Hi guys,
The USB floppy reader project is back on track as of about an hour ago.
I've found a distributor who has a couple of Altera FPGAs in stock, and
although it'll take a few days for them to arrive from Belgium, they were
quite happy to sell me just five of them. For anyone that wants to look up the
datasheet, they're Altera Cyclone II devices, p/n EP2C8T144C8N. Cost was
?11.58 +VAT.
This nifty device also has a pair of onboard PLLs - which means I can put a
relatively low-speed oscillator on the board, then boost the clock up to
whatever the acquisition clock needs to be, and generate the 32MHz clock for
the data separator / sync detector with the second PLL. Very cool.
A quick does-this-work-or-not test build of the code I was using on the
Xilinx chip clocked in at 5% utilisation of the Cyclone -- that means the
final version will more than likely use a smaller chip (likely an EP2C5; the
entry-level Cyclone 2).
I'm still using the "time the length of the time between RD_DATA pulses"
method for acquiring the data, but I'm increasing the acquisition clock so
that the reader can measure the timing down to an accuracy of 50ns minimum
(25ns with the 40MHz clock option). The counter is now 15-bit with an INDEX
(index pulse was high at data bit leading edge) bit for every counter word.
This gives a maximum counter period of 1.6384ms at 50ns, or 0.8192ms at
25ns... or a minimum bit rate of 610 or 1220 bits per second respectively.
Maximum data rate is likely to be around 5-10Mbps.
From what I've been told, the Trace disc duplicators had an accuracy of
50ns, which is where the base clock for the floppy reader came from (the SPS
have based most of their data analysis on Trace duplicators, so the clock
rates need to be close-or-identical).
I've also scrapped the SRAM storage in favour of SDRAM. For the ?5 unit
cost of the 256K*16 Cypress SRAM, I've managed to get a 4M*16 PC133 SDRAM
chip. This gives a maximum track length of 4*1024*1024 (4194304) magnetic
transitions; probably far more than any floppy disc ever made.
Like I said before - the aim isn't to get an image with the intent of only
decoding it (although the hardware can be rigged to do that). The aim is to be
able to get as much information off a disc to be able to state that:
- The data is accurate
- The data is original (timing will differ between two drives -- if e.g. a
high score table has been modified on a factory-written disc, the modification
will be at a very slightly different data rate).
Also, if you've only got one chance at reading a potentially-defective
disc, you want to get as much information from that disc as you possibly can
in the time you have.
This is what I consider to be the spec at this moment in time:
CPU: Microchip PIC18F4550 USB MCU at 40MHz (10MIPS peak) with
Altera FPGA coprocessor / DAQ controller
RAM: Micron Technology 4M*16 SDRAM
Interfacing: USB Full Speed (12Mbps), RS232 as a jumper selectable option
(115200 baud).
Power: 5V DC from USB port, external supply required for drives
Features:
- Open-collector outputs, high-voltage (30V) tolerant
- Over-voltage protected TTL level inputs with pull up resistors
- Standard 34-pin drive interface, with 6 User I/O pins
- Acquisition start/stop methods:
- Both leading and trailing edge event triggers available (trigger-at
and trigger-after)
- Event Counters for all events -- wait for event to occur N times
before triggering
- Instant On (starts as soon as START bit is set, not valid for STOP)
- Stops when memory full (always enabled)
- MFM Sync word detector -- detects a 16-bit MFM word (e.g. Sync A1)
- Index pulse -- typically start on leading edge, stop on trailing
- Hard-sector track mark detector -- detects the double-pulse track
marker and triggers from the index line
- Fully reprogrammable -- boot-block protected Flash on PIC, 8Mbit Atmel
DataFlash to configure FPGA.
- Two user-selectable FPGA microcode blocks -- store standard FPGA code
in one half of the DataFlash, and customised code in the other.
- Fully open-sourced design -- hardware, software and HDL code --
basically under the "Wisp628 licence":
- The design is open, so you can tweak, modify and play with it as you
see fit
- What you aren't allowed to do is sell kits, or pre-built units for
profit. So if someone asks you to build one for them from scratch (i.e. not
>from a kit), you can do so, as long as you only charge for the components you
used to build it.
