TTL computing

From: Richard Erlacher <edick_at_idcomm.com>
Date: Sun Apr 14 04:38:38 2002

Yes, they're getting ridiculous. but $500 isn't so bad when you consider that
it will program EPROMS, EEPROMS, varous MCU's, it will test logic, it will
test RAMs ...

If you buy a moderately cheap CPLD, e.g. the XILINX 95108, in a PLCC84, it
costs about $20-30 U.S. at DigiKey. Combine that with a socket, ($4 tops) and
a few wirewrap socket pins, ($.10 each) that's another $8.40. Now find a
cheap wirewrap board to which you can solder ... and then use the free
software and build the ~$5 ISP adapter. For the same money, you can use a
Xilinx SPARTAN-series FPGA which you can also program using the ISP
programmer, though you'll have to do it every time. Then you can design
pretty much whatever small computer (only because of pin-count limitations)
you want. These devices even allow you to put in some RAM.

I've heard it said, "Where there's a will, there's mourners."

Dick
----- Original Message -----
From: "Ben Franchuk" <bfranchuk_at_jetnet.ab.ca>
To: <classiccmp_at_classiccmp.org>
Sent: Saturday, April 13, 2002 9:40 PM
Subject: Re: TTL computing


> Tony Duell wrote:
>
> > Everyone knows you can get 'universal' device programmers that program
> > PROMs, PALs, GALs, EPROMs, microcontrollers, and so on. The original
> > question was clearly asking whether early PALs used a similar programming
> > algorithm to the bipolar PROMs of the same time period. I don't think
> > they ever did.
>
> But most companies think $500 is low cost for a programer.
>
> > But just as some enthusiasts like making and operating sailing ships, so
> > some enthusiasts like wiring up TTL.
>
> I like designing computers. I don't like wireing TTL. $125 US is the
> lowest cost CPLD developent kit I have seen. A $15 chip replaces 15 TTL
> at $.50 each -- $7.50 .I guess the savings must be in sockets and PCB
> board size.
> > -tony
>
> --
> Ben Franchuk - Dawn * 12/24 bit cpu *
> www.jetnet.ab.ca/users/bfranchuk/index.html
>
>
Received on Sun Apr 14 2002 - 04:38:38 BST