That darn Intel jingle... - test-drb@ccmp.vtda.org

3 Nov 2005

...

Subject: Re: That darn Intel jingle...
   From: "Chuck Guzis" <cclist at sydex.com>
   Date: Thu, 03 Nov 2005 16:17:54 -0800
     To: cctalk at classiccmp.org

On 11/3/2005 at 6:45 PM Allison wrote:

 Z80 PIO. 
16 measily bits of I/O in a 40 pin package. :(  What a waste of real
estate. 
But long lived.

...
  D72055 the last
version of the part hit 12mhz.  If your going on PCI 
why bother and just put a gate array to work 
Mostly laziness.  I could probably also just buy a PCI data acquisition
board, if I didn't want Mode 2 I/O (which I do). 
I used 8155s but then again I also use 8085s which work nicely with it.

...
  Well there are
plenty of 8251, 8253, 8259 around, then there are the 2681s
and (gag) 8250 series.  
Well, the 8259's a CPU support chip, and I tend to think of the
8253/54/57/37 the same way.   
the 53 (timer),54(Timer), 57(DMA) and 37(better DMA) are not strongly
related to any specific CPU and work fine with Z80, 808x even 8048.  

...
 The 51's a peripheral chip that's had its share
of warts, however.  
8251 is wartly enough but ok.  The Leading Edge  Model D XT clone used 
it rather than the icky 8250.

...
  The 8250 is a ridiculous National product that
can't do sync in a single-channel 40 pin package yet.  The Z80 SIO and the
Intel 8274 are essentially the same chip that should have probably been
made part of the PC instead of the 8250. 
8274 is the intel branded NEC D7201, and it's not essentually a Z80 sio
it's IS a SIO save for it supports 8080/8085/8088 interrutpts instead.
Even the register addresses and functions are the same save those for
the interrupts.

...
 Speaking of which--I've got a bunch of Z80 DART
chips.  I've been told that
these are really derated Z80 SIO chips.  Will they do synchronous I/O or
has that part been disabled?  I can't find my databook for the things any
more.

Cheers,
Chuck
 DART is Async only, still a good part.

Allison