - API TIMING DIAGRAMS Session Count = 2, Retries = 2 Session Count = 1, Retries = 1 www.aerocomm.
