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AeroComm AC4790, User Manual

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AeroComm AC4790 User Manual Download Page 14

 

 

14 

Serial Interface 

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. 

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.  The following 

asynchronous serial data formats are supported: 

 
 

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% of 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

14.7456E

Baud = 0x100 - 

64 x Desired baud

 

(1) 

 

 

Baud H = Always 0

Baud L = Low 8 Bits of BAUD (base 16)

 

 

 

Table 6 - Baud  Rate/Interface Timeout 

Baud Rate 

BaudL (0x42) 

BaudH (0x43) 

Minimum Interface Timeout 

(0x58) 

Stop bit Delay (0x3F) 

115,200 0xFE  0x00 

0x02 

0xFF 

57,600

1

 0xFC  0x00 

0x02 

0x03 

38,400 0xFA  0x00 

0x02 

0x08 

28,800 0xF8  0x00 

0x02 

0x0E 

19,200 0xF4  0x00 

0x03 

0x19 

14,400 0xF0  0x00 

0x04 

0x23 

9,600 0xE8  0x00 

0x05 

0x39 

4800 0xD0  0x00 

0x09 

0x7A 

2400 0xA0  0x00 

0x11 

0x 

FC 

1200 0x40  0x00 

0x21 

0x00

2

 

 
 

                                                 

1

 57,600 is the default baud rate. 

2

 0x00 will yield a stop bit of 421uS.  The stop bit at 1200 baud should be actually 833us. 

 

Data 

bits 

Parity 

Stop bits 

Transceiver Programming Requirements 

8 

N 

1 

 Parity disabled 

7 

N 

2 

 Parity disabled 

7 

E, O, M, S 

1 

 Parity disabled 

9 N  1 

Parity 

enabled 

8 N  2 

Parity 

enabled 

8 

E, O, M, S 

1 

Parity enabled 

7 

E, O, M, S 

2 

Parity enabled 

Mark (M) corresponds to 1 and Space (S) corresponds to 0 

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Summary of Contents for AC4790

Page 1: ...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 Downloaded from Elcodis com electronic components distributor ...

Page 2: ...s 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 ...

Page 3: ...rsion 1 2 4 26 2005 Updated Transmit Mode Section Version 1 3 3 27 2006 Corrected API Send Data Complete Added Australian Channels Added 1x1 documentation Added Original Max Power byte 0x8E and Full Product ID 0x90 Changed Sense Adjust default to varies Added Appendix 1 Power Supply Application Note Downloaded from Elcodis com electronic components distributor ...

Page 4: ...and 1 pins 1 and 9 respectively 20 TXD Transmit Data and RXD Receive Data pins 2 and 3 respectively 20 CTS Handshaking pin 7 20 RTS Handshaking pin 8 20 Test pin 12 20 RSSI pin 13 21 UP_Reset pin 15 21 Command Data pin 17 21 AD In pin 18 21 Session Status pin 20 21 CONFIGURING THE AC4790 22 AC4790 AT COMMANDS 22 Enter AT Command Mode 23 Exit AT Command Mode 23 ON THE FLY CONTROL COMMANDS CC COMMAN...

Page 5: ...s 8 Table 2 Input Voltage Characteristics AC4790 1000 AC4790 1x1 9 Table 3 Output Voltage Characteristics All 9 Table 4 Session Count Truth Table 11 Table 5 Supported Serial Formats 14 Table 6 Baud Rate Interface Timeout 14 Table 7 Maximum Overall System Throughput 16 Table 8 RF Channel Number Settings 17 Table 9 EEPROM Parameters 29 Table 10 Agency Identification Numbers 38 Table 11 AC4790 Approv...

Page 6: ...itecture 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 fair 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 sec...

Page 7: ...pical AC4790 200 100mW typical 200mW typical AC4790 1000 743mW typical 1486mW typical Supply Voltage AC4790 1x1 3 3V 50mV ripple AC4790 200 3 3 5 5V 50mV ripple AC4790 1000 Pin 10 3 3 5 5V 50mV ripple Pin 11 3 3 3 100mV ripple Pins 10 and 11 may be tied together provided the supply voltage never falls below 3 3 V and is capable of supplying 1 5 A of current Sensitivity 100dBm typical 76 8kbps RF D...

Page 8: ...nnected to Pin 11 AC4790 1000 3 3 5 5V 50mV ripple 11 11 PWR VCC2 AC4790 1x1 3 3V 50mV ripple AC4790 200 3 3 5 5V 50mV ripple Pin 11 is internally connected to Pin 10 AC4790 1000 3 3V 3 100mV ripple 12 23 I Test Test Mode When pulled logic Low and then applying power or resetting the transceiver s serial interface is forced to a 9600 8 N 1 rate To exit the transceiver must be reset or power cycled...

