Philip Pemberton wrote: Yeah, it is MMI. I've an ALL-02 (http://matthieu.benoit.free.fr/145.htm) which might be For BPROMs it support chips from the manufactures AMD, NS, SIG, TI and MMI - but the 6306 is not listed for MMI (the 512x4 Type listed for MMI is 63S240). But right now I just care about backing up all EPROMs and PROMs from this system here just in case something happens... (and the 6306's are now backed up as well :-) -- Oliver Lehmann http://www.pofo.de/ http://wishlist.ans-netz.de/

_Any_ device can fail. Fusible link PROMs can suffer from a form of bit-rot where the links actually grow back as well. Well, having a backup of the PROMs is surely a good idea for 2 reasons : 1) If the rest of the board is standard parts (even if they are failry rare ones), then shoulc something fail you have a chance to get the replacements. If it's one of the standard parts, you can hunt for another board that used it (not necessarily from this machine), if the PROM fails, you can burn a replacement. 2) Even if there are custom LSI parts on the board, then having a ackup of the PROMs means you can fix it if the PROMs go bad. Even if you can't do anything if the LSI device fails, you can fix some faults. -tony

Jules Richardson wrote: You could take out the cpu, build an own circuit around it and write a small program to output it's internal ROM content on its data lines where you fetch it from and store it then.. Complicated solution of course.... -- Oliver Lehmann http://www.pofo.de/ http://wishlist.ans-netz.de/

Chuck Guzis wrote: Ok, i don't know much CPUs with onboard ROMs, but I think it should work with Zilogs Z8 with on-chip ROM - or am I wrong at all? -- Oliver Lehmann http://www.pofo.de/ http://wishlist.ans-netz.de/

On Dec 31, 2008, at 9:27 AM, Jules Richardson wrote: "The Z8 is an embedded version of the Z80" is a very common mistake, one I've even seen in print in magazines. Nothing could be further from the truth...it is a completely different architecture that doesn't even bear a passing resemblance to the Z80. It's a pretty neat register-file-based architecture, kinda fun to program. They've been around for a long while, and are still current products. The current Z8 implementations are available in low-pin- count packages and are pretty fast. What's lacking is free development tool support, which is sad, and very unusual for today's embedded world. Zilog did a nice BASIC, which they shipped in a mask-ROM version (Z8671) which Steve Ciarcia had a ball with in several of his BYTE Magazine articles. There's also a Forth implementation which I've messed with, after having typed in the entirety of a faded printout of a hex dump in order to get into digital form...that was tedious. Your "Z8 ROMLESS" chip is just that; a Z8 microcontroller that is designed for use with an external ROM. Still others (Z8603, Z8613) are available which have a 24-pin EPROM socket permanently mounted atop the ceramic 40-pin DIP, with the die well pushed off to one side to make room for it. It's neat. I've got quite a few of those; they're what I use to mess about with the Z8671-shipped BASIC, and the Forth system I mentioned above. Here's a pic of a quickie board I threw together to exercise both the BASIC and Forth implementations, using one of those "EPROM socket on top" chips: http://www.neurotica.com/misc/Z8-board.jpg -Dave -- Dave McGuire Port Charlotte, FL

On Wednesday 31 December 2008, Jules Richardson wrote: It's possible that it's also a Z8000 (the 8002 MMU-less version probably); I picked up a pile of telephone switch stuff that was full of Z8002's. Pat -- Purdue University Research Computing --- http://www.rcac.purdue.edu/ The Computer Refuge --- http://computer-refuge.org

How you do that into a 8051? :)

If the protection is not set, you can read just like a EPROM microcontroller. If it is set...well, there are ways, but it is something hard to do :)

Jules, an internal ROM microcontroller is just like an internal EPROM microcontroller. It can be read as an EPROM one. Just needs to have the protection bit disabled :o)

If you're lucky, eitehr th microcontroller is old enough not to have any security features, or they're not used. In which case you remove the chip If you're unlucky then either the microcontroller doesn't have any external access to the ROM (some mask-programmed ones are like that), or the secutrity bit has been set so you can't read it out. In which case, alas, you just pray it never fails... -tony

Dave McGuire wrote: Only on the early mask revs. On the later chips, /EA is latched on reset, which means the "/EA toggle hack" doesn't work any more. Anything post-1990 is unlikely to be vulnerable, IIRC. -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

