cctech Digest, Vol 78, Issue 3

[Tony Duell]

> Quite a few 8-bit x80 micros used them them for various purposes 
> (yes, even Z80 systems); The 5150 BIOS refers to an 8255 in the 

I must have a strange colletion then. I can only think of 2 or 3 machines 
I own that contain 8255s. 

> But there really is no good reason to use an 8255, a Z80 PIO, a 6820 
> or even a 6522 in a new design today, other than for nostalgia's 
> sake.

I can think of many reasons : You have the chip in stock ('new design' 
doe not preculuse it being a one-off); Compatibility with existing 
hardware or software (then if the design doesn't work you know to look 
elserwhree for the fualt); It takes less time to use the chip than to 
design a replacement; And many more.

There;s no reason why ytou have to use anything other than 7400s, of 
course...

-tony