12 Dec
2008
12 Dec
'08
9:06 p.m.
Hi everyone
As a 4th year computer engineering student with a part time job, I
definitely have too much time on my hands, so I've been thinking about
doing something like building my own computer. I remember playing with
the 68k SBCs back in my assembly class, so I thought something from
that family might be an interesting choice. It's ambitious, but
ideally I'd like to do 16/32 bits and a few megs of memory.
Have any of you built something like this? I'm looking for links to
I've built several machines from scratch, but never a 68K-based one. But
I do feel that's a pretty good choice for a processor :-)
I would start by tracking down a _second edition_ of the 'Student Manual
for the Art of Electronics' (that may not be the exact title, but if you
can't find it I'll dig out my copy and post more details). This is the
'laboaratory book' for the famous 'Art of Electronics' book (which you
should have anyway :-)), and the last few exercises are making a
68008-based computer (so 8-bit data bus) with something like 8K of static
RAM a bit of I/O, etc. You won;t want to copy that design, but it'll give
you ideas.
As regards RAM, I really would use static RAM, at least to start with.
It's a lot easier to work with than dynamic RAM, and SRAM is getting
pretty cheap these days.
You also need to think what I/O you want. Do you want a toggle-switch
panel to load ROM, a monitor program (hex keypad and display, or an ASCII
terminal interface?), a bootstrap for some larger OS (to be loadrd from
what device?) and so on. Personally, I'd probably add a serial port and
have a simple machine code monitor in EPROM, but it's up to you.
-tony