tony@ELROYNET.COM wrote:
> I've been struggling with making a good quality sqare wave circuit for
a
> digital circuit I'm trying to build.
>
> I am having to feed the clock circuit to ~15 IC's, included in that is
a
> CPU.  I am trying to get it to run at between 10 and 12 MHz, but it
seems
> that I run into a few problems I don't know how to solve....
>
> I have been using TTL oscillator cans between 8 and 12 MHz feeding
into a
> 74LS04 as well as trying a 7404 to buffer it, I have also tried
building a
> clock circuit utilizing an 8 MHz crystal and a 7404 along with some
> resistors and caps (it has been more positive then other methods thus
> far).  I have tried swapping out the 7404/LS for a 74AC04 which has
made
> the ringing worse (appears to be that it is too sensitive and is
> amplifying my problems).
...
> Where can I go to learn more about this and how to fix my issue?  Or
does
> anyone have any suggestions?

Ask older professionals how they designed TTL PCBs in 197X-198X.
Designing "~15 IC's" 12mHz TTL PCB is not hobbyist job.
Better get PICs communicating over standard interfaces:
I2C, SPI, CAN, LIN ...

Anyway, start with a good EE book, say, Horowits & Hill.

Mike Singer.

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