On Tue, Jun 17, 2008 at 8:33 PM, Zane H. Healy <healyzh at aracnet.com> wrote:
>
> You should also be able to find a dirt cheap, piece of crap Chinese EPROM
> eraser that will do the trick off of eBay for about the same price.
I just bought one of these dirt-cheap, piece of crap Chinese UVPROM
erasers on Friday. It should be here tomorrow. I'll let everyone
know whether it's capable of erasing anything once I've given it a
whirl!
(My modern electronics buddies practically did a spit-take when I told
them I was still working with UVPROMs! The irony is, I'm only just
now getting into this stuff, so 'still working with' isn't quite
correct, either. I'm perfectly happy to be stuck in the past!)
-Seth
Emailing CP-M Z80 home brew computer circuit board.htm
Eric Smith eric at brouhaha.com
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9%40andrewdesktop>
Tue Jun 17 19:54:54 CDT 2008
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________________________________
Andrew wrote:
> Still how do you transfer stuff from a floppy ( or file online ) to a
> CP/M system with no external I/O devices?
I wrote:
> I have yet to see a CP/M system with no external I/O devices. That
> doesn't sound very useful, so why would one care about transferring
> stuff to it?
Andrew wrote:
> Who said the N8VEM SBC has no external devices?
I was replying to your question, quoted above. I never said anything
about an N8VEM SBC.
Eric
-----REPLY-----
Eric,
Oh, I think I see what happened. The quote you attributed to me is actually
>from Ben.
Everything I said is below the -----REPLY-----
I never asked that question and wondered why you asked it. Still, the
response is valid.
BTW, the N8VEM SBC is the actual name for the home brew Z80 SBC I built.
I am offering the PCB to others of similar interests.
Probably there has been enough discussion from me on the topic.
If anyone is interested please contact me offline or join us on the N8VEM
google group:
http://groups.google.com/group/n8vem
Thanks and have a nice day!
Andrew Lynch
73 de N8VEM
Hello CCtalk,
I'm hoping someone can help me with the pinout for the power connector
of a CDC 9410 Finch 8" 32MB harddrive. It has a power interface that I
haven't seen on other 8" drives. If you would like to see pictures:
http://www.dusicyon.org/temp/cdc01.jpghttp://www.dusicyon.org/temp/cdc02.jpg
I appreciate any advice or suggestions you can give.
Thank you,
Theo Wiegmann
But, I wonder if we've seen the last of that clone?
Tony
-----Original Message-----
From: tiggerlasv at aim.com
Sent 6/17/2008 10:06:36 PM
To: cctalk at classiccmp.org
Subject: Apple I back up on ebay
. . . . and, it has sold, for about $2000 . . .
Thud
(That was me passing out, from disbelief.)
T
Emailing CP-M Z80 home brew computer circuit board.htm
Eric Smith eric at brouhaha.com
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1%40andrewdesktop>
Tue Jun 17 18:19:21 CDT 2008
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________________________________
Andrew wrote:
> Still how do you transfer stuff from a floppy ( or file online ) to a
> CP/M system with no external I/O devices?
I have yet to see a CP/M system with no external I/O devices. That
doesn't sound very useful, so why would one care about transferring
stuff to it?
Eric
-----REPLY-----
Hi,
Who said the N8VEM SBC has no external devices? The SBC has some self
contained memory drives but supports external devices over the ECB.
The SBC supports a RAM drive (448K B:) and two ROM drives (32K A: and 992K
F:) internally.
The CBIOS *currently* (read the CBIOS source) supports IDE interface and
three hard disk partitions (8M C:, 8M D:, 1M E:) via the Disk IO board.
I know the 8M C: drive is fully functional since I have one on my workbench.
You can transfer temporary files in and out of the system using the serial
line into the RAM drive or burn them into EPROM.
The data is available on each device exactly the same except ROM drives are
RO and the RAM drive is RW.
CP/M CBIOS treats them as block devices and from an operators view they are
identical to disk drives.
Were there floppy disk with the same DPB as the ROM, the ROM image would
also work as a disk image.
I do not see why someone who wanted to couldn't write a serial based block
device in CP/M and treat the host PC as a block device disk drive.
It is of no real interest to me but the modifications to the CBIOS would not
be all that hard.
You'd also have to write an application on the PC side to handle the serial
IO block servicing and with the terminal emulation.
It'd be tedious but probably not too difficult.
For me XMODEM works just fine to transfer any files to/from the PC as
needed.
I also do a lot of work off target on the PC and transfer the final binary
image to the SBC for testing.
