test-drb July 2014

test-drb@ccmp.vtda.org

181 participants
190 discussions

by legalize＠xmission.com

I've been maintaining a page on nekochan's wiki containing all known CD part numbers and whether or not I have an archive of the CD. If you have SGI CDs laying around that aren't on this list, or aren't archived, please email me. <http://www.nekochan.net/wiki/User:Legalize/CD_Part_Numbers> -- "The Direct3D Graphics Pipeline" free book <http://tinyurl.com/d3d-pipeline> The Computer Graphics Museum <http://ComputerGraphicsMuseum.org> The Terminals Wiki <http://terminals.classiccmp.org> Legalize Adulthood! (my blog) <http://LegalizeAdulthood.wordpress.com>

9 years, 9 months

wanted: Mostek Z80 Micro-Reference Manual, Zilog Z80 DMA Technical Manual

by spacewar＠gmail.com

Does anyone have an extra copy of the Mostek Z80 Microcomputer System Micro-Reference Manual (a small 30ish page reference booklet, Mostek publication number MK78516) that they'd be willing to part with? I'd like to have an original, but a good scan would be the next best thing. There doesn't appear to be a decent scan of it online. There's a common scan of it that missing pages, poor registration, etc. Also looking for the Zilog Z80 DMA Technical Manual (not the data sheet). The more recent (late 80s through present) Zilog documentation is absolutely riddled with errors. It looks like it went through several generations of conversions between typesetting systems, getting worse at each step. I'm willing to pay modest prices and postage for those, and for other 70s and early 80s Z80 family documentation from either Mostek or Zilog, in order to produce good quality scans.

9 years, 9 months

VCFMW Roomates

by slandon110＠gmail.com

Sabrina and I were only able to get 2 queen bed room for VCF/ECCC. So if anyone wants to share let us know. We got the room

9 years, 9 months

Non-interrupt use of uPD765/8272

by spacewar＠gmail.com

I still haven't figured out how to get interrupts from the uPD765 FDC in the Quay. I think they're probably routed via a Z80-PIO input, but no luck so far. While the DMA support in the uPD765 is by design optional, they clearly *really* intended that interrupts be used. The Quay boot ROM just uses a very long fixed delay after the recal before doing a read. That's obviously not great if you want good performance. I tried several unsuccessful approaches to waiting for a recal or seek to complete before finally noticing that the FDC will reject the "sense interrupt status" command as illegal if there isn't a pending interrupt. Now my code issues that command repeatedly until it does not report an illegal command. Has anyone found an easier way to use the uPD765 without interrupts?

9 years, 9 months

6809 vs. 6809E

by mike＠fenz.net

I'd noticed that one, it looked promising. No mention of support for the E signals, but it seems likely that they'd available somehow. Given your signature, it's interesting that the main target is my Bally 'Doctor Who' pinball machine! On 3/07/2014 7:28 a.m., The Doctor wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA512 > > On 07/01/2014 09:34 PM, Mike van Bokhoven wrote: > >> Now there's a suggestion that has my attention. I have thought >> about this before, but I have no FPGA experience at all, and >> wouldn't know how to start. If it's just a matter of taking a a >> core model, > > For what it's worth, there's one out there right now: > > http://opencores.org/project,6809_6309_compatible_core > > I don't know if it's sufficiently developed to be of use to you (I > haven't tried to synthesize it), but it's a place to start. > > - -- > The Doctor [412/724/301/703] [ZS] > > PGP: 0x807B17C1 / 7960 1CDC 85C9 0B63 8D9F DD89 3BD8 FF2B 807B 17C1 > WWW: https://drwho.virtadpt.net/ > > "Why couldn't you put the bunny back in the box?"

9 years, 9 months

Motorola/AMI 6834 EPROM datashseet

by spacewar＠gmail.com

Does anyone have a datasheet for the Motorola or AMI 6834 EPROM? Thanks! Eric

9 years, 9 months

Looking for: Intertec Superbrain power supply schematic

by derschjo＠gmail.com

Anyone happen to have the schematic for the original SuperBrain's power supply / I/O board? I thought I'd found it on Bitsavers (see here: http://bitsavers.trailing-edge.com/pdf/intertec/schematic.pdf, pages 11 and 12) but now that I've sat down to do some debugging the two don't appear to match (the schematic is dated 1981, so it's likely describing a later revision than the one in my machine...) Mine's labeled: Intertec Data Systems (c) 1979 Power I/O Board 1424002-04 Rev. 04 Currently the +12V rail is only reading a couple of volts under load and a schematic'd help trace down the fault. (I will get better at debugging power supplies, I will...) Thanks, - Josh

9 years, 9 months

Sun-1 Update

by silent700＠gmail.com

I am still gathering info on the Sun-1 (or -2 in a -1 box) I posted about recently. I expect I'll be doing so for some time but I have gathered some interesting clues as well as historical bits that I will assemble at some point. For now, I have a board inventory and photographs for the Multibus voyeurs out there: http://silent700.blogspot.com/2014/07/sun-1-board-inventory.html - jht

9 years, 9 months

Noob analog question (no doubt simple)

by brain＠jbrain.com

Trying to help out some folks on the cbm hackers list read the 6500/1 ROM in the 1520 plotter. It turns out, based on the data sheet, there is a way to put the CPU in a "test" mode and send opcode data to the CPU, and we are going to try to to use that to read the contents of the ROM. The test mode is engaged by placing 10V on the RESET pin. And, you know, before tonight, I thought I was at least average on transistor theory and application, but I'm stumped, and I'm hoping someone can help. To support 3 voltages on RESET (0,5,10), I placed a 2n3904 with the collector on the RESET pin, and emitter on ground. base is biased via 10K resistor to an IO pin on an AVR uC I am using the drive the CPU. That works fine. TO support putting 10V on the RESET, I built a PNP/NPN pair. PNP has E on 10V, C on RESET, and B is biased via 10K to C on NPN. B on NPN is biased via 100K to another IO pin, and E is at GND. The thought was that driving the IO pin high, the NPN will pull the PNP base to ground, thus turning on the PNP, and placing 10V on RESET. And, it works, but it "fades". Over 2ms, RESET slow falls from 10V to ~6V. If I turn the transistor off and then back on, the cycle repeats. So, I obviously am doing it wrong, but I can't seem to determine where my theory fails me, and I thought someone on here could help (or suggest another simple way to support 3 voltages on the RESET pin under SW control. Jim -- Jim Brain brain at jbrain.com www.jbrain.com

9 years, 9 months

DEC 8881 OC Bus Driver Chips

by rick＠rickmurphy.net

At 01:28 PM 7/6/2014, Mattis Lind wrote: >When repairing a TU60 drive that had faulty DEC8881 I replaced them with >DM7439. They were $2.76 each when buying 25 pieces. The original faulty >chips were marked 7439 on the backside. By way of confirmation, I have a bunch of (I think Signetics) 8881 chips marked 7439 on the bottom as well. -Rick

9 years, 9 months

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test-drb July 2014