>From: "Brad Parker" <brad at heeltoe.com>
>
>
>Tony Duell wrote:
>>
>>My experience with simulators suggests that's a massive _underestimate_
>>of the time it would take.
>
>Well, I did manage to make a microcode simulator and it boots the lisp
>machine.
>
>I think there are a few very subtle bugs in the pipe, however, and I
>think the only way I'll find them is to watch the real hardware work.
>
>I think the timing on this machine, and the 74S/74LS parts it uses are
>slow enough that verilog will do fine. In reality what I am saying is
>not about verilog, but the accuracy of the models I have created. So,
>restated, I think I can make models which are accurate enough for this
>type of design.
Hi
Make the design race free. I'm not sure if I understand
you statement about accurate. A NAND gate is a NAND function.
Anything else is incorrect.
I hope you are not trying to do timing verification with
verilog modeling?
Dwight
>
>heh. we'll see.
>
>-brad
>
If you can find it, get a ROM dump or listing from one of the floppy drives
like the 2031LP disk drive or the 2040 dual-drive. The 2031 is a
1541-looking GPIB floppy drive for the PET.
http://www.funet.fi/pub/cbm/firmware/drives/old/2031/index.html
Here are the ROMs. Just run them through a disassembler and see what you
get. I haven't located a memory map yet.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
On Behalf Of Ethan Dicks
Sent: Friday, September 09, 2005 2:53 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: GPIB state machine info WTD
On 9/9/05, Dwight K. Elvey <dwight.elvey at amd.com> wrote:
> As I recall, the GPIB chip made by TI ( forget the number )
> had a data sheet that explained the states. Not much
> to it as I recall, mostly just handshake stuff and address
> recognition.
The common chips are:
TI TMS9914A
NEC ?PD7210
http://sine.ni.com/nips/cds/view/p/lang/en/nid/1267
> It seemed like there was some timed stuff that
> might not work well in software but for the most part I'd
> suspect that Ethan is right, one could do it all in software.
One issue is to identify what GPIB devices you expect to talk to.
Older ones, especially ones that implemented the protocol via ~1MHz
8-bit microprocessor, are unlikely to be able to handle 1MB/sec speeds
that the newer "IEEE 488.2" devices can. If all you want to do is
talk to old devices at a few KB/sec, it really doesn't matter if you
have a hardware or a software implementation. For the newer,
high-speed stuff, I'd expect you'd need an ASIC to pump the bytes
through in a timely fashion.
OTOH, even Commodore had a little fiddly hardware thing to handle
handshaking turn-around. Andre Fachat mentions that in his extensive
pages covering Commodore hardware and his own home-built
mostly-PET-compatible 6502 computer. I do not know about the
Commodore acoustic couple (C810?), but disks and printers tended to
have 6502/6504/etc software implementation of GPIB.
-ethan
I saw this article in the latest (Sept. 2005) 'Circuit Cellar' and
thought some of you 1802 fans might find it interesting:
*Replacing a Legend: *Build a Functional Equivalent to the CDP1861*
*/Bob Armstrong
/Bob built a functional equivalent to a CDP1861 video controller chip so
he could play video games on his COSMAC Elf replica. The design includes
two ATF22V10 GALs and a few standard 74HC chips. Ready to replace some
random logic? /p. 58/
-James Nugen
> As I restore this ET-3400, I am curious if anyone knows what
> kind of filter material Heathkit provided that sticks to the
> TIL312 7-segment displays? Mine have 4 of 6 displays
> covered, and 2 displays bare. It seems to be some sort of
> adhesive red tape or film, but I have no idea what to use for
> a modern substitute.
>
> Thanks for any tips.
Two ideas come to mind - lighting gels, used in stage lighting, and
Kodak makes lens filter gels in a huge range of colors. Both these items
will appear to be colored sheets of plastic. In the case of the Kodak
product, the "pass band" of the filter will be narrow and precise (an
exact shade of a certain color and it won't pass much else).
>From: "James Fogg" <James at jdfogg.com>
>
>> As I restore this ET-3400, I am curious if anyone knows what
>> kind of filter material Heathkit provided that sticks to the
>> TIL312 7-segment displays? Mine have 4 of 6 displays
>> covered, and 2 displays bare. It seems to be some sort of
>> adhesive red tape or film, but I have no idea what to use for
>> a modern substitute.
>>
>> Thanks for any tips.
>
>Two ideas come to mind - lighting gels, used in stage lighting, and
>Kodak makes lens filter gels in a huge range of colors. Both these items
>will appear to be colored sheets of plastic. In the case of the Kodak
>product, the "pass band" of the filter will be narrow and precise (an
>exact shade of a certain color and it won't pass much else).
