cctech Digest, Vol 78, Issue 3

[Tony Duell]

>    Z8530.  'Nuff said.
> 
>    Well, not quite 'nuff...it's an AMAZINGLY nice chip!  I've done  
> quite a bit with it (both in my designs and in existing systems) and  
> have always been impressed with its capabilities.

It has one gotcha that I remember. As ever, they ran out of pins on the 
package, and didn't have room for a reset pin. Instead you do a hardware 
reset by asserting rd/ and wr/ at the same time. 

This is only a problem if you're trying to produce rd/ and wr/ from a R/W 
line and you don't realise a momentaruy overlap (and the 'glitch' from 
one LS TTL gate is enough) will reset the Z8530, or worse still partially 
reset it. 

Please don't ask how I foudn that out...

-tony