AVT 84 Series User manual

1509 Manor View Road, Davidsonville, MD 21035 USA
[phone] (voice) [e-mail]
www.AVT-HQ.com
ADVANCED VEHICLE TECHNOLOGIES, Inc.
AVT - 841 & 842 & 843
Multiple Interface
Volume 1
J1850 VPW
CAN0: 2-wire (high speed)
CAN4: Single Wire CAN (SWC)
CAN ISO 15765 support
K-Line communications
LIN communications
AVT-841: Hardware revision “B1”
AVT-842: Hardware revision “A1”
AVT-843: Hardware revision “A2”
Firmware Version “4.4”
27 February 2018

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Advanced Vehicle Technologies, Inc.
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Table of Contents
1. INTRODUCTION ....................................................................................................................................................6
1.1 SPECIAL NOTE.........................................................................................................................................................6
1.2 HARDWARE.............................................................................................................................................................6
1.3 FIRMWARE ..............................................................................................................................................................7
1.3.1 Determining Firmware Version .........................................................................................................................7
1.4 COMMANDS AND RESPONSES..................................................................................................................................7
2. GLOSSARY ..............................................................................................................................................................7
3. AVT-84X OPERATION ..........................................................................................................................................8
4. HOST COMPUTER CONNECTION.....................................................................................................................8
4.1 AVT-841 CONNECTION TO HOST COMPUTER .........................................................................................................9
4.1.1 AVT-841 Baud Rate to Host Computer..............................................................................................................9
4.2 AVT-842 CONNECTION TO HOST COMPUTER .........................................................................................................9
4.3 AVT-843 CONNECTION TO HOST COMPUTER .......................................................................................................10
4.3.1 Ethernet Setup..................................................................................................................................................11
4.3.2 Ethernet IP Addressing Modes ........................................................................................................................12
4.3.3 AutoIP Addressing ...........................................................................................................................................13
4.4 PACKET COMMUNICATIONS WITH HOST COMPUTER .............................................................................................13
5. VEHICLE CONNECTION....................................................................................................................................14
5.1 POWER REQUIREMENTS ........................................................................................................................................15
5.1.1 Ground.............................................................................................................................................................15
5.1.2 Input Voltage ...................................................................................................................................................15
5.1.3 Power Consumption.........................................................................................................................................15
5.2 JUMPERS ...............................................................................................................................................................15
6. ADC CONNECTION .............................................................................................................................................15
6.1 ADC READINGS ....................................................................................................................................................16
7. CAN MODE ............................................................................................................................................................16
7.1 CAN SECONDARY OPERATIONAL MODES.............................................................................................................17
7.2 CAN0 -2-WIRE CAN ............................................................................................................................................17
7.3 CAN4 -SINGLE WIRE CAN (SWC) ......................................................................................................................17
7.3.1 Jumper JP1 ......................................................................................................................................................18
7.4 CAN0 CHANNEL NUMBER ....................................................................................................................................18
7.5 CAN4 CHANNEL NUMBER ....................................................................................................................................18
7.6 LIN SECONDARY OPERATIONAL MODE CHANNEL NUMBER.................................................................................18
7.7 KWP SECONDARY OPERATIONAL MODE CHANNEL NUMBER...............................................................................18
7.8 CAN COMMUNICATIONS GENERAL NOTES ...........................................................................................................18
7.8.1 Disabled...........................................................................................................................................................18
7.8.2 Normal .............................................................................................................................................................18
7.8.3 Listen Only.......................................................................................................................................................19
7.8.4 Transmit Command..........................................................................................................................................19
7.8.5 Receive Response.............................................................................................................................................21
7.8.6 Time Stamps.....................................................................................................................................................22
7.9 ACCEPTANCE ID AND MASK CONFIGURATION ......................................................................................................24
7.10 ACCEPTANCE ID AND MASK OPERATION ..............................................................................................................24
7.10.1 ID/Mask mode = 2.......................................................................................................................................25
7.10.2 ID/Mask mode = 4.......................................................................................................................................25
7.10.3 ID/Mask mode = 8.......................................................................................................................................25
7.10.4 ID/Mask Example #1 ...................................................................................................................................25

