test-drb

test-drb@ccmp.vtda.org

101090 discussions

by jingber＠ix.netcom.com

I have two different Lisa machines and both have a jittery display (one 1.2AMP PSU, 1 1.8 AMP PSU). I've followed the instructions in the Sun Rem. guide to adjust the power supply output. This works immediately after the adjustment, but the problem gradually comes back over time. I adjusted both machines around the September timeframe and the jitters have back on both machines. I'd like to get both of these machines in top-shape so I can have them running at my New Years party =) Before I go through the adjustment again, is there anything else I should be checking? I've also tried adjusting the V.Hold, but this doesn't seem to make a difference. Maybe I'm not using a precise enough adjustment? Thanks, Jeff

23 years, 3 months

Snoopy was Re: M200 interfacing

by Innfogra＠aol.com

In a message dated 12/30/02 1:13:16 PM Pacific Standard Time, cisin(a)xenosoft.com writes: > Don't forget how significant a part of the culture of the history of > computers is contained in all of those stupid line printer graphic > pictures of Snoopy ... Ah Yes, The first thing I printed out with my Litton 1251 when I got it into my living room in the mid 80s was a Snoopy calendar. All in punched tape. Nice machine, wished I had kept it. Paul Pierce has a Litton 1231 in his collection for when he gets his museum started in PDX. Punched tape, drum memory, console wi printer, Yum Yum... Paxton Astoria, OR

23 years, 3 months

Amstrad PPC640

by lott＠austarnet.com.au

G'day I hope that I am not interrupting anything but I was browsing through on just this subject of the Amstrad PPC640 Portable. I was given one of these machines sometime ago and it has been standing in my garage for a couple of years. I had been buy on other projects and there was no power unit. Today I plugged it into the cigarette lighter socket of my 81 Volvo using the adaptor that was available. It worked first time, and requested Date and Time. Checking with the manual I inserted the System Disk and away she booted into DOS. I used to run an Amstrad 1640 ECD which was my first taste of computing back in the dark days of 1988. If you would like me to I will copy and forward the SYS disk PPC512 / 640 MSDOS V3.30, which apart >from the Main Op sys also has a programme on it called PPC ORGANISER. This has a Word Processor / Data Filing / Diary and Calculator. I also found that this computer has a PC200 Modem inbuilt which uses a programme called MIRROR 2. Speeds of 75 to 2400 bps are quoted using V21, V22, V22bis and V23 modes. Unfortunately I do not have the driver disk for the modem. Anyway should you require any further Info Please contact me. Dave Lott, Eden NSW Australia

23 years, 3 months

VAX/VMS reference material

by eusty＠galaxycorp.com

Hi Justin, I'm interested in your VAX/VMS ref. material; please contact me off list at eusty(a)galaxycorp.com if they are still available, thanks Vincent

23 years, 3 months

Hi!/ Sharing the technology/ LK401/ Thanks!

by pete＠dunnington.u-net.com

On Dec 31, 5:04, Justin wrote: > Now I'm working on getting my VAXstation 3100 up and working. IT works > but my keyboard is shot. I have the LK201, which seems to have a matrix > fault. about 1/6 of the keys work. :-( I bought a LK401 on ebay and the > person said it had the right connector when I asked. I waited too long > after I got it and found out it didn't in fact have the right connector. > > Does anyone know about these? my VAX Station takes the 4 element RJ11 for > which I have the pinout from the netbsd archive. The LK401 I have though > has a 6 pin (5 of those are connected) minidin. ( I think its a minidin > anyway ). Oops. Sounds like you have an LK450, LK461 or LK471, not an LK401. LK401 uses a DEC protocol, the others are PS/2-style keyboards. They're not interchangeable, I'm afraid. There should be a label on the underside, with three barcodes, the top barcode being the model number. Does it say LK401, or something a little different? -- Pete Peter Turnbull Network Manager University of York