Page 9: ...9 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 8 5 0 0 6 V Command Data 2 31 3 3 0 0 99 2 5 5 0 0 8 V AD In N A 3 3 0 N A N A 3 3 0 N A V Table 3 Output Voltage Characteristics All Signal Name Module Pin 1x1 Pin Type High Min Low Max Unit GO0 1 19 O 2 5 8mA 0 4 8mA V TXD 2 6 O 2 5 2mA 0 4 2mA V RS485A B 2 3 N A I O 3 3 1 8 Unit Load N A V CTS 7 9 O 2 5 2mA 0 4 2mA V GO1...

Page 10: ...EEPROM address 0xC4 Broadcast Attempts EEPROM address 0x4D 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 inten...

Page 11: ...EEPROM address C4h value Session Count Refresh must not be set to 0h Help Me 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 suitab...

Page 12: ...ed by the radio is interpreted as command data Command Data can be either EEPROM Configuration or On The Fly commands Figure 2 Pending RF 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 ...

Page 13: ...01 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 API Send Data Complete can be used as a software send ...

Page 14: ...st 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 14 7456E Baud 0x100 64 x Desired baud 1 Baud H Always 0 Baud L Low 8 Bits of BAUD base 16 Table 6 Baud Rate Interface Ti...

Page 15: ...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 CAN I IMP...

Page 16: ...hen designing the system Quick Tip MAXIMUM OVERALL SYSTEM THROUGHPUT When operating as shown in the Table 7 an AC4790 transceiver is capable of achieving the listed throughput However in the presence of interference or at longer ranges the transceiver may not be able to meet the specified throughput Table 7 Maximum Overall System Throughput RF Status Half Duplex Throughput bps Full Duplex Throughp...

Page 17: ...hat Channel Number EEPROM address 0x40 can be considered as another byte of System ID All channels in 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 0x40 Frequency Details and Regulatory Requirements Countries 0 AC4790 1x1 AC4790 200 0x00 0x0F 902 928MHz 26 hop bins US Canada 1 AC4790 1x1 AC4790 1000 0x10 0...

Page 18: ...ow 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 3 Power dBm 10log Power mW 10 2 Power dBm 10 Power mW 10 3 Figure 5 Current vs Output Power for AC4790 200 Output Power mW Current mA EEPROM Setting 100 127 5 0x60 90 125 0x 1E 70 117 5 0x 0F 50 110 5 0x 0...

Page 19: ...72 2 0x 03 Quick Tip The max power is set during Production and may vary slightly from one transceiver to another The output power and current draws shown above can vary by as much as 10 from the values listed The max power can be set as low as needed however it should never be set higher than the original factory default setting Downloaded from Elcodis com electronic components distributor ...

Page 20: ...nabled 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 amoun...

Page 21: ...ce Additionally validated RSSI can be obtained from Receive Packet and Send Data Complete API commands and from the Probe command Validated RSSI is not available at the RSSI pin The following equation approximates the RSSI curve Figure 8 RSSI Voltage vs Received Signal Strength Signal Strength dBm 46 9 V 53 9 RSSI 4 UP_Reset pin 15 UP_Reset provides a direct connection to the reset pin on the AC47...

Page 22: ...n 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 ...

Page 23: ...e 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 There...

Page 24: ...its 1 7 0 Read API Control 0xCC 0x16 0xCC API Control Write API Control 0xCC 0x17 API Control 0xCC API Control Mac 2 1 0 RSSI RSSI Stale count Read Radio Table 0xCC 0x18 0xCC Of Transceivers in Table max8 Returned for all the radios in the Table Read Digital Inputs 0xCC 0x20 0xCC bit 0 GI0 bit 1 GI1 Read ADC 0xCC 0x21 0x01 AD In 0x02 Temp 0x03 RSSI 0xCC MSB of 10 bit ADC LSB of 10 bit ADC Write Di...

Page 25: ...eturned 4 Response 0xCC MAC3 MAC2 MAC1 Parameter Range 0x00 0xFF corresponding to 3 LSB s of destination MAC Address Read 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 0xCC 0x11 Number of bytes returned 4 Response 0xCC MAC3 MAC2 MAC1 Paramete...

Page 26: ... 0xCC Byte 2 of transceivers in this table 0x00 0x08 Byte 3 Mac 2 1 0 of transceiver 1 Byte 4 RSSI 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 n Stale Count of transceiver 2 and so on Stale Count The Stale Count Reload 0x4F determines the amount of time a radio will stay active in the Radio Table The Stale Count min 0x00 max depe...

