I forgot to say THANK YOU to all the folks that have sent in their defunct
AFMs and ECUs. It really has made this monster project begin to
be successful!

;)

Jon

On Tue, 19 Dec 2006, jon wrote:

> I have made great progress in reverse engineering AFMs, ECUs and other
> funny business in the Digifant injection system. It's classic 80's
> embedded CPU technology.
>
> I pulled apart a bad ECU to use part from to build a "sniffer". It was
> interesting to see how they did it. Here is a quick explanation:
>
> The "brain" is a standard 6803U4PV. It's a common 80's embedded
> microcontroller. Not sure what the differences are in the U4PV version,
> because I can't find a datasheet on the 'net. On the CPU daughterboard
> there is also a Parallel Interface Adapter, some glue logic, and a 2732B
> EPROM. The version label on this one is "FAEB02 02. 02". Anyone have an
> ECU open, and can tell me what their's says?
>
> On the main board, the interesting semiconductors are a Toshiba TA7900S
> regulator/watchdog with PNP shunt transistor (BD438). Across the heat sink
> is also a BD647 NPN Darlington, a Motorola TE2369 (Which I can't find,
> probably a house number. Anyone know what this is?), and a BT151-500R
> Thyristor. The big chip near the center is an Analog to Digital converter.
> Add to that some small signal transistors, couple of op amp/comparators,
> and finally a "Peripheral Clamping Array" on the input to the PIA/CPE to
> condition signals.
>
> These ECUs make magasquirts look simple. ;)
>
> More on AFM spring adjustments in a bit.
>
> Jon
>