MITS 2SIO serial chip?

From: Richard Erlacher <edick_at_idcomm.com>
Date: Sun Dec 16 20:55:23 2001

see below, plz.

Dick

----- Original Message -----
From: "Ben Franchuk" <bfranchuk_at_jetnet.ab.ca>
To: <classiccmp_at_classiccmp.org>
Sent: Sunday, December 16, 2001 3:31 PM
Subject: Re: MITS 2SIO serial chip?


> ajp166 wrote:
> > PALS are 1970s technology, really old to some of us.
> Arg! And here I thought the 8008 was 70's technology.
>
> > Actually thats not true. By 1981 you have peripherals in the 125ns read
> > write timing range. Then again Z80 at that time was just hinting at 6mhz
> > so z80 peripherals were of an according spped for that cpu. However,
> > other parts were faster and often far cheaper.
>
I got my first Z80B (6 MHz) in early 1981 and Z80H (8 MHz) in 1983.
>
> If you must know it is a floppy disk controller I need. Right now
> I plan to use WD2797 floppy disk controller. I would love to use
> a newer chip,but I can't find any! I want to stay with DIP's and PLCC's
> here. This may be the 21 century but my soldering skills are the 19'th.
>
Why? The WD37C65 is a much easier part to use, and it programs pretty much like
a NEC uPD765, drives the cable directly, and automatically deals with the
data/clock separation for 500 KHz, 250 KHz, and 125 KHz data rates at both 300
and 360 rpm. You can lift 'em from broken HDC's or order 'em from
www.rocelec.com (Rochester Electronics). They're most common in PLCC-44, which
you should be able to handle, even if, like me, you didn't listen to Mom when
she told you to stop that. If you must use a WD part, which I prefer also, then
use a WD179x with a FDC9229. That does everything in two chips, including
selecting the appropriate clocks. The 2797 uses an analog PLL and, unless you
are satisfied with a single data rate, that means multiple filters and analog
muxes, etc.
>
> > Personally if I wanted the SIO functionality for a NON-z80 system I'd
> > never use the zilog part. Reason it was not cheap,nor was it easy to
> > use for non-z80 systems. They were designed for the Z80, period.
> > Unfortunatly they were slow. If you wanted faster the 83xx or 85xx
> > parts from Zilog were a far better choice but Zbus was scary to most
> > people and they weren't cheap. The other part of this is NEC and
> > Intel did the MPSC (NEC D7201, Intel 8274) which was functionally
> > identical to the SIO and was "tuned" for 8080/8085/8088/8086 style
> > busses and faster as well. It was a more generic part than the SIO.
> > Also around that time Signetics and friends were doing the 2681 part
> > that was cheap and available in various flavors. Peripherals back then
> > were quite varied.
>
> I still favor the simple dumb uart chip. TR1602?. I like things than
> you hit reset, it starts ... not like the classic star-trek computers
> that always go down. Usually when you need them.
> --
> Ben Franchuk --- Pre-historic Cpu's --
> www.jetnet.ab.ca/users/bfranchuk/index.html
>
>
Received on Sun Dec 16 2001 - 20:55:23 GMT