Lpc2000

This is more like a job for a 6 pin PIC10 than a 32bit ARM part. You 
really don't need to get into the intricacies of internal 
communications, this is total overkill. The simplest way is to mess with 
the singal from the (normally) gear box directly. However this will be 
a) breaking the law, b) voiding any warranty, and c) potentially life 
threatening to other road users, so I would strongly recommend it be 
something you NOT try. If I were to do this personally, say for the sake 
of racing said truck, in legitimate competition, I would intercept the 
speed signal coming from the gear box and output my own 'scaled' signal. 
In most cases you can leave this alone until you approach the limit. In 
most ECU's I've seen (these were mainly cars, not trucks) the speed 
signal was not used for engine management, except to limit the vehicle 
speed, so by altering it you should not alter performance of the ECU or 
vehicle in any other way. This also means you can interfere with the 
signla just before the programmed limit is reached. The micro will 
monitor this, and as the limit is approached it will take over the and 
generate its own speed signal for the ECU, and maintain this below the 
limit. The downside to this is inaccurate speedometer, odometer, and any 
fuel/trip type computers. I would either see if these circuits are 
separately serviced by the singla, and, if so, only interfere with the 
feed to the ECU for speed limiting, or I would pass the true signal to a 
display which could then show the actual roadspeed vs the 'modified' one.

That's of course if I ever got into truck racing. Which is unlikely.

Cheers

Al

andrebesselsen@... wrote:

>Anybody already found some J1939 code? 
>
>I am working on my little hobby project to fool a trucks' speed limiter and I would really appreciate it if anybody could give some help to start up with a LPC2129. I do have pretty much knowledge of SAE J1939, but my knowledge about embedded programming is not (yet) enough.
>
>Regards,
>
>Andr\ufffd 
>
>The Neterlands
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>>Does anyone know of any J1939 stacks that can be used with the Philips   
>>LPC2xxx uC's. I've Googled around a bit but have not found anything   
>>yet...  
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>>Thanks!  
>> 
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