Special direct value output request

[tronicgr]

Hey, Nice idea..!!!

And looks simple enough to retrieve the data!

protocol data elm327.gif (4.46 KiB) Viewed 5880 times

I'll give it a try!

Just a quick question: It it using 9600bps or 38400bps serial speed???

Thanos

[sirnoname]

9600

Not all AT commands are implemented, I only choose the ones which are used by other software.
Commands which are not implemented give back "?".
I think also there is a command for increasing the port speed but did not see which it is ...

[tronicgr]

Yes I seen that... we don't need AT commands for this anyway. They are mostly used for diagnostic reasons. Maybe just a ATZ at start

So I just send "01 0C" and I get back "01 0C AA BB" where AA BB is the 2byte data for the rpm for example. Pretty simple!

Well, 9600 is enough to start experimenting. But 38400bps would be even better! My dashboard currently uses 115.200bps and has only 10ms delay in the USO parser... 100 times per second refresh rate!

Thanos

[tronicgr]

I did some tests on Monday, could speak to the ELM327 AT commands, but I still get "?" when requesting values... I also was trying to disable the LineFeed but I guess isn't supported AT command.

Arduino: "atz"
ELM237: "ELM327v1.4" LF ">"

Arduino: "ate0"
ELM237: "OK" LF ">"

Arduino: "atl0"
ELM237: "?" LF ">"

Arduino: "010C"
ELM237: "?" LF ">"



I'll keep trying...

For the baud rate it should be the "ATBRD hh" where hh is the baud rate divisor. I don't know what value should I use to get 38400bps...

*Edit: Found the baud divisor... "68" in HEX ... 4000000 / 104 = 38461 (where 4000000 is the clock rate of the ELM327)

Thanos

[sirnoname]

atl1 was wrong programmed, atl0 and 010c is working here. 010c must be without at
By the way one thread above it works at your side.
I have added the baudrate code now but I am rounding to common values.

[antenna]

Forgive the intrusion, can you explain me how did you send the command with arduino? i've tried in first place with a simple code found on the web but i wasn't able to view the result because opening the serial monitor giving the error that com port was already occupied. I'm using arduino uno r3.
Thanks.

[tronicgr]

Well, I didn't want to use software serial monitor, I used external data packet analyzer:

http://www.ikalogic.com/ikalogic-products/scanalogic-2/

When I have a working version of the OBDII arduino dashboard will post it for everyone to try it or modify it to their needs.


Thanos