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Advanced Vehicle Technologies, Inc.
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7.10.5 ID/Mask Example #2 ...................................................................................................................................26
7.10.6 ID/Mask Example #3 ...................................................................................................................................26
7.10.7 ID/Mask Example #4 ...................................................................................................................................27
7.10.8 ID/Mask Example #5 ...................................................................................................................................27
7.10.9 Summary......................................................................................................................................................28
7.11 SETTING UP A CAN CHANNEL FOR OPERATION......................................................................................................28
7.11.1 Communications Example ...........................................................................................................................28
7.12 CHANNEL ACTIVITY ..............................................................................................................................................29
7.13 PERIODIC MESSAGE SUPPORT ...............................................................................................................................29
7.13.1 Organization of Periodic Messages.............................................................................................................30
7.13.2 Periodic Message Master Timer..................................................................................................................30
7.13.3 Type1 Periodic Messages ............................................................................................................................30
7.13.4 Type2 Periodic Messages ............................................................................................................................31
7.13.5 Periodic Message Commands .....................................................................................................................32
7.14 ISO 15765 SUPPORT .............................................................................................................................................33
7.14.1 Terms and Definitions .................................................................................................................................33
7.14.2 Modes of Operation.....................................................................................................................................33
7.14.3 Receive Operations - General Notes ...........................................................................................................34
7.14.4 Receive Operations – Mode0.......................................................................................................................35
7.14.5 Receive Operations – Mode1.......................................................................................................................35
7.14.6 Receive Operations – Mode2.......................................................................................................................35
7.14.7 Transmit Operations....................................................................................................................................36
7.14.8 Transmit Operations – General Notes.........................................................................................................36
7.14.9 Operation Examples ....................................................................................................................................38
7.14.10 ISO 15765 Questions and Engineering Support..........................................................................................41
7.15 AUTO BLOCK TRANSMIT.......................................................................................................................................41
7.15.1 Operation Description.................................................................................................................................41
7.15.2 Command Descriptions (non-volatile parameters) ....................................................................................42
7.15.3 Command Description (control).................................................................................................................45
7.15.4 Operation Example......................................................................................................................................46
8. LIN OPERATIONS – IN CAN MODE ................................................................................................................47
8.1 JUMPER JP2 ..........................................................................................................................................................47
8.2 COMMUNICATIONS................................................................................................................................................47
8.2.1 Message Length ...............................................................................................................................................47
8.2.2 Checksum.........................................................................................................................................................48
8.2.3 ID Byte Only Message .....................................................................................................................................48
8.2.4 Communications Example ...............................................................................................................................48
8.2.5 Time Stamp ......................................................................................................................................................49
8.3 PERIODIC MESSAGE SUPPORT ...............................................................................................................................50
8.3.1 Modes of Operation .........................................................................................................................................50
8.3.2 Organization of Periodic Messages.................................................................................................................51
8.3.3 Periodic Message Master Timer ......................................................................................................................51
8.3.4 Type1 Periodic Message..................................................................................................................................51
8.3.5 Type2 Periodic Message..................................................................................................................................52
8.3.6 Slave Periodic Message ...................................................................................................................................53
8.3.7 Periodic Message Commands..........................................................................................................................54
8.4 ABIC SUPPORT .....................................................................................................................................................54
8.5 COMMANDS AND RESPONSES................................................................................................................................54
9. KWP OPERATIONS – IN CAN MODE ..............................................................................................................55
9.1 JUMPER JP2 ..........................................................................................................................................................55
9.2 COMMUNICATIONS................................................................................................................................................55
9.3 OPERATION COMMANDS .......................................................................................................................................55
9.3.1 Communications Example ...............................................................................................................................55
9.3.2 Time Stamp ......................................................................................................................................................56

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9.3.3 Fast Transmit...................................................................................................................................................57
9.4 PERIODIC MESSAGE SUPPORT ...............................................................................................................................57
9.4.1 Organization of Periodic Messages.................................................................................................................57
9.4.2 Periodic Message Master Timer ......................................................................................................................57
9.4.3 Type1 Periodic Messages ................................................................................................................................57
9.4.4 Type2 Periodic Messages ................................................................................................................................59
9.4.5 Periodic Message Commands..........................................................................................................................60
10. VPW MODE .......................................................................................................................................................60
10.1 JUMPER JP3 ..........................................................................................................................................................60
10.2 COMMUNICATIONS................................................................................................................................................60
10.2.1 Communications Example - Not Block Transfer .......................................................................................61
10.2.2 Time Stamp ..................................................................................................................................................62
10.3 MESSAGE FILTERING.............................................................................................................................................62
10.3.1 Example Network Message..........................................................................................................................63
10.3.2 Example #1 ..................................................................................................................................................63
10.3.3 Example #2 ..................................................................................................................................................64
10.3.4 Example #3 ..................................................................................................................................................64
10.3.5 Example #4 ..................................................................................................................................................64
10.4 MASK /MATCH /RESPOND FUNCTION ..................................................................................................................64
10.4.1 Operational Overview .................................................................................................................................64
10.4.2 Command Summary.....................................................................................................................................65
10.4.3 Example.......................................................................................................................................................65
10.5 PERIODIC MESSAGE SUPPORT ...............................................................................................................................65
10.5.1 Organization of Periodic Messages.............................................................................................................66
10.5.2 Periodic Message Master Timer..................................................................................................................66
10.5.3 Type1 Periodic Messages ............................................................................................................................66
10.5.4 Type2 Periodic Messages ............................................................................................................................67
10.5.5 Periodic Message Commands .....................................................................................................................68
10.6 BLOCK TRANSMIT EXAMPLE.................................................................................................................................68
10.7 BLOCK RECEIVE EXAMPLE....................................................................................................................................69
11. KWP MODE.......................................................................................................................................................69
11.1 JUMPER JP2 ..........................................................................................................................................................70
11.2 COMMUNICATIONS................................................................................................................................................70
11.2.1 Communications Example ...........................................................................................................................70
11.2.2 Time Stamp ..................................................................................................................................................71
11.3 INITIALIZATION......................................................................................................................................................72
11.3.1 CARB Mode Initialization ...........................................................................................................................72
11.3.2 FAST Initialization ......................................................................................................................................73
11.4 PERIODIC MESSAGE SUPPORT ...............................................................................................................................73
11.4.1 Organization of Periodic Messages.............................................................................................................74
11.4.2 Periodic Message Master Timer..................................................................................................................74
11.4.3 Type1 Periodic Messages ............................................................................................................................74
11.4.4 Type2 Periodic Messages ............................................................................................................................75
11.4.5 Periodic Message Commands .....................................................................................................................76
12. AVT-84X FIELD REFLASHING.....................................................................................................................76
12.1 AVT-84X REFLASHING -AVT PROVIDED APPLICATION ...................................................................................76
13. IDLE MODE - COMMANDS...........................................................................................................................78
13.1 IDLE MODE -RESPONSES ......................................................................................................................................78
13.2 OTHER RESPONSES ...............................................................................................................................................78
14. CAN MODE - COMMANDS............................................................................................................................80
14.1 CAN MODE -RESPONSES .....................................................................................................................................91