The SIMH simulator supports an N8VEM mode I use a lot for development and
test (Thanks Howard!)
The IDE interface requires the Disk IO board which I have on my bench as a
prototype built with prototype cards.
The schematics/CBIOS source are available if you'd like to build one too.
It also includes a NEC 765 based floppy controller interface.
The IDE interface works for sure as I used it for quite a while. The floppy
interface is built but never fully tested.
My prototype board based system started having problems with reliable
grounding when I took a break to work some other projects.
The next project is to make an ECB backplane and then a bus debugger from my
existing prototypes.
After that, recraft the Disk IO board as manufactured PCB.
The first thing I did when I restarted the project is begin the conversion
of prototype boards to manufactured PCBs.
Compared to my original prototype computer, the new manufactured PCB SBC is
MUCH more reliable and easier to build.
If there are enough units out there to make it worthwhile, I may order
several manufactured PCBs for other hobbyists.
If not, I will probably just go with another small run of barebone prototype
boards for the rest of my boards.
I did a run of two SBC prototype PCBs to verify the design before I did this
latest run of manufactured PCBs.
As for CP/M, you are not REQUIRED to use it. Write your own stuff and burn
your own EPROM.
However, a plain Z80 SBC is perfectly useful without CP/M. CP/M is just an
operating system.
CP/M works fine loading and running programs from the RAM/ROM drives however
you could just as easily just use the RAM monitor.
Better yet, write your own kernel and application. Whatever you like.
I split my usage about 50% between the monitor and CP/M.
Home brew computers are *not* all nicely finished and debugged so it
magically does everything want when you plug it into a wall.
That is what makes them a challenging and an enjoyable hobby. People who
take it on should expect to get their hands dirty.
If you are expecting a pristine flawless commercial product then this
project is not for you.
Thanks and have a nice day!
Andrew Lynch
I think the "Vintage computer expert" stuff got his last one canned...
If you notice, the ORIGINAL $10K listing had *NONE* of our "questions" posted.
All of a sudden, in the second listing, there were "experts" popping up all over the place.
Me, I'm no Apple 1 expert, by even the FURTHEST stretch of the imagination...
Even *MY* untrained-on-Apple-1 eyes could see it was a fake.
I'm hoping this dude ends up sharing a cell with a 6'5" 270lb guy named Bubba....
Tony
-----Original Message-----
From: Mike Loewen mloewen at cpumagic.scol.pa.us
Sent 6/17/2008 7:22:55 PM
To: General Discussion: On-Topic and Off-Topic Posts cctalk at classiccmp.org
Subject: Re: Apple I back up on ebay
On Tue, 17 Jun 2008, Grant Stockly wrote:
Can you guys still get to the auction page?
All I get is "This listing (220246863432) has been removed or is no longer
available. Please make sure you entered the right item number. "
Try this one: 220247416953
Mike Loewenmloewen at cpumagic.scol.pa.us
Old Technologyhttp://sturgeon.css.psu.edu/~mloewen/Oldtech/
Emailing: CP-M Z80 home brew computer circuit board.htm
bfranchuk at jetnet.ab.ca bfranchuk at jetnet.ab.ca
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ew%20computer%20circuit%20board.htm&In-Reply-To=4855CBD5.9050403%40bellatlan
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Tue Jun 17 11:09:33 CDT 2008
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________________________________
Allison wrote:
>
> Have you ever used 8"SSSD to do anything that required space? There
> isn't
> enough space to run a disassembled version of the BDOS through ASM
> unless you have at least two drives and don't mind doing cleanup.
>
I never could run the CP/M system I was using for more than 30 minutes
with out
the floppy stepper sticking. That was fun working with it. Still how do
you transfer
stuff from a floppy ( or file online ) to a CP/M system with no
external I/O devices?
> Yes you can roll your own data sep it only needs three ttl packages.
> With all the other hardware needed for the 765 case you end up with at
> least 10 chips
> though If you willing to miss a few features it's been done in 7 plus
> the FDC
> and that doesn't include the bus side of the FDC interface.
>
That I would like to see.
>
> Kicad for linux there are other like cadstd for winders.
> Of course the last 2901 design I'd done in the early 80s was
> with paper and pen! It's doable that way.
I still am using paper & pen. Mind you I have to buy JAPANESE pens
since the quality of the USA stuff is all cheap Chinese imports.
Now that I have a serious cad program - DIPTRACE on order
I think I will put the design in hardware.
