8088 project (was: Housing collections)

[Dave Dunfield]

> > I have an 8086/8088 monitor, which provides edit/dump memory/registers,
> > serial download, breakpoints, single-step, disassembly and lots of other
> > goodies in just over 4K of code space - completely independant of hardware
> > (ie: No DOS/BIOS requirements).
> > 
> 
> That's exactly the kind of firmware I want for the 8088 SBC
> project, at least to start.  Does your monitor use a serial
> console?  I need to add a serial port to the design.  Possibly
> using the 6402 UART.  Really, though, one of the 'design
> principles' of the projet is to re-use, so maybe a part from the
> 8250 family (which can be found on any old PC-clone serial card)
> would be easier for someone replicating the design to come up
> with.  Awhile back I 'won' a whole tube of 85C30 parts from
> someone selling them on eBay, but they never showed up.  And I am
> trying to stick to DIP packages to keep it easy to build with OTS
> parts.  Or I could stick a primative ISA slot on it and plug in
> one of my spare IBM Serial Adapters and use the current loop
> interface. (naw... heh.)

Yes, the monitor is designed to be completely hardware independant
(except for the CPU :-) and operates with any sort of serial console.
I provide sample drivers for the 8250, and also for PC keyboard/video
via BIOS calls (these are the only BIOS calls and are inserted only if
you assemble it with this driver option - it lets you run it as a .COM file
under DOS to check it out).

 
> I have fond memories of monitor-based systems from the past.  I
> have a first generation BigBoard in mothballs, for one example.
> It used to boot CP/M from the monitor prompt.

First thing I write when going to a new CPU is a monitor - I also have
monitors to stuff into a lot of vintage gear so that I can poke around,
very handy. If it is of use to you on the 8088 project, I also have HDM86,
one of my "Hardware Debug Monitors" - it's much simpler, but uses NO
RAM - handy for getting boards up and running.
 

> > I also have a PC based 8086/808 cross assembler intended for the "bare
> > metal" which produces downloadable code.
> 
> I've noticed the full line of cross-assemblers for all sorts of
> processors on the website linked at the bottom of your messages
> (and I think I remember, going way back, your ad in magazines
> like Circuit Cellar.)  Really what has been the 'missing link' in
> the 8088 sbc project has been an assembler designed like yours.
> There are many MANY tools available and many websites dedicated
> to x86 assembly programming, but it's almost all oriented toward
> a BIOS-based PC system.  I come from a 'bare metal' and prefer
> starting right at the bottom from a reset vector.

Yeah, thats me - I've been doing "bare metal" tools for quite a long
time...
 
> At one point I had the 'dream' of a monitor rom to drop in place
> on PC-XT motherboards to turn them into Single Board Computers.
> But these days an Xt motherboard is a scarce commodity, while
> there are still plenty of 8088 processors available.  (And
> keeping the design 'generic' the next generation can be an 8086
> based system, with 16 bit data path.)

Thats should be relatively easy to do, especially if you stick to a
serial console, or a single video card type (MDA for example) to
support.


--
dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: www.dunfield.com
com             Collector of vintage computing equipment:
                http://www.parse.com/~ddunfield/museum/index.html