Another aw, can't be done

xxalexx at ix.netcom.com xxalexx at ix.netcom.com
Sat Jun 20 22:46:41 GMT 1998


> From:          "Bruce Plecan" <nacelp at bright.net>
> To:            <diy_efi at efi332.eng.ohio-state.edu>
> Subject:       Re: Another aw, can't be done
> Date:          Fri, 19 Jun 1998 22:27:04 -0400
> Reply-to:      diy_efi at efi332.eng.ohio-state.edu

> -----Original Message-----
> From: xxalexx at ix.netcom.com <xxalexx at ix.netcom.com>
> Subject: Re: Another aw, can't be done
> 
> 
> I could write simple program to run the data as a rs232
> ouput.  Maybe use OBD2  J1979 or 2190 packets to download to PIC. or a
> multiple bus with CAN
> 
> The above I just don't have any knowledge of so I can't comment,
> on them as sources for info., etc.
> 
> How many D/A's do you need?
> 
> If D/A means digitial to analog, meaning from the recorded data to
> analog that we can input to the ecm., the ecm needs inputs for
> rpm. tps, vss, coolant temp., IAT, TCC, MAP/MAF  comments welcome.
> 
> Actuallly I could use just pots for the coolant temp, and IAT.
> 
> Also would be nice to be able to put it into a loop, ie just repeat a
> certain download, or steady state condition.
> 
> alex
> 
> Any one with real world simulation experience, I'd really appreciate
> any insights you may have.  Either from a programming point of view,
> or as a user.
> Cheers
> Bruce
> 
Those are protocols for obd2  helpful to have some type
of standard address scale and units.  Similiar what vehicle micro
data uses as listed in your 101. Example tps is PID $11 
with values from 0-100% with scaling of 100/255% applied to
a bit value. 
It seems feasable to download data to a 1 Meg X 8 SRAM and use two 
quad  DAC's  The MAX 5250 is a quad 10 bit , SPI, voltage out 
with external gain adjust on each output. settle time is 10usec. and 
can update all outputs with 16 bit word at 10M baud.
Use a  8 pin PIC as a rs232 to FIFO SRAM controller and a 
PIC 17C42 with 33 I/O to control DAC and do digital outputs.
Pricing is a about $10 for each of above and 2 bits for 8pin PIC     
Software can have virtual pots and repeat data forever.
alex  



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