RE: Confuzin signals

[Mika.Helander@softbit.fi]

I think that current output of the 2732 is not enough for driving LED. Put
one NPN-type transistor between LED and EPROM. "Clear" schematics follows

             5V
              |
             220R
              |
              _
              v Your led
              -
              |
One of D0..7|/
EPROM --1k--|
            |\>
              |
              - Ground

So one of the data bus D0..7 is driving NPN transistor thru 1k resistor...
Your current implementation is propably the same without transistor.
If driving more than like two LEDs why not use ULN type driver having
damping diodes etc (so possible to drive relays or bigger lamps).

-Mika

> OK, nother question.
> Working on one of the 7 notch on crank DIS modules.
> Hook Bosch reluctor/pick-up type dissy and spin it around and 
> flick it, and
> can get a nice coil fire signal (using LED as indicator).
>   Running a led off of the 2732, I thought That 1.8v (voltage 
> drop across
> LED)
> would trigger it.  But no dice.  Tried caps in series,  got 
> to be close,
> since if leave the timing cap out of the 555 it fires once 
> inna while...
>    Could the 2732 need to sink current?.
> My books say the pick for the 7 notch systen is a reluctor.
> I'm using a 555 to trigger a HEI module just fine, what am I 
> doing wrong?.
> Grumpy
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