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15. LIN OPERATIONS IN CAN MODE - COMMANDS .................................................................................108
15.1 LIN OPERATIONS IN CAN MODE -RESPONSES ....................................................................................................111
16. KWP OPERATIONS IN CAN MODE - COMMANDS...............................................................................117
16.1 KWP OPERATIONS IN CAN MODE -RESPONSES .................................................................................................120
17. VPW MODE - COMMANDS .........................................................................................................................126
17.1 VPW MODE -RESPONSES...................................................................................................................................131
18. KWP MODE - COMMANDS .........................................................................................................................138
18.1 KWP MODE -RESPONSES...................................................................................................................................143
19. APPENDIX A ...................................................................................................................................................151
20. APPENDIX B ...................................................................................................................................................154
21. QUESTIONS ??................................................................................................................................................157
22. BIT MAP FOR IDS, MASKS, COMMANDS, ETC. ....................................................................................158

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Advanced Vehicle Technologies, Inc.
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1. Introduction
This document describes the AVT-841, AVT-842, and AVT-843 hardware and firmware.
The AVT-841, 842, and 843 are nearly identical units. The only difference is the means by which they
connect to and communicate with the host computer.
AVT-841: RS-232 serial communications with host computer.
AVT-842: USB communications with the host computer.
AVT-843: Ethernet communications with host computer.
They are multiple network interfaces for in-vehicle networks. The hardware and operational firmware
support the following networks/protocols:
•J1850 VPW (GM Class 2 compliant) with 4x mode.
•2-wire high speed CAN; ISO 11898-2 : 2016;
(known as CAN0, channel number 0).
•2-wire high speed CAN; ISO 11898-2 : 2016;
or
Single Wire CAN (SWC); J2411;
(known as CAN4, channel number 4).
•LIN or K-line; (LIN1 is channel 5, KWP is channel 6).
NOTE:
CAN0 and CAN4 do NOT support low speed fault tolerant CAN; ISO 11898-3 : 2006.
Some simultaneous operations are supported. Some are not.
1.1 Special Note
References in this document to “AVT-84x” mean the AVT-841, 842, or 843 - depending on the unit
being used.
References to specific models are made where necessary.
All three units can be considered identical; unless otherwise noted.
1.2 Hardware
Refer to our web site for the most up-to-date information about the hardware status of each board.
The AVT-841 board revision stands at “B1.”
[Normally a stock item.]
Hardware status: www.AVT-HQ.com/841_hw.htm
The AVT-842 board revision stands at “A1.”
[Replaced by the AVT-852.]
Hardware status: www.AVT-HQ.com/842_hw.htm
The AVT-843 board revision stands at “A2.”
[Replaced by the AVT-853.]

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Advanced Vehicle Technologies, Inc.
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Hardware status: www.AVT-HQ.com/843_hw.htm
1.3 Firmware
The firmware version stands at “4.3”.
Refer to our web site for the most up-to-date information about AVT-84x firmware versions:
www.AVT-HQ.com/841_asm.htm
1.3.1 Determining Firmware Version
Perform the following to determine the version of firmware in your unit.
[This simplified method applies to version 3.0 and later.]
•Connect to a host computer running the Hex Terminal or equivalent.
•Power on the 84x interface unit.
•The power-on notification is:
$91 $12 indicates idle mode operation.
$92 $04 $xx where “xx” is the firmware version.
Example: “xx” = $25 indicates version 2.5.
•Or, at any time, send the $B0 command.
•The response will be: $92 $04 $xx where “xx” is the firmware version.
1.4 Commands and Responses
A list of commands, responses, error codes, notes, etc. is provided at the end of this document.
2. Glossary
Common terms, abbreviations, acronyms, and more.
$ sign Indicates a hex number.
ADC Analog to Digital Converter or Conversion.
CAN Controller Area Network
CAN0 CAN channel 0
CAN4 CAN channel 4
EEPROM Electrically Erasable Programmable Read Only Memory. Usually with the form of
small rows and sectors. Erase and program operations are usually done for one sector at
a time.
FLASH A form of EEPROM. Usually with the form of large rows and sectors. Erase and
program operations are usually done for one sector at a time.
I5P Means “ISO 15765” process or processing.
IDE ID Extended.
When this bit = “0” the CAN frame uses an 11-bit ID.
When this bit = “1” the CAN frame uses a 29-bit ID; extended ID.