23 years, 3 months

Unibus UDA50 pinout, qbus RL02

by felten＠vaxnet.de

Hi, Does someone have the pinout for a UDA50 ? I have the two-board-set M7485-YA and M7486 but I don't have the cables >from the controller and no bulkhead. I'd like to connect a single RA80 and I know about the "uneven number of cables"-rule. Currently the RA80 has two cables connected to the cabinet (mini bulkhead?), from there's another cable haning loose. Can I make a cable that fits onto this cable and the UDA50 ? What kind of coaxial cable should I use ? Anything else I should know or check before powering up the drive ? Another topic: M8061 (qbus, RLV12 for RL02) Something strage is happening when I try to boot from or access my RL02.... Configuration: PDP 11/83, 4mb ram M8061 and one RL02 (drive0), terminator When I boot the RL02, the run light simply goes off. No error message, nothing. the clock signal from the controller should be there, because i can load the disk, the drive spins up and the Ready "0" light goes on. When booting 2.11BSD (from RD54) the same thing happens: the run light goes off, again no error message. The loaded diskpack contains afaik no usefull information. Trying another diskpack didn't change anything. The controller is jumpered as described in the RLV Users Guide and set for Q22 operation. The drive & cable are ok, because I can hang it on my 11/44 and boot RSX11M from another diskpack with it. Thanks, lothar.

23 years, 3 months

Hi!/ Sharing the technology/ LK401/ Thanks!

by justin＠ingrid.raspberrytea.com

Hi guys. I stumbled upon your list while looking for LK401 schematics, and found that this is the kind of list I was looking for. My name is Justin, and I like classic computers. We have an interesting community of technology enthusiasts who hang out at a local coffee shop here in Houston, TX called Kaveh Kanes. For a while now I have been trying to get rid of a lot of my old computers, because I didn't really want to spend more time on them, but it was hard to part with them. So rather than toss them, I've been getting them functional and setting them up as internet terminals at the coffee shop. A friend, Barrett put his Intel FreeBSD machine up there to start. Now I have my SparcSTATION 5 exporting an X session from it so people can get on the web. Now I'm working on getting my VAXstation 3100 up and working. IT works but my keyboard is shot. I have the LK201, which seems to have a matrix fault. about 1/6 of the keys work. :-( I bought a LK401 on ebay and the person said it had the right connector when I asked. I waited too long after I got it and found out it didn't in fact have the right connector. Does anyone know about these? my VAX Station takes the 4 element RJ11 for which I have the pinout from the netbsd archive. The LK401 I have though has a 6 pin (5 of those are connected) minidin. ( I think its a minidin anyway ). It looks very similar inside, but I don't know what I can connect and I'm having trouble finding documentation for it. Well that was a windy introduction, but it tells you a little about myself, and what I'm trying to do. I just want to share old technology with people in a way that they can still use and appreciate it at the coffee shop. Incidently, I have the complete reference to VAX/VMS in 3 ring binders. I think its about 17 binders total. If anyone is interested, I'd be OK with parting with it. IT would be heavy to ship though. 70 lbs? Next on the list after the VAX is my Amiga 2000. It needs a 68020 processor card first before it can run either AmigaOS 3.9 or NetBSD.... -Justin

23 years, 3 months

WWII fire control 'computers'

by julesrichardsonuk＠yahoo.co.uk

> Suggest you head over to usenet and ask on uk.rec.subterranea - the > folks there are experts on most things concering British bunkers... Sure - I've actually been out exploring with quite a few of the people who hang out on that group! Generally they tend to be keen in the sites for the exploration value though, but are less interested in how the sites actually operated. After 60 years or so most of that knowledge has been forgotten, and much of the printed material of the time has been destroyed. Having a machine and getting it working again would be one thing. Trying to find details on something that was melted down at least 40 years ago is easier said than done! :-) cheers & have a good New Year's, Jules __________________________________________________ Do You Yahoo!? Everything you'll ever need on one web page >from News and Sport to Email and Music Charts http://uk.my.yahoo.com

