Hi guys,
Progress is going a little slower than I'd hoped.. I've been roped into
working most of the past few weeks, so all I've got done is the final block
diagram and part of the schematic.
What I have got is a box containing ?200 worth of CPLDs, Molex connectors,
and other parts I had to order from Digikey. What this basically means is that
after I've got the schematic and PCB done, I can get a prototype built up
within a day or so of finishing the PCB. Assuming, that is, I manage to etch
the PCB without any bridged/broken tracks (especially on the CPLD and PIC,
which are both QFP parts).
So here's the final spec as I see it:
- USB interface -- USB2.0 Full Speed (12Mbit/sec)
- 40-pin disc interface connector. All outputs are open-collector -- the
first 34 pins are wired exactly as the standard PC floppy connector is. The
remaining 6 pins are all open-collector outputs with internal 680R pull-ups to
+5V. The state of these pins can also be read back in, assuming they're set to
'output high' mode.
- Replaceable bus drivers. 74LS07 O/C buffers are used - these are not
generally ESD sensitive, and are rated to 20V over the outputs. All the
buffers will be socketed and can be replaced easily in the field (as long as
you have spares, that is).
- Flexible triggering options:
- Start of capture:
- MFM sync word detection, with programmable sync word (*)
- Rising or falling edge of index pulse
- Hard-sector track mark detection
- "Wait for N start events before triggering" option
- Termination of capture:
- MFM sync word detection, with programmable sync word (*)
- Rising or falling edge of index pulse
- Hard-sector track mark detection
- "Wait for N start events before triggering" option
(*): The capture CPLD only has one MFM sync detector, which is shared between
the Start and Stop events. Note that the acquisition clock divider must be set
correctly in order for the sync word detector to function.
[ A future version of the CPLD may offer the option of independent clock
generators for the sync detector and acquisition system - currently Facq is
locked at 32 times the disc's bit-rate, e.g. 500kbit * 32 = 16MHz for 3.5-inch
HD. This is a fairly simple mod, so I might do it before release, but 32*Fdata
should be enough to get a usable scan ]
- 128 kilobytes onboard high-speed SRAM buffer with end-of-capture-address
storage.
- Disc writes controlled by a simple microsequencer - commands are:
- Wait N cycles and strobe WR_DATA
- Stop writing
- Open/close Write Gate
- Wait for hard-sector track mark
- Wait for N index pulses (where 1 <= N <= 31)
- Onboard flash upgrading feature for both the main microcontroller and
CPLD, with failed-flash recovery and forced-reflash options for both devices
(as long as the bootloader is still intact). The boot block will also be
protected against overwriting, to reduce the possibility of irrecoverable
'bricking'.
- Multi-platform (Linux and Windows initially, OSX if someone ports it)
programming library to handle disc read/write operations, including full
source code and example 'dartutil' application.
- Open-source hardware design, but with hardware available for purchase
either fully-assembled or as a complete or partial kit (optionally with SMD
parts soldered down).
- Power supply: USB bus power or external 7-12V power supply unit.
Can anyone think of anything else before I start drawing up the schematics?
I'm also thinking about an extension to the ImageDisk file format to allow
storage of raw MFM data, though I'm not sure how to go about doing this...
creating a whole new format may be a better idea.
So to recap, this is done:
- Block diagram and outline design
- CPLD code (all major functional units tested and working)
And this needs doing:
- Schematics
- PCB layout
- Prototyping
I'm currently toying with the idea of moving the half-done schematic from
OrCAD/SDT to KiCAD [<www.kicad-eda.org>] (on the basis that KiCAD is
open-source, newer, and can do just about everything OrCAD can do), though
I've not decided yet. Other suggestions (please don't suggest EAGLE...) will
be given due consideration :)
--
Phil. | (\_/) This is Bunny. Copy and paste Bunny
classiccmp at philpem.me.uk | (='.'=) into your signature to help him gain
http://www.philpem.me.uk/ | (")_(") world domination.
>
>Subject: RE: AMD2901s (was e: Inside old games machines,was: Re: Simulated CP/M-68K?)
> From: "Antonio Carlini" <arcarlini at iee.org>
> Date: Mon, 25 Jun 2007 21:58:01 +0100
> To: "'General Discussion: On-Topic and Off-Topic Posts'" <cctalk at classiccmp.org>
>
>der Mouse wrote:
>> Ah. Then "undocumented (as far as I can tell)" here really means "I
>> haven't found the right manual yet".
>>
>> I'll keep your message around and go digging for the scans you refer
>> to some time when I have the leisure. Thanks for the pointer!
>
>Before I forget I should say that slipping "78032" into Manx gets
>you the CPU Chip guide and the KA630-AA User's Guide (which is
>equivalent to what was later usually called the CPU Technical
>Manual).
>
>Antonio
Then again there are odball hardware like the DEC ADVICE a MVII(78032)
on a board for in curcuit testing and development.
I'm still hunting for manual for that board or even a schematic.
