My DIY EFI

[Sandy]

At 12:52 PM 8/10/96 -0400, you wrote:
>Just a quick note on my DIY EFI project.
>
>Based around an 80c32, programmed via Keil C. To control both ignition and
>fuelling via TPS v RPM lookup tables stored in EEPROM, modified by coolant
>temp, air temp and battery voltage. Analogue inputs are via an LTC1090 which
>is a serial 8-channel 10-bits ADC. For the outputs at the moment I'm thinking
>of using MC3334s for the ignition and an MC33298 for the injection. Does
>anyone have any views on these chips or experience on equivalents?

I have bought some MC33298's I would be check some of the maximum ratings
before using this, at elevated temps, the ratings drop quite a bit. It may
not be a big problem as the injectors aren't on all the time. I would rather
tie a logic level MOSFET or an IGBT to a port if using saturated injectors,
one drawback is the loss of protection. Just my feelings.

As for the A/D converter, look at the MC145051 from moto, the part is about
$5, and is automotive rated. The problem with some of the LTC stuff is that
is is too expensive. I got the moto parts from newark, and all were stocked.

Let me know how it is going, I am right in the middle of the same project
with the 68332 Folks. I also have designed a 'universal' driver board that
uses the LM1949 Injector driver, that is being use for Injectors and
Ignition. It will also drive low impeadance injector (4amp/1amp). The
circuits are on John Gwynne's FTP site, as well as a bunch of other
schematics that were posted. Some are not so good (early ones I did) but
good starting point if you have not seen them.

Sandy