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Advanced Vehicle Technologies, Inc.
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ISO 11898-2 ISO specification for 2-wire high speed CAN physical layer.
ISO 15765 An ISO specification dealing with the formatting of data in the CAN frame data field.
Also used in sending blocks of data using CAN. Also known as Multi-Frame
Messaging (MFM) or Segmented Messages. This specification also deals with other
CAN network issues.
J2411 An SAE specification for Single Wire CAN (SWC).
K-line Single wire communications protocol. Refer to ISO 9141, ISO 9141-2, and ISO 14230
for more information.
LIN Local Interconnect Network.
RTR Remote Transmission Request.
When this bit = “1” it indicates a frame that is requesting a remote node to transmit an
answering frame.
SRR Substitute Remote Request. A fixed recessive bit that only exists in extended frames
(IDE = 1, 29-bit ID).
TVS Transient Voltage Suppression.
Type1 Type1 Periodic Message support, CAN, each message operates independently.
Type2 Type2 Periodic Message support, CAN, messages within a group operate sequentially.
SWC Single Wire CAN (SAE J2411).
XOR Bit-wise logical exclusive ‘OR’.
3. AVT-84x Operation
The AVT-84x does not have a power switch. The unit powers up and begins operations as soon as it is
plugged into a vehicle or other power source is applied.
On power-up, the interface will, almost immediately, report to the host computer: $91 $12 and
$92 $04 $xx (where “xx” is the unit firmware version number). This is the idle state, where the
AVT-84x is waiting for the host computer to issue a mode switch command. No network
communications are supported while in the idle state. Refer to Section 12 for a list of commands
supported while in the idle state.
4. Host Computer Connection
The AVT-841 uses an RS-232 serial communications connection to the host computer.
Detailed information in the following paragraphs.
The AVT-842 uses a USB connection to the host computer.
Detailed information in the following paragraphs.
The AVT-843 uses an Ethernet connection to the host computer.
Detailed information in the following paragraphs.

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4.1 AVT-841 Connection to Host Computer
The AVT-841 serial connection to the host computer com port is standard RS-232. It should be mated
to a host computer using a straight through wired 9-pin cable (NOT a null modem cable).
The AVT-841 uses RTS/CTS hardware handshaking for flow control. The host computer must be
configured for RTS/CTS hardware handshaking to proper operations.
Software flow control (XON/XOFF) cannot be used since communications between the AVT-841 and
the host computer is binary data.
For reference, the signals of the AVT-841 DE-9S connector pins are listed below.
Pins #1, #6, and #9 are tied together on the AVT-841 board through 10 ohm resistors.
Pin # Signal Direction
1 RI in to host computer
2 TX data out of AVT-841
3 RX data in to AVT-841
4 DTR out of host computer
5 GND
6 DSR in to host computer
7 CTS in to AVT-841
8 RTS out of AVT-841
9 CD in to host computer
AVT-841 RS-232 Connector Signals
4.1.1 AVT-841 Baud Rate to Host Computer
The serial communications baud rate between the AVT-841 and the host computer is 57.6 kbaud
(factory default).
The user can set the host communications baud rate by changing a value stored in EEPROM.
Available baud rates are listed here.
19.2 kbaud
38.4 kbaud
57.6 kbaud [default]
115.2 kbaud
Refer to the commands section for information about the “52 67 xx” command to change the host baud
rate. Also, refer to the User’s Manual, Volume 2 for detailed EEPROM information.
Note that this baud rate setting has nothing to do with vehicle network or Ethernet network
communications.
4.2 AVT-842 Connection to Host Computer
The AVT-842 uses the FTDI embedded USB to serial converter device (FT2232). USB 1.1 operations
are supported. Connection to the host computer is with a standard USB A/B cable.

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Note that the USB side of the AVT-842 is USB bus powered. You can connect the AVT-842 to your
host computer and it will be ‘discovered’ by the host and the port will be enumerated.
USB driver software is provided by FTDI (from their web site). AVT has tested and recommends
using the FTDI Virtual Com Port (VCP) drivers for communications between the user application and
the AVT-842 board. A separate document is available showing how to install the AVT-842 USB
drivers. That document is posted on the AVT web site, Product Documents page.
On the AVT-842 board, the microcontroller and the FTDI USB device communicate via an internal
serial link. The factory default for the internal serial link baud rate is 57.6 kbaud.
The user can set the host communications baud rate by changing a value stored in EEPROM.
Available baud rates are listed here.
19.2 kbaud
38.4 kbaud
57.6 kbaud [default]
115.2 kbaud
Refer to the commands section for information about the “52 67 xx” command to change the host baud
rate. Also, refer to the User’s Manual, Volume 2 for detailed EEPROM information.
Note that this baud rate setting has nothing to do with vehicle network.
4.3 AVT-843 Connection to Host Computer
The AVT-843 uses a Lantronix XPort embedded serial server to provide an Ethernet connection to the
host computer. On the AVT-843 this appears as an RJ-45 connector. It is 10/100 Ethernet; TCP/IP;
and configured with a static IP address = 192.168.1.70 (factory default).
The user can change the IP address of the AVT-843 unit. Detailed information about this is provided
in the Section 4.3.1 and Appendices “A” and “B.”
On the AVT-843 board, the microcontroller and the XPort device communicate via an internal serial
link. The factory default baud rate is 57.6 kbaud.
The user can set the host communications baud rate by changing a value stored in EEPROM.
Available baud rates are listed here.
19.2 kbaud
38.4 kbaud
57.6 kbaud [default]
115.2 kbaud
Refer to the commands section for information about the “52 67 xx” command to change the host baud
rate. Also, refer to the User’s Manual, Volume 2 for detailed EEPROM information.
Note that the baud rate setting of the XPort serial server must be changed to match that of the
AVT-843 microcontroller. Refer to Section 4.3.1 and Appendices “A” and “B” for information on
setting the XPort parameters.
Note that this baud rate setting has nothing to do with vehicle network or Ethernet network
communications.

