ELM329 Просмотр технического описания (PDF) - Elm Electronics

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ELM329

CAN Interpreter

Elm Electronics 

ELM329

AT Commands

Several parameters within the ELM329 can be

adjusted in order to modify its behaviour. These do not

normally have to be changed before attempting to talk

to the vehicle, but occasionally the user may wish to

customize these settings – for example by turning the

character echo off, adjusting a timeout value, or

changing the header (ID) bytes. In order to do this,

internal ‘AT’ commands must be used.

Those familiar with PC modems will immediately

recognize AT commands as a standard way in which

modems are internally configured. The ELM329 uses

essentially the same method, always watching the

data sent by the PC, looking for messages that begin

with the character ‘A’ followed by the character ‘T’. If

found, the next characters will be interpreted as an

internal configuration or ‘AT’ command, and will be

executed upon receipt of a terminating carriage return

character. If the command is just a setting change, the

ELM329 will reply with the characters ‘OK’, to say that

it was successfully completed.

Some of the commands require that numbers be

provided as arguments, in order to set the internal

values. These will always be hexadecimal numbers

which must generally be provided in pairs. The

hexadecimal conversion chart in the OBD Commands

section (page 26) may be helpful if you wish to

interpret the values. Also, one should be aware that for

the on/off types of commands, the second character is

the number 1 or the number 0, the universal terms for

on and off.

The remainder of this page, and the next page

following provide a summary of all of the commands

that the current version of the ELM329 recognizes. A

more complete description of each command begins

on page 11.

AT Command Summary

ELM329 Options

<CR>

repeat the last command

BRD hh

try Baud Rate Divisor hh

BRT hh

set Baud Rate Timeout

D

set all to Defaults

E0, E1

Echo off, or on*

I

print the version ID

L0, L1

Linefeeds off, or on

LP

go to low power mode

M0, M1

Memory off, or on

RD

Read the stored Data

SD hh

Save Data byte hh

WS

Warm Start (quick software reset)

Z

reset all

@1

display the device description

@2

display the device identifier

@3 cccccccccccc store the @2 identifier

Note: Settings shown with an asterisk (*)

are the default values

Programmable Parameters

PP xx OFF disable Prog Parameter xx

PP FF OFF all Prog Parameters disabled

PP xx ON enable Prog Parameter xx

PP FF ON all Prog Parameters enabled

PP xx SV yy for PP xx, Set the Value to yy

PPS

print a PP Summary

Voltage Readings

CV dddd

Calibrate the Voltage to dd.dd volts

CV 0000

restore CV value to factory setting

RV

Read the input Voltage

Other

C0, C1

IGN

IN1

IN2

Control Output off*, or on

read the IgnMon input level

read INput 1 level

read INput 2 level

ELM329DSB

Elm Electronics – Circuits for the Hobbyist

www.elmelectronics.com

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