23 years, 3 months

DEC 3000 300X/300

by fire＠dls.net

Jochen writes > Why? You need pairs of 8 MB or 32 MB FPM parity 72 pin SIMMs. > Not that uncommon. Thanks for the useful information about the memory. I have already managed to locate 1 pair of SIMMs on Ebay. I will continue until maxed out. >> Now I look at the back of the machine and my main >> question is what cable do I need to hook up my VT220, or my VT420, Jochen replies > Any regular "null-modem" cable should do the job. I see how to hook up vt220 with db25 f-f null modem cable, but how does that get vt420 hooked up? It appears to have some kind of RJ connecton in back, not DB style. Is there a special cable for that? > >> or what >> model monitor with keyboard and mouse is this thing supposed to work with? > You need a LK201 or LK401 keyboard and a VSxxx mouse. The same keyboard > (and mouse) as used on the VT[234]xx terminals and the VAXstations. > Where do they hook up to? I see on ebay cables with db15 end and 3 bnc, keyboard and mouse at the other end. I hook this into back of DEC 3000 where it has tablet port? or do I need two separate cables, one for monitor from 3w3 connector and one from tablet port for keyboard and mouse? >> In a typical DEC fashion, in the manual they do not mention model numbers of >> monitor to go with it, > The video timings for the on board Smart Frame Buffer are: > 1024 x 786 @ 72 Hz for the 300L > 1280 x 1024 @ 72 Hz for the 300, 300X, 300LX > Any sync on green capable multisync monitor can be used. You just need > a 3W3 video cable. I have plenty of monitors, but not quite sure what you are saying. Say I have monitor with 13w3 connector on back, then I need 3w3 to 13w3 cable and monitor is set? Where do keyboard and mouse come into picture? Special cable plugging into tablet port (DB15) in back of DEC 3000? Sorry for so many questions, but I do not know too much about these machines (as if that is not obvious). Still I hope to soon have OpenVMS or Linux running on them. Bradley

23 years, 3 months

Another Decmate III available

by trestivo＠concentric.net

Hi all, Happy New Year! Just wanted you all to know the first two Decmate III's have sold on Ebay, and A third one has been posted. These systems are pretty cool! Word processing software comes with it so it works right out of the box. Take a look at http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2085176520 There's also a brand new DEC mouse posted at http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2085185434 Have a great holiday! thom

23 years, 3 months

Jupiter Ace repair update

by philpem＠dsl.pipex.com

Hi, A little more news on the Ace repair front - I've pulled up the LS367s and found a load of tracks that were ripped up during resoldering - about half of these have now been repaired. It looks like the surge went straight through data line D3 - I've put the ROMs in my EPROM programmer and checked them against the ROM images Lee Davison sent me and they don't match at all. In every case, the output value is off by 0x04 - meaning data line D2 is probably cooked... I'm also beginning to suspect the video shift register - something isn't right. Address decoding is fine, the RAMs should have survived being de-soldered and re-soldered (IME they usually do) and I can't find any problems with the video timing chain (I assume the fact that I'm getting a video signal on my TV is good enough proof of this). It looks like the PCB was laid out with the main CPU section on the left and the video section on the right with a set of LS367s splitting them up. This is not as cheap a design as the ZX81 (IMO), but the PCB is complete and utter crap - the tin plating is stripping off all over the place, solder resist is cracking and has got thin, raised strips running along its length, kinda like the veins on a tree leaf. I've bodged a pair of 2732 ROMs I had in my junk box to fit the sockets and pinout. The video is reasonably stable, but it's mostly white. I haven't got any idea why the font RAM and video RAM aren't being loaded, though. Now if only Farnell still stocked 2532s and 2114s... Thankfully the buffers seem to have isolated a lot of circuitry in the video circuitry, especially the timing chain. The only possible fault condition I can think of is that Jupiter Cantab designed the Ace around National Semiconductor/Motorola/TI 74LS logic and the newer Fairchild Semi logic devices I'm using are incompatible with the existing logic... Stranger and stranger... Later. -- Phil. philpem(a)dsl.pipex.com http://www.philpem.dsl.pipex.com/

23 years, 3 months

Hi!/ Sharing the technology/ LK401/ Thanks! (fwd)

