>Date: Sun, 30 Jul 2006 19:07:00 -0400
>From: Dave McGuire <mcguire at neurotica.com>
>
>Tim Shoppa wrote:
>> For me, far higher yield for double-sided PCB's
>> comes from ordering boards over the
>> internet. Generally you have to use (gasp!) a modern PC with
>> Windows software, but other than that the experience is wonderful.
>
> GASP...I'm sorry to say this Tim, but this is SO untrue. The
>majority of the Internet-based PCB fab houses accept Gerber-format
>files...and while you *can* generate those with a legacy Windows PC, I
>can't come up with any good reason why someone would want to. I do it
>with Solaris on UltraSPARC all the time, for both commercial and hobby
>projects. Commercial EDA software for modern platforms is hellatiously
>expensive, but even that is unnecessary nowadays. I use two free
>packages: gEDA for schematic capture and PCB for circuit board layout.
>They also work nicely under MacOS X. I regularly do fine-pitch surface
>mount designs with this software.
For $200 one can get Osmond PCB for the Mac. It runs on 68K, PPC
Classic, and OSX. Until earlier this year it was in beta and
available free for testing. I completed two designs while Osmond was
in beta which were exported to Gerber and sent out for production.
It worked great. I'd do it again, but for my current designs, I
just don't want to spend as much per board.
Anyway, to avoid digressing too much, the point is, I agree. PCB
design can be done affordably on platforms other than a Windows based
machine.
*Most* (virtually all) PCB fabs expect gerber files, not a
proprietary file format generated by their in house software.
However, perhaps what Tim meant is that to get some of the great
deals available, one goes to the PCB fab which provides in-house
software, and to run that software you need a reasonably up to date
windows machine. This is certainly true for PCB Express or 4PCB or
whatever they're called.
Jeff Walther
I'm reposting this with the permission of the author. Please contact
cseiler at sdf.lonestar.org directly.
===
I've got a handful of DEC/Alpha equipment as part of an estate. I need to
get rid of it, and I'd hate to see this stuff just get disposed of.
I'd like to sell it cheap to an SDFer in the DFW area. Or anyone knows
dealers in the area who work with this stuff and might be interested in
buying, I'd appreciate a referral in their direction.
First up is a DEC Digital VRCX1-WA 21-inch monitor. This is a great
monitor. I'd even use it myself, but it's a huge CRT monitor that I just
don't have the deskspace for. Manufactured 1997. Bought used in 2002 for
$145. Works good. Would like to get $50 for it.
Also have Digital Server 3000 50mhz Alpha 128MB. Unknown hard drive.
He bought it with 4.5Gb SCSI, but I think he may have upgraded it. I
don't know enough about the monitor this thing boots up into, but an Alpha
person can contact me if they're interested and tell me how to figure it
out, maybe.
DEC Alphastation 400 4/233 with 256MB RAM. Have not even started this
one up.
DEC Personal Workstatioin 433au. Unknown RAM, appears to have no hard
drive. HP SureStore DAT24 tape drive.
I installed NetBSD on the Digital Server 3000 and got it to work just
fine several months ago, but now can't remember how I did it. Need room,
and don't have the time to fiddle anymore. The estate needs the money.
So, if I could get $45 a piece for the computers and $50.00 for the
monitor, I'd be really happy. It would be great if someone could take
them all off my hands.
I live in Denton, so I could meet someone halfway in Dallas, Ft Worth, or
McKinney, etc.
Money is not the huge priority, but I'd prefer not to have to ship them as
it would involve a lot of boxing up and packaging and whatnot. So I'd
rather sell them to someone in driving distance, even if it's for a small
amount. The amounts aren't hard and fast, and I'd definitely consider a
considerable discount if someone took it all of my hands in one batch.
> Message: 5
> Date: Sun, 30 Jul 2006 11:13:46 -0700 (PDT)
> From: Chris M <chrism3667 at yahoo.com>
> Subject: toner transfer circuit board etching
> To: talk <cctalk at classiccmp.org>
> Message-ID: <20060730181346.50833.qmail at web61021.mail.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> by any chance does anyone use this method, and would
> be willing to small *even* number of sheets? The one
> place I know of that sells it has a $50 minimum order
> (Halted). Or maybe someone knows of a place with fewer restrictions.
Here's an excellent news group that'll tell you everything you need to
know about homebrew PCBs:
http://groups.yahoo.com/group/Homebrew_PCBs/
It really is a fantastic resource on this topic because it has so many
active members who are experts on the subject and highly experienced.
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
If I'm reading things right, the Imsai 8080 directly switches AC power
through the front panel power switch. Can someone suggest a relay circuit
to remove the need to run so much power through the front panel?
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
Hi !
I am new in electronic.
I want to make an analog acquisition board with an ARM microcontroler (
Samsung S3C44B0x 66MHz) with
a 8Mbytes SDRAM and an A/D converter( Analog AD775 ).
The sampling rate of the A/D converter is at 30Mhz, and i would like to
connect its digital output to the S3c44b0x
data bus by using the DMA of the uC.
Data sent by the ADC will be wrote to the SDRAM by using the DMA of uC.
But the number of sampling can be very large, and the
acquisition/transfert occur at a fixed rate (30 Mhz).