Page 27: ...robe command the transceiver can perform normal RF communications Command 0xCC 0x8E Data1 Number of bytes returned 2 Response 0xCC Data1 Parameter Range Data1 0x00 Disable Probe 0x01 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 and make decisions on rerouting da...

Page 28: ...f bytes returned 4 Response CCh Data1 Data2 Data Parameter Range Data1 EEPROM address Data2 Length 1 80h Data Data written Quick Tip Reset Command The OEM Host issues this command to perform a soft reset of the transceiver Any transceiver settings modified by CC Commands will be overwritten by values stored in the EEPROM Command CCh FFh Number of bytes returned None Response None The EEPROM is lim...

Page 29: ...F US Canada AC4790 1x1 200 Set 1 0x10 0x2F US Canada AC4790 1x1 1000 Set 3 0x30 0x37 US Canada AC4790 1x1 200 Australia AC4790 1x1 200 1000 Baud Rate Low 0x42 1 0x00 0xFF 0xFC Low Byte of the interface baud rate Default baud rate is 57 600 Baud Rate High 0x43 1 0x00 0x00 Always 0x00 Control 0 0x45 1 0x00 Settings are bit 7 0 bit 6 DES Enable 0 Disable Encryption 1 Enable Data Encryption bits 5 0 0...

Page 30: ...ol of external RS 485 hardware 0xFF Disable RS 485 DE MAC ID 0x80 6 Factory programmed unique IEEE MAC Address Original Max Power 0x8E 1 Set in production and can vary Copy of original Max Power EEPROM setting This address 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 100...

Page 31: ...y 0x7F Wait 1 128 packet times then retry 0xFF Wait 1 256 packet times then retry Sense Adjust 0xC8 1 0x00 0xFF Set in production and can vary The minimum RSSI required by a transceiver to establish a Session Status on hearing a long beacon Probe Report 0xC9 1 0x00 0xFF 0xE3 When this byte is set to 0xE3 upon receiving a probe the transceiver sends a Probe Report to its OEM Host DES Key 0xD0 7 0xx...

Page 32: ...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 Figure 10 AC4790 with MMCX connector Mechanical Downloaded from Elcodis com electronic components distributor ...

Page 33: ...33 Figure 11 AC4790 with integral gigaAnt antenna on top Mechanical Downloaded from Elcodis com electronic components distributor ...

Page 34: ...34 Figure 12 AC4790 with integral gigaAnt antenna on bottom Mechanical Downloaded from Elcodis com electronic components distributor ...

Page 35: ...35 Figure 13 AC4790 1x1 Mechanical Downloaded from Elcodis com electronic components distributor ...

Page 36: ...36 Figure 14 AC4790 1x1 PCB Considerations Downloaded from Elcodis com electronic components distributor ...

Page 37: ...umber AC4790 200A 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 Downloaded from Elcodis com elec...

Page 38: ...4490 100 2268C AC4490 AC4790 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 Number Manufacturer Part Nu...

Page 39: ...beling Requirements Antenna Requirements 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 WARNING The Original Equipment Manufacturer OEM must ensure that FCC labeling requir...

Page 40: ...ing a Channel not approved for use by the FCC IC 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 Downloaded from Elcodis com electronic components distributor ...

Page 41: ...2 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 1 resistor This will change the output to 5 volts at 1 0 amps Bill of Materials Qty Reference Value Description Mfg Mfg part number 1 R1 210 Res 0603 210 1 16W 1 KOA RK73H1JT2100F...

Page 42: ...Appendix I Power Supply Application Note 42 Downloaded from Elcodis com electronic components distributor ...

Page 43: ...ems allowing the device to be used in a mixed 3 3 5V system The datasheet for the SN74LVC244A can 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 kΩ pullup resistor Aerocomm recommends that all unused inputs be pulled high 2 Passive Voltage Divider While a resistor voltage divider can successful...

Page 44: ... 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 Quick Tip III Broadcast API Packet This configuration has several variations and is ideal for applications in which one radio sends a string of data ...

Page 45: ...ansmits 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 tra...

Page 46: ... unit and the session expires after 8 hops 5 Master switches to radio C using TX API 81h 01h 08h 04h 12h 34h CDh AAh 6 Radio C receives the packet which tells it to begin transmitting its information Radio C sends the information back to the master unit and the session expires after 8 hops 7 Master switches to radio D using TX API 81h 01h 08h 04h 12h 34h EFh AAh 8 Radio D receives the packet which...

Page 47: ...Appendix IV API Timing Diagrams 47 Appendix IV API Timing Diagrams Session Count 8 Retries 3 Session Count 3 Retries 3 Downloaded from Elcodis com electronic components distributor ...

Page 48: ... Retries 2 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 Downloaded from Elcodis com electronic components distributor ...

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