by justin＠ingrid.raspberrytea.com

23 years, 3 months

M200 interfacing

by foo＠siconic.com

Ok, so far so good. I've got my wire harness all wired up (I basically used a good quality 40-pin DIP socket: the signal lines going into one side and the returns on the other). Nothing fancy required. The reader is putting out TTL signals so all is good. One oddity: before hooking anything up, I measured the voltage between the Apple's ground and the reader's ground. It would start off at a very low amount of microvolts, climb slowly, then all of a sudden it would shoot to +5 and then go back down to 0, where the cycle would repeat. The cycle period was about 5-6 seconds. What the heck is going on? I tested it out with the indicator signals, i.e. BSY (Busy), HCK (Hopper Check), MOCK (Motion Check), Error, etc., and the VIA is getting the signals. I wrote a little program to print out the status bits of the port that is accepting the signal and ran a batch of cards through and everything is as expected. The next step is to wire in the data signals and start to read data. The VIA gives me two 16-bit ports and an additional 4-bit port. The 4-bit port is special in that it can generate interrupts, so it will work quite well for error signals. The problem is I don't know how to access that port through the card I have. It's a custom 6522 card that I built for a class on microcomputer interfacing I took a lifetime ago and I can't find my class notes. Anyway, I'm in the process of figuring it out. Everything on the card is accessed through it's I/O addresses, being C080 + (slot * 16). So I have it in slot 4 which makes all it's I/O available at C0C0-C0CF. I've found the timer locations and some 16-bit registers. I also found by accident a timer that generates a RESET interrupt when it elapses--at least that's the theory I'm going under since the Apple reset itself after I was playing with the registers. I also believe I remember there being this feature on the 6522, but I haven't had a chance to read that part of the docs yet. One thing I'd like to investigate after I'm done with this is to see if there are enough inputs on the Apple itself to forgo the necessity of the 6522. The Game I/O port has 7 inputs, if you count the 4 joystick inputs that can be used as simple TTL inputs, plus the 3 push-button inputs. The other inputs would be the keyboard. It has 10 Y-inputs and 6 X-inputs, plus SHIFT and CONTROL. I'm wondering if there would be a way to hook up the data signals from the reader in a way that the character data from a card column triggers a key input, which can then be cross-referenced to determine what data was actually sent from the reader. Whether this will work depends on how punch card encoding works. From what I can tell so far, there will only ever be one of the 1-9 numbered rows punched per column, but there can be any combination of the 0, 11, and 12 rows. Is this correct? If so, then there should be enough combinations of inputs on the keyboard port to allow the data signals to go through that, and then the GAME I/O has just enough inputs to cover all the status signals (HOPPER CHECK, MOTION CHECK, ERROR, BUSY, INDEX MARK, and READY). Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org * Old computing resources for business and academia at www.VintageTech.com *

23 years, 3 months

Anyone have a Western Digital XT-IDE hard card or ROM image?

by erd_6502＠yahoo.com

I've been trying to extract the data off of a 20MB XT-IDE drive (WD-93024X) that was once part of a hard card. It has the software for my B&C Microsystems UP600 device programmer. Too many swaps and not enough sleep later, I have inserted the card in backwards (no bracket and it's an 8-bit card). It's now DOA. The Compaq Portable II I'm using complains of an I/O ROM error. So... I can check/replace any of the TTL on the card (74LS13, 74LS14, 74LS244, 74LS30, 73LS260), but the contents of the 2764 are possibly lost to me. Does anyone have a ROM image or an old XT-IDE hard card? The P/N on the ROM is 62-000352-031. The assy no. on the PCB is 60-000227-03, the P/N appears to be 61-000347-01. No smoke got out, but it sure is unhappy. Thanks for any assistance. -ethan __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com

23 years, 3 months

Anybody need a Telex FC500 keyboard?

by classiccmp＠crash.com

Anybody need an old Telex keyboard? The closest I could come to a model number was "FC 500" from a label on the underside. More or less normal pre-PC QWERTY keyboard, with a bunch of editing keys in the cursor cluster to the right. It's on a discount table at the MicroCenter in Cambridge, MA. If you really want this and will pay shipping, I'd be willing to go back for it. Probably $1.99, but I don't recall seeing it marked. I picked up a couple of Sun type 5c keyboards while I was there, since they have the control key where g*d and nature intended (just left of the "A" key). If you want such a beast for $1.99, check your local MicroCenter (www.microcenter.com) - matching Sun mice for $0.99, optical or mechanical. Dunno where they're coming from, but they've been there since before Thanksgiving. --S.

23 years, 3 months

Restoration Question

by dwightk.elvey＠amd.com

>From: "J.C.Wren" <jcwren(a)jcwren.com> > I have recently acquired a couple of build PC boards that are not solder >masked. There is some oxidation, ranging from minimal to mild (mild being >the not quite green, but a very hard oxide, as if the tin had reacted with >something else). Anyone got any good ideas on cleaning these? I'd like >something non-submersible, since one of the boards contains keyswitches. > > I have plenty of experience cleaning unbuilt boards. Normally, I'd just >hit them with some super fine steel wool, or buff them with 20lb paper. And >I've repaired boards, but usually to get them working, not to restore their >aesthetic appeal. > > I've considered using a baking soda solution and a stiff bristle brush. >This should neutralize any corrisive elements, and the baking soda might be >abrasive enough to remove the oxides without damaging the board. It would >wash off easily enough with water, and I could protect the switches during >that process. Hi Baking soda assumes that it is acid that caused the corrosion. If it was caused by leakage from NiCads, you'll need to use something like vinegar to neutralize it. You might try getting a fiber glass brush from a welding shop. These are sometimes used to clean aluminum. Sometimes it isn't the copper that is oxidized. They put a layer of nickel between the copper and solder on most PC boards. It may be nickel oxides ( bluish green ). If there is any kind of salts ( neutral ) you'll still have electrolytic corrosion. You need to make sure that it is well cleaned before you are done, regardless of what you use. Dwight > > Anyone got any ideas or standard procedures for this kind of thing? > > --JOhn > > >

