test-drb April 2012

test-drb@ccmp.vtda.org

195 participants
233 discussions

by c.murray.mccullough＠gmail.com

I came across some interesting reading the other day in a library book that I'm sorry I can't remember its name. It essentially said: Can one subscribe to the theory that vintage computers, such as the Coleco ADAM, went extinct because they used cassette drives where one spent more time finding information and recording such which greatly slowed down processing thereby defeating the purpose of electronic computing? I?m not sure if this applied to floppy drive systems but computing never really took off until hard drives came along in the 16-bit world, i.e., the mid-80s! Classic computing aficionados, particularly on this site, may have a different take on things. Murray--

11 years, 7 months

EPROM and EEPROM Programmers

by technobug＠comcast.net

On Mon, 30 Apr 2012 16:18:24 -0400, "Bill Sudbrink" <wh.sudbrink at verizon.net> wrote: > > Eric Smith wrote: >> Bill Sudbrink wrote: >>> Data sheet claims pin compatibility with 2732. >> >> No, the TMS2532 doesn't make any such claim. > > Interesting. Thanks for the correction. > >> It claims that it is "pin compatible with existing ROMs and >> EPROMs (8K, 16K, 32K and 64K)", but that does not include the >> 2732, and their reference to 32K and 64K was only in regard to >> ROMs. > > So, the 2532 predates the 2732? Interesting that they revised > the data sheet until 1982 without clearing that up. > >> The TMS2532 is most definitely *not* pin compatible with 2732 > > I see that now. I must remember that data sheets are at least > partially products of the marketing departments. Sigh... > > Bill S. To totally confuse the situation, the TMS2716 in not compatible with the Intel 2716 whereas the TMS2516 is, The TMS2732 is industry standard whereas the TMS2532 is not. This goes back to the time when the industry was sorting out what was going to be standard - one should be extremely careful when choosing, changing, or programming PROMs of this vintage. I just went through a learning process with a piece of failed HP test gear where a PROM failed. The unit had 2716 equivalents. I borrowed a friend's unit and attempted to read his PROMs and failed. An individual on the HP equipment list attempted to do the same and also failed until he looked at the schematics for his unit and found yet another pin out for what appeared to be a 2716 equivalent. The PROMs in question are NEC2316 about which information is unobtainium. -> CRC

11 years, 7 months

discrete transistor computer

by elson＠pico-systems.com

A while ago somebody mentioned thinking about building a discrete transistor computer. I ran across the link again of the one I saw (only online) http://www.6502.org/users/dieter/mt15/mt15.htm With all SMT, he packs the boards very closely, performance is of course not so great with discrete junction transistors running in saturation. Jon

11 years, 7 months

ibm funky 3 1/2 inch disk

by stefan.skoglund＠agj.net

i have one of the IBM:made minidisk ? (looks a bit like a normal 3-1/2 inch floppy) drives. Any source for disks ?

11 years, 7 months

EPROM and EEPROM Programmers

by fraveydank＠gmail.com

On Apr 30, 2012, at 3:34 PM, Bill Sudbrink wrote: > Dave Wade wrote: >> I have some "TMS2532" chips. Any suggestions on how to program them (I >> have a project in mind that will need these or a similar device) > > Data sheet claims pin compatibility with 2732. I would start there. Er. Electrically compatible, *maybe*, but the pinout is different enough that they're definitely not interchangeable. Defender uses a bunch of 2532s, which is unfortunate because they're a lot harder to find than 2732s. If you're looking to get rid of 'em, I'll gladly take them off your hands for a reasonable price. For new projects, find some 2732s; they're a lot easier to find (and thus cheaper) and enjoy wider programmer support. - Dave