>
>
Hi
One might try an auto parts store. The often have some
tape to cover broken tail lights.
Dwight
Do you have any information about the authenticity of this item on eBay?
5238346510
Gil
A. G. (Gil) Carrick, Director
The Museum at CSE
University of Texas at Arlington
Department of Computer Science & Engineering
Box 19015, 471 S Cooper Street
Arlington, TX 76019
817-272-3620
http://www.cse.uta.edu/TheMuseum at CSE/
Fellow techies,
I've been asked, on behalf of a friend of mine (John Lanfri), who does not have reliable Internet access at this time, to assist in finding those interested in acquiring a goodly collection of DEC'ish (pre-HP, pre-Compaq) hardware, software, and docs, along with various other Classic-era stuff which has yet to be unearthed.
This may, depending on what he's getting rid of at the time, include such things as a fully-loaded PDP-11/34 with all docs, including field service prints, RSTS/E, spare disks (RL02's), TU10's, etc. It may also include an 11/73, rebuilt tri-density 9-track drives (I don't recall if they're Fujitsu or NEC, but I do recall that they've not been used since being refurbed), SMD disk drives, large and small, and other goodies too numerous to list.
This project is long-term. It is expected to take place over the course of the next six months to a year. An inventory will be generated within the next couple of months.
Shipping will NOT be available. Period. This will be exclusively local pickup in the San Jose/Santa Clara CA area.
WHAT TO DO FOR NOW: Along with the inventory, we're working on generating a contact list. If you're interested in being kept up to date on this project, and would like to be among those offered the opportunity to acquire, please indicate as much in a private E-mail note to me, and please include a contact phone number. Either John or myself will contact those interested with further details of what's become available at what time.
PRICING: I can't speak for John, 'cause it's all his stuff, but I will say that he's not going to gouge anyone. He's indicated to me that he's more interested in getting the stuff to those who can appreciate and use it than he is in making a fortune from it. Pricing for each item, or set of items, will be shown on the inventory. Some items may be tagged as 'Make an Offer' (which you should also do if you don't like the price shown -- John is an astute bargainer). ;-)
Again, please remember -- BAY AREA LOCAL, or those who would be willing to drive to San Jose/Santa Clara ONLY. Shipping will NOT be available, and you may need (at minimum) a pickup or flatbed truck for some items. This will be noted on the inventory if a given item or set of items warrants it.
Looking forward to hearing from those interested in this. Thanks much.
-=-=-=-=-=-=-=-=-=-=-=-
Bruce Lane, Owner & Head Hardware Heavy,
Blue Feather Technologies -- http://www.bluefeathertech.com
kyrrin (at) bluefeathertech do/t c=o=m
"If Salvador Dali had owned a computer, would it have been equipped with surreal ports?"
>> If the DIN and DOUT are common on the MB
>Well, darn it, they aren't linked. It turns out that the memory
>controller on the
> IIfx buffers the writes, so that the CPU can go do something else
>after only 2
> cycles instead of 6, unless, of course, the next operation is a
>memory access.
> So the the data lines from the SIMMs are routed to 74F573 D-type latches. It
> appears that the SIMM's DIN comes from the latches' outputs and DOUT goes
> to the latches' inputs.
Okay, what if I put a pair of octal tristate buffers on the SIMM and
control them with the Write Enable line such that data can go from
DIN to the DRAM chips' data pins when WE is active, and data can go
>from the chips' data pins to DOUT when WE is inactive?
Something like the SN74ABT541 looks like it might do the trick:
<http://focus.ti.com/docs/prod/folders/print/sn74abt541b.html>
I see two potential problems. First, the buffer will introduce about
4 ns (max) of delay between WE changing and data flowing, so timing
might be dicey. Second, the timing will be even tighter, if the
computer tries to do a Read Modify Write to memory.
So one important question is whether the IIfx makes use of the Read
Modify Write function of DRAM. Checking some old datasheets, it
appears that that feature was present in old DRAM chips. Did
computers typically make use of it?
The tristate buffers are only about $.50 each, so they don't add much
to the cost, but they might blow the timing.
Jeff Walther
>From: "vrs" <vrs at msn.com>
---snip---
>
>What I did was buy a set of mini-banana to regular-banana adaptors,
>which I got a good deal on, and a bunch of stackable regular-banana
>patch-cords, which were also inexpensive.
---snip---
Where? Pomona wants an arm and a leg for these. They have
the mini banana's as well, for a price. I'm interested in
a cheap source of regular banana patch cords and also
dual mini connector plugs.
Dwight
