[Diy_efi] Re: looking for help with a prom N82S181

[mbelloli at speedymotorsports.com]

> Steve Ravet wrote:
>>
>> > Pin 19 (a10 on the 2716) which I was saying was noise - isn't
>> > is it?   Now
>> > from what Steve was saying, and please correct me if I am
>> > wrong, is that only half of the signal is usable?  When at
>> > Vcc ok, but when at Gnd I am going to have a problem when
>> > hooked to a 2716 eprom.  So only half of the time this signal
>> > would be usable.  Is that what was being said?  So this
>> > signal is of no use to me with the 2716.  Instead wire it to
>> > Vcc, or Gnd depending on which bank I want all my reading to
>> > be done from.
>>
>> Looks like a clock to me, but I don't know why a clock would be
>> connected to a chip enable.
>
> It might be the E clock.  It is common in 68xx and 65xx designs to
> include this in the chip select logic.  This insures that the device is
> only driving the bus when the address is stable.  For a read only
> memory, this shouldn't matter much.

     Ludis, I'm following you.  Now looking at that waveform trace it
never reaches ground, nor vcc.  When is the logic true?  This is what
I'm not following.  Is there a voltage threashold that needs to be
considered?  Something like the o2 voltage on a gm car crossing the
.42 volt threashold?

Thanks,
Marcello



>
> --
> Ludis Langens                               ludis (at) cruzers (dot) com
> Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/

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