Dave VanHorn wrote:
>
> > The obvious thing to do is to tap into the xtal output.
> > So, can somebody tell me what sort of electronic wizardry I have
> > to do to make the 4MHtz crystal drive some sort of gate so I can
> > divide by 4 and drive the ISD chip???
>
> Careful.
>
> Check the spec, there should be an output drive spec for that pin. If not,
> you're in shaky territory, no matter how many hobby projects or protos "just
> worked".  The most interesting part of a data sheet is often what is NOT in
> it.
>

Thanks - I'm with you, that it worked in the prototype means nothing. Otherwise
I'd stick a part in the breadboard and have an answer in the same time I could e
mail.

Buuuuut.......
this means I have to *understand* this circuit.

Well, found something interesting -
To quote the uChip data sheet:

OSC2 - Oscillator Crystal output. Connects to crystal or resonator in
crystal oscillator mode. In RC mode, OSC2 pin outputs CLKOUT which has 1/4 the
frequency of OSC1, and denotes the instruction cycle time.

OK - if I can find a reasonable price can oscillator, I don't need the divide by
 4
chip. That might justify some/all of the can's price.

> and the eng mgr told me that all the protos
> worked, and "don't worry.."   Guess who got to fly to kaohsiung christmas
> day to debug an assembly line full of product that didn't run... :(

Uhhh.... let me guess. It was the eng mgr? Right? No??? Did he happen to have po
inty hair?

--
Anniepoo
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http://www.idiom.com/~anniepoo/depot/motors.html