Re: Home brew Z80 CP/M computer
- From: Jack Crenshaw <jcrens@xxxxxxxxxxxxx>
- Date: Tue, 30 Dec 2008 01:30:23 -0500
[snip]Andrew, I saw your original post re the N8VEM system. That's what[snip]
prompted me to begin thinking, again, about adapting a true HD to one of
my SBC's. I had done it before (thinking -- grin), but never got past
the issue of a USB interface.
On the first hand, before I decide to start over with an N8VEM system, I[snip]
need to know that I'll be able to actually use it, not just tinker with
a soldering iron. To me, that means software and an HD.
Hi! Well the good news is that the N8VEM SBC and related parts are
available and relatively inexpensive. They are also simple to make
and use. It is 100% DIP plated through hole construction with large
feature sizes and large minimum clearance for easy building. I really
stressed making the design easy enough and inexpensive so that almost
anyone can afford to build one. Due to the large feature sizes nearly
any skill or experience level builder can successfully build their
There is a Disk IO board in the works. I am finishing PCB trace
routing at the moment trying to simplify the board. It should be
available before too long and will provide an IDE interface for HDs,
etc and FDC (NEC765A) for floppy disk drives.
However, you do not need any real drives to use the N8VEM SBC. With
just the SBC running in standalone mode it uses highly reliable and
extremely fast solid state memories (EPROM and SRAM) drives. Some
builders have modified the design to use NVRAM and such but the
reality is you really don't need *real* disk drives any more. A
decent serial interface and solid state drives give you a highly
reliable and easy to use system without all the hassle of large power
supplies, cabling, etc.
Various builder projects are in the works ranging from SD and CF and a
whole bunch of other peripherals. Personally, I use an old IDE hard
drive with my Disk IO prototype board. However, these additional
peripherals are all optional and not needed for basic operation.
You could use USB but the protocols are a PITA. Its doable but will
take work to write the CBIOS. One builder has already built a USB
interface which attaches to a network interface. It could be extended
to other USB devices I suppose.
One of the neat things about the N8VEM project is that since it uses
plain vanilla CP/M-80 from stock sources at http://www.cpm.z80.de/source.html
it allows almost the entire archive of stock CP/M applications. There
are hundreds of pieces of software available on the Walnut Creek CD --
all free. Builders use CP/M applications all the time from MBASIC,
Wordstar, etc. Moving the software to the N8VEM SBC is trivially
simple and builders are using different things all the time.
If you'd like more information, it is available on the N8VEM mailing
list and/or wiki page.
Thanks and have a nice day!
Well, you're right, I don't really need -- or even want -- to hang a real HD onto an SBC. I just want something that will hold enough data to make it worth using. My old system had 20 Mb. Anything bigger than that would be more than ample.
OTOH, it would sure be nice to be able to read my floppies. But then, Herb (is that right?) said he could translate them for me.
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