23 years, 3 months

6522 weirdity

by foo＠siconic.com

Ok, I've kinda figured out the control lines on the 6522. First of all, I've got them triggering a flag in the IFR whenever there is a state change on any control pin from a ground to either floating or +5V. For example, CB1 is plugged into ground. I reset the IFR (so no flags are set). I remove the ground from CB1. CB1's flag in the IFR gets set. I reset that flag. If I plug CB1 into +5V, I get no flag. If I unplug CB1 from +5V, I get no flag. If I plug CB1 back into ground, I get a flag. Why are the flags being set only when one of the control lines no longer senses ground? I tried playing with the PCR to see if setting whether the control pins are active positive edge or active negative edge changes this behavior but it doesn't. I can work with this the way it is: I'm basically tracking state changes on the control pins, which is fine for my purposes since the reader will go from TTL false to TTL true if there is an error, and back to TTL false when the error gets cleared. But I want to know how the behavior of the control lines is set. Now, I seem to have a problem with CA1. If I have CA1 connected to ground, it's stable. As soon as I remove it from ground and it's floating, CA1's state starts to fluctuate wildly for a little over 2 seconds. It's flag in the IFR keeps triggering over and over. If, right after I remove it from ground and it starts fluctuation, I plug it back into ground, it stabalizes (it stops changing states). As soon as I remove it again, it fluctuates wildly. Is CA1 tied to one of the 16-bit timers? It sure seems like it. The docs say something about being able to make one of the control lines trigger off a timer. Am I triggering the shift register somehow? What in tarnations is going on? Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org * Old computing resources for business and academia at www.VintageTech.com *

23 years, 3 months

6522 weirdity

by dwightk.elvey＠amd.com

>From: "Sellam Ismail" <foo(a)siconic.com> > >Ok, I've kinda figured out the control lines on the 6522. > >First of all, I've got them triggering a flag in the IFR whenever there >is a state change on any control pin from a ground to either floating or >+5V. > >For example, CB1 is plugged into ground. I reset the IFR (so no flags >are set). I remove the ground from CB1. CB1's flag in the IFR gets set. >I reset that flag. If I plug CB1 into +5V, I get no flag. If I unplug >CB1 from +5V, I get no flag. If I plug CB1 back into ground, I get a >flag. > >Why are the flags being set only when one of the control lines no longer >senses ground? I tried playing with the PCR to see if setting whether the >control pins are active positive edge or active negative edge changes this >behavior but it doesn't. I can work with this the way it is: I'm >basically tracking state changes on the control pins, which is fine for >my purposes since the reader will go from TTL false to TTL true if there >is an error, and back to TTL false when the error gets cleared. But I >want to know how the behavior of the control lines is set. > >Now, I seem to have a problem with CA1. If I have CA1 connected to >ground, it's stable. As soon as I remove it from ground and it's >floating, CA1's state starts to fluctuate wildly for a little over 2 >seconds. It's flag in the IFR keeps triggering over and over. If, right >after I remove it from ground and it starts fluctuation, I plug it back >into ground, it stabalizes (it stops changing states). As soon as I >remove it again, it fluctuates wildly. > >Is CA1 tied to one of the 16-bit timers? It sure seems like it. The docs >say something about being able to make one of the control lines trigger >off a timer. Am I triggering the shift register somehow? Hi What is the weird behavior? I haven't seen anything I wouldn't have expected. Dwight > >What in tarnations is going on? > >Sellam Ismail Vintage Computer Festival >------------------------------------------------------------------------------ >International Man of Intrigue and Danger http://www.vintage.org > > * Old computing resources for business and academia at www.VintageTech.com * > >