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4.3.1 Ethernet Setup
The AVT-843 XPort can be reconfigured in the field by the user. Basic information is provided here.
More information is provided in Appendices “A” and “B” at the end of this document.
Use care when changing the configuration. It is possible to corrupt the setup such that communications
with the AVT-843 will be totally nonfunctional.
Ethernet communications with the AVT-843 use TCP/IP. The factory default device address is listed
here as well as the various port numbers, depending on the type of communications to be established.
Note that several different communications sessions are possible with the AVT-843, depending on
what is to be accomplished and what port is used. A session can be established with the AVT-843
XPort to change settings such as the Ethernet IP Address (port 9999). In normal use, an Ethernet
session will be opened with the AVT-843 to communicate with the vehicle network (port 10001).
The AVT-843 uses the Lantronix “XPort” device. Detailed information about the XPort device,
configuration tools, and more can be obtained from AVT or from the Lantronix web site
(www.Lantronix.com).
4.3.1.1 Ethernet IP Address
The factory default IP address of the AVT-843 is static and is set to:
192.168.1.70
The factory default net mask setting is: 255.255.255.0
Depending on the particular network environment in which the AVT-843 is being used, the setting of
the net mask may not be important. Rule of thumb: if connected to a busy network, and the
AVT-843 is using static IP addressing, set the net mask to 255.255.255.0.
4.3.1.2 Hardware or MAC Address
The hardware or MAC address of the AVT-843 can be found on the serial number sticker on the XPort
device - which looks like an RJ-45 connector. The MAC address will start with: “00-20-4A” for
Lantronix.
4.3.1.3 Vehicle Network Interface Port
Communications with the AVT-843 vehicle network interface is via port 10001.
All communications with the AVT-843 vehicle interface is in binary bytes [not ASCII hex]. Refer to
Section 4.4 for a description of the ‘packetized’ communications protocol between the AVT-843 and
the host computer. All communications with the AVT-843 follow the exact same rules and formats as
that of the AVT-841 and other AVT interface equipment.
4.3.1.4 Telnet Setup Port
The configuration of the AVT-843 XPort device can be examined and changed using the Telnet
application via port 9999.
To start a Telnet setup session with the AVT-843 unit perform the following (on a Win98/NT/XP
computer):
•Start Menu

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•Run
•Type into the command line:
telnet 192.168.1.70 9999
•Click OK
•When the session banner from the XPort is displayed, you must hit ENTER within 5
seconds or else the session will time out and disconnect.
Refer to Appendix “A” at the end of this document for a listing of a Telnet session with an
AVT-843 XPort device. Factory default settings are shown.
4.3.1.5 Web Page Setup
The configuration of the AVT-843 XPort device can be examined and changed using a web browser.
The setup screen is an HTML web page.
To establish a web page session with the AVT-843 XPort, enter the following into the web browser
address line: http://192.168.1.70
The setup form will appear. The first page is the configuration summary page. Select either “Server
Properties” or “Port Properties” to change the configuration. After making changes, select “Update
Settings.” The AVT-843 XPort will store the new settings and then reboot. Wait 1 to 2 minutes for the
AVT-843 XPort to complete the reboot before attempting to access the unit with the new settings in-
use.
Refer to Appendix “B” at the end of this document for a complete listing of all setup information
available when using the AVT-843 XPort configuration web page.
4.3.2 Ethernet IP Addressing Modes
Three IP addressing modes are available on the AVT-843 XPort.
•Static
•DHCP
•ARP
4.3.2.1 Static IP Addressing
The factory default addressing mode for the AVT-843 XPort is static and the address is set to
192.168.1.70. In static mode the Ethernet address of the AVT-843 is always the same and does not
change when power is cycled.
4.3.2.2 DHCP Addressing
Setting the AVT-843 IP address to 0.0.0.0 will enable DHCP (Dynamic Host Configuration Protocol)
function.
In this mode, the AVT-843 XPort will, on power-up, search for a DHCP server. If one is found it will
obtain its IP address, gateway address, and subnet mask from the DHCP server.
If a DHCP server is not found, the AVT-843 XPort will then switch to AutoIP addressing, described in
the next section.
An AVT-843 IP address of 0.0.1.0 enables DHCP addressing and disables AutoIP addressing.