The acquisition time and transfert to SDRAM can be more than 64ms
(refresh time cycle of SDRAM).
So, my question is : ?is the internal refresh cycle of SDRAM can
disturb the data writing by the DMA to the SDRAM ?
The ADC send data to the SDRAM through the DMA at a fixed rate during
may be 1 or 2 second, and is this process
can be stopped/disturbed by the internal refresh process of SDRAM ?
If yes, is there a solution, to manage the two process ( fixed
acquisition and SDRAM refresh cycle) ?
Thank you very much.
--
------------------------------
M. BOYER Pierre-Marie
Hameau de Biranques
34380 Notre Dame de Londres
Tel : 04.67.55.09.17
------------------------------
>
>Subject: Re: large data transfert (write) to SDRAM at fixed frequency
> From: Pierre-Marie BOYER <pm.boyer at wanadoo.fr>
> Date: Mon, 31 Jul 2006 14:45:27 +0200
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>Le Dimanche 30 Juillet 2006 18:19, jim stephens a ?crit?:
>> Pierre-Marie BOYER wrote:
>>
>> >Hi !
>> >
>> >The ADC send data to the SDRAM through the DMA at a fixed rate during
>> >may be 1 or 2 second, and is this process
>> >can be stopped/disturbed by the internal refresh process of SDRAM ?
>> >
>> >If yes, is there a solution, to manage the two process ( fixed
>> >acquisition and SDRAM refresh cycle) ?
>> >
>> >Thank you very much.
>> >
>> >
>> >
>> If you are only collecting ADC data at that rate, can you use an I/O mapped
>> device instead of DMA, and just poll and read the data? Or are you saying
>> that the ADC data will start up and run at some rate approaching the memory
>> cycle time for 1 to 2 seconds?
>>
> No, ADC data run at a fixed frequency (30 MHz) during several seconds,
>so data, from the ADC, must be writen to the sdram at rate one byte every 0,03 usec,
>during several seconds.
>( ADC hasn't buffer).
>But what happend when the SDRAM enter in its refresh cycle, which occurs every 64ms ?
>
>Tanks
>
>P.M.B.
>
Maybe this will help... Refresh is the periodic reading of all rows of a Dram.
If you were to do a bulk write and the number of bytes written exceed the number
of rows in the DRAM then refresh or not you will have refreshed the ram.
Nominally refresh is handled in two ways bulk, doing all the rows in one long
pass every so many mS as required by the devices. The better and more common
technique is to interleave refresh in between accesses such that you will have
accomplished refresh of all rows in the required time.
My, $.02 is if your running an ADC at 30mhz and the system has SDRAM you still
only using a fraction of the bandwidth and refresh is not an issue. Since your
writing nearly (30mhz*2sec-60Mbytes) 60mbytes of data you will refresh the ram
nearly 31.25 times in two seconds, likely more than enough to satisfy refresh.
Allison
> Whilst browing Yahoo! auctions, I came across this Atari 825 printer:
>
> http://auctions.yahoo.com/i:Atari%20825%20printer:5025875
>
> Problem is, I can't figure out how it works. Where do you plug it in?
>
> :)
Well, it does have gold umm... connectors so that has to be good!
Cheers,
Bryan
Like the majority of you who participate here I love to tinker with old
stuff.
I have managed to buy a used Nicolet model 210 FTIR system complete with
PCI interface card and cable. These instruments fascinate me because they
depend on a combination of computers, electronics, optics, lasers and
precision mechanical movement to perform their function.
When I got it home it didn't work because the laser power supply was not
getting the 12V needed to power it up, when I corrected that and plugged it
back in the instrument went into a 'maintenance' type of mode with the
moving mirror scanning in a free run mode. The internal infrared source
appeared to be working also since it put out a soft orange glow.
This instrument and the software for it are not supported by Nicolet - now
Thermo Electron - because it is so old. It is from 1993, and I am looking
for someone who has the G-Series bench driver and OMNIC version 6.0 or below.
I'm asking the classicmp group for help since I think someone out there
might help me along. When I spoke to the Nicolet rep he told me that he
also had a machine at home [what a hobby!] so he could identify with me,
however my machine was retired and I needed to get an old version of Omnic
and the g-series bench driver, and it would have to run on Windows 98 or
earlier, but Nicolet wouldn't sell it to me.
So, if anyone out there knows of some laboratory/chemistry type who may
have old versions of OMNIC laying around and no longer need them have them
get in touch with me.
Thanks
Doug
Anyone here have a working Mac 128K motherboard available? I have an
old machine here with some strange memory problems that I really do
not want to invest any more time into.
--
Will
I'm transcribing the docs for a Radio Shack PT-210 printing terminal
because I don't see it online anywhere and I just recently acquired a
photocopy. This manual has a fair number of typos and a peculiar
capitalization scheme which is typical of writing from the 1700s. Here's
an example:
[begin quote]
If you set the PT-210 to Half Duplex and the Host is echoing the
character, you will see two of each character on the Paper -- one
character will be from the PT-210 and the other echoed from the Host.
[end quote]
So, is it a Good Idea to correct stuff like this? Should I be concerned
about maintaining the page numbering?
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