23 years, 3 months

M200 interfacing

by fmc＠reanimators.org

Sellam Ismail <foo(a)siconic.com> wrote: > 80 characters x 11 bits = 880 bits / 9600 bps = .092 seconds. Should be > no problem. I'll see what the manual says about timing between card > reads. Except that, if you want to read binary cards (trust me, you will -- those binary cards are contain boot and other code for these machines), you need to do all 12 rows. 80 columns x 12 rows = 960 bits / 8 bits per byte = 120 bytes per record. OK, now as for sending that over a serial line, remember that serial I/O adds framing information , so it becomes 10 bits per byte supposing 8 data bits, no parity, 1 start and 1 stop bit. So 1200 bits at 9600 bps = 0.125 second. You probably want to do at least a simple checksum of the data for each record and send that too (so the receiver can verify, send ack or nak, and the sender can retransmit on receipt of nak or just non-receipt of ack). You've got RAM in the Apple, use it as a buffer between the card reader and the serial port. 16KB would hold 136 full card images, which you might think would be more than enough time to tell the reader to stop picking cards and actually have it stop. So, when the buffer's fullness gets above some threshold, stop picking cards until it gets below some lower threshold. You may be able to do some cheap buffer- and serial-time savings by either run-length encoding or just keeping a record length and not storing or sending trailing blank (unpunched) columns. Depends on your data. I think I would go for this last. -Frank McConnell

23 years, 3 months

6522 weirdity

by pete＠dunnington.u-net.com

On Dec 30, 13:57, John Lawson wrote: > On Mon, 30 Dec 2002, Sellam Ismail wrote: > > > Now, I seem to have a problem with CA1. If I have CA1 connected to > > ground, it's stable. As soon as I remove it from ground and it's > > floating, CA1's state starts to fluctuate wildly for a little over 2 > > seconds. > > Try tieing it to +5 via a 10K resistor, so it's either solidly a 0 or > solidly a 1. Many digital chips get cranky when their pins 'float'. Yes. Worst example I came across was a CMOS circuit which was designed by an "expert". It worked on a breadboard, but when transferred to the final PCB it misbehaved and eventually died of "dead chip". It turned out that a couple of unused inputs were left unconnected and floating. On the breadboard, that wasn't a problem, because it was dirty and there was enough leakage (a hundred megohms or so) to keep them in a reasonable and constant state. But the PCB was waterproofed, and they really did float, eventually leading to excess dissipation in the chip, and destruction of one of the gates. The reason is that a CMOS gate is basically two MOS transistor switches, one connecting the output to the power rail, and the other connecting it to ground. If the input floats halfway between logic levels, both turn on (at least, in older devices), and the current destroys one of the MOS transistors. Another example was a TTL circuit that ran fine at low to medium frequencies, but not at several megahertz. Floating input again; that sort of thing has a drastic effect on the speed of the gate. -- Pete Peter Turnbull Network Manager University of York

23 years, 3 months

Selling my Transputer collection.

by tim.myers＠sunplan.com

A shameless plug for my Transputer collection that's now for sale on Ebay - hope nobody minds :) http://www.andale.com/gallery?cid=10192480&mid=1 Tim.

23 years, 3 months

6522 weirdity

by pete＠dunnington.u-net.com

On Dec 30, 10:30, Sellam Ismail wrote: > > Ok, I've kinda figured out the control lines on the 6522. > > First of all, I've got them triggering a flag in the IFR whenever there > is a state change on any control pin from a ground to either floating or > +5V. > > For example, CB1 is plugged into ground. I reset the IFR (so no flags > are set). I remove the ground from CB1. CB1's flag in the IFR gets set. > I reset that flag. If I plug CB1 into +5V, I get no flag. If I unplug > CB1 from +5V, I get no flag. If I plug CB1 back into ground, I get a > flag. You're sensing noise. The inputs are not level-sensitive, they're edge-triggered. If you have the PCR set to zero (which is the default after a reset), CB1's flag will set whenever CB1 sees a falling edge. You're probably generating small noise spikes when you remove the ground (this is a bit like key bounce) or picking up stray current (the inside of an Apple is a pretty noisy place, electrically speaking). This would explain why the flag gets set when you initially remove the ground from CB1, and then again when you ground it again. Without the noise, it wouldn't set the flag when you remove the ground, only when you restore it. > Why are the flags being set only when one of the control lines no longer > senses ground? I tried playing with the PCR to see if setting whether the > control pins are active positive edge or active negative edge changes this > behavior but it doesn't. Actually it does, but I bet you've not got pullups or pulldowns on the pins, and you're seeing noise. These pins are fairly high impedance. And because the inputs are edge-sensitive, the flag gets set not just because it's low (otherwise it would get set if it were low when you configure it, and you'd not be able to clear the flag) but because it *changes state* to become low. > I can work with this the way it is: I'm > basically tracking state changes on the control pins, which is fine for > my purposes since the reader will go from TTL false to TTL true if there > is an error, and back to TTL false when the error gets cleared. But I > want to know how the behavior of the control lines is set. See my post from a few minutes ago. > Now, I seem to have a problem with CA1. If I have CA1 connected to > ground, it's stable. As soon as I remove it from ground and it's > floating, CA1's state starts to fluctuate wildly for a little over 2 > seconds. It's flag in the IFR keeps triggering over and over. If, right > after I remove it from ground and it starts fluctuation, I plug it back > into ground, it stabalizes (it stops changing states). As soon as I > remove it again, it fluctuates wildly. Noise. Floating inputs are A Bad Thing. > Is CA1 tied to one of the 16-bit timers? It sure seems like it. The docs > say something about being able to make one of the control lines trigger > off a timer. Am I triggering the shift register somehow? > > What in tarnations is going on? Did I mention noise? :-) -- Pete Peter Turnbull Network Manager University of York

