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Topic: problems with elm323 (Read 901 times) previous topic - next topic

ozracing

Hi, so i have this problem using ELM323 with arduino
i can send AT command and i receive them correctly but whenever i send "AT Si" or "AT Fi" i get "BUS INIT: BUS BUSY"
Everything is made by ELM323's datasheet diagram just added a transistor inverter to ELM323 RX pin
inverter looks like this:

Any ideas how to make communication to car's K-line successful?
P.S. I am writing commands with arduino's usb-serial converter and the atmega328 is removed from board just in case of burning something
if (str = "arduino rulez") {
 delay(250);
 str = "Pic is crap";
}

Pavilion1984

Do you get the ELM's start up message "ELM323----"? You don't need to send them commands. Try sending an OBD command like 01 0C an see what you get.

I am currenty doing a project with this IC to create a digital dash.

ozracing

on startup and by sending "ati" it prints:
Code: [Select]
ELM323 V2.0
>

and by sending 01 00 or any other non AT command it prints:
Code: [Select]
BUS INIT: BUS BUSY
>

Any ideas what's wrong?
P.S. sorry but i know what commands to send for wanted results because i read that datasheet dozen times.
if (str = "arduino rulez") {
 delay(250);
 str = "Pic is crap";
}

Pavilion1984

For comands just Google OBD pids an look for the Wiki page, should be first result. Sounds like the IC is working then. When your trying this are you connecting the ELM323 device to the car? If so it sounds like you may have a wiring problem from the car to the ELM ic.

ozracing

i printed all the codes and i checked the connection between elm and car's obd connector and i made a separate wires for that (op-com still works as intended)
checked with: multimeter, old oscilloscope. but no luck.
maybe the chip is a fake one?
Because i didn't see any difference with "AT Fi" and "AT Si" as datasheet states the difference with three dots ( ... )
if (str = "arduino rulez") {
 delay(250);
 str = "Pic is crap";
}

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