Any *really* homebrewing going on?

From: Allison J Parent <allisonp_at_world.std.com>
Date: Sat Oct 3 19:31:52 1998

Doing something like a straight-8 is not trivial due to the shear number
of parts and interconnects needed. A ttl version is manageable.

The big thing is to experiment. I've considered doing a PDP-8E design
and each time I take out a fresh sheet of paper it ends up being a
16bit or even 24bit machine. a 24bit machine with the same format as
an 8 as some appeal.

<the past 20 years. It is true that some of today's tools of the trade
< for example, a good PAL/GAL programmer - are
< more expensive than many of tools of 1975. But in real dollars,
< today's $800 device programmer is much cheaper than, say, an 8080A
< CPU, which had a street price of US$250 or so in 1975.

There are Xilinx FPGAs (use an eprom for the pattern and it soft loads)
saving the expensive programmer. Or the Lattice ISP parts also using
minimally expensive interface cord (I think). Even if the parts cost
some the lack of programmer lowers the cost. The expense is the
software tools and the knowledge to write the VHDL/Xable code as
needed to define the parts function.

Check the TCJ web page for info about alta engienering for a cheap GAL
programmer.

There are parts like 8748/9 and 68705 that make programming pretty easy
and the programmer can be homebrew. Their advantage is that assemblers
can be had for free and the parts are cheap(or even salvaged).

There are lots of options.

Allison
Received on Sat Oct 03 1998 - 19:31:52 BST