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4.3.3 AutoIP Addressing
“AutoIP is an alternative to DHCP that allows hosts to automatically obtain an IP address in smaller
networks that may not have a DHCP server.”
[Quoted from Lantronix XPort User Manual, revision A 3/03, page 3-4.]
AutoIP addressing is only enabled if the AVT-843 XPort IP address is set to 0.0.0.0 and no DHCP
server is found.
If, on power-up, the AVT-843 XPort cannot find a DHCP server it will automatically assign itself an
AutoIP address (range: 169.254.0.1 to 169.254.255.1). It will then send out an ARP (Address
Resolution Protocol) request onto the network to see if any other node already has that address. If no
conflict is found, the AVT-843 XPort will use that address until the next power-on reset or reboot.
If an address conflict is found (another node is discovered to already have that address) then the AVT-
843 XPort will select another AutoIP address, send out another ARP request. The process will
continue until it finds an address that is not being used.
4.4 Packet Communications with Host Computer
Communications between the host computer and the AVT-84x, in both directions, uses a “packet”
protocol. This is the same protocol or method used by all AVT interface hardware.
•The first byte of a packet is the header byte.
•The header byte upper nibble (first hex digit) indicates what the packet is about.
•The header byte lower nibble (second hex digit) is the count of bytes to follow.
•If the header byte upper nibble is a zero (0) then the packet is a message to or from the
network.
•This protocol is limited to 15 bytes following the header byte (lower nibble = $F).
•Some messages require more than 15 bytes. For such a situation there are two “alternate”
header formats, which are of the form:
11 xx
12 xx yy
These alternate header formats only apply to messages to or from the network.
•If the byte count is more than $0F but equal to or less than $FF the packet will be of the
form: 11 xx rr ss tt ...
$11 indicates first alternate header format.
$xx indicates the count of bytes to follow (not including the “xx” byte).
$rr ss tt ... the packet data, including the message to/from the network.
•If the byte count is more than $FF but less than or equal to $FF FF the packet will be of the
form: 12 xx yy rr ss tt
$12 indicates second alternate header format.
$xx yy indicates the count of bytes to follow (not including the xx yy bytes).
$rr ss tt ... the packet data, including the message to/from the network.
•Example #1
Turn on the time stamp feature in CAN mode.
Command: 52 08 01

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Header byte upper nibble “5” indicates a configuration command.
Header byte lower nibble “2” indicates two bytes follow.
$08 is the time stamp command.
$01 commands enable time stamps.
•Example #2
Send a block of 348 bytes onto the VPW network.
Command: 12 01 5C rr ss tt vv ...
Header byte = $12, alternate header format #2.
$01 5C = 348 bytes
rr ss tt vv ... are the 348 message bytes.
•Example #3
Receive an 18 byte message from the VPW network.
Response: 11 13 rr ss tt vv ...
Header byte = $11, alternate header format #1.
$13 = 19 bytes follow
rr = is the receive status byte (indicates if any error were detected, etc.)
ss tt vv = actual message from the network.
Additional information about the AVT protocol is available at the beginning of the “Master Commands
and Responses” document available from our web site at:
www.AVT-HQ.com/download.htm#Notes
5. Vehicle Connection
The vehicle or network connector is an industry standard DA-15P connector and requires
a DA-15S mate. The pin out for the vehicle / network connector is shown below.
Pin # Description Notes
1 SWC Bi-directional
This signal goes through JP1
2 J1850 VPW bus + Bi-directional
This signal goes through JP3
4 Ground pins #4 and #5 are connected together
internally
3 [CAN4_H] [only on rev. “T” unit]
5 Ground pins #4 and #5 are connected together
internally
6 CAN0_H Bi-directional
7 K-Line
used for LIN and KWP modes
Bi-directional
This signal goes through JP2
11 [CAN4_L} [only on rev. “T” unit]
13 V-Batt supply Sourced by external equipment (vehicle)
14 CAN0_L Bi-directional

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P3 (the DA-15P connector on the AVT-84x board)
All other pins on the DA-15P vehicle network connector are “reserved.”
The user should not connect anything to unused or reserved pins.
5.1 Power Requirements
The AVT-84x board requires a nominal +12 VDC power supply; usually provided by the vehicle or
any suitable external power supply.
5.1.1 Ground
Common ground is required between the AVT-84x board and the subject vehicle or module. P3 pins
#4 and/or #5 are ground. They are connected together internally on the AVT-84x board. One is
needed for normal operations.
5.1.2 Input Voltage
V-Batt, the external power supply is applied to P3 pin #13.
Note that V-Batt is used to power the board. It also is the supply for the VPW signal; the pull-up and
reference voltage for K-Line communications; and for Single Wire CAN (SWC) signal.
For most normal operations, V-Batt supply can range from +7 to +24 VDC.
(The absolute maximum input voltage is +26.5 VDC.)
5.1.3 Power Consumption
Power consumption for each unit is listed here.
AVT-841: 750 milliwatts (nominal).
AVT-842: 1 watt (nominal).
AVT-843: 3.5 watts (nominal).
5.2 Jumpers
On the AVT-84x board are three jumpers: JP1, JP2, JP3.
They are for:
Single Wire CAN (SWC) network: JP1
K-line network: JP2
VPW network: JP3.
Note that AVT-841 revision “A” boards do not have JP3. The VPW network line is always connected
to pin #2 of P3 - the DA-15P “Vehicle” connector.
6. ADC Connection
The four position screw terminal block is used to access the three Analog to Digital Converter (ADC)
channels.
Terminal #1: ADC channel #1.