- Software is GPL2 without the "or any later version" clause, plain and
simple.
So the inevitable questions from me:
- Am I too late with this? Is it worth continuing and finishing the project?
- If I said one of these boxes would cost ?75 (around the same as a
Catweasel), would you buy one?
- Are there any features you guys think I should add?
- Does the licence sound too restrictive?
I've put around ?300 into the project thus far, not counting time. I know
I've got basically no chance of recouping all of it, but it would be nice to
make at least some of that money back.
Like the subject line says - this is a Request For Comments - I know I'm not
going to please everyone, but I'd like to get as close as I can :)
I've set up a mailing list at
<http://mail.philpem.me.uk/mailman/listinfo/floppy-reader_philpem.me.uk> to
carry announcements and discussions about the project -- saves cluttering up
classiccmp with it (unless people would rather discuss it here?)
Thanks,
--
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.
-----------Original Message:
Date: Tue, 19 Feb 2008 00:13:18 -0500
From: Dave McGuire <mcguire at neurotica.com>
Subject: Re: Bubble memory devices
To: "General Discussion: On-Topic Posts Only" <cctech at classiccmp.org>
<snip>
I've always been a fan of bubble memory, although I have no
functional bubble subsystems here. I've seen S-100 and Q-bus bubble
memory boards (the latter I missed on eBay by a few dollars maybe a
year ago), and there's at least one piece of test equipment made by
Fluke (I don't recall which one) that uses bubble memory cartridges.
I also have some brand new Sharp CE-100B cartridges, but no machine
to use them in.
-Dave
--------------Reply:
I've got the machine; want to get rid of one or two?
mike
On 19 Feb, 2008, at 18:00, cctalk-request at classiccmp.org wrote:
> From: Tim Riker <Tim at Rikers.org>
>
> I'm not sure what a europlus version of the machine is though.
The euro means 110/240 volt switchable power supply. I don't think
there was any other change, though it was common to have a colour
card (in slot 7?) which took the NTSC signal, decoded it and re-coded
into PAL. I guess there was a corresponding SECAM card for France. As
you probably know, the plus mean floating point Basic.
> From: Josh Dersch
I actually used one of those at CDC ca. 1974-75. You got the good
version--there was a version with a reduced linecount on it (8?). At
Sunnyvale ops, we had a roomful of them connected to the STAR-100
Cyber frontend in Arden Hills. At the time, department policy
wouldn't allow a terminal to reside on one's desk, so we had a
"terminal room". I think we ran them at 300 bps from a 9600 bps
link. I wrote the Star OGNATE text editor to operate with one of
these--and to see how creative I could get with all of those great
STAR string and vector instructions. Much to my horror, I found the
editor still in use at ETA in 1985. (OGNATE, BTW, stands for "Oh G-d,
not another text editor"). IIRC, the terminal was very "dumb".
At the time, I was also project manager for the STAR remote MCU. The
thing that I best recall was that the engineer at the Arden Hills end
took forever to design his own UART from SSI. It ran at some oddball
speed, like 1800 bps.
Cheers,
Chuck
>From Andrew Lynch:
> I searched around a bit and found SDRIVE.SYS which refuses to
> acknowledge any of the other FDCs I place in the computer at the
> secondary address (IO address $170).
I/O port 0170H refers to the secondary *hard drive* address (the
primary being 01f0H). The secondary FDC address is 037xH (the
primary is 03FxH).
Let me look around--I've got several old MS-DOS secondary port
drivers kicking around here.
A word of warning, however. For a secondary controller using the
same DMA and IRQ (2 and 6) as the primary, the primary needs to have
implemented the "enable" bit at I/O port 03F2H so it can float its
own DMA and IRQ lines when the secondary controller is active. Not
all controllers will do this, even though it's documented as part of
the standard PC architecture.
If you want to check out the operation of your secondary controller,
hook a drive to it and find copy of FORMATQM or COPYQM (or 22DISK...)
and set up a DISKETTE.CFG file for it to use.