On Dec 31, 2008, at 5:50 PM, Tony Duell wrote: Doesn't it?? Hmm ok. I've not done much with the 8048. I guess that was one of the things they added in the 8048->8051 evolution. -Dave -- Dave McGuire Port Charlotte, FL

Jules Richardson wrote: Hmm, shouldn't be too hard with modern programmable-logic devices. Or four FIFOs, for that matter. 24 bytes, 8 ways (4 host-to-parasite and 4 parasite-to-host FIFOs), plus a couple of status registers, with an operating frequency of 3MHz or so. Not exactly groundbreaking (though the Tube ULA DMA stuff doesn't seem to be documented anywhere obvious). If you went discrete-logic (i.e. 74LS chips and FIFOs) you're going to need rather a lot of ICs, and a fairly big PCB. Probably about ?100 worth of parts (the cheapest FIFOs I can find are ?5 each, times 8 is ?40, plus the PCB, and some 74LS chips). Truth be told, the documentation is ambiguous enough that I'm not even sure all the FIFOs *are* 24-level deep... A CPLD or FPGA version should be doable, probably at around the ?30 mark. Small FPGAs run about ?5 (or less), but nearly all of them use +3.3V I/Os, and very few of them are 5V-tolerant. -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

Tony Duell wrote: Not *completely*, AFAIK - although there are fragments all over the place. I think there's enough amassed wisdom around now that it *could* be done though, because the software to drive either side is understood enough, as is the electrical (physical) interface, and there are still survivors of all the vintage hardware which made use of the ULA. The problem is that very few people have both a grasp on that knowledge and the ability to do the necessary electronic design - it's only really worth it for a drop-in replacement (i.e. a single chip or a very small daughter-board to plug into the ULA's 40-pin to DIP socket) because (as Phil says) it'd be a reasonably large board to do it as discrete logic. cheers Jules

Philip Pemberton wrote: Yeah, I sold a couple on there just over a year ago - pretty much my only foray into selling on ebay (and not something I care to repeat). I offloaded another four or so via word of mouth. I've got another six Acorn ones with the TUBE ULA but as they're all different I don't want to part with them I'm afraid! Yeah. I blew one up by plugging a copro in backwards once and felt guilty (in my defence, the silk-screening was wrong on the copro PCB, but I still should have checked with a meter first!) Kind-of. I figure that a combination of you, Sprow and JGH are probably the best three to get something like this up and running... :-) Sadly all my TUBE docs are in storage*, and I'm not sure what I have scanned here with me - I know I've got some TUBE notes from Hugo and a TUBE app note (but I think the latter's online anyway). * i.e. stuff like the A500 manuals might have something useful inside. To be honest, lay out your own 6502 board. I've got schematics and ROM images, and there's nowt special to it, assuming you have the ULA. I keep forgetting to poke Sprow about buying a ULA - I still need one for one of my Springboards, and I suspect that the one in my '286 copro might be duff. cheers Jules

Tony Duell wrote: It seems to be 80%-documented: - The 6502 and Z80 Second Processor Service Manuals explain how big the FIFOs are, and how to write to them: - http://acorn.chriswhy.co.uk/docs/Acorn/Manuals/Acorn_65022ndprocSM.pdf - http://acorn.chriswhy.co.uk/docs/Acorn/Manuals/Acorn_Z802ndprocSM.pdf - Acorn Support Group Application Note 004 explains a bit about the host<=>parasite interface, but not a lot. Mainly useful for the Parasite->Host FIFO #1 size (24 bytes, or 20 bytes depending on who you ask) - http://acorn.chriswhy.co.uk/docs/Acorn/AN/004.pdf - Yellow Pig (?!) explains a lot of stuff about the ULA on his website (<http://www.cowsarenotpurple.co.uk/bbccomputer/master512/tube.html#tubeula>). This explains (in some detail) how the first Status register works. - The New Advanced User Guide (Dickens and Holmes) p.327 onwards lists the ULA registers, but then goes on to say "you won't need to control the ULA directly". From what I've gathered, there are three FIFOs -- one 24-byte, two 2-byte, and the rest of the transfer paths are latches. The problem, of course, is that 20% of undocumented stuff. Things like: - The inner workings of the DMA system (DREQ, DACK and friends) - What happens if you write 25 bytes to the 24-byte FIFO? What about the 2-byte FIFOs? - What does a Parasite-originated reset clear, if anything? If I had a Tube ULA (or a complete 6502 2nd processor), I might be tempted to breadboard it and do some "experimental analysis" with the logic analyser and a digital signal generator. Duplicating the "known 80%" in Verilog HDL is probably about a day's work; probably a week for the whole thing assuming no hold-ups or "WTF?!" moments. -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