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Terminal #2: ADC channel #2.
Terminal #3: ADC channel #3.
Terminal #4: ground.
The input voltage range for all three channels is: 0 to +5 volts.
The inputs are passively pulled to ground through a 24.9 K ohm resistor. In most cases, with no input
applied, the reading for a channel will generally stay below a reading of about $03.
The inputs are ESD protected with a 27 volt TVS diode.
The inputs are over and under voltage protected. That does not mean the inputs can withstand abuse.
Damage may still occur if subjected to a voltage outside the range of 0 to +5v with respect to ground.
6.1 ADC Readings
The ADC output conversion value range is: $00 to $FF. Full scale is $FF.
Input voltage of 0.0v equals a reading of $00.
Input voltage of 5.0v equals a reading of $FF.
The conversion is linear, monotonic, with no missing codes.
There is no input filtering of the signal and readings are not averaged.
The ADC channels are read continuously and the most recent value is stored. The command to read an
ADC channel returns the value most recently read. ADC conversions are not synchronized with
commands from the host to take an ADC reading.
The 52 58 0x command is used to read a specified ADC channel; where x = channel number 1 to 3.
The 52 59 xx command is used to disable or enable and set the rate at which all three ADC channels
are reported to the host. Parameter ‘xx’ is the number of timer ticks between reports.
The timer for the 5x 29 command is set by the 5x 63 command.
7. CAN Mode
Enter CAN mode with the $E1 99 command.
The report $91 10 indicates the AVT-84x has entered CAN operations.
The report $83 11 00 00 indicates that CAN channel 0 is disabled.
The report $83 11 04 00 indicates that CAN channel 4 is disabled.
The report $91 19 indicates that LIN mode of operation is active.
The AVT-84x supports operations of two simultaneous CAN channels and one LIN or KWP channel
when in CAN mode.
CAN0 is a 2-wire high speed CAN channel that is ISO 11898-2 compliant.
It is channel 0.
CAN4 is a Single Wire CAN (SWC) channel that is SAE J2411 compliant.
It is channel 4.
LIN mode is based on revisions 1.2, 1.3, and 2.0.
It is channel 5.
KWP mode is based on ISO 9141, ISO 9141-2, and ISO 14230.
It is channel 6.

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When CAN mode is first entered, the following defaults are set:
•CAN0 and CAN4 operations are disabled.
•CAN0 baud rate is set to 500 kbaud.
•CAN4 baud rate is set to 33.333 kbaud.
•ID/Mask mode is set to 4 for both channels.
•All IDs are set for 11-bit with a value of $07FF.
•All masks are set to zeros (must match condition).
•LIN mode is enabled and the LIN bus speed is 9600 baud.
7.1 CAN Secondary Operational Modes
When operating in CAN mode, one of two secondary operating modes are supported. Either LIN mode
or KWP (Key Word Protocol) mode can be selected to operate simultaneously with both CAN
channels.
One secondary operational mode can be supported: LIN or KWP; not both.
After entering CAN mode, LIN mode is enabled as the default secondary mode.
(Same as the 52 69 01 command.)
KWP mode can be selected using the 52 69 02 command. LIN mode is disabled.
The 52 69 00 command disables both LIN and KWP secondary modes.
7.2 CAN0 - 2-wire CAN
CAN0 is a 2-wire high speed CAN channel that is ISO 11898-2 compliant. It uses the Philips
TJA1050 transceiver. The CAN_H signal is routed to the D-15 network connector pin #6. The
CAN_L signal is routed to the D-15 network connector pin #14.
The AVT-84x board has been designed to support a variety of network termination schemes for CAN0.
The factory default is the split termination consisting of two 60 ohm resistors in series across the
CAN_H and CAN_L signal lines. The mid-point of the two termination resistors is routed through a
10 ohm resistor and a 10,000 pF ceramic capacitor to ground. This configuration provides the standard
120 ohm DC termination and provides good common mode noise rejection.
Other termination configurations, including Ford compliant AC termination, are available - contact the
factory for details.
7.3 CAN4 - Single Wire CAN (SWC)
CAN4 is a low speed single wire CAN channel that is SAE J2411 compliant. It uses the Philips
AU5790 transceiver. The SWC signal is routed through jumper JP1 to the D-15 network connector pin
#1.
The factory default for jumper JP1 is OFF (to prevent possible damage in the event the AVT-84x is
connected to a vehicle that does not have the SWC signal on pin #1).

