Hello,
indeed it's been a faulty drive. Now the machine works pretty fine.
Thanks to everybody, especially to Scott Quinn for pointing me to the
diagnostic program IDE.
Fabian
the 100ua only applies to the 74L family and it only represents the high logic level current that it will supply into other logic inputs. One of the key design specs for TTL was the input current to guarantee a specific logic level. For normal TTL, TI specs call for -1.6ma for a logic low and 40ua for a logic high (these are input currents). In other words, ten standard TTL loads for both low and high logic levels. Ten was the usual output capability of TTL outputs.
Short circuit current is spec'd too and at a minimum, is 18ma for a TTL output that is high.
You can find the standard logic currents on page 1076 of the 2nd edition on bitsavers and the short circuit current on the same page. Of note, the 18ma was only the minimum short circuit current, TI spec's 55ma for the maximum. It also states that you should not short more than one output at a time. Frankly, as I said before, shorting anything for any amount of time is a great way to create noise transients.
I have tried to never recall anything from memory anymore on this list because there is always someone who disagrees...
best regards, Steve Thatcher
-----Original Message-----
From: "Dwight K. Elvey" <dwight.elvey(a)amd.com>
Sent: Jan 10, 2005 3:46 PM
To: cctalk(a)classiccmp.org
Subject: Re: RTL Logic
Hi
The 16ma is for sink of the NPN to ground. The pullup
is limited to around 100ua as I recall.
Dwight
>From: "Steve Thatcher" <melamy(a)earthlink.net>
>
>well, I design by specifications. The TI specs say that the short circuit
current for 74xx series is 18ma which is also not within specs for the general
output current capability of 16 ma. Transient shorts like this are a great way
to generate power supply noise. I guess I never applied any type of "preliminary
hackery" to systems I have developed.
>
>-----Original Message-----
>From: der Mouse <mouse(a)rodents.montreal.qc.ca>
>Sent: Jan 9, 2005 5:15 AM
>To: cctalk(a)classiccmp.org
>Subject: Re: RTL Logic
>
>Except that totem-pole outputs usually have just a transistor to
>ground, but a transistor and resistor to Vcc. This means that the one
>driving the signal low will win, and, provided not too many outputs are
>wired together, it will sink the current without damage. (I've
>actually built circuits that depended on this, though I've never liked
>it and never considered it suitable for more than preliminary hackery.
>I've also always never done it for anything where the conflict will
>last more than nanoseconds, as when building an ~R/~S flip-flop out of
>two cross-coupled inverters rather than the more usual NANDs or NORs.)
>
>
Ok, sorry I can't help.
Then the graphics chip was the NEC7220.
- Henk.
> -----Original Message-----
> From: cctalk-bounces(a)classiccmp.org
> [mailto:cctalk-bounces@classiccmp.org]On Behalf Of Philip Pemberton
> Sent: dinsdag 11 januari 2005 11:49
> To: cctalk(a)classiccmp.org
> Subject: RE: uPD7210 datasheet
>
>
> In message <3C9C07E832765C4F92E96B06BDC0747A011134D0(a)gd-mail03.oce.nl>
> Gooijen H <GOOI(a)oce.nl> wrote:
>
> > it's been a long time, but I vagely remember the 7210 as
> the graphics
> > processor from NEC.
>
> Nope - the 7210 was NEC's IEEE-488/HPIB/GPIB controller chip.
> I've got a CEC
> PCI-488 GPIB card that uses it and the "Advanced Programming"
> section of the
> manual makes a lot of references to the 7210 datasheet...
>
> What I want to do is make the CEC card act like a GPIB device
> that's been set
> to "Always Listen" mode so I can take copies of the screen on
> my HP 1651B
> logic analyser. It shouldn't be too hard to write a bit of
> code to convert
> the Laserjet control codes into a bitmap image...
>
> Later.
> --
> Phil. | Acorn Risc PC600 Mk3,
> SA202, 64MB, 6GB,
> philpem(a)philpem.me.uk | ViewFinder, 10BaseT
> Ethernet, 2-slice,
> http://www.philpem.me.uk/ | 48xCD, ARCINv6c IDE, SCSI
> ... Eagles Soar!, but weasels aren't sucked into jets!
>
Hi Philip,
it's been a long time, but I vagely remember the 7210 as the graphics
processor from NEC. AFAIR it was used in the HX-10 or something like
that (a small "laptop" thingie).
If the 7210 is indeed that graphics processor chip, I can help.
Possibly that graphics chip has a number that resembles 7210. I that
case I'm of no help - sri
- Henk, PA8PDP.
> -----Original Message-----
> From: cctalk-bounces(a)classiccmp.org
> [mailto:cctalk-bounces@classiccmp.org]On Behalf Of Philip Pemberton
> Sent: dinsdag 11 januari 2005 11:10
> To: cctalk(a)classiccmp.org
> Subject: WTD: uPD7210 datasheet
>
>
> Hi,
> Does anyone have a complete copy of the NEC uPD7210
> datasheet? I've just
> spent the past hour Google-ing for it and all I've found is a
> pair of "We'll
> give you this d/s if you pay $500" type sites, and a bunch of
> copies of the
> first page or so of the datasheet.
>
> Thanks.
> --
> Phil. | Acorn Risc PC600 Mk3,
> SA202, 64MB, 6GB,
> philpem(a)philpem.me.uk | ViewFinder, 10BaseT
> Ethernet, 2-slice,
> http://www.philpem.me.uk/ | 48xCD, ARCINv6c IDE, SCSI
> Warning: Windows is broken. Watch out for glass fragments.