Alexandre Souza wrote: Yep (well, LVROM in Philips' terminology, but same thing). They're awesome. Hmm, well there's a working one at Bletchley in England if you ever get over there. One day I'll have mine shipped out to the US and have it running at a VCF... cheers Jules

Chuck Guzis wrote: Who knows - think of short circuits... All the other 74 logic, z80 chips and so on are more or less replaceable by just reading what is written on them - but w/o having a backup of any "custom" chip those are the single point of failure ;) Even if it turns out to be impossible to get those bPROMs (who knows...) to restore the backup - I could replace it with other (EP)ROM stuff more or less easily - but w/o the contents... you get the picture? ;) -- Oliver Lehmann http://www.pofo.de/ http://wishlist.ans-netz.de/

Of course, you can always use a 2716 or like EPROM on the place of PROMs :o)

At 10:22 AM 12/31/2008, Dave McGuire wrote: http://www.national.com/rap/Story/widlar.html "We still have a sign around our lab, "This is not a black-smith shop." But there were times when Bob would discover he had wasted a day or two, just because one bad part had screwed up his circuit. He would bring this bad part -- a capacitor, a pot, a transistor, an IC, or whatever -- over to the vise and lay it on the anvil part. Then he would calmly, methodically beat it with a hammer until the smallest remaining part was indistinguishable answer. He explained that it makes you feel much better if you do this, and, you know that bad part will never come around again and goof you up. He was right. And I recommend that you join me in doing this "Widlarizing" when a bad component fools you. You will feel a lot better." - John

On 31 Dec 2008 at 18:00, Doc Shipley wrote: I remember my father losing his composure and giving the fuel gauge afterwards. Cheers, Chuck

On Wed, 31 Dec 2008 11:54:53 -0600 John Foust <jfoust at threedee.com> wrote: This shows how to fix a unfixable camera lens that way: http://www.hermes.net.au/bayling/repair.html -- tsch??, Jochen Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/

On Wednesday 31 December 2008 12:54:53 pm John Foust wrote: "One of the celebrated things Widlar did was to put a "hassler" in his office.2 When a person came in to his office and spoke loudly, this circuit would detect the audio, convert the audio to a very high audio frequency, and play back this converted sound. The louder you talked, the lower the pitch would come down into the audio spectrum, and the louder it would play. So if you really hollered, it would make sort of a ringing in your ears. Of course, if you noticed this "ringing" in your ears, and stopped for a while to listen, the "hassler" circuitwould shut up. He gradually got people to stop yelling at him. I mean, Bob really was almost always a soft-spoken person. He didn't have to yell or shout to get his message across. When he did speak, and softly at that, people would soon realize that it was a good idea to listen to him." I *want* one of these...! -- 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

Philip Pemberton wrote: http://electronicdesign.com/Globals/PlanetEE/Content/3080.html

---------------------------------------- Hi I found it interesting but I do know what a LM337 is. I've had the honor to have lunch with Bob once. Dwight _________________________________________________________________ Windows Live? SkyDrive?: Get 25 GB of free online storage. http://windowslive.com/online/skydrive?ocid=TXT_TAGLM_WL_skydrive_042009

---------------------------------------- Hi As I said, I knew that. It is the negative voltage compliment of the LM317. Dwight _________________________________________________________________ Rediscover Hotmail?: Get quick friend updates right in your inbox. http://windowslive.com/RediscoverHotmail?ocid=TXT_TAGLM_WL_HM_Rediscover_Up…

On Tue, Apr 28, 2009 at 12:50 AM, dwight elvey <dkelvey at hotmail.com> wrote: As do I. Nice. I've been reading his columns since I don't remember when (early 1990s?) I always learn something. I wonder what he'll be doing next. -ethan

On Thursday 08 January 2009 11:54:38 am Philip Pemberton wrote: Yeah, I started browsing through his other articles after reading that one, and ran across a link to that device somewhere in the process. Saved the page with the smallish diargam on it (I couldn't really see it on my screen), and will look into it one of these days... -- 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