Re: [opendiag] Noise on K line?

Hi Ezequiel,

I don't think that's any noise on the K_Line, could be the timing.
If ECU is busy, your request can remain unanswered (remember, it is VW - software is writen in kindergarden).
So:
a) set time _till_ecu_answer to 450mS ( ** see 1 **)
b) repeat request min. 3 times
c) if, after 3 times your request still remains unanswered, send TesterPresent Message
d) if your TesterPresent message remains unanswered, communication is broken, do new InitSequence.

1. Some ECU's have max. InterMessageTime of 500mS, instead of 5000mS.

bye,
bole

----- Original Message -----
From: acetoel
To: opendiag@yahoogroups.com
Sent: Tuesday, September 30, 2003 02:50
Subject: [opendiag] Noise on K line?

Hello,

I'm trying to make my own scanner with an AVR and my own version of
Jeff's interfase. I can stablish a communication to a VW GOL Diesel
Pump ECU.

If I ask the ECU for the RPM data with the Engine ON, in a ramdom
moment the program halts. I can halt when the RPM reach an elevated
number or when just started.

I think is a kind of noise but don't know if it's on the K Line or
in the Supply. All the components are on a protoboard, and I know
this is not good for noise reduction. Can I filter the K Line with a
0.1uF capacitor? or something like that.

Thanks
Ezequiel

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Received on Thu Oct 02 10:37:56 2003