At 08:33 12/16/97 -0600, Guy wrote:
>>Subject:     Re: Digifant help!!!
>>Sent:        12/15/97 4:28 PM
>>Received:    12/15/97 1:45 PM
>>From:        Don Gibbons, dgibbons@PRESRAY.COM
>>To:          Vanagon@GERRY.SDSC.EDU
>>
>>I once took apart a digifant I ECU to see what PROM chip it used. There
>>were no
>>non-volital chips other than the PROM chip. There is nowhere for any fault
>>codes
>>to go. When the ignition is turned off the power to the ECU is turned off
>>too.
>>There is no power to retain any memory.
>>
>>But here are the chips:
>>
>>MC6803U4CP       40 pin          8 bit MCU, No rom, 256k ram, no a/d. 13 IO
>>lines
>>
>>MC6821CP           40 pin          Peripheral Interface Adaptor
>>
>>CD74HCT373E      20 pin          Tri-state Octal D-type latch
>>
>>ADC0809CCN        28 pin         8 bit A/D (8 channel MPX)
>>
>>AM2732A-3DI        24 pin          4K x 8 EPROM
>>
>>I have the equipment to burn (and copy) PROM's like this but do not have the
>>assembler/dis-assembler to do any changes. Note: my ECU had all the chips
>>soldered in.
>>
>>When you know how low buck (compared to today) the digifant brain is you
>>can see
>>why problems are so hard to fix.
>
>
>Okay now lets make a new computer for the digifant.  Can I just interface
>the old 486 33mhz I use as a door stop?  We can program error finding,
>like for a faulty O2 sensor or temp sensor.  We can also have it adjust
>timing for older engines or for different driving habbits.
>And when the 486 fails in 2 years we can just plug it the ones we are
>using right now cause they will be obsolete.  Now if I only find a heads
>up display to replace the monitor, and where should we mount the joy
>stick (mouse).  Yea and we can have software upgrades every year.
>
>Sorry for dreaming!
>
>Guy
>Leaking headed 87 syncro

So, next year we will have to upgrade to Vanagon 98 software?  Sounds too
much like Bill Gates to me!  :)

Out of all seriousness it doesn't sound THAT hard to do with a bit of time
and tinkering.   An XT should control it fine... but where would you put
the XT?

-- David Marshall        Email: david@volkswagen.org --
-- 80 VW 2.0L Caddy,            87 Audi 5000 quattro --
-- 85 VW Cabrio, 88 VW Double Cab Syncro Transporter --
-- Volkswagen Homepage http://www.volkswagen.org     --
-- VW Caddy Homepage http://www.volkswagen.org/caddy --
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