> FYI using 250nS eproms will make it terminally slow unless
> you do two things, use a wide microword 64bits or more and
> pipeline the address and decode so you can work right to the
> eprom Tacc minimum limit.
I got that covered if I read the 2901 data sheets correctly.
I will be using a 6809 style memory cycle optimized for
D-RAM access and clock the 2901 in 4th phase of
the memory cycle. This is retro computing project for the feel
of the late 1970's not using a 8 bit CPU. I am aming for
a 800ns memory cycle and the slow access of micro-code
is not a problem. The only thing pipelined is the next memory
cycle - Read/Write/Refesh and the default is refresh while
doing the the 1st cycle of op-code decoding. The front
panel does RUN/STOP, Single Instruction,Address Load,
Deposit,Read.
-----REPLY-----
Hi,
I can answer the question on how to get programs and data into and out of
the SBC.
There are three ways with the basic SBC;
1) XMODEM at the CP/M prompt
2) Intel Hex format transfer at the RAM Monitor prompt and
3) burn your own EPROM with the supplied image or your own custom disk image
(utilities are on the website)
Here is a little background on the N8VEM SBC design principles
The N8VEM SBC is meant to be flexible and low cost. If you start with the
PCB only, you can minimize cost by not installing unneeded functions such
as;
1) RTC
2) 8255 PPI and parallel port connector
3) ECB Bus transceivers and DIN 41612 connector
You can also substitute some parts to reduce cost. Replace the 1Mx8 EPROM
with a 128Kx8 27C1001 is a drop in replacement.
Scrap and salvaged parts can be used directly or with minor modifications.
All the chips are commonly available plain TTL and can be substituted.
All of the other components can be substituted if you know what you are
doing.
Scrap 29C020 Flash ROM chips (PC BIOS) can be reused with a simple shim
socket.
Most likely 128Kx8 SRAM parts with a shim socket can be used but I haven't
tested it yet
Installing and running CP/M 2.2 OS is strictly a convenience and an option.
Any generic CP/M application should work.
The RAM and ROM drives are lightning quick and silent. You'll never see a
hung stepper motor with SRAM!
The SBC boots into the RAM monitor so you may never need to run CP/M at all
if you don't want to.
The system I built is rock solid. It runs for hours doing things without a
sound or glitch. I used some CMOS components so the SBC runs cool.
Power supplies are easy and cheap. Use spare ATX/AT PS or your own with the
common Molex drive connector.
Of course, all the hardware and software details are fully published and
with datasheets for all the components.
Except for the EPROM there are no custom or programmed devices at all. All
components are bog standard common 74LSxxx TTL and LSI peripherals.
It is designed to be built with low cost tools and simple test equipment
such as 25W soldering iron and VOM.
EPROM programmer, logic probe and/or oscilloscope are useful but optional.
You can easily write your own replacement software like a FORTH kernel or
custom Z80 boot code if you'd like.
The EPROM on the N8VEM site is strictly optional and I actually discourage
people from using the pre-programmed part.
Write/burn your own and save $$$ on construction.
With the low cost PCB available and using standard low cost components
anyone can build their own SBC for low cost.
You can add the features you like later on and even expand the system via
the ECB to be a full blown microcomputer.
Once a few of these systems get built "out in the field" I would like to
start a challenge to see who can build an SBC for the least cost.
Those with a well stocked junk box or access to scrap PC electronics would
have an advantage of course.
Compared to a design it yourself using wire wrap/prototype
boards/breadboards, this SBC PCB will save you time and money on
construction.
Manufactured PCBs are also more reliable than temporary construction methods
in the long term.
It will be fun to make, useful, and educational.
Thanks and have a nice day!
Andrew Lynch
Now it looks like his buddies are doing the "ask seller a question"
One says:
"Hello Sir, I am an expert in vintage computers, and you sir have the real deal, this is not a fake. The style of the board will show, and the use of vintage chips. Good luck"
Wow - some expert. Actually, from the wording, sounds like that person wants to send a certified check for 3 times the amount, and then send the balance to his shipper in .......
Wish we knew who THAT was, so we know who else to avoid!
There's also:
"This looks like its the true Apple 1, how can you say its not?"
What a scammer...
Tony
-----Original Message-----
From: dwight elvey dkelvey at hotmail.com
Sent 6/17/2008 1:27:21 AM
To: General Discussion: On-Topic and Off-Topic Posts cctalk at classiccmp.org
Subject: RE: Apple I back up on ebay
Hi
One might check out:
http://www.newtontalk.net/archive/newtontalk.2006-02/0072.html
Dwight
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