In the meantime, I'll look for a good driver.
Cheers,
Chuck
>I am working on restoring a DEC TU10 tape drive for my PDP-8/E and want to
>see if anybody has experience repairing them before I do too much to it.
...snip...
>David Gesswein
>http://www.pdp8online.com/ -- Run an old computer with blinkenlights
I'm interested in following this restoration project. I have two TU10
tape drives. One is somewhat dismantled, but complete, and was used
with a PDP-11/45. The other one is in the rack connected to an 11/40.
Do you plan to keep some type of online log on your web site?
Thanks,
Ashley
http://www.woffordwitch.com
Does anyone have the Mouse Systems driver MOUSESYS.COM? This is for their
early PC optical mice.
If you've got it, can you please contact me directly?
Thanks!
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
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Hey all --
Picked up an old dumb terminal (and I feel secure in calling this one
"old") today at Re-PC in Tukwila, WA (I'm starting to really dig this
place...). It's a CDC, labeled on the back as a "Display Terminal" (go
figure), Equip. Id #CC5A5-A, Series Code 2, Part #15551800. I haven't
been able to find any information on this beast at all on the 'net.
I've put up some pictures here:
http://yahozna.dyndns.org/computers/cdcterminal/ (Haven't had a chance
to clean it up yet, so it's kinda smudgy...)
My favorite thing about this terminal is the huge, backlit buttons on
the front for Power, etc... very cool :). I've powered it up after
giving it a check-out, and it appears to work fine. I haven't hooked it
up to a serial line yet, but that's coming... maybe Linux has a termcap
entry for this thing? :)
Opening it up reveals repair tags with dates in 1974. There are four
PCBs mounted inside, connected by a ton of ribbon connectors (there's no
backplane to speak of). Looks like it's all TTL, though I haven't taken
the boards out to investigate. Not sure I want to disturb them :).
Anyone know anything about this thing? What's it capable of? What was
it originally connected to?
Thanks!
Josh
Hi,
Whilst waiting for a video to download (I'm still on dial-up) I decided to have a flick through an issue of 80 Microcomputing. It's issue 10 (October 1980) and inlcudes an article about the row about whether the US government and/or patent office should honour copyrights for computer software.
Anyway, on page 46 I stumbled across an interesting article (called "A Slow Road To Bubble Memories") about bubble memory. The main bubble memory manufacturers of the time were Intel Corp., Texas Instruments and Rockwell Int. The article also mentions that Rockwell had a bubble system, a 256K bit board, available for $1,800. Meanwhile Intel had a bubble system in kit form - 7110-1 Magnetic Memory board came with all control and support circuitry - and sold for $2,000.
What happened to bubble memory? Did it die out due to the costs, or did people prefer to use cassettes, disks etc. instead?
Regards,
Andrew B
aliensrcooluk at yahoo.co.uk
Hi,
I am building a test station using an old 486 ISA only computer to test
floppy disk drives and old ST-506/ST-412 style hard disk drives.
The computer seems to work OK and has a Western Digital ST-506 MFM hard disk
controller with a FDC on the card (IO address $1F0).
To help with testing floppy drives, I thought I would add a secondary FDC
however that is turning out to be much more difficult than I planned.
It seems there are drivers required to make floppy drives attached to the
secondary controller appear as drive letters under MS-DOS.
I searched around a bit and found SDRIVE.SYS which refuses to acknowledge
any of the other FDCs I place in the computer at the secondary address (IO
address $170).
There are some references to a DC2.SYS program but I cannot find it anywhere
online.
http://www.seasip.info/VintagePC/floppies.html
Does anyone know how to add multiple FDCs to a PC so I can have multiple
floppy disk drives?
Of course, the Compaticard IV would be nice but those are very expensive and
almost unobtainable these days. I have a Compaticard I which "sort of"
works but the drive gives errors every other time I access it.
Thanks in advance for any help -- especially if someone could send me or
tell me where I could find the DC2.SYS files.
Andrew Lynch