Allison
Hi, i was reading up on bitmap (mainly .bmp, with some
.wbmp) images last night and was wondering why
everything is stored backwards (e.g. BGR instead of
RGB and the bottom of the image first, instead of the
top)? Also would i need to pay a license if i wrote a
program to create .bmp files? My main aim is to write
a .bmp to (amiga) .iff format, but would love to add
full .bmp support to an art program i wrote for the
amiga and then stick it online (on Aminet.com ) for
other people to use if they wish. - Andrew B (via
mobile phone)
--- cctalk-bounces at classiccmp.org
<RodSmallwood at mail.ediconsulting.co.uk> wrote:
> Yes definitly existed..
> Same case as a VT52.
> Difference may have been
>
> a) 12 x 80
> b) Uppercase only
> c) 20mA only.
>
> Rod Smallwood
> DEC Terminals Product Line 1973
>
> -----Original Message-----
> From: cctech-bounces at classiccmp.org
> [mailto:cctech-bounces at classiccmp.org] On Behalf Of
Ashley Carder
> Sent: 12 June 2007 18:28
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: Re: Strange VT50 Decscope
>
> >> Are there any former DEC employees (or anyone
else) here who have
> ever seen or heard of anything like this?
>
> Richard said:
> >I saw one of these for sale on ebay recently,
advertised as a VT52.
>
>
> This is the one that was on ebay. It was listed as a
VT50. It also
> came with the VT50 engineering prints and a VT50
manual.
>
> Ashley
>
>
>
On 6/19/07, woodelf <bfranchuk at jetnet.ab.ca> wrote:
> Providing the word length is a multiable of 4 bits that is.
It sure would be "fun" to debug microcode issues with nine of those
puppies chained together.
-ethan
It's just 3 weeks until the third annual Vintage Computer Festival,
Midwest edition. We've got a few interesting speakers lined up, and
more to be added shortly.
So come all ye collectors, see the speakers, and even exhibit your
favorite items from your collection! We still have plenty of space to
fill up with exhibitors. If you're interested in being an exhibitor,
please sign up before Sunday, July 8th. Don't wait until the last
minute, or there may not be space left!
VCF/Midwest 3.0 will be July 14-15, at Purdue University's Stewart
center. Speakers will run from 11a to 2p each day, and exhibits and
the marketplace will be open from 2p to 6p. Admission is $5 per day
for access to the whole event, and kids 17 and under get in for free.
For more details, and to sign up as an exhbitor or vendor, please see
the official VCF/Midwest 3.0 website at:
http://www.vintage.org/2007/midwest/index.php
If you have any questions, feel free to send me a message at:
vcfmw at computer-refuge.org.
Pat
--
Purdue University Research Computing --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
My taste for the last several years is to play around with
1: dedicated industrial logic (e.g. elevator and machine controllers)
2: Analog computers
3: Electromechanical stuff, especially if somewhat programmable
Now, none of the above are things with video screens and
keyboards, and in most cases they don't even have readily
recognized "instruction sets", but they all do computing in a
pre-Von-Neumann sense.
I heavily, heavily try to stay away from stuff with keyboards
and video screens and, even worse, anything with an
"operating system" of any sort! I don't want to have anything
to do with installing software. I want to solder tube sockets,
read meters, turn knobs, and watch scope traces.
Tim.
Just wondering, do any of you guys know of something that'll remove epoxy
potting compounds?
Only suggestion I've seen so far is some pretty nasty acid that I really don't
want to mess with....
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
Well if you if you will pardon the expression,
"Its heading in the right direction"
I agree, the charges build up is a bit of an unknown.
> 'has 1 cubic meter of volume and the first 1000 kilos'
That seems to be a lot of weight in a small space.
Port to port is less of a problem for me as the UK is that much smaller
than the US.
I can get to most of the UK ports in an hour or two.
Thers a good chance that there's a service from US east coast ports to
UK west/south ports.
So...
Boston to Liverpool or Southampton
New York to Liverpool or Southampton.
Etc.
Rod
-----Original Message-----
From: cctech-bounces at classiccmp.org
[mailto:cctech-bounces at classiccmp.org] On Behalf Of Mike Ford
Sent: 11 June 2007 19:05
To: On-Topic Posts Only
Subject: Re: My sale or swap list (Update)
Rod Smallwood wrote:
> Hi
> I am curently investigating shipping costs between the UK and US.
> As collectors we don't need next day delivery but we do need full
> cover insurance.
>
> Don't go away. The cost is not that bad.
>
> Rod
I'm looking at LCL oceanic shipping, its Less than Container Load,
basically a rectangular box that fits about 20 to a container, has 1
cubic meter of volume and the first 1000 kilos is part of the base
shipping cost of about $150.
As usual lots of quicksand around the treasure, port fees, brokerage,
customs, and its a port to port service, not terminal to terminal or
door to door without adding a local ground shipper to the mix. Also its
targeted to business, not private goods, so some places don't seem to
want to even talk to a one time shipper. Complete and accurate paperwork
seems essential.
It does tend to be SLOW, as in couple weeks transit, with a month or
more of sitting on a dock at either end.