ECU/MAX232 noise

[Peter Gargano]

I'd be interested to hear if powering the MAX232 from the
serial interface, as I've done in the URL below, will
also solve this problem too. If EMI to the MAX chip is the 
problem, then my schematic may not address this issue
as there's only a couple of caps, and the Vreg, to cut
out EMI. Anyone in a position to try this out (I'm not!)?

  http://www.techedge.com.au/vehicle/aldl/8192/8192hw.htm

Barry Tisdale wrote:
> 
> There was a recent thread on the noise pickup @ WOT on some of the MAX232
> serial interfaces.  Solved mine by running the interface off a separate
> battery; no amount of noise filtering seemed to have any effect when
> applied to the +12v line.  Even a shielded cable carrying the serial data
> from the ECU to the interface didn't help, nor did pulling up & down the
> serial data line.
> 
> That chip must be *real* sensitive to noise!

-- 
Peter Gargano