Hi
The 16ma is for sink of the NPN to ground. The pullup
is limited to around 100ua as I recall.
Dwight
>From: "Steve Thatcher" <melamy(a)earthlink.net>
>
>well, I design by specifications. The TI specs say that the short circuit
current for 74xx series is 18ma which is also not within specs for the general
output current capability of 16 ma. Transient shorts like this are a great way
to generate power supply noise. I guess I never applied any type of "preliminary
hackery" to systems I have developed.
>
>-----Original Message-----
>From: der Mouse <mouse(a)rodents.montreal.qc.ca>
>Sent: Jan 9, 2005 5:15 AM
>To: cctalk(a)classiccmp.org
>Subject: Re: RTL Logic
>
>Except that totem-pole outputs usually have just a transistor to
>ground, but a transistor and resistor to Vcc. This means that the one
>driving the signal low will win, and, provided not too many outputs are
>wired together, it will sink the current without damage. (I've
>actually built circuits that depended on this, though I've never liked
>it and never considered it suitable for more than preliminary hackery.
>I've also always never done it for anything where the conflict will
>last more than nanoseconds, as when building an ~R/~S flip-flop out of
>two cross-coupled inverters rather than the more usual NANDs or NORs.)
>
>
People have made mention of ubuntu in this thread. My boss tried it out and
like it a lot so he created a bootable cd for me and I tried it out on a
computer I built from leftover parts. I used a crappy PC chips system board with
onboard video and sound and put a 3com etherlink III NIC in the only slot and
added a PII 400 and 512M RAM. I booted up the CD and it set up the blank
hard drive and everything else with little intervention. It picked up the video
card and the NIC and connected to my broadband connection. After a few
hardware problems, it's up and running with mozilla. There's a package manager
which can be used to bring down all the updates for installation. I expected to
have to do some user configuration but it was essentially hands off! Runs
pretty good and still plenty of space left on the hard drive. The sound does not
work, but I expected that since I don't know what sound chipset the system
board has.
anyone curious about linux should check it out. also www.ubuntuforums.org
Took in a big load of S-100 material this past weekend, including
5 complete systems (Altair 8800, Vector-1+, 3 homebuilts), and a
total of 76 S-100 cards, with about 40 different types.
I believe I have documentation for them all, which I would like to
eventually make available in electronic form.
As there is really no need for multiple people to scan documentation,
I propose the following:
- If you have already scanned documents for any of these cards, or
otherwise have "electric" form, please let me know.
- If you are looking for documenation on any of these cards, please
let me know and I will move the ones requested up my priority
list.
A=AndiCom B=oBjective designs C=eleCtronic systems
D=Drc E=Ems G=GodBout
H=HomeBuilt I=Ithaca Audio L=simpLiway
M=Mits N=Northstar O=newtrOnics
P=Processor-tech. R=m.t.wRite S=Solid State music
T=Tanner Computers V=Vector Graphic W=WMC
Mfg Model Description
-------------------------------
A AM1000 64k RAM
B VDI Video Display
B Programmable Character Generator
C S-100 Active Terminator
D S-100 Sound Effects
D 32k RAM
E VC8024 Single Board Computer (CPU/ROM/RAM/VID/KBD)
G EconoRam II 8k RAM
G EconoRam IV RAM
G 106C Active Terminator
G 106E Active Terminator
H 1793 Disk Controller
H TRS-80 Eprom Card
H ? (full of sockets)
I IA-1100 Video
L Video/Keyboard
M CPU BD REV.0 8080 CPU Board *
M 88-1 SIO Serial I/O *
M 88-SIOB Serial I/O with Modem/Cassette daughter card
M 4K RAM BD
M 4K Synchronous RAM BD
N MDC-A4 Single-Density Disk Ctrlr *
N MDS-AD Double-Density Disk Ctrlr *
O 64K S-100 memory
P VDM-1 64x16 Video
P CUTS (revB) Cassette/Tape Interface
P 3P+S I/O (rev2) Parallel/Serial I/O
P GPM EPROM
P 16KRA 16k RAM
R I/O - proto
S CB1 8080 CPU
S CB1A 8080 CPU
S CB2 Z80 CPU
S IO-4 Serial/Parallel I/O
S PB1 EPROM Programmer
S VBTC Video
T 32K EPROM II 32K memory (RAM populated)
V 8080 CPU
W MEM-3 32k RAM (2114)
* = I already have these scanned from my other S-100 projects.
Guy was also really into TRS-80's - I received two Model IIIs
and a Model IV-D - also with tons of documenation and technical
material - if anyone is interested in this documentation, contact
me and I will forward an inventory when it becomes available.
** Two of the S-100 homebuilts are actually complete TRS-80's
implemented on S-100 cards - they run the TRS-80 ROMs unmodified
(with disk system) and load/run TRS-80 software!
A few other interesting odds and ends as well, such as a SWTP C-64
terminal and docs, Full collection of Micro-80 magazine, and much
more - this will all eventually get listed on the web site, so check
in in a few months (years?) in case there is anything of interest.
Regards,
Dave
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.parse.com/~ddunfield/museum/index.html
Patrick Finnegan wrote:
>
>I've got an RA81 that has bad electronics, so it may (or may not) have a
>good HDA still. If you want it, we could probably arrange something.
Ah. Well, I have an RA81 with good electronics and no HDA :-)
Give me a day or so to see what Jay comes up with.
thanks!
-brad
Hi,
I just found your message on the list from April 2004. Do you still have
the Data General boards, if so I would be interested in obtaining them. Let
me know.
Thanks,
George Wiegand