11 years, 7 months

Subject: Re: Gone extinct; From: Fred Cisin <cisin@xenosoft.com>

by c.murray.mccullough＠gmail.com

On Sat, 28 Apr 2012, Murray McCullough wrote: > I came across some interesting reading the other day in a library book> that I'm sorry I can't remember its name. It essentially said: Can one> subscribe to the theory that vintage computers, such as the Coleco> ADAM, went extinct because they used cassette drives where one spent> more time finding information and recording such which greatly slowed> down processing thereby defeating the purpose of electronic computing? Now I'm wodering, could the conveniently non-attributed "came across some interesting reading" question may not have been disingenuous, and somewhat rhetorical? I have never considered the Coleco Adam to have ANY historical significance, and tend to assume that any mention of it is an attempt at comprehensive completeness, or personal fondness. Yet, it turns out that C. Murray McCullough is the author of a history about microcomputers. On the cover of it, he gives Adam a position of greater importance than the others that he mentions: ADAM (in ORANGE, the others are in white) APPLE II TRS-80 MODEL I ZENITH HEATHKIT In the index (I could not get Amazon's "Look Inside" to show me any of the text past the Preamble, which doesn't get to the time of microcomputers),He has 25 entries for "Adam", enormously disproportionate (12 for "Commodore" PLUS 6 for "COMMODORE", 2 for TRS-80, . . . ) Dare I guess what Murray's first computer was? (Baby duck syndrome?) Nevertheless, the writing style looks intersting, and I may seek out a copy. "JPL (Job Control Language)"??!? ************************************************************************************ With unlimited stars in the universe so there seems to be an unlimited opinion on when things started & where & by whom in the microcomputer universe. (There is no consensus on what a microcomputer is!) Corporations, individuals protect valuable information and certain knowledge that is never made public. We can only hope that inaccurate information from these sources doesn?t occur. I came across the book in the Toronto Reference Library and I seldom get there because of the distance from my farm. I did not copy the name of the book or authour down and this is a serious error on my part. There was no disingenuosity on my part and in no way was it my intention to denigrate the book or authour. A reasoned argument around mustered facts, as was present in this book as far as this reader was concerned, cannot easily be dismissed nor ignored. I did write a book on the history of microcomputers ? A Historical Research Guide to the Microcomputer. ( Many thanks for mentioning it. ) It was on the early years of micro-computing up to the arrival of the IBM PC. I?ve been a member of the (Coleco)ADAM computer convention organization since 1989 and this was why I highlighted the computer in my book. I do indeed have a personal fondness for a computer Coleco abandoned and was taken up by die-hard followers. [ BTW my first computer was the Heathkit which I spent many an hour assembling, debugging and trying like the devil to get working! And what an expensive computer to buy in Canada. ] As Grumpy Ol? Fred wrote -> Because we have an interest in the computers that existed before y'all cared and/or we REALIZE that we came in late, and we're INTERESTED in what had already been happening. OR we're just a bunch of old farts who wish that we could go back half a century. <- To be involved in the early years of micro-computing I consider myself privileged but possibly cognition and memory are getting fuzzy. It?s not a reason to justify what I?ve written, errors committed, but may explain it as an excuse! Murray--

11 years, 7 months

EPROM and EEPROM Programmers

by dave.g4ugm＠gmail.com

On 30/04/2012 20:34, Bill Sudbrink wrote: > Dave Wade wrote: >> I have some "TMS2532" chips. Any suggestions on how to program them (I >> have a project in mind that will need these or a similar device) > Data sheet claims pin compatibility with 2732. I would start there. > > My Willem, when powered correctly and strapped for 2732 seems to do > a 21 volt VPP. The TMS2532 data sheet says it wants 25. I don't know > if you can get away with that or not. You may want to spring for some > 27c32 chips. They have a 12.5 volt VPP and I've done lots of them on > my Willem. > > Bill S. > Thanks Bill, The clone Willem's look cheap enough to buy one to experiment with, even in the UK. I think I might just order one and give these a whirl. Dave

11 years, 7 months

EPROM and EEPROM Programmers

by eric＠brouhaha.com

Bill Sudbrink wrote: > So, the 2532 predates the 2732? I have no idea whether the TMS2532 was announced before or after the Intel 2732, but it's obvious that TI was far along the development path before Intel announced the 2732.

11 years, 7 months

EPROM and EEPROM Programmers

by eric＠brouhaha.com

Dave Wade wrote: > I have some "TMS2532" chips. Bill Sudbrink wrote: > Data sheet claims pin compatibility with 2732. No, the TMS2532 doesn't make any such claim. It claims that it is "pin compatible with existing ROMs and EPROMs (8K, 16K, 32K and 64K), but that does not include the 2732, and their reference to 32K and 64K was only in regard to ROMs. The TMS2532 is most definitely *not* pin compatible with 2732, and attempting to program a 2532 as a 2732 will likely damage it. They aren't read-compatible either, but damage is far less likely to occur when attempting to read a 2532 as a 2732 (or vice versa). pin TMS2532 2732 --- ------- -------- 18 A11 CE* 20 PD/PGM* OE*/Vpp 21 Vpp A11 As with the earlier TMS2716, which was not compatible with the Intel 2716 or anyone else's, TI tried to second-guess what the standard pinout for the 2732 would be, and failed. At least they anticipated this possibility and referred to their part as the 2532; if it had matched, they could later have dual-marked it 2532 and 2732.

11 years, 7 months

EPROM and EEPROM Programmers

by dave.g4ugm＠gmail.com

On 30/04/2012 13:16, Bill Sudbrink wrote: > Jim Brain wrote: >> I know others have defended the Willem units, and I'll add my note as a >> satisfied customer. > I'll add another. > >> Be aware most Willems will require a parallel port. Most newer units >> will also sport a USB port, but it's for power only. > If you decide to use the "USB power" be sure whatever USB port on your > computer can handle it. I had mine plugged into one of the "back" > ports on my computer and it worked fine. Later, I put the same > motherboard in a different case that allowed me to hook up some "front" > USB port connectors to the pin headers on the motherboard. Apparently, > these ports did not supply enough current and the Willem behaved badly. > I was just considering pitching it when it occurred to me to plug it > into the back port as before. Sure enough, that fixed it. > >> Either way, buy a unit with a socket for an external power supply. The >> on board charge pump can't do enough with USB supplied power to handle >> all of the EPROM programming variants. > Yes, after the above experience, I went ahead and rigged up a "wall > wart" supply. > > Bill S. > I have some "TMS2532" chips. Any suggestions on how to program them (I have a project in mind that will need these or a similar device)

11 years, 7 months

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test-drb April 2012