23 years, 3 months

Recovering from disk failure - attn Adrian Vickers and Jim Austin

by t.myers＠protasis.co.uk

Hi, I've just had my disk holding my main mailbox fail on me (Yet another Fujitsu MPG fails, that's three in as many months.) Could Adrian and Jim please get back in touch with me, I've lost everything :'( Tim

23 years, 3 months

M200 interfacing

by pete＠dunnington.u-net.com

On Dec 30, 8:02, Sellam Ismail wrote: > On Mon, 30 Dec 2002 pete(a)dunnington.u-net.com wrote: > > That's an odd VIA. You mean a single 6522, right? > Sorry, it was a typo. I meant two 8-bit ports. Ah, I suspected it might be. > This is starting to make sense. > > But alll the documenation I've read so far indicates that the function of > the CA and CB lines is controlled by the PCR (Peripheral Control > Register). I'll go poke a 0 into the IER and then see if I can get bits > in the IFR to toggle by putting +5 on the CA1, CA2, CB1 or CB2 pins. The easiest way to set it up to play with, is first to pull each of CA1, CA2, CB1, and CB2 to +5V through four suitable resistors (anything from 1k to 100k will do for this). Then write 0x00 into the PCR, which makes the four handshake lines operate as independant inputs, with negative edge triggering. Write 0x7F into the IER to disable all the interrupts (so the Apple doesn't do any more resets), and 0x7F into the IFR to make sure it's cleared. Then keep polling the IFR while you ground one or more of the handshake pins. Look for any non-zero value. The relevant bits in the IFR should become set, according to which line(s) you ground. Note that this won't ever set bit 7 (MSB) of the IFR, because that only happens if interrupts are enabled, unfortunately. Also remember you have to manually clear the flags once they're set. If you want to use positive-going edges instead of negative-going, use pull-down resistors (don't rely on an unconnected input being low, it might float to any value) and set 0x55 in the PCR. If you are keen to use bit 7 in the IFR as a flag indicating "any input", stick an RTI instruction on the end of your code, and store the address of that RTI at IRQLOC ($03FE) first. That will prevent the interrupts upsetting the Apple. Alternatively, have the Apple execute an SEI instruction (0x78, sets the IRQ mask in the status register, to disable interrupts). Then write 0x64 into the IER to disable all the interrupts except from the handshake lines, and then write 0x9B into the IER to ensure all the handshake interrupts really are enabled (the default state, after a chip reset, is all disabled). -- Pete Peter Turnbull Network Manager University of York

23 years, 3 months

WWII fire control 'computers'

by mross666＠hotmail.com

Suggest you head over to usenet and ask on uk.rec.subterranea - the folks there are experts on most things concering British bunkers... Mike (the CoreStore is more than just ancient computers - see http://www.corestore.org/sub.htm ) http://www.corestore.org _________________________________________________________________ The new MSN 8: smart spam protection and 3 months FREE*. http://join.msn.com/?page=features/junkmail&xAPID=42&PS=47575&PI=7324&DI=74… http://www.hotmail.msn.com/cgi-bin/getmsg&HL=1216hotmailtaglines_smartspamp…

23 years, 3 months

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb