TTL computing

From: Richard Erlacher <edick_at_idcomm.com>
Date: Mon Apr 15 21:30:56 2002

Just WHAT have you been smoking?

They haven't made bipolar PALs in ages, since the CMOS parts are not only
easier on power/heat, but are more reliable, cheaper, and reprogrammable as
well. If the makers of the low-cost devices we all use had intended that you
repair them when they break, they would have provided documentation. In a few
years, when you buy a computer it will have a circuit board with a splatter of
epoxy in the middle, the way the cheapo game cartridges were made a few years
back, and that's all that there'll be on the board. Of course there'll be no
place for expansion boards, so the box may be welded shut.

You're certainly free to be happy about whatever you like. It's true that
PALs (SPLD's) are an obsolete technology, seeing an occasional application
among hobbyists the way TTL devices did a decade ago.

 Dick

----- Original Message -----
From: <jpero_at_sympatico.ca>
To: <classiccmp_at_classiccmp.org>
Sent: Monday, April 15, 2002 3:28 PM
Subject: Re: TTL computing


>
> > Yes, and they save on space and not only because of their size. You don't
> > have to route unused inputs to Vcc or Gnd, and you don't have to
accomodate
> > the device pinout so much, since YOU get to decide what the order of the
> > outputs and inputs will be, which facilitates layout.
> >
> > Dick
>
> Snip,
>
> > > >
> > > I think this was because they expected PAL's to replace TTL. CPLD's now
> > > do that job.
> > > But then with higher CPU speeds, PALs have been the work horse of
> > > address decoding and glue logic enables.
> > > --
> > > Ben Franchuk - Dawn * 12/24 bit cpu *
>
> Well, I find PAL distasteful since these runs hot and some of them
> had death spiral finally fries themselves to death.. I see that
> fequently on 386 boards and ati wonder cga.
>
> So hot that 6 PALs made brown spots on that ati wonder card then
> card dies, I see that frequently on many of those. :-P
>
> And if PAL dies, not possible to repair yet I knew some can be
> pulled to make copies if maker didn't burn fuse to protect contents.
> Wrong way to discharging CRT in compact Macs fries two of 6 PALs.
> Same PAL parts in 128, 512 and Plus.
>
> I'm glad PALs went away when late 386 and late 486 boards came.
> Still, knew some other makers are still using PALs.
>
> Cheers,
>
> Wizard
>
>
Received on Mon Apr 15 2002 - 21:30:56 BST