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ISO9141/ISO14230 Implimination

PostPosted: Fri Oct 03, 2008 10:44 am
by romstef
Hi Guys,

I was using an ELM 323 and a PIC Microcontroller to communicate with my 1999 Dodge Caravan. Everything worked well, however, now I am trying to write my own software to run on the PIC, but so far, no luck.

This is what I do;

1/ bring the K-line HI for 300ms then
2/ send 33hex
3/ then configure the UART module to receive @ 10.4kb/sec
but there seems to be no response at all.

So now I would like to ask if anyone could tell me what voltage level on the bus would represents a "1" and a "0". And would this be true during the;

1/ transmission of 33hex

2/ receiving the reply after the 33hex and

3/ during all other communication after Initiation

4/ does the ISO14230 have the same Bus Voltage specification as the 9141?

Should the k-line be left HI after each byte is transmitted?

Thank very much guys for your reply. :?:

Re: ISO9141/ISO14230 Implimination

PostPosted: Mon Apr 13, 2009 2:51 am
by praneethoct11
Hi romstef,

Where you able to figure out your problem.
ISO 9141 and KWP2000(ISO 14230) are almost similar.
You can check out the link at viewtopic.php?f=4&t=2761&p=21052&hilit=Initiation#p21052
It gives links to download ISO14230 standards.

Did you happen to check the signal voltage and if you have generated the 5 baud using bit bang method , then have you verified each bit time(200ms for each bit)
Were you able to succeed. I am also trying to do the same but still not yet landed up any communication with the car.
I am also having the same question or doubt as yours.