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7.3.1 Jumper JP1
Jumper JP1 on the AVT-84x board connects / disconnects the Single Wire CAN (SWC) line from pin
#1 of P3; the DA-15P “Vehicle” connector. Usually, the factory default position of JP1 is installed.
7.4 CAN0 Channel Number
CAN0 is designated channel “0”.
Note: Bits in the upper nibble of the channel number have special meaning for some commands and
responses.
7.5 CAN4 Channel Number
CAN4 is designated channel “4”.
Note: Bits in the upper nibble of the channel number have special meaning for some commands and
responses.
7.6 LIN Secondary Operational Mode Channel Number
When LIN mode is active as a secondary operational mode, it is designated channel “5”.
ABIC operations (in LIN mode only) are designated by channel “$15”.
7.7 KWP Secondary Operational Mode Channel Number
When KWP mode is active as a secondary operational mode, it is designated channel “6”.
7.8 CAN Communications General Notes
A CAN network has to consist of at least two functioning CAN nodes.
(The AVT-84x can be one of the nodes).
Each CAN channel of the AVT-84x is independent of the other channel.
(This applies to all channel parameters.)
Each CAN channel of the AVT-84x has three operating modes:
Disabled
Normal
Listen only.
Messages to and from the network are of the form: $0x yy rr ss tt vv ... where “x” is the count of
bytes to follow. Refer to Sections 4.4, 7.3, and 13 for detailed information about CAN messages and
packets to and from the network.
7.8.1 Disabled
The CAN channel can not receive any messages and it can not transmit any messages.
Command: 73 11 0x 00 Status report: 83 11 0x 00
7.8.2 Normal
The CAN channel will receive all messages from the network. It will assert the CAN frame ACK bit
for all frames it receives without error. Only those frames it receives, where the message ID matches

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the acceptance ID according to the mask and associated rules, are passed to the host. Refer to Section
7.5 for a discussion.
The CAN channel can transmit messages.
Command: 73 11 0x 01 Status report: 83 11 0x 01
7.8.3 Listen Only
The CAN channel can only receive messages. It can not transmit messages and it can not assert the
CAN frame ACK bit.
The CAN channel will receive all messages from the network. It can not assert the CAN frame ACK
bit. Only those frames it receives, where the message ID matches the acceptance ID according to the
mask and associated rules, are passed to the host. Refer to Section 7.5 for a discussion.
The CAN channel can only monitor received messages.
Command: 73 11 0x 02 Status report: 83 11 0x 02
7.8.4 Transmit Command
The fields and construction of a transmit command are shown here. The transmit command is also
explained in the Commands and Responses – Section 14.
There are three forms of the transmit command. The number of bytes in the transmit command
determines the format of the command to use.
7.8.4.1 Format ‘0x’
The ‘0x’ form of the transmit command can be used for when the total byte count is $0F or less. All
fields of the command are explained here.
0p xy tt vv ww zz mm nn ...
p: count of bytes to follow
x: b7: IDE
0: 11-bit ID
1: 29-bit ID
b6: RTR
0: normal frame
1: RTR true, remote transmit request
b5: 0
b4: 0 = transmit message ‘as-is’
1 = format message for ISO 15765
y: Channel number: 0, 4, 5, 6
tt vv: 11-bit ID, right justified
tt vv ww zz: 29-bit ID, right justified
mm nn ...: message data
7.8.4.2 Format ‘11 xx’
The ‘11 xx’ form of the transmit command can be used for when the total byte count is $FF or less.
All fields of the command are explained here.
11 pp xy tt vv ww zz mm nn ... :

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pp: count of bytes to follow
x: b7: IDE
0: 11-bit ID
1: 29-bit ID
b6: RTR
0: normal frame
1: RTR true, remote transmit request
b5: 0
b4: 0 = transmit message ‘as-is’
1 = format message for ISO 15765
y: Channel number: 0, 4, 5, 6
tt vv: 11-bit ID, right justified
tt vv ww zz: 29-bit ID, right justified
mm nn ...: message data
7.8.4.3 Format ‘12 xx yy’
The ‘12 xx yy’ form of the transmit command can be used for when the total byte count is $1004 or
less. All fields of the command are explained here.
12 pp qq xy tt vv ww zz mm nn ... :
pp qq: count of bytes to follow
x: b7: IDE
0: 11-bit ID
1: 29-bit ID
b6: RTR
0: normal frame
1: RTR true, remote transmit request
b5: 0
b4: 0 = transmit message ‘as-is’
1 = reformat message for ISO 15765
y: Channel number: 0, 4, 5, 6
tt vv: 11-bit ID, right justified
tt vv ww zz: 29-bit ID, right justified
mm nn ...: message data
7.8.4.4 Byte Count Limits
The total number of message data bytes permitted in a transmit command depends on whether or not
ISO 15765 processing is enabled or specified for the transmit command.
When ISO 15765 is disabled, maximum is 8 data bytes.
When ISO 15765 is enabled, maximum is 4095 data bytes.
7.8.4.5 Pacing Note 1
The AVT-84x will process a transmit command from the host as quickly as possible. It is possible that
the host can send transmit commands to the AVT-84x so quickly that the transmitted CAN frames
cause problems for the downstream module. This can happen with ISO15765 processing enabled or
disabled.